save_the_t/a

I have a stock 1997 trans am lt1, 6 speed, 150k miles. I was sitting at a red light idling and I heard a "clunk" then it shut off. I tried to restart but it only spins over and i only got a few exhaust pops. Pushed it into a parking lot and tested the fuel pump. It has 52lbs of pressure and she is getting spark. Possibly skipped time? I did get on it kind of hard the day before and heard a faint squeaking noise near the water pump on and off the rest of the day. If it skipped time would much damage be done to the valves/pistons being that I was at idle when it shut off/broke? The guy at the shop said there is a tooth missing on the timing sprocket, but the chain is on and timing is lined up correctly. He pulled the plugs and one was "smashed" and says it looks as though it may have dropped a valve and is suggesting engine replacement?!?!?!?!? I looked at the plug and saw that the gap was just pushed closed and a tiny part of the ceramic was missing. I call BS, even if this is true the car should still at least fire up right? and wouldnt i have heard alot more than a single clunk when it died? When one skips timing does it do any damage to the plugs? the car ran fine before, no smoke, no oil usage or leaks, no engine noise, but a little engine vibration due to a bad plug wire.

save_the_t/a

heres the "smashed" plug

warriorcustoms

iTrader: (10)

The only way to tell is to start pullin stuff apart!!! IF its a high milage motor get a rebuild kit from Northern Auto Parts. Cheap price & good parts Ive got a set of LT4 rods & pistons from a 60k motor, Id let go cheap!! PM me if ya need pics, Im buildin a 396 so I dont need em! Ive seen worse on the plugs

93M6Formula

!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!???????????????? ?????????????????????????????????????????????????? ???????!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!


But seriously, I'm thinking your Opti had a catastrophic failure. I'd bet on that failing more than the timing chain. You don't hear of those breaking all that often but it can happen.

Pull off the Opti and inspect the insides. If that checks out i'd pull the timing cover.

save_the_t/a

he said it was getting spark. im new to the opti, what is there to look for to tell if its bad?

lt1-xjs

I'd invest in some new plugs first and give it a try.

SS RRR

iTrader: (2)

You are at the shop's mercy if your car is there. I call complete horse **** on everything they've told you thus far, but arguing with them is going to get you nowhere especially if you do not fully understand what you are saying and you cannot prove anything. No one here is going to make your experience with this shop any more pleasant. Only thing I would suggest is telling them to stop all work, pay for what you owe, bring it home and delve into it yourself. Whatever way you chose it will not be easy. Good luck.

quik95lt1

iTrader: (7)

only thing that smashes a plug like that is debris flying around in the cylinder........chances are they're right.....something broke off and smashed that plug in....if it broke a piston it'd still fire but clack away.....if its popping and not starting its possible the chain broke it smashed some valves from the timing being off and ate one of the valves or at least the head of it.....one way or another its coming apart....

bufmatmuslepants

iTrader: (3)

You need to get it home and pull the valvecovers, put a bar on the crank and slowly have someone turn the crank while you watch the valves.

TwoFast4Lv

iTrader: (8)

If it dropped a valve pulling the valve covers will tell you for sure

bufmatmuslepants

iTrader: (3)

And if you rotate the crank an no rockers move your chain is broke

RamAir95TA

iTrader: (2)

If the timing chain broke, cranking the engine should sound COMPLETELY different - the starter isn't fighting compression so it should sound like it is spinning very easy.

guppymech

iTrader: (7)

I don't know if I would crank the engine with a broken timing chain. If a valve is at max lift the piston will probably hit it.

bufmatmuslepants

iTrader: (3)

I would not crank it anymore with the starter there is definitely something broke or bent in a cylinder, steel valves, aluminum heads and pistons, in an interference engine, your gonna have to get it home and pull the heads honestly

save_the_t/a

I did just that! I pulled the valve covers, spent an hour inspecting each and every valve, spring, retainer, rocker, and push rod. Everything is in place as it should be. Optispark assembly is all there. I am going to put the timing chain back on tomorrow and do a compression test on the cylinders.

save_the_t/a

Timing chain was intact but missing a tooth on the crank sprocket. maybe it jumped time? the engine would spin, but not fire up. If it were a dropped valve, it would still start up and run. I am doing a compression test tomorrow, but im almost 100% certain its jumped a tooth or more.

save_the_t/a

better view of that plug.

save_the_t/a

Also, he said when he pulled the timing cover there was alot of small hard plastic pieces he could not identify. any idea what it could have been?

save_the_t/a

bufmatmuslepants

iTrader: (3)

Nothing can crush a spark plug like that except debris in the cylinder, or a bent valve. My advice, as much as you are going to hate it, is to pull the head that that plug came out of. You said a piece of the electrode is missing, I have seen some horrible damage to piston faces, cylinder walls and combustion chambers from electrodes breaking off. At this point the motor may still be salvageable, but attempting to start it again without knowing what is going on in the cylinder could kill it. At the very least I would get a hold of a tiny fiberoptic camera and stick it in the plug hole to see if the valves are both seated properly. Also, get a new stock replacement timing set.