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Posted by: kkid Feb 11 2015, 10:20 PM

Got a quick question,

Is our lifter supposed to be convex on the camshaft side? Mines are all flat.

Thanks in advance,

kkid

Posted by: colingreene Feb 12 2015, 02:00 AM

All the parts ive seen have been flat.

Posted by: Racer Chris Feb 12 2015, 08:07 AM

Oem lifters are slighty convex.
When two new lifters are held together they should rock, not sit flat.
If used lifters are held together and they don't rock - they are worn out.

Posted by: Mark Henry Feb 12 2015, 08:37 AM

flat or concave they are done.

Posted by: kkid Feb 12 2015, 11:34 AM

Same here, they all must be 40+ yrs old.

Posted by: kkid Feb 12 2015, 11:45 AM

Thanks Chris for clarifying this.
Haynes and above mentioned reason made me confused.

How about the aftermarket lifters like this Scat lifters? http://www.pelicanparts.com/catalog/SuperCat/0978/POR_0978_ENGCYL_pg2.htm#item5

Can I use these if the cam lobes are clean with no damage?

Posted by: Jake Raby Feb 12 2015, 11:54 AM

Crown radius dictates lifter surface speed, which is directly related to point loading, and ultimately, wear.

Posted by: kkid Feb 12 2015, 11:56 AM

If I find a concave lifter, does this mean the lobe is done too? It's very hard to see the condition in the cave even with a strong light. So I might wanna split the case to make sure.
Thanks!

Posted by: Racer Chris Feb 12 2015, 12:20 PM

Generally speaking, the cam and lifters have to be properly matched at time of installation.
For instance, its not safe to install new lifters to go up against a used camshaft, or vice versa new cam/used lifters.

Posted by: Mark Henry Feb 12 2015, 12:26 PM

I know I'm going to get shit for this one

Being a cheap Canadian I've reused stock cams many times without ill effects. Damage to the cam is often obvious, pitting, scoring and it can wear a divot into the cam. Measure the lobes they should be close to the same. I measure on V blocks/dial indicator for runout on the center bearing surface. Polish with 800 grit paper and I'd use new OE german lifters.

But I haven't done this in at least 10+ years because to me it's no longer worth taking the chance.




BTW I do have a mystery cam, aftermarket bolt on, no grind numbers and no history, looks close to stock with matching and order numbered good lifters.
Came out of a engine that was supposed to be rebuilt, but some idiot power washed it and the cylinders were full of water.

Posted by: Steve Snyder Feb 12 2015, 05:41 PM

Not matching the cam and lifters is a risk not worth taking IMHO.

Posted by: kkid Feb 12 2015, 10:34 PM

Thanks guys for the inputs.
So I change either whole thing(cam and lifters) or nothing.
As being cheap I might wanna change nothing this time then I don't have to split the case. But there is another reason why I might wanna open the case. I see slight oil leak from the mating surface on the bottom so I thought resealing is a cure.