Valvetrain problems...Comp Cams XE268
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Instructor
Joined: Jan 2002
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From: Wichita Falls TX
Valvetrain problems...Comp Cams XE268
I posted this on the C2 side, but I'll ask here too.
"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"
"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"
Thread Starter
Instructor
Joined: Jan 2002
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From: Wichita Falls TX
Re: Valvetrain problems...Comp Cams XE268 (MasterDave)
The heads are 434 castings (I think the 305 heads) that have been reworked to bigger runners, 3 angle etc...2.02/1.60 valves. EZ sends
Burning Brakes
Joined: Oct 2001
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From: Tracy California
St. Jude Donor '05
Re: Valvetrain problems...Comp Cams XE268 (EZG63Conv)
I've run that cam in the past. It's not that radical! I susgest you check a few things before you put it back together this time.
1) Make sure you have enough clearance between the retainer and the stem seal to accomodate the lift.
2) Make sure your springs aren't going into coil bind. You need about .060 between the coils at Max lift.
3) Make sure the rockers aren't touching the retainers near the trunion.
Good Luck
KM
1) Make sure you have enough clearance between the retainer and the stem seal to accomodate the lift.
2) Make sure your springs aren't going into coil bind. You need about .060 between the coils at Max lift.
3) Make sure the rockers aren't touching the retainers near the trunion.
Good Luck
KM
Safety Car
Joined: Aug 2000
Posts: 3,909
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From: Clymer PA
Re: Valvetrain problems...Comp Cams XE268 (EZG63Conv)
EZG63Conv:
That cam isn't radical by any means, so you can rule out too aggressive of a cam. You mentioned that you are running stock springs? XE cams are supposed to be used with matching Comp Cams springs....you can get away with running stock springs with the High Energy series cams.
The fact that you are busting springs and rocker studs means that something is stacking up solid. Have you checked your coil bind? If you are using double valve springs, be sure to check the inside spring for coil bind too.
That cam isn't radical by any means, so you can rule out too aggressive of a cam. You mentioned that you are running stock springs? XE cams are supposed to be used with matching Comp Cams springs....you can get away with running stock springs with the High Energy series cams.
The fact that you are busting springs and rocker studs means that something is stacking up solid. Have you checked your coil bind? If you are using double valve springs, be sure to check the inside spring for coil bind too.
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Instructor
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From: Wichita Falls TX
Re: Valvetrain problems...Comp Cams XE268 (bence13_33)
Replace the stud and reset the valves...Some were out of adjustment. Checked the springs as best I could but did not see coil bind, plenty of clearance. I think when I get time I'll just change all the springs to the Comp Cam recommended match. Engine builder felt those springs would be fine, last time I work with him though. Have had all kinds of problems with this motor..since I got it. Really strong when I get it tweaked but something always comes up putting it out of commission. I know my 'bubba' work ain't that bad :D
