Valve adjusting help
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Elder User
Joined: Nov 2003
Posts: 576
Likes: 9
From: Rockford, IL
Valve adjusting help
I'm trying to pin point some excessive noise issues I'm having with my '86 302. I recently bought it "rebuilt" but thats not the issue. I know nothing about the history of the engine except that "it came out of a Marquis" and even that isn't guaranteed. I got it running this week and I now have what seems like lifter noise. The engine could have sat for a while I don't know. I'm going to try some Seafoam or Marvels Mystery Oil to see if the noise will go away on it's own. I will then replace the lifters if needed. I was just reading my Haynes manual and it says that I can check clearences between the rocker arm and the valve stem tip and then compensate with a longer or shorter puch rod. Do any of you know what the dimension should be? Would that be the "collapsed lifter gap clearence" of 0.096" - 0.165"? I hate to ask stupid questions but I've never done any valve adjustment more than tightening down the rocker arm nut until I hear tapping and then backing it off. So any advise you would have would be appreciated. Also where would I find a tappet bleed down wrench? Thanks, John
Last edited by black58; Jun 3, 2006 at 12:37 AM.
Hotshot
Joined: May 2004
Posts: 12,170
Likes: 5
From: The hills of No. Calif.
Make sure it's decent oil pressure (check it with a mechanical gauge) and run it for a bit. Hopefully the lifters will unstick. It's not all that uncommon, especially if it's been sitting a while. The Marvel crap (or something like it...personally I'd go with the Seafoam) may help, worth a try. You really don't want to go changing the valve clearance (or in this case, the lifter preload) to try and compensate for the sticking lifters. If/when they do free up, then they'll be too tight which can bring rise to all sorts of new problems. Worst case scenario, replace 'em. And then you can take the opportunity to replace the intake with a nice aftermarket one at the same time.
These would be pedestal mount rockers, in which the lifter preload is set by setting the valve stem height (a machine shop task with the heads off the vehicle.) Replacing the pushrods with longer or shorter ones is a sort of quicky on-the-car adjustment.
These would be pedestal mount rockers, in which the lifter preload is set by setting the valve stem height (a machine shop task with the heads off the vehicle.) Replacing the pushrods with longer or shorter ones is a sort of quicky on-the-car adjustment.
Last edited by TigerDan; Jun 5, 2006 at 08:56 AM.
