Rollerisation of the 8V.

[guzzisteve]

Pete,      I was told by the Rep to document everything on the stuff here in the states. Got one to look at now, actually 2 coming up.

[Vasco DG]

Where are you working now Steve? I thought you'd jumped the shark and gone to work at a Harley shop?

Look, if I can help in any way please feel free to bounce ideas off me. I'm pretty much at a loss as to why there seem to be so many random factors in the failures.

One thing that I was considering is that the beginning of the failures I've seen in the last year coincided with my chosen oil supplier ceasing production of the lubricant I'd used for the entirety of the 8V motor's life. Having said that I remain deeply sceptical about that factor having any relevance or validity.

Pete

[Chuck in Indiana]

I'm pretty much at a loss as to why there seem to be so many random factors in the failures.

 

 

[Vasco DG]

Arse!

[pyoungbl]

Pete, et al;
     I wonder if the flat tappet failure is due to the fact that each tappet is opening two valves and thus compressing twice the spring pressure. The actual rocker arm assembly might also be part of the problem due to its geometry.  Truth be told, I'm grasping at straws here!

Peter Y.

[Vasco DG]

Spring pressure really isn't a problem. Due to the small mass of the valves and the variable rate of the beehive springs loadings are pretty light, (I've established this in the time honoured manner of hammer biffing and palm heel depression, one day I'll actually get some figures at the engine shop but as its not vital I can't be arsed. ).

The rocker geometry? Dunno for sure but the old Hi-Cams worked their rockers hard enough to snap them if used hard. Ratio is different with the Nuovo Hi-Cam but even so the spring pressure and valve train weight in the old engine was much higher but their tappets didn't fail. Cams weren't as odd though.

Pete

[molly]

You wouldn't have thought that such small amounts of metallic particles in the oil would do so much damage considering he build  up you often see on magnetic sump bolts.
Did the bearing  failures relate to bikes with DLC coatings? I ask this this because DLC particles are considered highly abrasive when mixed with engine oil.

[guzzisteve]

"Where are you working now Steve?"  Just 1 day a week, got a real good apprentice working w/me. He's been to the school to familiarize w/product.       
http://www.mariettasportscar.com/sportscar-dealer-marietta/     

[lucian]

It seems apparent that most of the cams involved with early tappet failure show mild heat tingeing on the noses but no significant scoring . That gives me hope that the same will be the case with the crank journals as perhaps any particulate wear will be on the softer shell if caught early. Again it seems wise to inspect  preemptively to try and  prevent more significant damage. I look forward to giving mine a thorough douching and looksee. It's odd that the griso pdf manual shows an oil thermostat in the sump. whats up with that? I did just check my valve gaps after 1200 miles since rollerizing and they remain spot on. However I also found the front half of both valve covers lined with mayo. It had disappeared all summer but is now back with the cool temps.  I have reinstalled the o.c. baffle and although the oil temp comes up quickly, it takes a prolonged thrashing to get the valve covers hot. As soon as I get all the required gaskets ect. I will be taking a look. Is it possible to check the rods for oval wear without pulling them out from the top?   dave   

[Aaron D.]

 

Oh now that's just mean!

Funny, though!

[Wayne Orwig]

I thought I read somewhere/someone, suggesting using a different valve clearance after converting to rollers. But now I can't find that info.
 
Also, Pete, I plan to pull a rob cap to inspect the bearings. Have you noticed more damage to the front, versus the rear, on the damaged ones? If so I will just pull that one.

Thanks.
 

[Vasco DG]

Roller engine clearances are 4 & 6 cold and they open up appreciably when hot! Go figure!

Rear rod bearings have been worse on the ones I've seen let go. Note the crank is colour coded so if you do decide to fling in a new set of shells make sure you get the right ones! The differences are only fractions of thou but best to be *Right*. I'd also strongly recommend replacing the bolts, they are torqued to something outrageous and I never re-use rod bolts on principle.

Pete

[Muzz]

One thing that I was considering is that the beginning of the failures I've seen in the last year coincided with my chosen oil supplier ceasing production of the lubricant I'd used for the entirety of the 8V motor's life. Having said that I remain deeply sceptical about that factor having any relevance or validity.

Pete

Pete, are you talking about the firm starting with "P" who used to make a 10W/60 specifically for motorcycles but have since altered the weight?

I have a pack of Sin 10 waiting in the wings; I was actually going to pm you to ask what you have changed to.

[Vasco DG]

When they stopped making the 10/70 I started seeing failures. Is it connected? I doubt it but it is a strange coincidence innit?

I now use 10 Tenths premium 10, the replacement 10/60.

Pete

[Muzz]

When they stopped making the 10/70 I started seeing failures. Is it connected? I doubt it but it is a strange coincidence innit?

I now use 10 Tenths premium 10, the replacement 10/60.

