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32v chain derailment

 
Old 07-22-2017, 07:05 PM
  #1  
Landseer
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Default 32v chain derailment

Not pretty
My.takeaway:
Dont neglect clicking sounds.
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Old 07-22-2017, 07:37 PM
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skpyle
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Sheet...

Since I am still a bit of a newbie to 32V engines, was there resulting damage from valve to piston contact?
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Old 07-22-2017, 07:56 PM
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928NOOBIE
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OMG...

So..I have 130k and have tried to read this forum with some regularity and haven't really came across much in the way of cam chain info/maint. for 1st gen 32V...?
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Old 07-22-2017, 08:45 PM
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Ed Scherer
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I'm seeing some sheared off teeth on the cam gear and a trashed head (chain isn't looking too good, either. ). Yikes.

Sorry to see this. Hope the rest of the damage (valves, etc.) is minimal.

Was anything in there recently serviced? I remember being paranoid about the tensioner screws (that fasten the tensioner to the head) backing out when I did mine, but never thought about the whole damn thing breaking off like that.
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Old 07-22-2017, 09:27 PM
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Adk46
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Sorry you're facing this trouble. Interesting, though. Is it clear that the primary failure was the tensioner going wonky? What do we expect to see if the chain breaks first? (What do the broken ends of the chain look like?)

Wait - am I seeing a fracture surface intersecting two bolt holes for the tensioner?
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Old 07-22-2017, 09:39 PM
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Ouch!

That looks exactly like the failures I've seen on the 4 valve 944 engines...."snatched" the tensioner right off the cyliner head. This is the first failure, like his, that I've seen on the 928.

Because you have heads with the early valve cover hardware, I'm also assuming that you still had the original early tensioners and not the S4 tensioners fitted to the later 1986 models? I never leave the early tensioners in (nor the early valve cover hardware), when rebuilding, but always update to the S4 style tensioners.....much better design.
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Old 07-22-2017, 10:01 PM
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Sorry to see that man. Sucks.

Here's a funny to help you smile.
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Old 07-22-2017, 10:09 PM
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ouch wonder why this happened?
how many miles?
how old is the oil ?
what was the last thing you fixed?
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Old 07-22-2017, 11:09 PM
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Recycle everything other than valves and springs and start over?
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Old 07-23-2017, 12:14 AM
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That sucks Chris!

Any clue which bit of the tensioner failed? Are both the nylon pads still intact on the tensioner?

I've got a few tension-side plastic pads from S4's with varying degrees of wear - one with around 1.6mm deep grooves and little chunks missing at one end, which I figure isn't a big step to "falling apart and having a flapping chain".
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Old 07-23-2017, 02:37 AM
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I wish you happy salvaging.

I notice the surface of the shoe looks pretty rough. Might be a sign that the plastic was starting to get crumbly and prone to breaking.
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Old 07-23-2017, 06:50 AM
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Indeed very sad. Let's hope the heads are salvageable and not too many bent valves.

Best wishes for a swift and not too painful recovery.
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Old 07-23-2017, 10:37 AM
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I was lucky enough to investigate the 'ticking sound' on my '90 944cabriolet when it started (maybe 10 year ago) I found the guides on mine were near worn through and bits /pieces falling off into the motor. Mine did not detonate. Very sorry this happened and best of luck.

Sean, I do believe that is how a person would look!
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Old 07-23-2017, 01:09 PM
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The engine is from the 85 USA platinum metallic car that I've had since '08.
Mileage was low, just over 100K.

It had sat for 10 years, Stan Shaw rescued it from the original owner and just transferred it to me to get running.

I struggled with that, biggest issue was running warm and stumbling at throttle --- turned out to be running lean due to partially clogged injectors. I worked it pretty hard before I sorted out the reason. So, the engine got some unusual use in that respect.

Ran great for several years, did a number of long distance runs from Indiana to Virginia and back.

On a trip, it starting ticking out of the blue. We drove it home, did an oil change to a 15W50, seemed to quiet it down, then continued to commute in it locally for several months. One day I followed the neighbor to work, 996T, and pushed it.

At lunch, one turn of key, engine started then made wierd noise and I think I heard the valves tink tink tink as it stopped. Turned key another time, half the engine tried to start.... bad noises.

The body on this car was rough, so I have slowly parted the body.
Yesterday I removed the engine and finally opened up the covers to reveal what I expected. Thought you all would want to see it.


Truly I am remorseful for not addressing the ticking. Embarassing and wasteful.

Last edited by Landseer; 07-23-2017 at 07:06 PM.
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Old 07-23-2017, 02:03 PM
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Do you think it was a broken guide on the non-tensioned side that caused it? Looks like the plastic on the tensioned side is intact.
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