Hydraulic Lifter Issues - Cam Failures

[al_roethlisberger]

Not "news" for many, but from the MGNOC list, just an FYI:

 

 

 

Some of the new hydraulic motors have been lunching cams in under 3,000

miles. Others have been running fine for many more than that. I've done

a little inside digging on the issue, and found it an interesting tale.

My sources strictly insisted on anonymity (you have probably all heard

their names, though). You can choose for yourself whether that reduces

the credibility of the information.

 

Here's what I believe MGNA will be admitting in the coming months and

here's what I'd do if I owned one of these to minimize damage until

they admit what's really wrong:

 

1) It appears that the real problem is with  low oil pressure on some

machines, not hardening of the cam. My sources said the P.I. engines

run less than half the oil pressure internally, and that the

oil-pressure takeoff on the block gives an artificially high reading at

that location. Some run even less, especialy when very hot and idling

in traffic-stopped situations.

 

2) Because the real problem is low oil pressure, the cam problem is

just a symptom of further damage that could ensue if you don't on your

own, right now, address the oil-pressure problem. That means big end

bearings, which typically are the first thing to suffer from low oil

pressure on the Guzzi engine.

 

3) Because the real problem is low oil pressure, you should strongly

consider ignoring the factory mandate that you use ONLY 5w-40 oil,

since that exacerbates the low-pressure situation. Use a good synthetic

20w-50. If you're worried about warranty, just do it, and don't tell

the dealer.

 

4) Keep the revs up at idle when the engine is hot. This will give a

substantial rise in pressure while you''re sitting at a stoplight. Or

you could just raise your idle speed from 1100 rpm to 1500-1800. That

won't hurt anything.

 

5) Strongly consider the following this procedure on cold-start: Turn

the engine cut-out to  "stop" (ignition off) and crank the starter for

10-15 seconds to build some oil pressure before turning the cut-out to

"run."

 

6) Be as patient as you can while Guzzi sorts this out, which I believe

it will. Likely, it will mean the retrofit of a higher-capacity oil

pump. Beggio recently (November) fired nearly the entire group of

powerplant engineers who were responsible for this and other recent

engine and tranny gaffes. I was told he gathered them all in one room

and told them, "Congratulations gentlemen, int 18 months you have

accomplished what I never though possible: You have ruined the

excellent reputation of the Guzzi engine. You're all fired."

 

I also still believe that part of the problem is that neither the cam

nor lifter is hard-chromed. Apparently, the factory has not even

considered this yet.

 

When I learn more, I'll share it.

 

Greg Field

 

 

 

As an aside, it's too bad that MG tried to "fix something that wasn't broke" with the "self adjusting" hydraulic lifters on these motors, only to create a new reliability/durability issue I'm sure part, if not all, of the reason for going with the new lifters was EPA noise regulatory related, however

 

I feel for the owners of these bikes...

 

al

[Lex]

Beggio recently (November) fired nearly the entire group of

powerplant engineers who were responsible for this and other recent

engine and tranny gaffes. I was told he gathered them all in one room

and told them, "Congratulations gentlemen, in 18 months you have

accomplished what I never though possible: You have ruined the

excellent reputation of the Guzzi engine. You're all fired."

 

If this is true I'm liking this guy Beggio more and more. I hate to see anybody lose their jobs but these guys (and gals, if appropriate) surely deserved what they got.

 

Lex

[Kiwi Dave]

5) Strongly consider the following this procedure on cold-start: Turn

the engine cut-out to  "stop" (ignition off) and crank the starter for

10-15 seconds to build some oil pressure before turning the cut-out to

"run."

 

I've got one of these engines, but despite this I had to double check be I responded!

 

How do you manage to crank the starter with the cut-out switched to stop? None of my Guzzis past or present have managed to achieve this. I've got a lot of respect for Greg Field, but surely he would try out his tip before committing it to print?

[Guest Fonzarelli]

There are a few issues here that do not make sense:

 

1) Low oil pressure. A camshaft is lubricated by flying oil in the crankcase. When the engine is operational, it is absolute chaos in the crankcase. Oil spray and mist is everywhere. Even at idle a cam will see some lubrication.

 

2) Yes, main bearings and rod bearings would be the" first to go" with inadequate oil pressure. Not necessarily the camshaft.

 

3) Don't confuse oil pressure with oil flow. Sure, run a higher viscosity oil to raise the pressure, but that can bite as the oil flow would be reduced.

 

4) It would be interesting to know if the oil pressure indicator illuminates at idle.

 

5) People do not realize that an engine actually runs for several seconds or longer before oil FLOWS through the engine. You will initiate your oil flow by starting the engine better than running the starter.

 

It will be interesting to see what the problem really is.

[Guest Fonzarelli]

I posted this earlier on the WildGuzzi forum regarding the same subject.

 

It has not been rare to have camshafts supplied by vendors that are not properly heat treated.

 

Moto Guzzi, I would be willing to bet, does not grind their own camshafts, let alone cast their own cam cores. Camshaft cores are case hardened several thou to provide a hard durable surface for the lifter to ride. This is done after the camshaft is ground to spec.

 

If the case hardened surface is not of a proper depth or incorrectly processed (this has happened in the past to many manufactures), cam failure will result.

 

If the lifter in a hydraulic cam engine has that type of serious clearance issue, you will hear plenty of noise. If the lifters are collapsing due to excessive bleed off, the engine will not RPM.

 

I would even check into the lifter itself. The lifter has a crown of approximately .0005" ground into the foot of the lifter to force the lifter into rotation. This insures that the very high loading of the lifter foot is evenly spread over the radius of the lifter foot.

 

Here's another potential problem area: Valve Springs. Has Moto Guzzi gone to a different spring rate (softer) for the hydraulic motors? To stiff of a valve spring can also prematurely wear a cam.

 

I hope for everyones sake involved this issue is resolved. But to say a spacer in the lifter is going to correct the problem, I would not hold my breath.

[al_roethlisberger]

...ahh, but keep in mind we are not talking about the cam itself in regard to lubrication, but oil-pressure pumping up the new hydraulic lifters.

 

It appears that the new hydraulic lifters, once collapsed, take a moment to "pump up", and until then the lifter smacks against the lobe face causing damage. Without sufficient oil-pressure, this damage is cumulative.

 

More on the issue:

 

http://www.wildguzzi.com/forum/viewtopic.php?t=4046

 

al