Pete

Thanks Pete.  I have a few miles to go of course with a 5lit pack in stock and only requiring 1.8lits for a fill. The one you mention is the one that their site suggests.  I guess that the lighter weight would still be fine with our overall lower temps over here compared with Oz.

[Wayne Orwig]

Well, I was finally able to spend some time in the garage. I finished up the right side , then pulled the left side, after spending a lot of time collapsing the cam tensioner with care.
The left had not been showing any measurable signs of wear. But the exhaust follower is toast.......

I have a mediocre photo that I added.

So what the heck is going on with the exhaust side. I believe Pete also mentioned that the exhaust was more likely to fail. Yet it is a smaller valve.
Odd.

[Vasco DG]

My guess would be more heat. Welcome to my world....



Pete

[lucky phil]

Well, I was finally able to spend some time in the garage. I finished up the right side , then pulled the left side, after spending a lot of time collapsing the cam tensioner with care.
The left had not been showing any measurable signs of wear. But the exhaust follower is toast.......

I have a mediocre photo that I added.

So what the heck is going on with the exhaust side. I believe Pete also mentioned that the exhaust was more likely to fail. Yet it is a smaller valve.
Odd.

Remember although the exhaust valve is smaller and lighter it also has to open the valve against the remanents of comustion pressure BBDC wich could well be 200-300 psi or more.

Ciao

[lucky phil]

When they stopped making the 10/70 I started seeing failures. Is it connected? I doubt it but it is a strange coincidence innit?

I now use 10 Tenths premium 10, the replacement 10/60.

Pete

I know Guzzi recomment 10W-60 weight oil for these engines but in my opinion for what its worth I think a 60 weight oil is a joke.
You cant use the bearing loading argument for it and a 40 weight oil would not only have better flow rate through the exhaust oil cooling passages ( with no appreciable loss in heat carrying ability) and therefore cool the head better but it would also have better characteristics all around.
And before I'm accused of the old "so you think you know more than the designer" argument just remember the "designer" gave you the failing tappets in the first place and the use of DLC coating.
In case you wonder about my scepticism on designers I was considering DLC for the lifters and cams in the Daytona engine I'm building but 30 min reaserch on the internet with professional US based V8 race engine builders cured me of that notion.
You sometimes wonder about these factory guys.   
Mobil 1 0W-40 full group 4 synthetic would be perfect, i would  think

Ciao
 

[Aaron D.]

You may be right, Phil-I hear Honda designed the CG125 with OHV to improve lubrication of the cam as CB125 riders (OHC) didn't change oil or check oil, and the cams wore out.

[Vasco DG]

Remember although the exhaust valve is smaller and lighter it also has to open the valve against the remanents of comustion pressure BBDC wich could well be 200-300 psi or more.

Ciao

Yup, hadn't thought of that.

[molly]

My guess would be more heat. Welcome to my world....



Pete

]]

My local Guzzi dealer as a collection like that too Pete. He has been out of denial for sometime and is rollerising anything with flat tappets that comes his way.
His latest pet theory is the overhang between the cam chain sprocket and the lobes. I tend not to comment when he mentions possible causes it only leads to a little black cloud descending over us.

[lucian]

Pete ,  are you replacing the cams on all or the roller swaps? dave

[Vasco DG]

Roller cam profiles are different to flat tappet profiles due to how the follower actually rides the cam so you can't use flat tappet cams with roller tappets.

Apart from this the tappets themselves are physically very different so when you do the swap you actually replace the entire cambox. The way the camshafts are preloaded to eliminate end float is also different. The only parts of the entire assemblies that is re-used are the rockers and alignment/oil feed dowels.

Pete

[Wayne Orwig]

The way the camshafts are preloaded to eliminate end float is also different.

And I hope the 'cement mixer' rattle goes away with that.

[Vasco DG]

Not wanting to promote another hysterical hissy-fit from the delicate and paranoid but *IN MY EXPERIENCE a healthy engine when rollerised is substantially quieter than an A5 or early A8 with flatties. The AA's seem to have been a lot quieter, as do the later A8's.

On the three machines I've rollerised that subsequently ran their big ends the one thing they had in common was that they remained noisy and that noise, especially on Mark S's bike really sounded like top end rather than bottom end knock. Why? No idea! Perhaps the camchain tunnel allows the noise to *Move* so it appears more evident from the rocker area? Even a stethoscope seemed to indicate top end rather than bottom. It got progressively worse though and eventually we both agreed I had to go in and that's when the story started unfolding. Mine I think was already well on the way before I rollerised it. Ralf's, while quieter was still louder than other *Good* engine's I've converted. His was also the only machine that suffered a sudden catastrophic failure. There is no denying the motor is tough! To keep going with big end damage like this is truly extraordinary!

