G5 1000 engine in an 850T?

[CanBike]

I've come into an entire G5 1000 engine...

A few questions:

- did the 850 perform in any better way to the G5?
- Maybe the g5 doesn't pull much better than the 850? More torque at least?
- are the vibration issues of 1000 top end on 850 bottom worth worrying about?

Thanks!

[fotoguzzi]

The 850T has a cultish vibe but putting in the 1000 engine will just enhance that. It will still feel like the same old slug. Oil filter= ++

My first Guzzi was a T,

[LeRoy]

Unless I'm mistaken (an occasional peril), the 1000cc G5 barrels won't slip right into the 850T's block. I believe that the 1000cc barrel spigot diameter would need to be turned down or the 850T block openings enlarged.

With that as my initial assumption, what I'd do is just transplant the whole 1000cc engine into the 850T bike. It should just bolt together. That would eliminate any concerns about needing an engine rebalance due to mixed-motor parts. It will also give you a modest but meaningful boost in torque. As far as smoothness, a stock 1000cc G5 engine is a fine motor in its own right. I'd take a G5 over an 850T any day.

As to matching numbers, I wouldn't worry about it. You still have the original 850T motor so "originality" could be restored if there was ever a time when an 850T became sufficiently sought after.

[Perazzimx14]

Why not just get a set of 850cc Gilardoni piston/cylinder kits and be done with it. The big gain from 1,000cc kits verses 850cc kits is more torque. If you are going to use your 850T as a pusher then I'd suggest more CC's. But sidecar rigs also come with their own set of issues. 

I've installed Gilardoni's on my 1972 Eldorado and my 1975 850T then when reviving my 1976 T3 Gilardoni's were backordered everywhere.  I had Millennium strip and re-plate my stock cylinders and reused the stock pistons & wrist pins. I had all 3 Guzzi's at the same time and rode them back to back to back mutiple times and there was no difference in vibration levels and the vibration level was no different that any other carbed BB Guzzi I've ever owned.




 

[LeRoy]

[quote author]
Why not just get a set of 850cc Gilardoni piston/cylinder kits and be done with it.
[/quote]

I'm not looking to be snarky, but perhaps it's because he already has come across what is apparently a perfectly good 1000cc G5 engine? If he owns the G5 engine and the transplant can be effective - and I don't see why it cant - there's no need to spend further money on a Gilardoni kit.

[Turin]

If it's in good shape, I'd slap the G5/SP1000 motor in as well. Does your T have a oil filter?

[Rick4003]

I would also vote for swapping the complete G5 motor in. Much easier than to swap all the parts from one to the other. If you later decide that you like the 850 motor better, you could rebuild that while still being able to ride the bike with the G5 motor.

[Shorty]

For years, 850Ts were bastardized into V7 Sport clones. Stock, the front brake had a poorly matched master cylinder with poor "feel". The hot set up was to add another disk, thereby "fixing" the ratio. The rear brake was often like a light switch, either skidding or working poorly. There is a fix for that also, buried in either Guzziology or the fun filled MGNOC "Tips" books.  Also, some of them had a different rear drive ratio some folks didn't care for. One more thing, the Ts had a weaker charging system, which was slightly improved starting with the T-3. If you have the rotor and stator from the G-5, you can bump up the electrical output with the addition of a couple connections, if I am recalling correctly. Might also need a different rectifier, can't remember. Good luck!

[pete roper]

The only thing I'd like to say is that both engines, and the rest of the bike, are now in excess of forty years old.

I would strongly recommend going through the whole machine thoroughly rather than simply tossing a 'New' forty year old motor into it.

Pete

[Perazzimx14]

I'm not looking to be snarky, but perhaps it's because he already has come across what is apparently a perfectly good 1000cc G5 engine? If he owns the G5 engine and the transplant can be effective - and I don't see why it cant - there's no need to spend further money on a Gilardoni kit.

No snark taken. If a G5 motor is in good running condition it is a viable candidate. It'll take more work transplant verses cylinder swap for little ROI in the performance department. I'd also assume the G5 motor is not free so is it a monetarily a win over replacing cylinders. Is there a carb issue. If memory serves there is a 2mm difference in the VHB carbs when bumping up to a liter sized motor.

I would also vote for swapping the complete G5 motor in. Much easier than to swap all the parts from one to the other. If you later decide that you like the 850 motor better, you could rebuild that while still being able to ride the bike with the G5 motor.

If its an ease thing replace cylinders is MUCH easier than doing a motor transplant. The hardest thing about replace the cylinders is remove the base gasket. Fortunately with the aid of some aircraft paint stripper this too can be done with ease. The cylinders can be swapped easily  in a couple hours.

For years, 850Ts were bastardized into V7 Sport clones. Stock, the front brake had a poorly matched master cylinder with poor "feel". The hot set up was to add another disk, thereby "fixing" the ratio. The rear brake was often like a light switch, either skidding or working poorly. There is a fix for that also, buried in either Guzziology or the fun filled MGNOC "Tips" books.  Also, some of them had a different rear drive ratio some folks didn't care for. One more thing, the T's had a weaker charging system, which was slightly improved starting with the T-3. If you have the rotor and stator from the G-5, you can bump up the electrical output with the addition of a couple connections, if I am recalling correctly. Might also need a different rectifier, can't remember. Good luck!

Another much more cost effective and easy fix for the front brakes it to buy a 12.9mm master cylinder and run the stock single disc setup. They can be had for as little as $20.00.

None of the answers are wrong. If the OP want to transplant a Pratt & Whitney F119-PW-100 turbofan it doesn't matter to me. From his post the biggest thing the OP seems concerned with is vibration not performance. 850 Gilardoni kits IMHO are not going to add or detract any discernable vibration over the stock 850 motor. It is also my opinion that the G5 motor will be no more or less smooth. 

