pushrod length
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Senior User
Joined: Nov 2001
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From: Calgary Canada
pushrod length
The 302 in my '72 F-100 has positive stop rocker studs so valve clearance is adjusted via pushrod length. How much should the pushrod compress the lifter for proper operation?
Thanks
Thanks
Senior User
Joined: Jan 2001
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pushrod length
Hydraulic lifters do not require any valve lash, so if you have stock length rods you will be safe. If your not sure, or have done any mods that may have changed the valve train geometry, check out the site below to see that proper way to check and adjust lifter preload.
[http://www.cranecams.com/hydlfaq.htm]
[http://www.cranecams.com/hydlfaq.htm]
Laughing Gas
Joined: Nov 2002
Posts: 1,198
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From: Fairmont
pushrod length
Seems like years ago Ford had a spec called a "dry lash"
What you did is rock the rocker arm untill the lifter is fully compressed, then you were suppose to have about .070"-.100" clearence. If they are new it's easy, if used it's hard to compress them.
I've checked the full movement of a hyd. lifter before and it seems like it's about .185"
What you did is rock the rocker arm untill the lifter is fully compressed, then you were suppose to have about .070"-.100" clearence. If they are new it's easy, if used it's hard to compress them.
I've checked the full movement of a hyd. lifter before and it seems like it's about .185"
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From: Calgary Canada
pushrod length
The instructions I got with the cam says to compress the lifter by .02" to .06". The threads on the rocker stud are 24 tpi so 1 turn of the rocker nut should give about .4" which should be just about right. So I went through and turned the rocker nut down while spinning the pushrod with my fingers until I felt some resistance. I then checked the amount I had to turn the nut until it bottomed out. As long as it was 1/2 to 1 turn I figured it would be OK.
When I got the engine running it ran like crap. I went through and found some of the valves still had tension on them when they were on the heel of the cam so that valve was being help open. Now I'm going through and backing off on the lifter preload with shorter pushrods and that seems to work.
Has anyone else had similar experience? What did you do?
When I got the engine running it ran like crap. I went through and found some of the valves still had tension on them when they were on the heel of the cam so that valve was being help open. Now I'm going through and backing off on the lifter preload with shorter pushrods and that seems to work.
Has anyone else had similar experience? What did you do?
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