Push Rod Length Q
Push Rod Length Q Ok,
Still a mystery to me why cylinders 2 and 4 required a shorter PR than 6 and 8.....
Anyways I rotated the engine over a million times, re-measured a million times. These are the numbers
7.300" for 2 and 4
7.312" for 6 and 8
So....Add .050"-.080" pre-load...
Options are
7.350"-7.380" and 7.363"-7.392"
Does 7.375" seem like a good compromise?
Is that an odd PR for a LS1 with heads milled .020"??
Thanks
Still a mystery to me why cylinders 2 and 4 required a shorter PR than 6 and 8.....
Anyways I rotated the engine over a million times, re-measured a million times. These are the numbers
7.300" for 2 and 4
7.312" for 6 and 8
So....Add .050"-.080" pre-load...
Options are
7.350"-7.380" and 7.363"-7.392"
Does 7.375" seem like a good compromise?
Is that an odd PR for a LS1 with heads milled .020"??
Thanks
TECH Regular
Joined: Jul 2011
Posts: 452
Likes: 2
Did you have head/valve work done? A 0.012" difference really isn't much if there was machine work done.
Did you use a pushrod length checking tool? If so, was it a Comp Cams? Com Cams pushrod tool measures in "gauge lenght", so if you buy pushrods that are not Comp Cams they could be ~0.017" off.
Did you measure any other cylinders?
Did you use a pushrod length checking tool? If so, was it a Comp Cams? Com Cams pushrod tool measures in "gauge lenght", so if you buy pushrods that are not Comp Cams they could be ~0.017" off.
Did you measure any other cylinders?
Did you have head/valve work done? A 0.012" difference really isn't much if there was machine work done.
Did you use a pushrod length checking tool? If so, was it a Comp Cams? Com Cams pushrod tool measures in "gauge lenght", so if you buy pushrods that are not Comp Cams they could be ~0.017" off.
Did you measure any other cylinders?
Did you use a pushrod length checking tool? If so, was it a Comp Cams? Com Cams pushrod tool measures in "gauge lenght", so if you buy pushrods that are not Comp Cams they could be ~0.017" off.
Did you measure any other cylinders?
I did use the comp cam tool, I only have the pass side head on. This way I can see the cam lobes orientation for measurements
6.800" + 10 turns on 2 and 4
6.800" + 10.25 turns on 6 and 8
Are you checking both the intake and exhaust lobes for your measurements?
If you cam has a big difference in lift between the two, and you're mixing your measurements, that could account for the variation you're seeing.
If you cam has a big difference in lift between the two, and you're mixing your measurements, that could account for the variation you're seeing.
The measurements are the same for I and E. The difference is the cylinders.
On the pass side of the engine the 2 forward cylinders are 7.300 for I and E.
The rear two are 7.312 for I and E. The inconsistence is cylinders not intake and exhaust.
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Verdad Gallardo They told me .050 to .080 5-6 months back, but I am using LS1 lifters. Looking back at why I got the 7.375s...
If I did get 7.350" That would leave a couple lifters with .038" pre-load and the rest a .050"....
7.375 gives me .075" and .063"
Last edited by badazz81z28; Oct 2, 2012 at 08:52 AM.
7.375" will be fine.
Guys, the range is very broad...you could go from .020-.11x" and be fine, just with some more noise in the lower preload range. We shoot for between about .050-.090"...that gives enough of a range that there will be a readily available pushrod available for most anything (because they are available in .025" increments).
Guys, the range is very broad...you could go from .020-.11x" and be fine, just with some more noise in the lower preload range. We shoot for between about .050-.090"...that gives enough of a range that there will be a readily available pushrod available for most anything (because they are available in .025" increments).
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Largest Stocking Distributor of LS-x Engines / CHECK OUT OUR NEW WEBSITE!
COMP - FAST - PACESETTER - DIAMOND RACING - EAGLE SPECIALTY PRODUCTS - CALLIES - COMETIC GASKETS
RAM CLUTCHES - MOSER ENGINEERING - KOOK'S HEADERS - ARP - GM BOLTS AND GASKETS - MSD - NGK
POWERBOND - ASP - AND MORE!
