turboost

iTrader: (1)

Motor is a stock rebuild with EPS 226/230 and TEA stg 2 243s w/.45 HG. Started out with 7.4 cheap PR (thought they were stronger) which it destroyed almost all of them and broke the tip of an inner spring after test driving it. Checked PR length and came up with 7.350 and put some BTR PRs in and went ahead and changed all the springs since wasn't sure of dual springs that came with heads (bought used) with some BTR .650 springs. After about 100 miles on the street it broke 2 intake rocker tips (stock w/trunion upgrade) while idling.

Question is, could this have been from previous event with too long pushrod weakening them or am I looking at bigger issues?

Additional notes: morel 5315s, PTV was checked by builder and was good, heads are milled .020, preload is about .50 (1/2 to 3/4 turn)

Thanks for any help

KCS

iTrader: (20)

Coilbind maybe?

turboost

iTrader: (1)

The previous springs Ti retainers were reused and probably even the seats. Went back with BTR 650 springs instead of what came on the head from TEA. This was after the PR incident. Could this have caused binding? Its awfully concerning that I destroyed some PRs and now Im breaking stock rockers which seems to never happen.

turboost

iTrader: (1)

Both are on the intake

chevy1224

iTrader: (2)

I will sell ya a set of rocker arms to replace those. Need a good cleaning, and it would be a good idea to take those trunnions you have and put em in this set.

dr_whigham

iTrader: (49)

What's the lift on the intake side?

Maybe the longer PR's you had, which destroyed your lifters, contributed to weakening the rocker arms?

That's really all I can come up with.

turboost

iTrader: (1)

Lift is .598 on the intake. And as far as I know there is no lifter damage. Do you know something I don't....

vertenaotne

This was after the PR incident. Could this have caused binding?

dr_whigham

iTrader: (49)

First post was a bit hard to decipher what happened when. I thought you meant lifters trashed, not PR's.

Point is still valid though. If the PR's were trashed with the 7.4's, and after measuring and coming up with a 7.350, it's highly likely the PR's beat the absolute **** out of the lifters, hence them (the PR's) being the part that gave up the ghost.

And still, all I can come up with is the longer PR's contributed to weakening, possibly cracking a few of the rocker tips. This doesn't happen very often at all. I'm just thinking out loud here...

farmington

iTrader: (14)

"Builder said PTV was good" what exactly was PTV? I would bet you have smacked some valves (and bent them). You don't break these rockers very easily.

turboost

iTrader: (1)

I replaced the springs after the PR incident due to breaking one of them.

Going to be removing the heads soon and assessing the damage. I'll pull the lifters as well and check them. The builder clayed the piston and said the valves never touched them so that's what I meant by PTV was good. If it is a PTV issue, why would it break at idle as opposed to 4k rpm? A lot of questions that I hope to find a smoking gun during disassembly but would like to have a good hunch before. Really appreciate the ideas so far.

BlwnLs1GTO

iTrader: (12)

That's strange.
I would start all over from the beginning with the top end.

Also,
check out Manton or Trend for PR's. I got a nice set of Manton's 11/32' sized to my exact specifications. 7.363". and 4 at 7.353".
They'll cut them to whatever length you need, and how every many you need at different lengths, too.