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Catastrophic Loss Of Compression

coupe72001
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coupe72001 Mentor

coupe72001

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I've had it in my head that I wanted to impress all comers at the NDSOC show and shine this year (in 3 days time). I built an sexy looking L28, sprayed my engine bay, and recently had the body sorted an resprayed as well.

Unfortunately, driving home from the painters on the highway tonight the throttle caught on some plastic under the dash and jammed open on full for about 5 seconds. Nothing seemed amiss till I reached my first red light 30kms later and the car stalled. Attempts to restart resulted in a very unhappy noise - the engine turning over, with the utter absence of a compression note.

I have been towed home and will have a look tomorrow. It seems the pistons and the valve train have got a divorce somehow, possibly in the form of a thrice dead harmonic balancer, or a stripped timing chain gear, or... I don't even want to know what.

BUMMER!

If I can't make the show and shine my feelings are definitely going to be hurt. Deeply hurt.

At least my car looks friggen' unreal, maybe Ill just push the damn thing to the show!

Anyway... off to see how quickly I can get, like, seriously drunk.

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coupe72001 Mentor

coupe72001

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It took me months to build that bloody L28 - its coming out over my dead body! Hopefully its something fairly minor and stupid... maybe I got the timing chain to jump half a dozen teeth... err... somehow.

noddle Rising Star

noddle

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Hopefully its something fairly minor and stupid... maybe I got the timing chain to jump half a dozen teeth... err... somehow.

Well then you would have bent valves, and a lot of work on your hands..

sorry to hear that your work on the engine may have been for nothing.

Nigel

coupe72001 Mentor

coupe72001

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I didn't hear smashing crunching valves, the car just stalled and wouldn't start again - really odd seeing I had been booting along the freeway only minutes before. The exhaust is new, but say, just for example, someone shoved a banana up it, would that result in the car not being able to generate enough compression to fire?

The first thing that I'll do when I get home is have a look to see if the timing chain is actually turning the crank and pistons.

Cheers for the offer on the E88 J, Ill let you know.

D

N1GTR Grand Master

N1GTR

Posted
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Anyway... off to see how quickly I can get, like, seriously drunk.

"Son, its no about winning and losing, its about how drunk you get" - Homer Simpson :ninja:

Maybe RB20det in there? Cheap option, and its well documented how much punishment they take :)

coupe72001 Mentor

coupe72001

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Removed head today. The pistons have made contact with the valves, and the timing was miles out, chain must have jumped a few teeth. The valves look pretty good, but there is minor scoring on the pistons. Ill throw on my old E88 head, reset the timing and hope that there aren't any hairline cracks in the pistons.

BensDR30 Experienced

BensDR30

Posted
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Removed head today. The pistons have made contact with the valves, and the timing was miles out, chain must have jumped a few teeth. The valves look pretty good, but there is minor scoring on the pistons. Ill throw on my old E88 head, reset the timing and hope that there aren't any hairline cracks in the pistons.

Standard L-blocks don't jump timing teeth until way beyond the far-side of 8000rpm. Might I suggest that you may have a chain guide or tensioner issue?

Aside from this, a rev-limiter is a wonderful invention...

coupe72001 Mentor

coupe72001

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Actually, when the throttle jammed on I panicked and put the clutch in for a couple of seconds (rather than... you know, just switching off the bloody ignition). My lovely new engine saw w-a-y the wrong side of 8,000 rpm. I suck. Cam timing was miles off.

Who'd have thought I'd ever need a rev-limiter... I'm so careful and all.

Also hang onto those calipers for me Mags, Ill make a time to come get them soon.

D

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