Wildguzzi.com
General Category => General Discussion => Topic started by: DaSwami on January 31, 2021, 11:01:20 PM
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Does this Cycleworld comment raise an eyebrow with anyone?
"An unexpected and fairly radical technical modification separating the V7/V9 V-twin engine from all previous editions, and from the V85 TT, is that the crankshaft here is of the press-fit type, with one-piece con-rods turning on plain bearings, rather than a forged one-piece unit. This follows the same engineering approach used on all Piaggio four-stroke scooter singles. Reducing production cost is the ultimate reason for the change. The more powerful, higher-revving V85 TT retains its solid forged crankshaft and cap-type rod."
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Does this Cycleworld comment raise an eyebrow with anyone?
"An unexpected and fairly radical technical modification separating the V7/V9 V-twin engine from all previous editions, and from the V85 TT, is that the crankshaft here is of the press-fit type, with one-piece con-rods turning on plain bearings, rather than a forged one-piece unit. This follows the same engineering approach used on all Piaggio four-stroke scooter singles. Reducing production cost is the ultimate reason for the change. The more powerful, higher-revving V85 TT retains its solid forged crankshaft and cap-type rod."
Just like a roller big end but different. Doesn't sound appealing although if its bullet proof should be ok. Nobody's going to be rebuilding engines in 15 years time.
Ciao
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Harley has been using press together cranks form its beginnings to this day (on the big twins).
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^ No they were not ! Press fit cranks on Harleys didn't start until the Twin cam model ( FWIW) . The Laverda triples had press fit
cranks and were fairly durable . Not to forget most 2 strokes were also pressed together cranks !
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well there is the reason for not using the v9 engine in a performance twin.
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The biggest benefit of the industry moving away from roller bearing bottom ends in the 70s and before was the elimination of pressed together crankshafts. It’s an archaic concept that only survived as long as it did due to concerns about reliable oiling of plain bearings that themselves should should have been put aside in the 1940s or before. Just because Piaggio has equipment to make built up crankshafts for scooters and apparently cuts cost of production using them does not make pressed together multi-piece crankshafts a good thing for the owner of a Guzzi.
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Yes I agree very obsolescence in an engineering sense. Controlling run out during the manufacturing process is difficult, and HD keeps upping the tolerance.
A better way would be a one piece crank forging with an articulated rod like a radial aircraft engine.
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Should make rebuilding a engine easier !
for current smallblocks no oversize bearings are available so any wear means a scrap crankshaft.
With a pressed up crankshaft guzzi might actually provide the crankpin, making the crankshaft rebuildable.
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also means you can't replace or inspect big ends without disassembling the crank
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I'd like to see pics of this, having a hard time picturing. I've never had a Guzzi motor apart, closest look I've had was when I dropped the pan on the Convert to change the oil filter Was surprised to not see a windage tray or much to keep oil from schloshing onto the crank.
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Carlo Guzzi and Lino Tonti are rolling over in their graves... :cry:
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Should help with dial indicator and large hide mallet sales .
Dusty
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Harley has been using press together cranks form its beginnings to this day (on the big twins).
And thats a recommendation?
Ciao
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The biggest benefit of the industry moving away from roller bearing bottom ends in the 70s and before was the elimination of pressed together crankshafts. It’s an archaic concept that only survived as long as it did due to concerns about reliable oiling of plain bearings that themselves should should have been put aside in the 1940s or before. Just because Piaggio has equipment to make built up crankshafts for scooters and apparently cuts cost of production using them does not make pressed together multi-piece crankshafts a good thing for the owner of a Guzzi.
Yep all true but 99% of todays buyers wont understand and will never need to. More interested in connectivity than engineering. I personally hate the way modern engines are designed around cheapness to manufacture and fast assembly on a production line, makes insitu maintenance very difficult. Both my cars as do many other engines now utilise friction drive for the OHC's so no keyed crank or camshafts. If you loosen off the front pulley bolt to remove it for a seal replacement for instance then its re do the valve timing which isn't as easy as it sounds with the dismantling of half the top end to fit the timing tools and removing accessories like the HP fuel pump and vacuum pump. Painful and many amatures have been caught out by this alone.
Ciao e
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Wait, I always thought that pressed cranks were quite a bit more labor intensive and expensive to build. This is the first time I've ever read the opposite. I don't know why two piece rods could be revved at higher RPMs and more stress than one piece rods; if there is a difference, I'd think would be the other way around.
OK, since I'm the least mechanically inclined person on the Board, someone please educate me.
Thanks.
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And thats a recommendation?
Ciao
In a word no.
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^ No they were not ! Press fit cranks on Harleys didn't start until the Twin cam model ( FWIW) . The Laverda triples had press fit
cranks and were fairly durable . Not to forget most 2 strokes were also pressed together cranks !
I thought all Harleys had press fit cranks.
Isn't that how they installed those "knife and fork" rods?
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I thought all Harleys had press fit cranks.
Isn't that how they installed those "knife and fork" rods?
Like older British bikes some were a tapered pin with a nut to hold in place from memory.
The side by side rods on a common pin like a Ducati has is the best option unless crank width/length is an issue. Articulated rods in all there forms whether a "master rod" situation or a forked arrangement like a Merlin engine uses are less desirable and generally for low rpm applications only.
Ciao
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Wait, I always thought that pressed cranks were quite bit more labor intensive and expensive to build. This is the first time I've ever read the opposite. I don't know why two piece rods could be revved at higher RPMs and more stress than one piece rods; if there is a difference, I'd think would be the other way around.
OK, since I'm the least mechanically inclined person on the Board, someone please educate me.
