RADEoN

iTrader: (12)

I broke a timing chain (I think). Didn't hear any clanging or anything when I was cranking the car.

It's a 408 stroker with a TSP Texas Giant Camshaft (248/254, .615/.622 lift), with Wiseco forged pistons with reliefs in them. I'm really hopeful that the reliefs may have saved me. I'm pretty certain it's something valvetrain related because the starter is doing enough to crank the serpentine belt, but if you shine a light in the oil fill hole, there's no rocker arm movement whatsoever coming from the visible rocker.

I'm thinking the reliefs may have saved me... hopefully.



When I work up enough courage to go start tearing apart, I'm gonna throw a timing chain on it, and try compression testing each cylinder, rather than rebuilding it just to find out I have bent valves. I've also been told to take the valve covers off and watch, and it'll allegedly be really noticeable.

kossuth

iTrader: (12)

Only one way to know sir, but I wouldn't get my hopes up. If you get it tore down and there isnt any damage then I would run right out and play the lottery because the odds are very slim.

babbage1109

iTrader: (11)

Did you ever have it on a dyno? Off-topic

Bramlok

iTrader: (7)

Was this engine previously running or did it break on first start up? What kind of timing chain is it?

garygnu

put the new timing chain on and do a leak down test ,and a compression test.

vettenuts

iTrader: (4)

What PTV did you measure during assembly?

gMAG

iTrader: (1)

Well, the first thing I'd do is to remove the heads and take a look.
You might have gotten lucky.
If there's damage, you'll likely need a valvejob and valve(s). The heads will already be off.

LilJayV10

iTrader: (39)

Replace the chain and see how it runs and/or do a compression test. I would that first before I pulled the heads off and found out I didn't have too.

IMO its worth it unless you just love pulling the heads off.

Firehawk441

iTrader: (41)

You don't need a timing chain to verify bent valves.
Just take a few minutes to remove the valve covers, then remove all the rockers. Chances are you'll see a few valves lower then the rest without wasting any further time on a leakdown. If you don't then the next step would be a leakdown.

If you broke the chain, then my guess is you'll find about 4 bent valves.

gMAG

iTrader: (1)

If I knew what the compression figures were, before the incident, then this would work for me.
But, I have no idea what the figures were, but, perhaps the OP does know.
Given the circumstances, I'd rather spend the time to inspect the heads. I can't say that I'd love to do this, but IMO, a direct inspection is best.
Replacing the chain, then running it, is not the way.
Also, a valve can be bent just enough, so that it doesn't seat correctly, but appears to be closed. So, unless you have an obvious problem with a bent valve, compression and/or valvecover inspection may or may not be the indicator.
I've had this happen to me.
The title reads "100 percent guaranteed".
Wouldn't you rather be sure?

crcdude

ya, what Firehawk said. Pop the valve covers off an have a look. if they are to close to tell then you can use a tape measure ( vernier calipers more accurate) to check valve height.

Compression test aint gonna tell ya chit.. Leakdown would be only legit info you could use.

Im gonna guess 6 bent

I seen a 4 banger bend all 24 once. Had a different 4 banger pop a belt, fixed it on the side of the road.. then drove it another 20K

Just luck of the draw sometimes

dreww

iTrader: (1)

Blew my chain at 4500rpm on 100shot spray.

Blew out ls6 intake, bent 7 valves. Was a stock ls1 chain or cammed ls1

IMO, pull heads....don't try to run it again.

td1168

iTrader: (2)

If the motor turned over without the timing chain you have bent valves. If you don't have bent valves you're the luckiest man alive!

LilJayV10

iTrader: (39)

You can pressurize each cylinder via the spark plug hole with no lift on the either lobe or take the rockers off. That will tell you if a valve is bent. If an intake valve is bent you will hear it blowing out of the T/B. If an exhaust valve is bent you can hear it rushing through the headers/exhaust manifold. You will hear a little get past the rings because the engine is cold and depending on how good your rings are.

gMAG

iTrader: (1)

I see what you're saying, but had a situation where an intake valve slammed shut after losing the chain. Everything looked good, and passed this leak test, until the chamber side of head was inspected. The intake valve rebounded into the head with such force, that the big end of the valve tipped slightly, and slammed into the seat. After pulling the valve, the inside edge of it had bent with such force, that the edge now conformed to the seat, & vice-versa.
This might be a rare situation, but it was one that was hard to forget.

LilJayV10

iTrader: (39)

Damn.

ls1 1990 VN

Do not replace chain only and fire it up!!! What idiot info!

remove valve covers & check rockers, valves.

I broke a dual Rollmaster road racing at 5800rpm, 4 forged pistons took a good hit, bent 4 valves.

Slowhawk

iTrader: (12)

this is the easiest way.