UFO in oil pan 8v92

[robertglines1]

1/2 of what appears to be a retaining ring.. is about 1/16 thick round ..turned up on end about 30 degree angle 1/4 inch long on turn up..appears to be about 1inch in diameter.no sign of wear on piece..I have pan off now what should I look for..

[luvrbus]

Robert, on each side of the block inside the oil pan you have 2 valves at the front of the engine held in place by 2 bolts both of those have snap rings but my guess would be it came from when someone installed a compressor,alternator,power steering pump or some other device on the rear of the engine.

They have other snap rings and when they break it affects the engine performance you should see some of the parts I found in oil pans on 8v92's left over from previous repairs


good luck

[robertglines1]

Thanks will look at it tomorrow..that makes sense and is about the rite od..

[JohnEd]

I think(operative word) that anything like a retaining ring being broken would have some problems associated with it.  If your oil analysis doesn't show anything bad I would assume it is a left over part....as others have said.  I really don't think you have much choice as tearing an engine down "looking" for something just wouldn't compute....unless the analysis said "lots of cast iron in the oil".

I am trying to be supportive here, believe it or not.

John

[robertglines1]

Mystery solved.... retainer was for cam follower spring ...spring came out in 3 pieces..push rod is mushroomed...spring clip missing.looks like a fresh problem and bottom of inside cam follower shows no damage..will replace rod ,spring,and clips..will this do it?

[bevans6]

I'm not a detroit expert so treating this like any other engine.  I think that I would be inspecting the roller cam follower for damage, and from the condition of the roller making a determination as to whether the cam lobe has an issue.  I'd also look for what started the problem, did a valve or injector hang up, that sort of thing.  The manual implies that you can get the cam follower out from the top, and if you can you could maybe inspect the cam lobe visually.

Was it a valve or an injector?  two valve or four valve head?  is the pushrod straight or does it have a detectable bend in it?

Brian

[luvrbus]

Robert,was it on the injector or valves the pushrods have a mushroom end that is the keeper that will effect the performance of the engine was it missing.
If it was my 8v92 I would pull the head and replace the follower and check the cam if you can remove it from the top something else is broke they have a keeper on the bottom side of the head with 2 bolts holding the followers in place.  
If it was exhaust check your stands and bridges



good luck

[robertglines1]

according to my book it is exhaust valve (not the spring on the valve) the broken spring is called a push rod spring. this assembly drives the exhaust valve. the bridge was still in proper position and was actually holding the exhaust valve partially open as per cam position.

[JohnEd]

Would this mech failure have been detected by an oil analysis?  I understand the concept of developing a "history" with oil analysis over time but I would think that some failures might be detectable during the failure without history.

Thanks,

John

[robertglines1]

I am sure a oil test could have told us what kind of metal was involved.From there we could know where to start looking..I'm in no hurry for we don"t have trip planned til January...so will pull the head and examine it..still curious what caused the problem ,valves it operates appear to be functioning correctly..engine performance did not change..no noticeable noise...just glad I caught it before the big bang!!

[luvrbus]

Robert, if you pull the head you are going to need a set of head guides if you do not have a set here is a place to buy a set for 31 bucks www.monacotools.com or 541-689-8579 they are in Eugene Or no sales tax 


good luck

[bevans6]

All that spring does is keep the roller cam follower in contact with the cam when the valves (or injector) are closed, so that the roller keeps rolling and isn't subject to acceleration.  When it broke, there would be no change in performance to speak of, the valve would still go up and down the same, but there would be a potential wear issue with the roller and the cam lobe.  I would expect that if the parts just broke, as parts sometimes do for reasons known only to themselves, then there would be no metal particulate dispersed within the oil to be found in an analysis.

Modern cars with roller followers use hydraulic pressure to achieve the same effect.  Bearings like that love to turn, they hate being stopped and started.  obviously a 92 series head might be different, but my 71 series manual swears you can re and re the follower with the head on.  Just an option, but for me, if I take the head off then I would need to do a valve job, then I would need to get into taking the other head off, do that valve job, then I'd be doing injectors, and changing all the springs and putting in all new retainers and six months later I'd still be taking it apart, not putting it back together!    I had an idea that if one could get the follower out one could go and get one of those new fiber optic scopy things and have a good look at the cam lobe.  Throw in a new follower, spring, retainer etc, and Bob's your uncle...   Just a thought!

[bevans6]

URL was wrong, it's www.monacotool.com  No "S"...  I'm having a nice browse through the web site!

Brian

[luvrbus]

thanks Brian I never get the links right 



good luck

[robertglines1]

nice tool page am checking it out. I'm going to check the cam lift on that lode..and then its decision time. the inside of the follower looks clean no nicks or scrapes.Maybe I caught it right after it happened..never noticed any change in performance.