Pre-loading lifters- some hard lifters, some soft ones
02-23-2005, 06:53 PM
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Pre-loading lifters- some hard lifters, some soft ones Hello. I am rebuilding my LS1 and a couple lifters were soft when I pulled them, and the other 14 lifters are still "hard." I'm thinking this will make it near impossible to accurately set my pre-load on the softies since they offer such little resistance.
Can anyone offer some insight on what I should do?
Thanks
Ben
Can anyone offer some insight on what I should do?
Thanks
Ben
02-23-2005, 07:06 PM
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I'm using non-adjustable rockers, but I'm armed with 7.35" and 7.40" pushrods to make sure I get the correct lifter pre-load.
Thanks for the quick reply
Ben
Thanks for the quick reply
Ben
Originally Posted by smask04C5
Oil just bled out of two of them, reinstall and preload as you normally would. spring inside lifter body will offer enough resistance to adjust properly. assume you have adjustable rockers?
02-23-2005, 07:15 PM
#4
if you are running stock profile cam, torque rocker bolts to 22 ft#'s with stock 7.400 pushrods. if base circle is smaller on aftermarket cam install 7.350 pushrods and torque to same spec. most perf. ls1 cams have .030 smaller base circles, equates to .051 @ valve, hence the .050 shorter pushrod. keeps geometry correct
02-23-2005, 07:26 PM
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From what I've read the stock pushrods are 7.38" in length.
I'm using a Magic Stick v.3 cam which has a bit smaller base circle, though my heads are shaved .040" and the headgasket is Cometic .040". The head is about .052" closer vs. the stock headgasket/head setup. The cam had a base circle RADIUS that was .065+" smaller. From what I could calculate this works out to an ideal pushrod length of 7.393". With this in mind I think the 7.40s are the ones most likely to work as I don't think I'll get enough pre-load on the stock lifters with the 7.35" pushrods.
Ben
I'm using a Magic Stick v.3 cam which has a bit smaller base circle, though my heads are shaved .040" and the headgasket is Cometic .040". The head is about .052" closer vs. the stock headgasket/head setup. The cam had a base circle RADIUS that was .065+" smaller. From what I could calculate this works out to an ideal pushrod length of 7.393". With this in mind I think the 7.40s are the ones most likely to work as I don't think I'll get enough pre-load on the stock lifters with the 7.35" pushrods.
Ben
Originally Posted by smask04C5
if you are running stock profile cam, torque rocker bolts to 22 ft#'s with stock 7.400 pushrods. if base circle is smaller on aftermarket cam install 7.350 pushrods and torque to same spec. most perf. ls1 cams have .030 smaller base circles, equates to .051 @ valve, hence the .050 shorter pushrod. keeps geometry correct
02-23-2005, 07:41 PM
#6
pushrods i took out of my 04 vette were 7.400. i went with VHP Boss II cam .551 lift 216/224 duration, but used 1.8 crane adjustable rockers, lift now .590, used 7.250 pushrods. PP ls6 style heads 64cc chamber with mr gasket .042 head gaskets. if your base circle R is .065 smaller, your calculations appear correct.
