Joe Kizzire

When I went from a .615 lift to a .650 lift cam I noticed a 10 to 15lb drop in oil pressure.

Just this week I found out the cause of the problem while in west Houston.

It seems that when using the Crain solid lifter on a large lift (.650+) cam the reduced base circle enables the lifter to travel to far down uncovering the lifter bore oil galley thus causing an internal oil leak. The amount of the leak will be different from cam to cam depending on the base circle and the block machining. For instance in one block a .700 lift cam was ok and a .750 lift traveled .020 to far.
In my iron block a .615 was ok and .650 is marginal.

The fix!!!! Comp Cams part number 859-16 lifter.
It requires a little grinding on the link bar for clearance but other than that it's a drop in.

<small>[ March 07, 2003, 10:00 AM: Message edited by: Joe Kizzire ]</small>

GeorgeC

Interesting info, Joe... What are the differences in that lifter? I'd have to go and look for myself, but I can't see how you can run lifters w/link bars in an LS1...

I have the "drop-in" Crane lifters (don't remember the P/N), and haven't seen any kind of problems.

Joe Kizzire

George the problem varies from cam to cam. Judson had a 700 lift cam that was ok and then installed a 750 lift and the problem was there.
20lb pressure max.... They removed the head and pressurized the oil system and found the problem when oil poured out between the lifter and the bore. If you've got a block sitting around slide a lifter in and you can see how it would happen.

The part number I posted is for a 455 Pontiac. It allows for about .400 inch futher travel down the bore before uncovering the oil galley hole.

All the testing was done at SAM on the engine dyno.

I'll email you my number. Call me if you need anymore info.

GeorgeC

No biggie, Joe... I was just wondering about using lifters with the alignment bars on them.

I haven't experienced any oil pressure issues (just oil leak issues <img border="0" title="" alt="[Razz]" src="gr_images/icons/tongue.gif" /> ), and I don't plan on swapping cams anytime soon.

I just found your post to be interesting/informative...

Joe Kizzire

</font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by Tim98TA:
<strong> How could you see what was going on from where your head was?

Tim </strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">Unlike you Tim I have no need for a step stool to see what other people see.

WeatherGuy

Very interesting info . . . thanks for the heads up on this.

I will be checking on this to see how my car does since it will be running a pretty high lift.

Greg

Tim98TA

iTrader: (7)

How could you see what was going on from where your head was?

Tim

Tim98TA

iTrader: (7)

</font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by Joe Kizzire:
<strong>Unlike you Tim I have no need for a step stool to see what other people see.</strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">Just an extractor. <img border="0" title="" alt="[Big Grin]" src="gr_grin.gif" /> <img border="0" title="" alt="[Big Grin]" src="gr_grin.gif" /> <img border="0" title="" alt="[Big Grin]" src="gr_grin.gif" />