Thanks.
The factory (HD) does not sell parts for the crank but you can pull them apart and put them back together in your shop if you have the right equipment, Most of the people that do this send them to someone (only one place really) and they will refresh the crank, balance and weld the pin up if requested.
The rods are blade and fork. You can get away with a bit more RPM 'cause w/the blade and fork rod (
s) there is no offset of the cylinders thus no shaking order side to side like a Guzzi twin of a BMW.
The first press together crank from the factory was the XR, then later the twin cam (which I used to always call the big twin)
If they, HD machines, are not too abused with big after market cylinders and other hop up stuff they do OK more or less. For me the 45 deg cylinders are only good for the unique sound and produce surprisingly good traction, much like a big single.
Still a bad way to do it in my opinion.
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I always thought that pressed cranks were quite a bit more labor intensive and expensive to build. This is the first time I've ever read the opposite. I don't know why two piece rods could be revved at higher RPMs and more stress than one piece rods; if there is a difference, I'd think would be the other way around.
OK, since I'm the least mechanically inclined person on the Board, someone please educate me.
Pressed together cranks with roller bearing rods, assembled by hand are more expensive to build. Apparently pressed together single throw V-twin cranks with simple one piece rods/bearings assembled on the same machine that does the same for single single scooter engines is cheaper, or so believes Piaggio.
One piece rods may well be stronger and better for high RPM, when fitted with a plain bearing as in this case. But it imposes a burden on anybody who ever has to work on the engine, and this engine doesn’t rev high enough for it to matter, or close, because pushrods prevent high RPM.
It’s just a cost saving thing, squeezing pennies out of something in exchange for reducing its practical lifespan. Fine for the first buyer who likely never knows, fine for Piaggio because there won’t be as many multi-resale used bikes for them to compete with in selling new bikes. Not so good for anybody who thinks long life is a measure of quality.
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thanks for the replies, more confused than even. :shocked:
are Harley cranks solid or pressed? are pressed cranks really cheaper? how would one piece rods fit on a solid crank?
still confused.
don't worry about answering because I probably won't understand. :sad:
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Keep in mind when making references to HD , they sell more bikes with pressed together cranks in a couple of months than Guzzi does in a decade :popcorn:.
I worked on them at dealerships for decades and of course went to their factory for specialty training , so kinda familiar with them . And owned and ridden
Guzzi's for 38 years . I definitely prefer my Guzzi's , but that doesn't make H-D's bad bikes , just not my style ( and my pockets aren't that deep either :) ).
Peter
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It’s just a cost saving thing, squeezing pennies out of something in exchange for reducing its practical lifespan. Fine for the first buyer who likely never knows, fine for Piaggio because there won’t be as many multi-resale used bikes for them to compete with in selling new bikes. Not so good for anybody who thinks long life is a measure of quality.
This was my initial thought, that this move may save them a few $$ at the cost of a more robust unit longterm. Glad I have my V7III's.
However, I know just enough to be dangerous.
Most interesting to me, was that Cycleworld even bothered to mention it. Seems like a detail that could just as well be left unsaid with no skin off their nose.
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The way I see it is;
If the crank pin is the same size then it should be as strong as the existing big end.
It will allow them to use very hard material in the pin.
The rods will be lighter thus allowing a better balance situation.
If the big ends fail in either type (seems to be very rare on modern V7s) then the crank has to be removed, repaired if possible or replaced.
What is the problem?
As long as the the crank doesn’t slip in the press fit all will be as normal.
Plus they are still making the V85 in the normal way so they could use that bottom end in the long awaited V85 Lemans.
Maybe even have another try at 4V per cylinder as some people have suggested might happen after they looked at the
Castings on the hemi motors.
Cheers, voncrump
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The question are the fittings a Hirth sp? style firrting similar used on old Porseche's and eventually the V8 gp racer or are they some dodgy tappered fitting i'm thinking the latter.
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Like older British bikes some were a tapered pin with a nut to hold in place from memory.
The side by side rods on a common pin like a Ducati has is the best option unless crank width/length is an issue. Articulated rods in all there forms whether a "master rod" situation or a forked arrangement like a Merlin engine uses are less desirable and generally for low rpm applications only.
Ciao
Yes, the large threaded nut provides the "press" onto the tapered joint.....Kawasaki 900 was a multi piece crank along with a few other Japanese 4 strokes..I believe they were pressed..
WW2 Merlin and Allison used knife and fork bolted rods with a one piece crank . The Dailmer Benz used both side by side and knife and fork with one piece cranks...
When Allison dominated unlimited hydro plane racing the 1710 cube engines crowded 4500 rpm and made over 4000 hp...
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So, I've read a lot of opinions here.
What are the real world consequences of this design change?
The engine will last less miles?
The new crankshaft will now be the first point of failure?
Does any of this matter to someone who might put 2000 miles a year average on a small block?
What percentage of motorcycles, other than touring models, ever see 80,000 miles?
How many 1998 - 2003 bikes have we seen on this forum recently purchased with under 35,000 miles on them?
Maybe we need a survey for just Moto Guzzis on this forum with Year, Model, Mileage so we know if this design change will have real world affects on future Guzzi riders.
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Much ado about not much, as far as I'm concerned. :smiley: I've never managed to wear out a motorcycle engine yet..
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Crazy panic time!
Thinking of all the older sports and racing cars with built-up cranks. Not to mention my Laverda triple.
Like Chuck I have never worn out an engine. I suspect this will be a big savings for Piaggio.
To help with the angst, I should point out that you can't buy main bearing inserts for Vespa engines-they are sold as part of the case.
