billy25us

This is a ls1 with ls6 heads,intake,and a comp cam. I bought this car used and use it primary as a HPDE car. Third day on track katech chain breaks , I just bought the car so I chaulked it up as age and fatigue. Put a new katech chain in , after rebuilding heads. And again third day on track chain breaks. I have a issue somewhere. I have some play in the cam itself I can push it back and forth 50th of a inch. Does anyone know what the tolarance is? May need a spacer. Also when I spin the cam it will scrub the retainer screw on each rotation. Could the front surface of the cam not be true which is creating a wobble. Could it be I need a chain dampner that they do not make anymore for the ls1. I am either going to have the front of the cam checked and go with a double roller or just put in a new ls6 block and be done with it. Any help is appreciated.

Bill Curlee

That much chain slop is not good. Check that you dont have excessive crank drive gear and cam driven gear wear. Has the engine ever been line boared. That can sometimes increase chain tension by reducing the distance between the crank and cam bearing centers.
The chain damper provided insurance against chain wind up and reduces the chain flex.

Use a dial indicator and check the gear run out.

Bill

lucky131969

Curious as to what balancer you are using?

vettenuts

I have the information at home, but there are known harmonics between 3,800-4,500 RPM (from memory). The discussion I have is from someone who worked this issue with GM when they were breaking chains. Two things solved it. First, the timing chain damper. Second, the harmonic damper that was built for them by ATI. His recommendation for HPDE was to either use the ATI harmonic damper or use stock. All the other dampers tested didn't resolve the issue.

What is the harmonic damper being used, stock?

Also, did you check alignment of the timing chain sprockets? There is a tolerance on how much they can be offset (mis-matched).

AU N EGL

Katech C5r chain http://store.katechengines.com/c5-r-...chain-p30.aspx

billy25us

Both chains were c5r chains. My heads have more damage now so instead of dropping 1500 bucks in them I am going with a crate ls6 and solves the problem for good.

vettenuts

What damper were you running?

Eric D

This is a valid question. Most will try and put a bigger chain when the cause could be the wrong or a bad harmonic balancer. If I remember correctly, there is a fuss period at about 6100 rpm that you don’t want to linger at for any length in time.

jedblanks

Are you running catless? We broke two chains before figuring out the cat was plugged up on my dad's Turbo Buick. Of course the car didn't run right either. Unlikely in your case given you are doing HPDEs. Any other possible restriction in the exhaust?

AU N EGL

Yes what kind of dampener are you running?

without a timing chain dampener any quick accelerations will just snap ANY chain.

ppl love high HP engines, but tend to go cheap on the valve train components. they keep breaking this or that and yes that is why the LS6 crate motor is a good choice.

rebelheart

LOL Plugged cats? That would only reduce power,it wouldnt have a thing to do with a broken timing chain!

billy25us

There is no chain dampner on it. My ls1 block does not have the holes to mount.

0Randy@DRM

I have a jig to drill the holes, then you have to tap it. It's not real flashy, but it works well. Pay the shipping and you can use it! I will even throw in the right tap.

Randy

jellis

have you thought about using a gear drive?

Bill Curlee

HOLY MOSES! What a deal! BRAVO!

AU N EGL

go 4 it

Wicked Weasel

billy25us

I would definatley take you up on it but I just bought a ls6 crate engine. They were on special for 3200. I can take my old motor back to stock and sell it and recoup enough diffrence to justify the difference in rebuilding my heads,head gaskets,bolts timing cahin set,and all other costs. But thanks for the offer that is well above and beyond what most vendors would do. Anyone looking for a ls1 engine.

printmanjackson

since he never said I would guess stock. To break a Katech chain there has to be something wrong.

vettenuts

Still don't know what harmonic damper is being run, which can cause this problem.