Head Gasket woes

[wirespokes]

This 'new' G5 has been a true test of my patience. I've worked through most of the issues and have been close to the finish line a few times. Without going into the long version, the main culprit appears to be the left side head gasket.

I got the bike mid June and have been working on it ever since. It was a rolling basket case with many missing parts when the PO got it. He installed new gilardonis, but the bike would stall when warm. I'm guessing he got frustrated trying to get it running right and parked it. Five years later he sold it to me.

I thought it was a tuning issue, at least that's the place to start - valve lash, timing, etc. It would pop and spit at low throttle opening, but run well otherwise. It dawned on me that I should check head torque. I loosened the nuts 1/4 turn and it took 1/2 turn to get them up to torque.

Wa La! No more popping spitting at low throttle opening.

Gradually it started spitting again and, as before, I'd think "it needs larger pilot jets...". And then I got smart and figured I'd revisit the head torque. Sure enough, that fixed it. It had been five or six hundred miles.

So I rode to a friend's house 10 miles away yesterday and it ran perfect. He rode it around the block and it ran fine. Then an hour later I rode home. it spit back two or three times on the ride home.

The left side idle adjustment has been a bit odd, so I'm thinking there's something wrong with the head gasket on that side. My thoughts are that it's been run too many miles needing retorqued and the gasket is damaged or, hopefully not, there's some erosion to the head or cylinder.

Have you ever run into anything like this?

[cliffrod]

I think I understand. 

As a new Guzzi owner decades ago with little guidance beyond the factory and haynes manual, I had similar head gasket problems on my V7 Sport after rebuilding it from a basket case. After a couple of failures (first, no or only one retorque and then 2-3 retorques) I finally decided to do the drill at least 5-6 times.  Torque to spec, run engine (not riding) until fully hot, let it cool, retorque. After 6 cycles, there was no additional gain when retorquing.   I never had a head gasket failure after that. 

A few years later, when the entire engine needed a rebuild from unaddressed chrome bore debris issues, I reassembled it and did the same thing.   No head gasket failure.

I understand doing this is excessive in comparison to what service manuals recommend, but it works for me. 

[blackcat]

Is there any evidence of oil leakage from that cylinder?  Even if there isn't, I'd buy a new gasket just so you can take it off the list of possible problems. I usually torque the heads with new gaskets after three heat cycles. Also, have the valve clearances been very tight on that cylinder?

[wirespokes]

You know, I've NEVER had to retorque a head gasket. I've taken airheads apart and put them back together with the original head gaskets (no retorquing) with never a problem. Not complaining - this is just new to me.

What sort of poor running problems have you had when they need retorquing? With this one it acts like it's running very lean at low throttle opening. I'm wondering if a gasket is compromised into the pushrod channel - it's not weeping at all that I've noticed.

I retorqued the left side this morning but it didn't seem to need it. Valve clearance was fine and the head nuts seemed to go back to the same position. Maybe the problem is on the other side... ?? Maybe your right blackcat - just replace them both to be sure.

Another thing is there's a lot of adjuster above the valve lash lock nut. Like the same distance as the thickness of the nut. And, while I'm on that subject, are the rocker jam nuts high strength or low grade? Mine are pretty beat up and certainly don't feel hardened. I know of other rocker jam nuts that are hardened.

cliffrod - was there any damage to the heads or jugs in your case with failing head gaskets?

[Tony F]

I encountered this issue  with head gaskets on my SP1000 about 30 years ago. The gasket would compress and close up the valve clearances so it wouldn't idle. It would take 3 or 4 tightening cycles to bed them down. But no trouble with later gaskets a few years after that. It seemed like there was a bad/soft batch of gaskets in circulation. A friend of mine went through it all as well at about the same time.

[cliffrod]

You know, I've NEVER had to retorque a head gasket. I've taken airheads apart and put them back together with the original head gaskets (no retorquing) with never a problem. Not complaining - this is just new to me.

What sort of poor running problems have you had when they need retorquing? With this one it acts like it's running very lean at low throttle opening. I'm wondering if a gasket is compromised into the pushrod channel - it's not weeping at all that I've noticed.

I retorqued the left side this morning but it didn't seem to need it. Valve clearance was fine and the head nuts seemed to go back to the same position. Maybe the problem is on the other side... ?? Maybe your right blackcat - just replace them both to be sure.

Another thing is there's a lot of adjuster above the valve lash lock nut. Like the same distance as the thickness of the nut. And, while I'm on that subject, are the rocker jam nuts high strength or low grade? Mine are pretty beat up and certainly don't feel hardened. I know of other rocker jam nuts that are hardened.

cliffrod - was there any damage to the heads or jugs in your case with failing head gaskets?

No damage, just a puffing head gasket.  It almost feels like it’s only firing on one cylinder but you can hold your hand to the cylinder-head joint and feel the puff.  Never had any problems since then.

