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So last week I did a compression test to see if that was where my missing power was at. I wasn't able to get my tester into 5 & 7. Cylinders 1,3,4,6,8 were between 145-155. Cylinder 2 was right at 120. I just did heads and cam about 1000 miles ago. Bought some ported pro comps from a buddy of mine and he had no history on them. Thinking the valve seats might be bad I decided to pull the heads today. Here's what I found
Each exhaust valve hit the piston
I measured for pushrod length and cam up with 7.4. I even backed the checker off .050 and it had play. My question now is, sand the sharp edges down, get shorter pushrods and run it? Or new pistons?
Smooth down any ridges on that piston, it should be fine. The valve however, even if it looks good and straight must be changed. Do not reuse that valve.
Pushrod length isn't your root issue. Loss of valve control (bad springs), cam timing off, too big of cam, heads milled excessive.
And what happened to the block face in the upper and lower right of the picture? Looks like a beaver was chewing on it.
Last edited by ironmanLS1; 04-29-2017 at 08:23 AM.
Smooth down any ridges on that piston, it should be fine. The valve however, even if it looks good and straight must be changed. Do not reuse that valve.
Pushrod length isn't your root issue. Loss of valve control (bad springs), cam timing off, too big of cam, heads milled excessive.
And what happened to the block face in the upper and lower right of the picture? Looks like a beaver was chewing on it.
thats left over gasket material. The heads must be milled, I got them from a guy who got them from a guy and Nobody had info on them. I'll probably just use the 241's I have in my garage.
thats left over gasket material. The heads must be milled, I got them from a guy who got them from a guy and Nobody had info on them. I'll probably just use the 241's I have in my garage.
Is there anything stamped on the face of the head that may indicate how much it was milled, like 30 or 0.030?
No stamp or anything. I got the 241's assembled and on, just gotta torque them down and put it all back together. Hopefully I can fire it up around lunchtime tomorrow.
Poor valve control likely. I had this happen with a stock ls1 cam
I really don't want it to be loss of valve control. I'm running comp double .675" springs. None are broken or anything. I will try to measure the heads I pulled off to see if they were milled. As for now I have my other heads back on and everything together again, just gotta fix that stupid ground wire on the back of the head 😡
I really don't want it to be loss of valve control. I'm running comp double .675" springs. None are broken or anything. I will try to measure the heads I pulled off to see if they were milled. As for now I have my other heads back on and everything together again, just gotta fix that stupid ground wire on the back of the head 😡
Here's a lesson I learned a while back that i'll pass along. valve control isn't only the springs. I ran high spring rates with too weak pushrods, and the pushrods flexed, followed by "pole-vaulting" the valve. I went from comp 5/16 x .080 to manton 11/32 x .105. problem solved.
04-29-2017, 12:35 AM
Well this happened today 
