69mach1377

First one was OEM and it lasted almost 2k miles. Broke the block too.
2nd one was one piece SS made by Carr and it lasted about 20k miles. Beat up one piston and chamber.
I later figured out that the second block was not drilled correctly for coolant flow, the holes were not big enough like that sketch shows.
So after all that drama, I went to W heads.

barnett468

ok thanks, the stock ones are supposed to explode but i have never heard of Carr . . did you have high spring pressure?

69mach1377

Not really. Carr was in biz in the 90s. No trace of them can be found now.

barnett468

i wonder if thats because their valves broke in half.

69mach1377

What do you mean by 'in half'?

barnett468

i was just guessing by your comment that it broke in half to beat the piston up as you mentioned . . if it stuck in the guide, the guide was too tight or it had some old gas/tar residue miseed wit the gas.

what exactly did happen to the stainless valve?

69mach1377

it broke not in half, but where the stem blends into the flat portion, at the beginning of the radius
it apparently got real hot while cruising along the highway, no shenanigans were going on, after about 20k miles