Valvetrain Help...Breaking things
Thread Starter
Instructor
Joined: Jan 2002
Posts: 161
Likes: 0
From: Wichita Falls TX
Valvetrain Help...Breaking things
Just a brainstorming session here. I keep breaking parts on my valvetrain. Busted a spring, now a rocker stud. Don't have many miles on the engine, probably around 3000mi. I heard the XE camshafts design can cause some increase in valvetrain wear, but only at 3000 miles? The heads have stock springs and rockers so thinking might need to beef up some. Any other thoughts.....Thanks, EZ sends
Melting Slicks
Joined: Oct 2001
Posts: 2,740
Likes: 4
From: Marblehead MA
Re: Valvetrain Help...Breaking things (EZG63Conv)
I had a similar problem many years ago, when I replaced my cam and went with roller rockers and new springs. It turns out the springs were too brittle, they made a bad batch of them. We found the problems by taking the springs off and testing them. Two of the springs broke on the test machine. The manufacturer replaced all the springs free of charge.... natch.... they wouldn't assume any liability the resulting damage.... Good luck - :cheers:
Le Mans Master
Joined: Feb 2001
Posts: 8,017
Likes: 2
From: The problem is all inside your head she said to me.
Re: Valvetrain Help...Breaking things (EZG63Conv)
I've had a rocker stud break before but never had any problems since. I think what someone will eventually say is "check your valve train geometery" and I presume they will mean get a pushrod length checker, and probably also check for coil bind? Good luck.
Thread Starter
Instructor
Joined: Jan 2002
Posts: 161
Likes: 0
From: Wichita Falls TX
Re: Valvetrain Help...Breaking things (INMYBLOOD)
Gonna just replace the stud, luckily they are screw ins so it is quick. Gonna redo the valve adj too. If the rockers are too tight would that cause premature failure?
Pro
Joined: Jun 2002
Posts: 705
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From: Dearborn mi.
Re: Valvetrain Help...Breaking things (EZG63Conv)
Here we go again! What speed books and mail order joints don`t tell you that not all camshafts are drop ins. I personally do not know what a XE camshaft is, but the basic proceedure for any performance camshaft is all the same. Coil bind, and guide to retainer measurements are critical. Breaking studs may come from taller lift camshafts that can be corrected with long slot rocker arms because of the increased movement. And valve springs and retainers should also be tailored to the cam. Some of the SB engines use rotator style retainers and shorter springs on the exhaust valves which close up clearances that should be checked before the cam goes in and discarded. A completely tailored cam kit {Springs, lifters, retainers, and cam} would be helpful but the other clearances must be checked. [coil bind, retainer to guide and rockers arms} Get in touch with a local racer and he will explain all these areas. Good luck, :cheers:
Thread Starter
Instructor
Joined: Jan 2002
Posts: 161
Likes: 0
From: Wichita Falls TX
Re: Valvetrain Help...Breaking things (Matt Gruber)
stock chevy springs....
Update, changed the studs, readjusted the valves. Some were loose and some were good to go. No poly locks on them but they shouldn't be loosening up so fast? Wonder if the cam is wearing from something. EZ sends
Update, changed the studs, readjusted the valves. Some were loose and some were good to go. No poly locks on them but they shouldn't be loosening up so fast? Wonder if the cam is wearing from something. EZ sends
Race Director
Joined: Oct 2000
Posts: 15,068
Likes: 79
From: central FL, near the beach.
Re: Valvetrain Help...Breaking things (EZG63Conv)
a stock Z28 spring is a popular spring.
Need to know the seat and open pressure and compare it to the proper spring.
I would expect a lot of problems if the seat pressure is under 95#.
Even with the proper matching spring, if the installed height is too high i would expect a lot of problems.
i spent a lot of time building my heads; needed a .060" shim. Brand new heads!
You might be able to use a bathroom scale and a block of wood to get a bubba estimate :nopity
On 2nd thought it sounds more like coil bind.
[Modified by Matt Gruber, 7:01 AM 3/15/2003]
Need to know the seat and open pressure and compare it to the proper spring.
I would expect a lot of problems if the seat pressure is under 95#.
Even with the proper matching spring, if the installed height is too high i would expect a lot of problems.
i spent a lot of time building my heads; needed a .060" shim. Brand new heads!
You might be able to use a bathroom scale and a block of wood to get a bubba estimate :nopity
On 2nd thought it sounds more like coil bind.
[Modified by Matt Gruber, 7:01 AM 3/15/2003]
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