Pushrod Angle problems

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Good thread, what's the best tool for this problem? A carbide reamer or would a carbide bit for porting work just as well? I wonder if I'll have pushrod angle problems with RHS heads on a factory hydraulic roller LA block.
 
T56MaxTorq said:
Good thread, what's the best tool for this problem? A carbide reamer or would a carbide bit for porting work just as well? I wonder if I'll have pushrod angle problems with RHS heads on a factory hydraulic roller LA block.
Click to expand...

No you won't have problem. This problem comes from sticking a roller cam into an older LA block (340, in this case).
 
T56MaxTorq said:
Good thread, what's the best tool for this problem? A carbide reamer or would a carbide bit for porting work just as well? I wonder if I'll have pushrod angle problems with RHS heads on a factory hydraulic roller LA block.
Click to expand...

It is possible to have the problem any time you deviate from the stock configuration. A high lift cam can/will make things worse also. Heck I've even ran into problems with pushrod clearance on a 340 block with a flat tappet cam. The cam was a .630" lift solid (.590 measured at the valve due to lash and angle losses) and the heads were Edelbrocks. That's why you always mock it up before assembling and finding out the pushrods don't clear and have to pull it all back apart to grind on the heads. A standard carbide bit is sufficient.
 
Like Fishy said... The later factory heads have larger pushrod holes than the earlier ones. The aftermoarket heads are basically all based off the earlier ones. So you have to adjust the holes. It's not a big deal when the heads are apart for the valve job fixing. So most better shops won't charge for this and the mess cutting aluminum or iron creates is easy to clean. There's no way I'd do it on an engine. And honestly it would take a while for me to mask everyhing to do it on a bench with the head assembled. If you use a cutter, make sure you use cutting fluid or ATF to lube the bit first...
 
Ah, so are aftermarket roller lifters that much longer than factory roller lifters? I can see how a high lift cam will make it worse and we're all doomed to the 59* lifter angle. Time to break out the carbide bits. What's the desired clearance between pushrod and head? .030?
 
hi, the best way is in a milling machine. set up head so pushrod hole is vertical. then bore with a 1/2 " end mill. I move hole .125 seems to give plenty of room. might need more , depending on lifter height. this takes about an hour to do. looks way better also. just food for thought.
 
T56MaxTorq said:
Ah, so are aftermarket roller lifters that much longer than factory roller lifters? I can see how a high lift cam will make it worse and we're all doomed to the 59* lifter angle. Time to break out the carbide bits. What's the desired clearance between pushrod and head? .030?
Click to expand...

Hyd. Rollers are 3/4 longer/taller then standard lifters. I probably would have this problem if I had got solid roller lifters.
 
You really don't want to ream the hole making it larger in diameter, unless you are going to bigger pushrods. You want to make the hole into an oval, running from intake to exhaust face, not removing any more material from the push rod pinch are of the head.
 
Lovely, it looks like im taking my assembled by IMM RHS heads apart if i want to clearance these holes. I really hope i won't have any problems being its a factory roller block, though the high lift cam and 1.6 rockers probably dont help.

DOH!
 
The pushrod holes in the RHS heads are HUGE compared to the eddies.
 
hi, the original pushrod holes are 1/2" diameter already. using a 1/2" end mill elongates the hole. does not enlarge it. If concerned, use a 7/16" mill. just food for thought.
 
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