supermx96

Thanks for all the good reply.

I am sure that the cam timing is right the intake is tight and the exhaust side have almost full lift of clearamce. Now is at 110 intake centerline on cyl #1 i will try to put it at 112 intake centerline and take some measure...

BillK

Are you using clay ? If not, there is no way to "see" where your clearance problem really is

The cutout might be plenty deep, just not big enough around.

supermx96

Yes i have use clay. I so already cut the valv e notch on the radial side .080" but i have see now that the cyl #1 and 3 have .095" i think the #4 is not cut at the same place that the other posibly an error.
Before i cut them i only have .021" at the intake. Now the head are bolt on and this sumer time i will try to get enougth clearance with the cam timing i know i will lose some bottom end but this a blower engine that will help for that.

MILD THUNDER

iTrader: (3)

Something just doesnt sound right. My cam has similiar intake opening and closing timing, slightly more lift than yours, 110* install, and I had plenty of PTV clearance when I clayed it. I have flatop JE pistons with a single valve relief.

With a stock deck height, your piston should be .025 in the hole with that piston you have.

Have your blocks been decked alot? What head gasket are you using? How far in the hole is the piston?

supermx96

Yes the block deck height is at .010'' so the piston is .010 in the hole, and head gasket is felpro mls .040'' compressed thickness.

This measure is at orond 9-10 deg atdc.

I have put my cam now at 112deg intake centerline instead 110 deg and i have recheck the measure, now the closest measure is ,098''.

The speed pro piston dont have a big notch on them and i think that is not desing for a 2.250 intake valve dia.

MASCH

If memory serves me correct....the valve pockets on those pistons arent machined like a J/E. The pocket is just part of the forging. Like others have stated check and recheck because you dont want to take out more than you have to because that is the weakest area in a BBC piston.

rmbuilder

Supermx96

The issue is with the design of the relief on the Speed Pro piston when used in conjunction with the Edelbrock Marine series cylinder head. This series head is a 26.5º valve angle which alters the orientation of the valve in conjunction to the relief. This effect is both radial and to the plane of the valve angle vs. the relief angle. P to V clearance is most influenced by duration rather than lift, therefore your only solution would be to fly-cut the pistons to correct for radial, depth and angular clearance.

Bob

MILD THUNDER

iTrader: (3)

Bob, you had me at hello. Once again, you've provided excellent information!