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Crazy panic time!
Thinking of all the older sports and racing cars with built-up cranks. Not to mention my Laverda triple.
Like Chuck I have never worn out an engine. I suspect this will be a big savings for Piaggio.
To help with the angst, I should point out that you can't buy main bearing inserts for Vespa engines-they are sold as part of the case.
Um, no. Just another example of how the cheapest solution is the way Guzzi is run now. If the pressed together crank is a better solution, why are they still using the forged crank on the V85?
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Because of tooling. They have forging dies $$$$ and most likely a lot of raw forging blanks. Cheaper to use up what you have.
:-)
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I've replaced big end bearings several times, it's easy to do and relatively cheap if you don't have to disassemble the crank, maybe I'm hard on them, or particularly picky, but you can't even check if it is a pressed crank. I had a pressed crank on my first motorcycle and learned that is an expensive repair option.
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Um, no. Just another example of how the cheapest solution is the way Guzzi is run now. If the pressed together crank is a better solution, why are they still using the forged crank on the V85?
Were you lining up to buy a new V7 or V9, and now this news is going to stop you?
There is something in the industry about building to a price point.
You can build the most amazing motorcycle out there, but if you can't build it to a price point where it is competitive, then you have to price it with enough profit to justify the low volume sales.
Every bike in your signature was built to a price point and compromises were made.
I'm just thankful Moto Guzzi hasn't gone to overhead cams.
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There was a time when the big block Guzzis were what serious admirers of quality bought, and small block Guzzis were mainly for European commuters who didn’t care if the thing was by comparison a cheaply made throw away bike. Ducati once did the same thing with bevel drive bikes and belt drive engines, but stopped the bevel drive engines around 1986. Nowadays Piaggio has followed Ducati’s 1980s model and down-selected to the less expensive to produce engine family. It then follows that they’ll build higher spec versions and lower spec versions of that engine to span the market, as Ducati did in the 90s with everything from 600 cc 2V engines to the 996 race spec engine, all based on their less expensive basic engine design.
Yes, if I were buying a new Guzzi the built up crankshaft would stop me, but I’m not in the market for a low budget commuter bike - I use my four cam, one piece crank SV650 for that job if needed. However, I might well be buying a V85TT in the future and if that model were by then to transition to the built up scooter crank with one piece rod/bearing assemblies I’d buy something else. If I wanted a Vespa I’d buy one.
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I'm riding with Chuck on this one. I have been riding motorcycle continuously for the vast majority of my life, and I have yet to wear a single motor out.
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I’ve worn out and replaced the rod bearings on a Honda VF750 that developed a rod knock after 30K hard miles, a big block Guzzi (part of a dumb maintenance error when I was young) and a high mileage bevel drive Ducati twin. The bevel drive twin with built-up crankshaft was a big project, the Guzzi was a half day job at most, the Honda was somewhere in between. This was one of several experiences that made me appreciate and buy Guzzis.
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I'm riding with Chuck on this one. I have been riding motorcycle continuously for the vast majority of my life, and I have yet to wear a single motor out.
This
I have seen a friend "wear out" a pressed Harley crankshaft motor, well sorta, he was above 200k miles on his rubbermount Sporty when he made a critical error during an oil change and managed to (unknowingly) drop the seal into the bottle and pour it into the oil tank. Sadly he discovered this after he started hearing a bearing knock and only after tearing the bike down to find the foil blocking the oil feed from the tank.
But much ado - we have no evidence that this means the cranks won't last and if I'm not mistaken the previous cranks couldn't be ground and there were no oversize bearing inserts for them anyway right? So no effective change in ability to rebuild.
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Still confused. I can't see why a pressed crank is cheaper than a solid one.
Also is the Guzzi crank forged or cast? I don't think my Corvette has a forged crank (the rods are powdered metal, forged and cracked)
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I believe the forged and cracked conrods is the latest and greatest tech for strong rods
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Still confused. I can't see why a pressed crank is cheaper than a solid one.
Also is the Guzzi crank forged or cast? I don't think my Corvette has a forged crank (the rods are powdered metal, forged and cracked)
Because it sometimes depends on what the factory is already set up to produce. On top of that the real saving is in the rods. Much simpler to produce a 1 piece rod with around 3 machining processes (grind the big end bore ID, the gudgeon ID press in and ream the gudgeon bush, press in the big end bearing) and done. It would need to be deflashed after forging of course as well but it's a hell of a lot simpler to make than a two piece rod.
Ciao
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I believe the forged and cracked conrods is the latest and greatest tech for strong rods
Not really, they are the latest tech for mass produced rods because they save machining processes. No upgraded performance rod I know of use fractured rod technology or sintered material for that matter. It's about manufacturing ease. Doesn't mean they aren't fit for purpose but you dont find them in race engines generally.
Ciao
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I wonder how many people out there think that this means Luigi from the Vespa factory will be putting together MG cranks and rods using vise-grips :grin:
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Wait, I always thought that pressed cranks were quite a bit more labor intensive and expensive to build. This is the first time I've ever read the opposite. I don't know why two piece rods could be revved at higher RPMs and more stress than one piece rods; if there is a difference, I'd think would be the other way around.
OK, since I'm the least mechanically inclined person on the Board, someone please educate me.
Thanks.
John,
The modern HD engine (45deg) has two separate rods,(not two piece). They are called a fork and blade set up so one rod (the blade) fits into the other rod(fork) and when the holes for the crank pin are lined up roller bearings are pressed in and then assembled onto the crank pin and then the whole thing is pressed together using terrific pressure.