 I had replaced cylinders with Moto Guzzi nikasul cylinder kits (pre-gilardoni years…). The gasket failures were pretty obvious so engine wasn’t significantly stressed once the gaskets failed.  I chalked it up to my lack of experience with Guzzi stuff.    The bike was a mess when I got it and I was trying to figure it out as I went,

No joke- I decided I would buy a case of beer (that was the most common solution back then) and drink 3-4 beers between every retorque cycle to help from getting impatient.  It worked just fine.

I’ve also had base gasket failures on my shovelhead.  When I got it I was warned if I didn’t let it warm up adequately in VT during very cold weather that the base gaskets would be prone to fail.  Think I had two failures, although the second failure was probably related to inadequate torquing during replacement.  Same deal- all of a sudden you’re riding a single thats huffing a lot like an old tractor with the petcock open.

Imho, your valve adjusters should normally be roughly even.  If one is noticeably different than the others, maybe it’s just me being anal but I would figure out why. Usually when one of my machines has one thing that much different than the other parts of the same system, it’s because i did something wrong or missed something that needs address.

[wirespokes]

I've been setting the valves to Roper's recommendation of 5 and 7. It's possible I should set them at factory spec until the gaskets stabilize.

Maybe there's something else going on because it idles just fine, doesn't pop or cackle on decel, but does spit and pop arbitrarily now and then at steady almost-closed throttle openings. And sometimes I'll open the throttle from almost closed and it'll bog. Opening more doesn't increase RPMs, but shifting down takes care of it.

It's funny because it seemed like all that went away and it ran perfect right after retorquing. As has already been suggested - replacing the gaskets might be the solution, or at least would drop that out of the equation.

[Dukedesmo]

Quote from: wirespokes on Today at 02:28:44 AM

You know, I've NEVER had to retorque a head gasket.

___________________ ___________________

Whilst I've only rebuilt 1 Guzzi engine - my LM2, I torqued the head bolts at the time (9 years ago) and haven't touched them since, not had any issues.

I have also built many other engines (bikes, cars, lawnmowers, outboards etc.) and never re-torqued anything

Do they really need re-torquing?

[Tom H]

Generally yes they do at least on a Guzzi. Some if not all newer automotive head gaskets do not need to be re torqued.

Tom

[John Croucher]

Maybe the head has been torqued so many times the studs are pulling out of the block. Threads are stripping out.

[moto-uno]

  ^^^ I guess we'll see  . Maybe there's been some tech update to the gaskets you've used , BUT , in the past re-torquing was a given and a necessity . AND, you
know it's not that big a deal to perform it .   

[wirespokes]

Agreed - it's actually pretty simple and quick to retorque.

And, no, the threads aren't pulling out. I know what that's like - it's one of the problems airheads have. I've got the tools to repair them.

I haven't heard of guzzi head studs pulling loose - is that a pretty uncommon problem?

[chuck peterson]

Head gasket from the wrong model?

Pushrod from the wrong model combined with the above…

You know Ive heard of a pushrod rubbing thru the wrong gasket to create a hole in the wrong place…something from back in the T T3 Vert G5 universe

[Pescatore]

Recently I had to replace the head gaskets of a small block because of a small oil weep.  Torqueing helped, but not enough.
I found corrosion and pitting on the head, so I took it to a shop.
The shop also found the head had a slight warp.  They resurfaced the head with a fly cutter.
I've taken only one ride so far and no oil weep.
I plan to retorque once I get a chance.
Guzziology recommends using Permatex 300 so I applied that as well.  Fingers crossed.

Someone mentioned the studs. Could they be stretching?

[wirespokes]

I think the Previous Owner used this bike as a learning project. So anything's possible. The cylinders were replaced, so who knows? If I wind up replacing head gaskets, I'll certainly take a very close look at everything else.

Permatex 300 on head gaskets... good info! Thanks. I've got two copies of Guzziology and will probably read that very section, but then again - might never see that reference. So thanks!

[Pescatore]

.......   but then again - might never see that reference. So thanks!

I'm not near the book for another couple weeks.
It should be easy to find in the engine section. He mentions it a few times.

[Dukedesmo]

To revive an old thread.


Whilst servicing the LM2 I decided (after having re-read this thread) to check the torque of my head bolts - I partially rebuilt the engine after a piston to valve encounter (new; Gilardoni 88mm cylinders/pistons, exhaust valves, bearing shells) 10 years ago and, obviously fitted new head and base gaskets at the time.


I can report that all head nuts/bolts were all spot-on torqued to spec with no re-tightening required, this is 10 years and 7,000 miles post fitting.


Maybe the newer supplied gaskets are of a more modern construction and didn't require any 'seating'? Valve clearances were all also still good, last checked 3,000 miles back.


So all good to go for the summer.