lash questions
lash questions
OK, I realize this is probably the 5,000th post about valve lash.
but please, somebody just humor me and make sure I'm doing this right
I'm doing lots of modifications at once and I just want to make sure I didn't screw up the simple stuff. This is exactly what I did.
put piston 1 TDC (found it with cam gear marks)
followed the chart on shoebox's page.
put the rocker on
slowly tightened the hex nut while spinning the push rod
as soon as I felt drag, I gave it a half turn (stock lifters) and then held it
while I tightened the jam nut.
how does that sound.
when I'm done the pushrod should be snug but still able to turn right?
Thanks guys
but please, somebody just humor me and make sure I'm doing this right
I'm doing lots of modifications at once and I just want to make sure I didn't screw up the simple stuff. This is exactly what I did.
put piston 1 TDC (found it with cam gear marks)
followed the chart on shoebox's page.
put the rocker on
slowly tightened the hex nut while spinning the push rod
as soon as I felt drag, I gave it a half turn (stock lifters) and then held it
while I tightened the jam nut.
how does that sound.
when I'm done the pushrod should be snug but still able to turn right?
Thanks guys
Last edited by Eff; Dec 17, 2004 at 01:54 PM.
Re: lash questions
this is a good post.. there is alot of info out there but it never seems to discribe it to the point where i would be comfortable doing it. What you discribed is exactly how i plan on doing it so im interested to see replys..
Craig
Craig
Re: lash questions
I adjust mine with each individual cylinder on TDC. I start with number one and then follow the firing order until all 8 are done. Don't forget that with the polylocks you need to give one last torque on both the center screw and the nut at the same time turning both together to help lock it.
Re: lash questions
Okay, I was in the same boat as you guys. Had never opened a motor up before, let alone adjusted for valve lash. Well, here is the procedure I went by and it set the bitches up 1st try. I was also using Comp R lifters, which are notorious for being bastards to get set correctly.
1st off, I don't like the spinning pushrod method. I heard it is VERY easy to over tigthen the rockers doing this method. I went with the up/down method. Basically I had the motor at #1 TDC and followed Shoebox's diagram as to the firing order/TDC order. Basically when you get to a certain TDC, whether #1 or #6, he had exactly which intake and exhaust valves you could adjust. Here is the basic guidelines I went by:
put roller rocker on
put roller rocker nut on the studs
slowly tighten the nuts while pulling up/down on the back of the roller rockers (side where the pushrods are).
Once you get where you can't move the roller rockers up or down, that is Zero Lash.
Tighten the poly locks while making sure that the nuts don't tighten down any more.
Now in my case (Comp Rs) I only tightened them MAYBE 1/16th of a turn to set the preload. In your case, stock lifters, I believe it is a 1/4 turn. Don't qoute me on that but check it out for yourself.
And that is it guys. We haven't had a single problem with my little brother's cc306 95 Formie. It just dynoed 347rwhp corrected, so I know the valvetrain that I adjusted will hold together to 6600 rpms.
Good luck and feel free to email/PM me if you have any other questions. But most of all, don't worry it ain't that bad.
1st off, I don't like the spinning pushrod method. I heard it is VERY easy to over tigthen the rockers doing this method. I went with the up/down method. Basically I had the motor at #1 TDC and followed Shoebox's diagram as to the firing order/TDC order. Basically when you get to a certain TDC, whether #1 or #6, he had exactly which intake and exhaust valves you could adjust. Here is the basic guidelines I went by:
put roller rocker on
put roller rocker nut on the studs
slowly tighten the nuts while pulling up/down on the back of the roller rockers (side where the pushrods are).
Once you get where you can't move the roller rockers up or down, that is Zero Lash.
Tighten the poly locks while making sure that the nuts don't tighten down any more.
Now in my case (Comp Rs) I only tightened them MAYBE 1/16th of a turn to set the preload. In your case, stock lifters, I believe it is a 1/4 turn. Don't qoute me on that but check it out for yourself.
And that is it guys. We haven't had a single problem with my little brother's cc306 95 Formie. It just dynoed 347rwhp corrected, so I know the valvetrain that I adjusted will hold together to 6600 rpms.
Good luck and feel free to email/PM me if you have any other questions. But most of all, don't worry it ain't that bad.
End all be all method of setting preload.
An old machinist showed me this method that he has used for over 30 years and I have yet to see it in an manual.
(1) Bring up the rocker you are going to set using your prefered method, there are many.
(2) Instead of "feeling" the pushrod and fighting oily fingers, dirty lifter cups, and burred pushrod ends. Use a .004 feeler guage just like setting lash on a solid lifer cam and then tighten your usual 1/4 to 1/2 turn. This eliminates all variables and gives consistent preload every time.
An old machinist showed me this method that he has used for over 30 years and I have yet to see it in an manual.
(1) Bring up the rocker you are going to set using your prefered method, there are many.
(2) Instead of "feeling" the pushrod and fighting oily fingers, dirty lifter cups, and burred pushrod ends. Use a .004 feeler guage just like setting lash on a solid lifer cam and then tighten your usual 1/4 to 1/2 turn. This eliminates all variables and gives consistent preload every time.
Re: lash questions
when i did mine on my 91 i hand tightened them till i felt drag. then gave it a little last snug. i used the crane gold roller rockers and they felt a little loose, and the pushrod still had rotating movement left but no up-down movement.
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