pushrod length
Thread Starter
Pro
Joined: Apr 2011
Posts: 696
Likes: 7
From: Sacramento Ca
pushrod length
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?
Melting Slicks
Joined: Mar 2002
Posts: 2,203
Likes: 63
From: Staten Island NY
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.
When I swapped heads and did a cam my measurement was 7.350.
My engine doesn't have the dreaded sewing machine sound.
Drifting
Joined: Oct 2006
Posts: 1,724
Likes: 23
From: Minnesota
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.
Drifting
Joined: Oct 2006
Posts: 1,724
Likes: 23
From: Minnesota
I think its .060"-.080". Do a search for "lifter preload" the stock lifter preloads are on here somewhere.
Thread Starter
Pro
Joined: Apr 2011
Posts: 696
Likes: 7
From: Sacramento Ca
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...
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...
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Drifting
Joined: Mar 2000
Posts: 1,956
Likes: 135
From: Maryland
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.
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...
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...
Tech Contributor
Joined: Apr 2007
Posts: 10,924
Likes: 78
From: Forney Texas
ISIS SUCKS FAT CHOAD
Joined: Oct 2008
Posts: 8,124
Likes: 53
From: Earth, United States
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. :-)