FRiCK916

Hey guys I know I should measure.. but I figured ide take a poll and see what you all said first. Stock motor with 317 heads .010 milled, LS6 lifters, LS9 gaskets which are the same thickness... The cam is from Arun less than 2 years ago on LXL lobes, stock rockers... currently running 7.400 and I just feel like it's too noisey. Should I try .425 or .375? Or should .400 be on the money?

warren s

Get a pushrod checker for $20 and just measure a few cylinders. Its a waste of time and money to guess.

When I swapped heads and did a cam my measurement was 7.350.
My engine doesn't have the dreaded sewing machine sound.

FRiCK916

What lifters do you have and what preload did you go with?

warren s

I used LS7 lifters and went with a .080 preload.

PRC Stage 1 LS6 heads with a TSP 228R cam. Stock headgaskets and GM headbolts.

reactor2

The pushrod checker is the only way to go.

I went with the Comp Cams OEM lifters. I went with ~.080" preload. Motor was noisy. I replaced the rockers with shimmed Yella Terras and remeasured for ~.040" preload. Motor is less noisy. Don't be a preload junky.

FRiCK916

I ordered one tonight... been researching preload all night. I'm using ls1 lifters... what preload should I shoot for here? .065?? I don't even know what I'm sitting at right now...

reactor2

I think its .060"-.080". Do a search for "lifter preload" the stock lifter preloads are on here somewhere.

FRiCK916

So with 7.475 I get a little more than 1.5 turns out of the rocker bolt... with 7.450 I get a little more than 1.25 turns and with my current 7.400 I get about 1 turn. And I'm finding zero lash at 7.375 maybe a hair lower, but 7.350 is audibly too loose...


What you think guys? Should I go tight with the 7.475 that way when the aluminum expands I'll still be good? Or???

Thanks for any help...

BLOWNBLUEZ06

When I've measured total plunger depth on a "LS7" stock lifter, I've gotten .200" before bottoming out. I've run as much as .120" preload but prefer around .080-.090".

FRiCK916

So with what I wrote above could you elaborate to what size I should be looking at?

Rx7Rob

I would not use the rocker bolt method. When I did my cam I tried rocker bolt, adjustable length pushrod, and measuring the difference in cam base circle. All three resulted in different lengths. I went with the length checker results and after 1.5 years it still seems good to me.

BLOWNBLUEZ06

That depends. Are you running stock rocker arms and turning the rocker bolt or turning an adjusting nut on an aftermarket one?

MVP'S ZO6

I too got .200 when checkin full plunger depth on a LS7 lifter. Currently running .080 preload.

To the op as its already been stated 20 bucks will get you a comp cams pushrod length checker. Easy to use.

Measure twice order once. :-)