Exhaust and Intake preload different ?
Thread Starter
Instructor
Joined: Apr 2008
Posts: 245
Likes: 2
From: melbourne florida
Exhaust and Intake preload different ?
Good evening to all,
Have a question that I am sure has been answered numerous times here but I have not had any luck getting the exact input I am looking for.
I am getting to ready to swap out my older comp cams 26918 beehive springs for the Pac 1518's. 15,000 on the older beehives,its time to freshen the springs up.I am also upgrading to hardened pushrods over the stock pushrod as well as comp cams trunion upgrade kit as well.This is basically a ls1 block with ls6 ported and polished heads shaved .003 just as a clean up,, 273 XER CAM, 224/230, 581,588 @114. 4 years ago I had a good friend of mine that worked at chevrolet set this car up.It has gm replacement ls1/ls6 lifters,not the ls7 variety that seems so popular here..Rocker arms like I said presently are stock,pushrods as well ,with the exception of comp cams beehives.Car runs strong,no problems just time to upgrade.
One night I went out to the garage and was just curious as to what type of preload these pushrod/lifters were dialed in at.Strangely enough, every intake preload was right at .080 where every exhaust preload was at .070. I would think that they should be all the same? Every pushrod in this block is the same exact length,could it have something to do with the lobes on the cam I have? I know that one full turn after 0 lash is .047,so it was easy to determine. Dnt get me wrong,these are consistant numbers throughtout the valvetrain....Anyone help me out here? Thanx again.
Have a question that I am sure has been answered numerous times here but I have not had any luck getting the exact input I am looking for.
I am getting to ready to swap out my older comp cams 26918 beehive springs for the Pac 1518's. 15,000 on the older beehives,its time to freshen the springs up.I am also upgrading to hardened pushrods over the stock pushrod as well as comp cams trunion upgrade kit as well.This is basically a ls1 block with ls6 ported and polished heads shaved .003 just as a clean up,, 273 XER CAM, 224/230, 581,588 @114. 4 years ago I had a good friend of mine that worked at chevrolet set this car up.It has gm replacement ls1/ls6 lifters,not the ls7 variety that seems so popular here..Rocker arms like I said presently are stock,pushrods as well ,with the exception of comp cams beehives.Car runs strong,no problems just time to upgrade.
One night I went out to the garage and was just curious as to what type of preload these pushrod/lifters were dialed in at.Strangely enough, every intake preload was right at .080 where every exhaust preload was at .070. I would think that they should be all the same? Every pushrod in this block is the same exact length,could it have something to do with the lobes on the cam I have? I know that one full turn after 0 lash is .047,so it was easy to determine. Dnt get me wrong,these are consistant numbers throughtout the valvetrain....Anyone help me out here? Thanx again.
Pro
Joined: Aug 2009
Posts: 662
Likes: 0
From: Loxahatchee FL
there is always a difference between, that is why there is a low and high side to preload.
why are you changing the springs at 15k, stock ones last for ever and the beehive should easily last 30-50k unless your beating them to death.
I have them and believe that unless you are maxing out the spring load .650 you shouldnt need to replace this early.
why are you changing the springs at 15k, stock ones last for ever and the beehive should easily last 30-50k unless your beating them to death.
I have them and believe that unless you are maxing out the spring load .650 you shouldnt need to replace this early.
