mpatton

Hey everyone. Recently I put 243 heads, valve springs, pushrods, ls7 lifters, cam and asp under drive pulley on my 01 ss. Car ran great and sounded great, not even a hiccup for a few days. Went to my buddys to have it tuned we did some part throttle and what not and went sd on the tune. Everything was good. Then we do 2 wot pulls and think I have a major exhaust leak. Turns out its coming from.the top end.

I started home was gunna pull the valve cover and all the sudden the car died all the lights stayed on and the car still cranks. I took.it to a mechanic because i didn't feel.like messing with it. He says no.burnt wires good fuel pressure etc. He thinks the timing chain broke. It is the one thing I didn't swap while.I was inthere. Does this sound right?? Never had it hppen so.I don't know the symptoms. Thanks.

crainholio

iTrader: (2)

Easy to diagnose a broken timing chain, just pull a valve cover and watch the rockers while **slowly** turning the crank. No rocker movement = timing chain/gear failure.

Need more info on the assembly:

Did you use Loctite on the timing gear bolts?

What torque value did you tighten the bolts to?

mpatton

Yes I did, and I dont remember I used ls1howto.com for a guide.

BlackScreaminMachine

iTrader: (17)

Well stuff can happen but like said if the rockers dont move, then your screwed, Most likely all the valves hit and it sucks.

mpatton

One other thing, the cam isn't that big by any means but could it have bent a valve or two when it broke.
Specs are: .225 .223 dur .571. 564 lift 114 lobe sep.

mpatton

That would suck. Bad... I guess that would be time to upgrade valves also huh.

BlackScreaminMachine

iTrader: (17)

Look up what a interference motor is. That is what we have, the cyl heads cannot suck the valves in so as soon as the chain breaks or comes loose, its not spinning the car which acutates the rockers and down the the valves but the pistons are still flying.

I have gotten lucky on my old 2000 Hyundai Accent, i bent the valves and a quick swap and cyl head checked I was able to save it and it still runs today. It was due to skipping a tooth on the best and then it nicked up the valve. In our motor, its just going to smash ****.

Had a guy I know with a similar issue. Long story short running TFS heads and cam on a stock timing chain/oil pump and it broke and basically from what I heard, heads are trashed and holes in the pistons, not sure if the block is cracked but basically took a good motor and trashed it. He is an idiot for doing what he did and not changing the parts over but thats a learning exp. Problem is he thinks he knows it all. Well I can show you one car that is not running and is broken to say otherwise....

Take the heads off and look. Get it over with.

ls1 1990 VN

I broke a dual Rollmaster road racing, 6k in 4th & the engine died. It would turn over & not fire. 4 bent valves, 4 of my Mahle pistons took a good hit but are ok, engines repaired & running well.
If you have standed pistons they would not fair as well, possibly lucky you were not revving it.

mpatton

Thanks for the info guys will look and see how much damage was really done and post the results. Thanks

Eagle02

iTrader: (20)

Any update? I think the same thing happened to my car this past Sunday... going to start taking it back apart tonight, likely won't get the heads off until the weekend.

Mine is a turbo car... I was in first and beating it too.