verbs

Well, I have a 20% and 25% exhaust leakdown on cylinders 5&7 respectively, and some marks on the pistons from the valves kissing them. My guess is bent exhaust valves, and I'll know for sure tomorrow.

I guarantee you that this is from the combo of low p/v clearance of .085, YT rockers, and my Comp 987 springs.


Just a warning to those running the same combo, because I know a few are around here. Keep in mind I have less clearance than most heads due to the way TEA set up their 5.3L heads at the time, and my heads are milled .010


***Update*** 5 intake valves bent, and 2 exhaust valves bent

Hershey Squirt

iTrader: (6)

What about the new 1.5s? I just ordered a FM11. Should I be ok? No Yella Terras.

BB

iTrader: (7)

I am one of those, same combo as you. But, for me it was the intakes that kissed the pistons. However, none of the valves bent. I think the issue is valve float from a heavier rocker tip mass on the valve, springs at their limits for our cams, and not quite the clearance we thought since TEA doesn't seat there valve so much - not a bad thing just a design/engineering choice.

What are you going to do with that G5X? cam you have? Gonna fly cut the pistons?

6.0vette

Was the rocker coming into contact with the valve retainer behind the roller tip?
I had jesel rockers with rev duals that were doing this.I had to claerance
them with a die grinder a bit so they wouldnt bind. Oh yea this causing the valve not to seat properly.

BB

iTrader: (7)

The Yella Terra's cleared the retainer on my setup. I definitely looked for this during the install and when I took the rockers off I didn't see any wear on the rockers anywhere on the rocker body.

CHRISPY

977s probably would have helped. It looks like there is more than one spring issue out there!

Scalpel

iTrader: (4)

Can we really blame it on the springs if we don't know for sure what the true cam specs are. Verbs isn't even sure if the cam is indeed a TR230/224. If the cam is a different grind the cam may have been inappropriate for the 987s from the getgo? What do you think, Verbs?

Too bad we couldn't get that cam "doctored".

verbs

Well, I'm going under the assumption that the guy I bought the cam from was truthful, since most people I talked to who knew him said he was a standup guy (although I may think otherwise).

Also, my dyno graphs mirrored those of individuals who ran the 230/224 cam as far where I made peak power, and graph "shape" if you would.... I also have identical P/V clearances and valve float symptoms from those running the same setup as me.....too many "coincidences" IMO.

I may get the cam doctored now that it's out of the car.

verbs

I don't have a G5X cam in my possession at this time.

White Fire'99

iTrader: (15)

but xtreme does

Mike K.

Man that sucks at least its only exhaust valves though.

JaSSon

iTrader: (11)

Thats why I upgraded to the 978s for $35 more and bought comp Rs on my 1.5s and X1 to be installed in the next week. Only bummer is shimming the lifters but peace of mind and durability are priceless. Good luck

verbs

No, Xtreme doesn't have a G5X cam in their possession at this time either.

AZ Power & Sound

iTrader: (2)

The black SS thats gonna smoke you sunday sure does though!

SSean

I dunno....I've read a few other posts, on this board actuallym where people complained about valve float with this cam and the 987 springs.

verbs

Trap speed yes, but ET I still own you

Brian Tooley Racing

iTrader: (13)

I would think that with the intake valve having much less clearance then the exhaust valve, and the fact that the exhaust valves are bent, that you probably have a symptom of a missed gear shift, more then anything else. You may want to go ahead and upgrade those springs or replace with new while you have them off.

BB

iTrader: (7)

What springs do you recommend Brian? The 978 have an advertised max lift of .600 and the Comp tech line says it is really only .595. In either case that is less than a lift on the G5X2 or 3 these guys are puttin' in. The 921 advertises a max lift of .650.

Kurtomac

iTrader: (5)

yes i want to know too....i have a set of TEA stage 2 5.3s cut .015 and im using the FMS F13 cam 230 232 591 595 113+2 haven't taken her up there much and dont think i will until i get some springs for this bad boy.....since i got the opened up spring pockets might as well use the 978's if theyre installed the same as the 987s or i was thinkin of going with the 921's what would be involved in installing a set of 921 is these milled spring pockets.....with my 224 581 112 cam and these 987's i ran to 6600 and saw no signs of floating...wondering if i should just throw it on the dyno and see if its floating before i freak out and buy new springs.....anyways TTT for this thread

2000Blackout

iTrader: (1)

How about me Verbs