This is done so the cylinders are lined up on the crankcase in a straight fore and aft line, therefore no shaking moment. Your Guzzi cylinders are off set...shaking moment present.
That's the why.
With the 45 deg setup there is enough back and forth rocking that vibration is a problem so one thing the designers did was eliminate the shaking moment as much as possible.
The RR merlin engine used in the P-51 is a V12 and in order to minimize vibration they used the same method, as in blade and fork rods.
These rods are difficult to machine correctly thus labor intensive and $$$.
As for being cheaper to press together???, by using the roller bearings and having a flywheel on each side, the HD method of pressing them together makes some sense rather than the tapered shaft with nuts torqued on both ends. Unknown.
It works but I know folks that are designing and have been testing a forged single piece crank with a master and an articulated rod (plain bearings) and have been riding test machines for about a year.
FWIW
:-)
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I'll add my 2 cents. All of the radial aircraft engines I worked on had two piece cranks. The two piecs were held together with a pinch bolt.It took a lot of force to tighten the bolt, it was checked for proper torque by the amount of stretch. It was a lot of work to set it up and make sure it was correct when finished. So I am not sure how much money it is going to save Piaggio by going this way. I would think that the crank pin could be hardened to extreme levels if desired. I know that the slave rod pins in a radial were hard as hell and couldn't be scratched no matter how hard you tried. I had to mark id #'s in the ends with an engraver and that was the end and not the bearing surface.
Harley has used pressed cranks for a very long time with a very minimal number of failures. Most of the Harley failures were from modified engines with mega hp. The cranks that failed were usually scissors, one of the press fits slipped putting the two halves out of phase. Easily prevented by welding the joints.
I wouldn't have a problem with a pressed crank bike, especially a MG as MG engines are not overly stressed. I once lunched a single cylinder Yamaha crank from hopping it up well beyond design limits. It was not terribly expensive to have it repaired. I would not be concerned with pressed cranks from Moto Guzzi. Luigi has to be careful when putting these together.
A closing thought, not all 2 strokes use pressed cranks. Mercury outboards in the 50's and 60s that I am familar with used one piece forged cranks for their twins, fours and sixes. The main failures were from rod journals with the needles starting to slide from pitting on the needles or the journal itself. Unbelievable destruction.
kk
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Does this Cycleworld comment raise an eyebrow with anyone?
"An unexpected and fairly radical technical modification separating the V7/V9 V-twin engine from all previous editions, and from the V85 TT, is that the crankshaft here is of the press-fit type, with one-piece con-rods turning on plain bearings, rather than a forged one-piece unit. This follows the same engineering approach used on all Piaggio four-stroke scooter singles. Reducing production cost is the ultimate reason for the change. The more powerful, higher-revving V85 TT retains its solid forged crankshaft and cap-type rod."
I’m calling journo BS on this one, not the crank/rods, I totally believe a pressed crank/ plain bearing set up could be lighter and better than 2 piece rods, modern metals/ machinery etc.
But that it’s cheap ? No press release I’ve ever read said that about new technology UNLESS the product itself was cheaper than before.
This article reinforces my thinking
2021 V7’s with flat tappets, steel valves, bolt up rods still on sale
https://www.webbikeworld.com/2021-moto-guzzi-motorcycle-lineup/
There’s the cheap one, retail prices will confirm, no way will they sell roller tappet, titanium valve bike with or without this crank cheaper than getting rid of old flat tappet engines.
My bet
This crank set up will be in the new model to be announced
Marginally more power than the v85tt but as in 1970 the difference will be in weight, handling, braking and suspension.
Good name Tonti chose —-V7 Sport , the true game changer, the Le Mans (which I bought and still ride) was first twin to make revs and be competitive with state of art but the v7 sport led to multitude of other models too.
A new lightweight chassis with v85 engine, even I might buy one, pressed up crank and all.
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John,
The modern HD engine (45deg) has two separate rods,(not two piece). They are called a fork and blade set up so one rod (the blade) fits into the other rod(fork) and when the holes for the crank pin are lined up roller bearings are pressed in and then assembled onto the crank pin and then the whole thing is pressed together using terrific pressure.
This is done so the cylinders are lined up on the crankcase in a straight fore and aft line, therefore no shaking moment. Your Guzzi cylinders are off set...shaking moment present.
That's the why.
With the 45 deg setup there is enough back and forth rocking that vibration is a problem so one thing the designers did was eliminate the shaking moment as much as possible.
The RR merlin engine used in the P-51 is a V12 and in order to minimize vibration they used the same method, as in blade and fork rods.
These rods are difficult to machine correctly thus labor intensive and $$$.
As for being cheaper to press together???, by using the roller bearings and having a flywheel on each side, the HD method of pressing them together makes some sense rather than the tapered shaft with nuts torqued on both ends. Unknown.
It works but I know folks that are designing and have been testing a forged single piece crank with a master and an articulated rod (plain bearings) and have been riding test machines for about a year.
FWIW
:-)
Thanks Mike,
I knew HD had the "knife and fork" rods but I didn't know why. In fact keeping the cylinders directly in line would keep the rear one totally out of air flow.
I never considered that vibration from the 45 degree V, might be the reason. I did think the Master Rod was the fork and the Articulated Rod was the blade. Odd cylinder radial engines a have master rod and the the articulated rods are "pushers followers".
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I thought it was strength because it was originally a one piece, but this link suggests it is precision:
https://www.ms-motorservice.com/en/technipedia/post/cracked-connecting-rods/
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Whatever it has I am sure I wont be able to wear it out if I knuckle under to Anniversary edition V7 bike lust.
