Hot Rod Forum : Hotrodders Bulletin Board - View Single Post - small backfire
Thread: small backfire
View Single Post
  #8 (permalink)  
Old 07-30-2011, 10:38 PM
Leoman's Avatar
Leoman Leoman is offline
Registered User
 
Last photo:
Join Date: Jan 2011
Location: leominster ma
Posts: 118
Wiki Edits: 0

Thanks: 5
Thanked 8 Times in 8 Posts
Quote:
Originally Posted by lg1969
I think your rockers are not set properly. I adjust the rockers same way you did except i turn the crank by hand until I see the exhaust valve closes then bring the piston close to TDC. Then I tighten to push rod until there is no play then 1/2 turn for the final setting. Then go to the next cyclinder do the same thing again. And I never adjust it when it's running.
Not to harp on it, but I must agree with this. It's the prescribed method, and the standard thread size on normal 3/8 rocker studs makes between 1/2 and 3/4 turns after zero lash the correct preload on the lifter plunger. Less and it's loose. More and it can (or will) bottom. I know having the stock-style cross-threaded locknuts makes it a total pain, but it can be done anyway. Just be sure you gauge zero-lash at the point where the rocker no longer lifts off the pushrod, not when you can't turn the pushrod at all. Depending on whether the lifter is fully primed with oil or some has bled off, you could go way too deep trying to get the pushrod so tight that it won't turn at all before you do that last 1/2 turn to preload the lifter. Then it could be bye-bye cam lobe.

I suppose that rechecking them with the motor running eliminates any worry about how well you found the lobe's base circle during initial static adjustment (along with accounting for any other inaccuracies that could exist like pushrod length etc.), but it's awfully messy with standard-type rockers. With roller rockers it would be a snap. They don't squirt oil at you.

Last edited by Leoman; 07-30-2011 at 10:56 PM.
Reply With Quote