LT1SS

ok, so about a month ago my friend and i did a h/c package on his 99 vette.... prc stage 2.5 ls6 heads with 228r cam. springs good to .675. we installed the cam straight up, double-checked everything and it ran great untill last night. we were doing a few pulls last night and all of a sudden it started sounding like it was missing a cylinder. we tore into it today and found a blown head gasket and a broken spring on the exhaust of the no. 8. with a bent valve and a small dent in the piston. my question is; is it ok to run the piston still or do we need a new one? also has anyone had a problem with a spring breaking like that with such a small cam. any ideas how it could happen or could it just be a faulty spring.

JRENIGAR

iTrader: (37)

I dont know, but this " broken spring" **** that has happened alot lately is why I didnt do heads n cam. Hell, Id rather own a slow stocker that a broke screamer.

O2Form

Were the springs installed at the proper height? The piston may be ok post up some pictures.

xpensivehabit

We got everything straight from Texas Speed, so I would assume everything was done correctly.

I will get pics up tonight

O2Form

Wow time to call them, one thing for sure i'd be changing those springs. You're lucky it didn't break the piston.

garygnu

the piston should be ok.you will have to remove the head .maybe you can send it back to TSP for repair.test and change the springs if needed.

LT1SS

no 8 cyl exhaust

Bramlok

iTrader: (7)

Piston doesn't look too bad. But its bad to hear about the valve spring breaking. Sounds like a mild build to be breaking springs. What kind of springs did they put on those heads?

01FbTaWs6

iTrader: (12)

He said above that he got it all from TSP. So I would assume these are there dual gold kit, since he said good to .675 lift. This is a pretty mild setup to be shelling springs. Kind of scary really.

LT1SS

yes they are.

LT1SS

is it possible it was just a bad spring?

whynot

That sucks, but it doesn't look as bad as I expected from the texts. I was worried at first that it may of cracked it through and if you reused it that it would burn through but that doesn't look bad enough to really worry about. I'd have no problem reusing it. But like I told Jon I'd have the head checked out well, as well as replacing the valve and springs. Let me know if you need a hand.

whynot

Oh and yes, I'd say it was probably just a faulty spring.

O2Form

Till it drops another.......... forget that! Go get other springs!

whynot

Yea, if you notice on my first post I mentioned new springs

01ssreda4

iTrader: (96)

Get some Lunati Golds

xpensivehabit

The bummer is that these were brand new out of the box heads a month ago.....

vettenuts

iTrader: (4)

How high were you pulling this setup? Is there any indications in the dyno curve that indicate instability? Why did the head gasket fail?

Just because a spring is good to a certain lift doesn't preclude other issues such as surge. I think you need to examine all the parts and how the motor was used and assembled to ensure a valve spring swap to a different one will solve the issue.

LT1SS

on the last run, (on the street) the motor went to 6400. we havent dynoed it yet.
we were using stock gm head bolts with mls gaskets. and tightened them down to spec. as per ls1howto.com 1-10 22 ft lbs, 1-10 90 degrees, 1-8 90 degrees, 9-10 50 degrees, then 11-15 22 ft lbs. prep work was good. i have no idea what could have done it. it ran like a champ for a month. maybe the spring letting go caused the blown head gasket????

vettenuts

iTrader: (4)

That's what I am struggling with, not sure how that could happen. Were any of the piston exceptionally clean? Where was the leak, to the outside of the head or into a cylinder?

If you can't sort this out, you may want to put a machinest's straight edge across the block and the heads and check for flatness. How is the surface finish?