(https://i.postimg.cc/rw71tMcY/v7cent.jpg) (https://postimg.cc/k2F60r2x)
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Whatever it has I am sure I wont be able to wear it out if I knuckle under to Anniversary edition V7 bike lust.
(https://i.postimg.cc/rw71tMcY/v7cent.jpg) (https://postimg.cc/k2F60r2x)
I love that they copied my photoshopping on the side covers! :cool:
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+1 on kev
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I love that they copied my photoshopping on the side covers! :cool:
Kev is officially on the blame line........ :police:
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Kev is officially on the blame line........ :police:
I am sure Kev is smiling all the way to the bank with those royalty payments he is receiving. :wink:
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Thanks Mike,
I knew HD had the "knife and fork" rods but I didn't know why. In fact keeping the cylinders directly in line would keep the rear one totally out of air flow.
I never considered that vibration from the 45 degree V, might be the reason. I did think the Master Rod was the fork and the Articulated Rod was the blade. Odd cylinder radial engines a have master rod and the the articulated rods are "pushers followers".
FWIW
All 4 cycle radial a/c engines have odd # of cylinders. And the rear cylinder on the HD loses very little air while in motion. Flat aircraft engines have cylinders in line but they do use baffles to direct air 'cause they operate at high power (65% or more) when inflight at cruise/take off.
:-)
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Thanks Mike,
I knew HD had the "knife and fork" rods but I didn't know why. In fact keeping the cylinders directly in line would keep the rear one totally out of air flow.
I never considered that vibration from the 45 degree V, might be the reason. I did think the Master Rod was the fork and the Articulated Rod was the blade. Odd cylinder radial engines a have master rod and the the articulated rods are "pushers followers".
With regards to the fork and blade rod design It's got virtually nothing to do with eliminating rocking couple, that's just a minor albeit nice to have by product of the fork and blade style rods in a V twin design and not really worthy of the effort alone as Ducati, Guzzi and many others that produce a very smooth running largish capacity V twins that also make high specific output and rev to 12,000 rpm safely without rocking couple or secondary vibration mitigation can testify to.
No the primary reason for it in Harleys case was simply expedience and a minimal design change to effect a twin cylinder engine and then like Chevrolet when they had to design a new V8 engine they stuck to pushrods primarily because that's what they had experience with and were too conservative to go the way of the rest of the world to OHC. Harley did the same with the fork and blade style rods.The advantages of fork and blade design are primarily reduced frontal area and engine width having the cylinders in line and reduced crankshaft length which is an advantage in a V12 aircraft engine but not so much in a V twin motorcycle engine. The elimination of a rocking couple is a minor by product. You cant really compare the aircraft rod designs directly to motorcycles as their specific output is quite low compared to Motorcycle engine. A Rolls Royce Griffon engine (the largest and most powerful V12 engine RR made during the war that powered the latest Mk's of Spitfires to speeds of nearly 500mph were 37 litres and 2400 HP for a specific output of 65hp/L and turned around 2800 rpm maximum) A Ducati 1198 for example makes around 190 hp from its 1.2 Litres and turns over 10,000 rpm for an output of 158 HP/L. I can tell you now Taglioni would never have even had the though of a blade and fork rod design even cross his mind when he sat down to draw up the first Ducati V twin.
This may interest some. I dont agree with Cameron on the aircraft engine logic. Not every design principle is transferable between every engine application.
https://www.cycleworld.com/harley-davidson-roller-bearing-crankshaft-explained/
Ciao
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I agree with Phil for the most part..RR Merlin was built on the evolution of dozens of years of V12 aircraft engines.It's fork and blade rod may have been used out of tradition in a somewhat conservative industry...Allison being a very small manufacturer building their fist liquid cooled engine was likely going with the trend...
Engineers call it a fractured rod, not cracked, LOL..
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No the primary reason for it in Harleys case was simply expedience and a minimal design change to effect a twin cylinder engine and then like Chevrolet when they had to design a new V8 engine they stuck to pushrods primarily because that's what they had experience with and were too conservative to go the way of the rest of the world to OHC.
I think Harley did it their way because it was 1908 at the time, and there wasn’t a whole of prior experience one way or the other. That which did exist was with early aircraft engines.
Re the V8 Chevrolet engine: the rest of the world (outside of the US industry) wasn’t doing a whole lot with high volume production automotive V8s in 1955, or high volume OHC car engines in 1955 either. However Chevrolet was planning on making a whole lot of them, for example 100,000,000 small block V8s were eventually built, and I think they had fundamentally the right idea. It wasn’t exactly the product of arbitrary decision, it was more like genius. The extremely low cost and completely effective valve gear and rocker arrangement was part of it.
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There is no more room for discussion on this subject. Settled business. Whatever you thought going in, is still the case.
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I think Harley did it their way because it was 1908 at the time, and there wasn’t a whole of prior experience one way or the other. That which did exist was with early aircraft engines.
Re the V8 Chevrolet engine: the rest of the world (outside of the US industry) wasn’t doing a whole lot with high volume production automotive V8s in 1955, or high volume OHC car engines in 1955 either. However Chevrolet was planning on making a whole lot of them, for example 100,000,000 small block V8s were eventually built, and I think they had fundamentally the right idea. It wasn’t exactly the product of arbitrary decision, it was more like genius. The extremely low cost and completely effective valve gear and rocker arrangement was part of it.