[kfz]

The 850T has a cultish vibe but putting in the 1000 engine will just enhance that. It will still feel like the same old slug. Oil filter= ++

My first Guzzi was a T,

Cracked me up that picture mate. Not sure why, silly out of context background and stupid sign, Captain America lid, its just out there. Made me laugh.

Kev

[Antietam Classic Cycle]

Is there a carb issue. If memory serves there is a 2mm difference in the VHB carbs when bumping up to a liter sized motor.

No, both 850-T and G5 both use 30 mm carburetors.

[Perazzimx14]

No, both 850-T and G5 both use 30 mm carburetors.

 

[wirespokes]

Since his T doesn't have a filter, it makes sense swapping in the 1000 engine for that alone.

[Perazzimx14]

Since his T doesn't have a filter, it makes sense swapping in the 1000 engine for that alone.

Is an oil filter THAT big of a deal? I mean Ambo's and Eldorado don't have oil filters and will run for hundred of thousands of miles. I can't ever remember anyone posting that there filterless Guzzi went tits up because it had no oil filtration. You do hear about engine failures due to internal oil filters unscrewing and the enging getting starved of oil because of loss of oil pressure. So is a filltered motor really better??

Changing the oil in a filterless Guzzi is dead dimple. Undo the drain plug and release 3 quarts of oil behind it. 1 minute later put drain plug back in and refill with 3 quarts of ndw oil. 5 minutes total your back on the road and good for another 3,000 miles.

 

[Turin]

I've got a bastardized 850T. I Got around the brake issues by fitting a EBC rotor and four piston caliper (with adapter from Guzzi power). Fitting rear sets necessitates a shorter brake lever which in turn provided less leverage to the rear brake drum. The rear brake feel is nice and progressive.

[TOMB]

If you have access to the G5 engine  go for it
Fyi the G5 came with a higher output alternator
Larger U  joint
Timing , valve adjustment  , cam same as a T3 carbs heads etc.
G5 balanced better, and mechanically quiter
Installs the same and in my case felt smoother .

See my in in signature below

TOMB

[Testarossa]

850T has a different swing-arm drive shaft spline that may not fit later gearbox output or U-joint -- may have to use the original gearbox.

[LeRoy]

Long-winded summary. Having done a bit more digging, I can confirm my earlier point about the incompatibility of the G5 1000cc cylinders and the 850T engine block:

 - The 850cc Guzzi big block engines (83mm bore) use cylinders with a relatively small diameter spigot on the cylinders. The diameter of the bore in the block is relatively small to accept them.
 - The 1000cc Guzzi big block engines (88 mm bore) use cylinders with a relatively large diameter spigot on the cylinders. The diameter of the bore in the block is relatively large to accept them.
 - The cylinders from a 1000cc Guzzi big block engine will not simply drop in to an 850cc engine block.
 - To use 1000cc cylinders in an 850cc block, you must either have the 1000cc cylinder spigots turned down to match the diameter of the bore in the block, or bore out the hole in the block to accept the larger diameter cylinder spigot. It is not a simple swap.

As a result, and assuming you already own the 1000cc G5 engine, the simplest and most cost-effective approach would seem to be to swap the complete engine into the frame of the 850T. This gains a number of advantages as enumerated in comments above:

 - It's a direct bolt-in swap, assuming you use the existing 850T transmission
 - You gain a useful bump in power, primarily torque in the low-to-mid-rpm range
 - You get the advantage (in the minds of many) of an oil filter
 - You gain a more powerful charging system (assuming you also have the alternator that came with the G5 engine. Some modest updates to other parts of the charging system may be necessary; Guzziology speaks to this
 - The 1000cc G5 engine uses iron bores, a proven long-life design without significant drawbacks
 - You can re-use your existing carbs from the 850T. Some modification to jetting may be required; see Guzziology again
 - You can set the complete 850T engine aside. I doubt that there's a big jump in 850T value over the horizon, but you'll have the unmolested original engine, just in case

Lastly, don't ignore the point made by Pete Roper; you're dealing with 40-year old bits and bikes. At the least, get yourself a top end gasket set and go through the G5 engine to check the usual suspects. it's also simple to check the connecting rod big-end bearings while you're at it. Their condition will tell you much about the engine's overall condition.

Good luck and have fun. You've a nice project on your hands. If you need a complete set of factory manuals for your 850T (or the G5) just send me a PM. I'll send you a CD with all the relevant manuals in PDF form, wiring diagrams, helpful hints and how-to information, period advertisements and road tests, and a bit more. No cost. Just send me a PM with your mailing address. The same offer is open to any WildGuzzi member. I have model-specific CDs for most big block Guzzi models from the mid-70s to the early 90s. Sent worldwide, no charge.

[fotoguzzi]

For sure use the whole G5 engine.. when you get in the timing chest ditch the rubbing block they call a tensioner and replace with a proper one that will actually put tension on the chain.. Valtec is what you want.

[Testarossa]

If the 850 cam followers are scored, it's a good bet the oil pump is toast. Use the engine with an oil filter.

[pete roper]

Completely buggered!

If you're very lucky you might be able to linish the crank and not go undersize on the pin and just have the rods closed and ground to suit. The sludge trap will be full of the shite that caused the damage and the mains are probably rooted as well. Chances are the oil pump is history too.

Go through the G5 motor and use it and then follow through on the T one to see if much of it is salvageable.

[Chuck in Indiana]

Yep, what Pete sez. "She's dead, Jim.." Put the G5 engine in it.

[s1120]

Yep, what Pete sez. "She's dead, Jim.." Put the G5 engine in it.

Yup, way to many issues going on, or waiting to..  Stash it aside, and keep it for a future rebuild and pop in the other one..