Generally speaking in the engines I've done that have *Sounded right* from the get go the top end racket of the A5's is all but gone and will be replaced by a very distinctive sound I can only describe as a 'Whickering' which I think is made up of a mixture of the sound of the cam chains whirring and the rollers, errr? 'Rolling'. it's one of those noises you'll recognise as soon as you hear it and know what I'm talking about!

Pete

[Muzz]

Roller cam profiles are different to flat tappet profiles due to how the follower actually rides the cam so you can't use flat tappet cams with roller tappets.

Pete

Years ago (and I mean about thirty) I read a book written by one Woctaw Nawotny.  I was trying to organise a more mellow cam for the AJS 7R that I was shoe horning into my G12 frame. He was the designer of many engines including the Tatra flat10 aircooled diesel and the Jawa twin 500 OHC racer amongst others. He got in to the causes of the OHC gear failures on the early Jawa race motors and the differences in cam profiles between flat tappet and roller set ups.

In the Jawa's case it proved to be the acceleration and in particular the de-acceleration as it came off the cam flank.  There was a brief moment on the way down that the follower left the cam, and over a period of time it caused a failure at the point where contact was remade.  A subtle change to the profile which still left the cam timing the same and the problem went away. Is it the same reason? Insert Chuck's <shrug>.

Never got the cam sorted and someone made me an offer for the two motors I had that I could not refuse. Every now and then I wish I still had them.

[lucian]

Pete ,  are you replacing the cams on all or the roller swaps? dave

Sorry Pete,  I was mistakenly thinking it was the cams I reused on mine but it was only the rockers. Thanks for jogging whats left of my memory. I did recently drop the sump and oil cooler for a thorough cleaning and found nothing remarkable. Also seems no louder than it's always been, it is an a5 and still runs as strong as ever. I opted to skip on dropping the spacer and inspecting the shells after finding the sump and filter remarkably clean. I guess only more miles will determine if I made the right call. I will keep a keen ear tuned for any new knocking. Thanks for all the follow up.   dave

[Wayne Orwig]

So I finally have kit C installed. I am glad I wasn't in a hurry.
I won't go over the part where my homemade valve spring compressor slipped and sent the tiny collets flying across the garage.

Around August, I found the right exhaust valve clearance had opened a good bit. I adjusted it. A couple hundred miles larger, it had changed a lot again. Per instruction from the mechanic at the shop, I pulled the cam. Not too hard to do, and found the tappet coating gone.
That mechanic quit. But I have his emails. Email is a good thing.

I find that I need "Kit C". The new mechanic couldn't get the kit, because there was a secret open campaign on my bike. There is a center stand upgrade that I was never told about. He orders that, and a few weeks later, that comes in.
Once that was in, we still couldn't get the kit because there was a double secret campaign on my bike. An ECU condom had to be install. Later, that comes in.
Two months has passed, and I had to have surgery, so I am out of commission for weeks.
Once I get back on my feet, I start talking to them again about getting the kit. No can do, since I pulled the cam, I broke the triple secret rule that says the owner shall not pull the cam. So I continue to talk to them, letting them know that I WAS simply following the instructions that I had been given by a Piaggio mechanic. And my Stelvio right cylinder, gas tank, etc., is scattered around my garage so it is immobile. I always keep the conversations friendly. I find you get more done when you make friends. And I was asking them for a freebie.
It took some time, which I had plenty of as I was recovering from surgery, but they came through and allowed the order for Kit C.
A couple of weeks later, and it comes in. I then install the parts per Vasco's awesome instructs. (thanks Pete, very helpful)

So it is now alive and pretty well. I'm still waiting on back ordered rod bolts, to inspect the bearings for contamination. Hopefully that isn't an issue.

I DO appreciate Piaggio coming through with parts for a 6 years old, 50,000 mile bike. I know for a fact that Honda will tell you to pound sand on a 3 year old bike with just 6,000 miles on it when the cam fails. The grass is not greener on the other side.
Why does Piaggio make it such a time consumer for their dealers. The new mechanic really struggled to learn the goofy system, and the hidden secret campaigns that prevented the order from being entered. If it is a required campaign, then make it required and tell me about it. If it is just some optional campaign, then don't make it required. Geez.
I DO appreciate the help the new mechanic give me. His name is Dean Graham and he has been around airhead beemers for years. Hopefully he stays around Guzzidom and doesn't run away from Piaggio, but I wouldn't blame him if he did.
And I can't overlook Anthony at Riders Hill. He wasn't directly involved, but every time I stopped at Riders Hill, he was concerned that I was getting the parts. I'll miss those guys.

If you install the kit, it will make a LOT of noise when hot if you use clearances for the exhaust valves that are a bit over .006".
If you have kit C, clean all of the goo out of the stepper motor circuit while you are in there.

And a word of warning, if you are doing it yourself, get approval in writing from the regional rep. If you don't, don't expect to get the parts.

[Chuck in Indiana]

So, how are you getting along, Wayne?