If you read the history of the Gen111 engine the pushrod comfort factor/no OHC experience among its design team was a big component of the design decision to not go OHC. However in defence of Chevrolet the engine is very compact and used in everything from delivery trucks to Corvettes in various stages of tune. I've owned Gen111 engines in 2 cars and am actually a fan of them however Ford when faced with a similar decision did decide to go DOHC which I'd like to have in either a Cobra replica or GT40 replica one day. There's a long path from what the engineering team would like and what pops out the production line:)
Ciao
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I'm riding with Chuck on this one. I have been riding motorcycle continuously for the vast majority of my life, and I have yet to wear a single motor out.
What about a multi cylinder engine? have you worn out any of them? :grin:
Ciao
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If you read the history of the Gen111 engine the pushrod comfort factor/no OHC experience among its design team was a big component of the design decision to not go OHC. However in defence of Chevrolet the engine is very compact and used in everything from delivery trucks to Corvettes in various stages of tune. I've owned Gen111 engines in 2 cars and am actually a fan of them however Ford when faced with a similar decision did decide to go DOHC which I'd like to have in either a Cobra replica or GT40 replica one day. There's a long path from what the engineering team would like and what pops out the production line:)
Ciao
Phil, I don't remember if it was you or one of your fellow countrymen that trolled me about the Chevy V8 on the LeMans board. But I'm pretty sure it was you.
HAHA.
Funny you didn't mention pushrod Guzzi engines. :rolleyes:
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Phil, I don't remember if it was you or one of your fellow countrymen that trolled me about the Chevy V8 on the LeMans board. But I'm pretty sure it was you.
HAHA.
Funny you didn't mention pushrod Guzzi engines. :rolleyes:
Really, I don't believe I've ever trolled anyone. It wouldn't be the first time I've been mistaken for some other poster though. What was I supposed to mention about Guzzi BB engine? We all know the BB is an archaic engine as is most of the rest of it. The Griso 8 valver roller tappet version is the zenith of the Guzzi BB line but its a Hi cam.
As for the Chev Gen111 and subsequent, well I like the engine but I'm under no illusions. It's not like the most efficient way to make torque, it's all about the cubic capacity which is a bit of a blunt instrument way to go about things.
Ciao
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Really, I don't believe I've ever trolled anyone. It wouldn't be the first time I've been mistaken for some other poster though. What was I supposed to mention about Guzzi BB engine? We all know the BB is an archaic engine as is most of the rest of it. The Griso 8 valver roller tappet version is the zenith of the Guzzi BB line but its a Hi cam.
As for the Chev Gen111 and subsequent, well I like the engine but I'm under no illusions. It's not like the most efficient way to make torque, it's all about the cubic capacity which is a bit of a blunt instrument way to go about things.
Ciao
Zenith ?
Making Carcano’s 700cc a 1200 follows the blunt thing
You may have meant omega
Dead now, for sure
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Zenith ?
Making Carcano’s 700cc a 1200 follows the blunt thing
You may have meant omega
Dead now, for sure
I actually meant Zenith, dictionary definition..... "the time at which something is most powerful or successful" The roller tappet Griso is the Zenith of the BB engine. Or the ultimate iteration if you like.
Ciao
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Really, I don't believe I've ever trolled anyone. It wouldn't be the first time I've been mistaken for some other poster though. What was I supposed to mention about Guzzi BB engine? We all know the BB is an archaic engine as is most of the rest of it. The Griso 8 valver roller tappet version is the zenith of the Guzzi BB line but its a Hi cam.
As for the Chev Gen111 and subsequent, well I like the engine but I'm under no illusions. It's not like the most efficient way to make torque, it's all about the cubic capacity which is a bit of a blunt instrument way to go about things.
Ciao
The Chevy LS is lighter and far more compact than DOHC engines. It does need more capacity than a DOHC to make the same power but usually gets better fuel milage and displacement on a street engine only matters to internet forums... :grin:
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I’m on the fence on this one . I would prefer a solid crank , that said I’m guessing the current press fitting technology has come up a bit since the days of “adjusting” them with a wooden mallet ! BMW is fond of using heat & liquid nitrogen in many of its fitments . Perhaps someone like Kevin Cameron could help with this knowledge or someone equally smarter . Another thing I’ve noticed in this thread is the reference to “oversized “ bearings . All the crank shafts I’ve had done required “undersized “ bearings as you’re removing material , just sayin.
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Another thing I’ve noticed in this thread is the reference to “oversized “ bearings . All the crank shafts I’ve had done required “undersized “ bearings as you’re removing material , just sayin.
Maybe saying the same thing but semantics - i.e. one talking about diameter and the other about physical size of the shell and amount of material?
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Really, I don't believe I've ever trolled anyone. It wouldn't be the first time I've been mistaken for some other poster though. What was I supposed to mention about Guzzi BB engine? We all know the BB is an archaic engine as is most of the rest of it. The Griso 8 valver roller tappet version is the zenith of the Guzzi BB line but its a Hi cam.
As for the Chev Gen111 and subsequent, well I like the engine but I'm under no illusions. It's not like the most efficient way to make torque, it's all about the cubic capacity which is a bit of a blunt instrument way to go about things.
Ciao
Repeating my points from the LeMans forum. Comparing the LS/LT series Chevy to the Ford DOHC. Both engine have comparable power, torque and fuel economy. The Chevy has a larger displacement at 376 cu in, whereas the Ford is 302 but revs higher. The Chevy engine is less complicated, cheaper, smaller, lighter, and not as top heavy. Not saying one is better than the other. But sometimes hitting with blunt hammer once is better than hitting 20 times with a claw hammer.
I own an LS and have driven the Ford and both have their charm and drawbacks. The big difference is whether the driver likes to rev a smaller engine or the muscle torque of the larger one.
