which pistons would work best?

[adumb]

i have dart iron eagle heads with 2.02 valves and 64cc combustion chambers. i had stock 4 valve relief pistons in there. while breaking in my comp cams xe174 cam my valves were slightly contacting the pistons. it looked like the valves were hitting in the corners of the valve reliefs, i was looking at these, http://www.summitracing.com/parts/UEM-KB120-060/, i wouldnt for see any clearence issues with those but i would also like to get a balanced assembly so i was looking at this, http://www.summitracing.com/parts/ESP-B13402E030/, but with those just being the 4 valve relief pistons i would think i would have the same issue. has anyone had this issue before or can anyone put in there two cents? thanks

 

[jrm81bu]

If they were just barely hitting you could look into fly-cutting the pistons. What kinda lift numbers is on that cam?

 

[adumb]

whats fly cutting?


its not crazy numbers on the cam, i almost think it was the faster ramp up on the xe cam

and i typo'd xe 274


heres the cam specs http://www.compcams.com/Cam_Specs/CamDetails.aspx?csid=87&sb=1

 

[adumb]

heres a pic of one of the pistons

 

[jrm81bu]

Are you sure a valve hit it or did some carbon build up just flake off?

 

[adumb]

there are a couple that the piston only hit the carbon but half of them i have very small knicks in the pistons. plus that was only from the break in, 2k rpms, so i imagine that 6k would put the knicks alot deeper.

 

[adumb]

 

[DRIVEN]

Some less involved alternatives you could try:
-Thicker head gaskets.
-Retard your cam timing.
-Rockers with smaller ratio.
-Slightly "smaller" cam profile.

 

[NAILS]

re-examine your quench space.

 

[megaladon6]

what are the full engine specs? decked heads, compression ratio, rocker ratio, pushrod length, head gasket thickness, etc.
honestly, i'm VERY surprised that you have interference issues. i have the same cam and a stroker with very tight quench, and good clearance, granted i also have d-dished pistons.