firechicken_3

iTrader: (4)

i'm just curious about something, a friend built a 383 stroker, it had dual quads, headers, etc.... motown 220 heads, roller rockers, girdles, and a solid lifter flat tappet cam.

to make a long story short, after less than 2 hours of actual running time. the engine started to rattle and knock. when torn down, it is discovered that several cam lobes are flat. the machine shop says, that the cam went flat because they used solid lifters, on a hydrualic cam, and the part number supposedly proves it.

my question is this, why would a solid flat tappet lifter, chew up a hydrualic cam ??

if the the valves are lashed properly it should not matter, i am thinking, either the cam was not properly hardened, or the seat pressures on the springs when open, was WAY to high, or he had coil binding problems. don't ask for specs, because i was not directly involved in the buildup, so i don't know all i know is the cam was BIG, and the motor was meant to run big RPM 7000 plus

RB83L69

That will not eat a cam. It may make the motor run funny, and be bad for long-term longevity of lots of valve train parts most especially valve seats; but that isn't what trashed his cam that fast.

I'd bet it's a valve spring issue. What's the peak lift, and what springs are they? And are the rockers 1.6, but the lift numbers given for 1.5s?

firechicken_3

iTrader: (4)

like i said i don't know specs, if i find out, i'll post here.

i didn't think that using a solid lifter on a hydro cam shou cause any problem, since they were both flat tappet. the machine shop that told him that was a pretty reputable place, guess they won't be surfacing my flywheel

RB83L69

Did they also sell him the heads?

firechicken_3

iTrader: (4)

he did not get any of the parts there, they got all the parts mail order from jegs, and summit., they just did the machine work on the block.

DukeofBird

the rockers were comp pro magnums with 1.52 ratio, heads were assembled world products motown 220 cast irons with the 1.43" dual springs that came on them that were capable of .600 lift, cam was crane powermax solid flat tappet, with 245/255 deg @.050, .558"/.579" lift also all not just some lobes were flat as were all the lifters.