When comparing these engines to the big block Guzzi, consider that the 8v version had a larger displacement than the pushrod version so had advantages of both V8 engines. Unfortunately, there were reliability problems in the first Guzzi iteration.
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I actually meant Zenith, dictionary definition..... "the time at which something is most powerful or successful" The roller tappet Griso is the Zenith of the BB engine. Or the ultimate iteration if you like.
Ciao
This is the internet and hence, opinion, you are entitled to yours
But I wonder about the criteria you use
For powerful, the MGS 01 is hard to beat, especially when you take in power to weight, my choice for zenith there
Hp/litre ? Your Daytona ?
Successful ?
Sales ?
Competition ?
Last time I looked there were 3 NOS Grisos for sale in Aus, made in 2016 I believe.
Worldwide there could be 100’s on showroom floors, I seriously doubt history will ever record the last BB as being the most successful of the line.
Anyone ever enter one in any form of competition? Let alone won?
The 750 Land Speed loopy might top chart
Or the original Le Mans in proddy racing
Mk3/4 in US Endurance racing ?
Perhaps you measure success as most recalls and least sold ?
Omega and sad death for the 50 years of BB Guzzis
By all accounts the worst BSFC figure of the whole lot, so perhaps if we use use the most fuel to make same power, it wins hands down. My favourite criteria , just my opinion, of course
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This is the internet and hence, opinion, you are entitled to yours
But I wonder about the criteria you use
For powerful, the MGS 01 is hard to beat, especially when you take in power to weight, my choice for zenith there
Hp/litre ? Your Daytona ?
Successful ?
Sales ?
Competition ?
Last time I looked there were 3 NOS Grisos for sale in Aus, made in 2016 I believe.
Worldwide there could be 100’s on showroom floors, I seriously doubt history will ever record the last BB as being the most successful of the line.
Anyone ever enter one in any form of competition? Let alone won?
The 750 Land Speed loopy might top chart
Or the original Le Mans in proddy racing
Mk3/4 in US Endurance racing ?
Perhaps you measure success as most recalls and least sold ?
Omega and sad death for the 50 years of BB Guzzis
By all accounts the worst BSFC figure of the whole lot, so perhaps if we use use the most fuel to make same power, it wins hands down. My favourite criteria , just my opinion, of course
My opinion is an engineering based one. The Griso roller engine is a way better engine from an engineering standpoint that the Daytona/Centy engine and all the other BB engines for mine. I dont believe anyone that knows the Daytona/Centy/MGS engine intimately would even consider it a contender. Just my view based on my experience and what I've seen of the BB engines.
Out of interest who has NOS Grisos available in aus? sounds tempting esp an SE.
Ciao
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My opinion is an engineering based one. The Griso roller engine is a way better engine from an engineering standpoint that the Daytona/Centy engine and all the other BB engines for mine. I dont believe anyone that knows the Daytona/Centy/MGS engine intimately would even consider it a contender. Just my view based on my experience and what I've seen of the BB engines.
Out of interest who has NOS Grisos available in aus? sounds tempting esp an SE.
Ciao
Lovely, truly
Nothing to do with logic or performance or success
You might want to read about Luap’s MGX (same engine, hit with blunt thing)
Hydraulic camchain adjusters might turn you on
But disaster to bloke who rides the fkn thing,
Re buying one 5 years after the last off line, try google but entirely possible Aussie dealers have cut losses and parted them out. Plenty of slightly used private sales, buy em up
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I believe that all the V7iii engines have one piece rods, unlike the V7ii before and the V85. I am not clear about the new V7 850 and would love to know.
I hypothesize that the new 850 has the pressed together crank and that is why they have limited the output to 65 hp. Indeed there may be other features of the V85 internals that are not in this new engine.
Here is a photo of a crank from a V7iii racer that is a used part on ebay.
(https://i.ibb.co/f1GPTK1/Crankshaft-from-V7-iii-Racer-used.jpg) (https://ibb.co/f1GPTK1)
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I have a heron head which means I'm unfit for further discussion. Or something like that.
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That crank assembly in the photo above sums up the nowadays throw away culture, it seems that it is a BIC lighter, the timing sprocket looks like it is non replaceable too. :undecided: DonG
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That crank assembly in the photo above sums up the nowadays throw away culture, it seems that it is a BIC lighter, the timing sprocket looks like it is non replaceable too. :undecided: DonG
It wouldn't surprise me if you cant even buy big and shells and rods for these as a spare part. Triumph engines were also like this 25 years ago. Have a worn valve guide in your Triumph Daytona engine? buy a complete cylinder head sir because we don't sell guides a spare part. Yes the cam sprocket looks like its been machined into the crank nose. It MAY be on an integral sleeve thats a shrink/interference fit on the crank. Triumph also did this on their 90's triple engines for the balancer drive gear. When they moved as they did occasionally it would destroy the engine. I hate this throw away engineering shit.
Ciao
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Although this design rubs traditionalists including me the wrong way, maybe it is no big deal. Someone pointed out that small block cranks could not be reground anyway because shells are not available. If that is so then making a crank assembly that is not intended to be dismantled to minimize costs may be good.
It seems that the V7iii cranks are very reliable and long lasting as dealers I spoke to have never had to replace one.
I saw that crank assemblies are only $500 or so in Europe so much less than reconditioning an old one unless you had a machine shop.
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Although this design rubs traditionalists including me the wrong way, maybe it is no big deal. Someone pointed out that small block cranks could not be reground anyway because shells are not available. If that is so then making a crank assembly that is not intended to be dismantled to minimize costs may be good.
