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Push rod length options with faced block and head
Posted: Sun Sep 29, 2013 12:29 pm
by WNX700H
Just trying to set the tappet clearances on my rebuilt 1275S motor which has the head and block faced. Just tried to set the valve clearances but seems like the amount taken off the block and head has been sufficient for me end up with not being able to achieve enough specified valve clearance. With the forger rocker the adjusting screw is wound so far into the rocker that it no longer has thread engagement .
What are the alternatives
1- shim the rocker posts
2 use shorter puch rods but believe shorter ones form 998 etc will be too short.
Recommendations?
Re: Push rod length options with faced block and head
Posted: Sun Sep 29, 2013 1:20 pm
by CooperTune
Would it be to much to ask how much was removed from head and block? It must have been quite a bit. It's quite normal for me to remove .020 to .040 from a block to zero deck that. Working toward 10 to 1 CR .005 to .015 off head is about what it takes depending on chamber CC. and pistons. You can have the push rods machined to shorten a little but shimming the rocker posts gets it twice as quick. Don't forget the rocker oiling hole on one shim or drill them all to be on safe side. Steve (CTR)
Re: Push rod length options with faced block and head
Posted: Sun Sep 29, 2013 9:52 pm
by carbon
Shimming the rocker posts will also change the valve geometry.
Out of interest are you using the long or short 'S' valves?
Re: Push rod length options with faced block and head
Posted: Mon Sep 30, 2013 7:45 pm
by WNX700H
Not sure to be honest its a stage 4 Minisport head with rimflo valves.