It seems that the V7iii cranks are very reliable and long lasting as dealers I spoke to have never had to replace one.
I saw that crank assemblies are only $500 or so in Europe so much less than reconditioning an old one unless you had a machine shop.
It's all logical arguments in the here and now but as a general concept what about when you have a single component failure. In this case like a cam drive sprocket tooth and you need to go and buy a whole assembly. Will whole assemblies be available in 20 years time? Everything is getting this way now and the Triumph cylinder head is an example I have given. I know you can re sleeve guides, I've done a few now but to eliminate the new guide option is not good. What about the modern car engine now, the cams are driven by friction from the crank, no keyways on the crank or the cams. On the engine in both my cars removing the front timing cover to simply replace the oil seal is now a major piece of work with half the engine coming apart and the cam timing needing to be done again. And from a lot of personal experience I can tell you the average dealership mechanic doesn't have the skills to do it now. Personally I'd pay an extra grand on the purchase price and have some maintainability retained. I don't like the concept of the throw away car or bike which is exactly the direction we are well into now. Then they just become a consumer item like a fridge or washing machine which aren't worth fixing anymore either.
Ciao
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That crank assembly in the photo above sums up the nowadays throw away culture, it seems that it is a BIC lighter, the timing sprocket looks like it is non replaceable too. :undecided: DonG
Every single small block engine has the sprocket cast into the crank since day one..God knows why...
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Every single small block engine has the sprocket cast into the crank since day one..God knows why...
Yea, amazing ain’t it ?
44 years and no one’s worn a sprocket out
Tonti wasn’t silly after all, design was meant to be cheap transport for the masses, whole bike was half the price of my Le Mans, cheap and cheerful we said. Time has proven otherwise.
One piece rods may last as long, I certainly wouldn’t lose sleep if I had them in my Lario, in fact if I ever build a long stroke one I will use them, just to prove point.
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I believe that all the V7iii engines have one piece rods, unlike the V7ii before and the V85. I am not clear about the new V7 850 and would love to know.
I hypothesize that the new 850 has the pressed together crank and that is why they have limited the output to 65 hp. Indeed there may be other features of the V85 internals that are not in this new engine.
Here is a photo of a crank from a V7iii racer that is a used part on ebay.
(https://i.ibb.co/f1GPTK1/Crankshaft-from-V7-iii-Racer-used.jpg) (https://ibb.co/f1GPTK1)
So this means the article was wrong? MG has gone to this design beginning with the V7III series? I'm not an expert. But if you look at the parts catalogues, they show a 2-piece con rod in the V7II series and what appears to be the same assembly in the pic for the V7III series. So my smugness was premature?
Much ado about nothing? Just take good care of the motor and it will be ok?
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When I check the online parts diagrams the 2017 V7iii ones show the conventional two piece rods. The 2018 ones show the one piece. If anyone has access to the official ones that a dealer has it would be good to confirm this.
When I enter the 2017 part numbers it does show the two piece rods as being available and the crank by itself. The only part number for 2018 is for the complete crank with one piece rods on it.
Note that the price of the latter is way less than the former.
From this it would seem that the change was made in 2018, in the second year of the V7iii. Strange! Or maybe it took a year for the parts diagrams to be updated and they never went back to correct them.
As an aside I called one of the large US dealers. He had never had the need to open a V7iii but had an engine that had been torn open in a wreck, He checked and confirmed that the crank was pressed with one piece rods.
Guzzi do make life entertaining!
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RESOLVED!
I have just seen the parts diagram for the new V7 850 engine and the crank and rods are the same configuration as in the current V7iii. The rods are one piece. The part number for the assembly is different so I assume it is beefier.
It is not a detuned V85 engine at all but a new engine based more on the 750. Not really all that much to get excited about.
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So my 2018 Milano and Carbon Shine have the "newer" style crank and con rod assembly. Time to ride them until they wear out!
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This is interesting topic. I suppose that pressed crankshaft has roller bearing instead plain bearing. But how they managed to put oil thru bearing to hollow rod?
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So circling back around to this topic leaves me with the question WHEN did Guzzi really go to the pressed cranks in the V7.
This came up recently in the V7 FB group and I had remembered this thread. But I hadn't looked into it as deeply when we first discussed it.
Here's what I've found so far:
750 V7 EU4 Eng manual published in 2016 - clearly shows removeable rod caps and replaceable bearing inserts
2017 V7 Anniversario parts manual - clearly shows same - removable rod caps and replaceable bearing inserts
https://www.af1racing.com/V7-III-Anniversary-OEM-Parts-Catalog
2018 Milano and Carbon Dark parts manuals - DO NOT show removable caps or rod bearing inserts (that's not to say it's not possible, both both rods and crankshaft are shown as a single part number, other things like main bearing inserts are still shown).
https://www.af1racing.com/V7-III-Milano-OEM-Parts-Catalog
Plus there was that photo earlier in the thread which was supposedly a used V7III crankshaft which seems to pretty clearly show a pressed crank.
So what is it? Separate con-rods only through 2017 and pressed crank 2018+ and no updated engine manual was published (or I just haven't seen it yet)? Or did all of the V7IIIs retain removeable con rods?
It's a curiosity thing, but still.
Anyone here install a sump spacer and get a look at the crank on their III? (can you see the crank from there on the smallblock, I don't remember, it was like 9 years ago when I installed the spacer on the MKI Stone)?
Anybody?
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This is interesting topic. I suppose that pressed crankshaft has roller bearing instead plain bearing. But how they managed to put oil thru bearing to hollow rod?
No, pressed crank and plain bigend bearing.
Ciao