pushrod tech question...
Cruiser
Joined: Dec 2007
Posts: 129
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From: NE Ohio
Flhrsi
cam lift and cam timing is what affects valve to valve and valve to piston clearance.
I don't know where to start but suggest you look at the service manual first and then come back and ask some questions.
There are many good folks here that will help.
B
Outstanding HDF Member
Joined: Jul 2007
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From: Daytona, Fla.
I thought you might be pullin' our leg. No offense, but it is the internet......
In an attempt to answer your question, you can't change the lift or profile of the cam with the push rod. The profile will determine when & how fast the valve opens, how long it's open, & when & how fast it closes. That will remain the same regardless of the push rod. The lift of the cam will determine how far the valve opens. Shortening the push rod enough to change that will result in a lot of clatter & possibly some serious motor damage.
If you have piston to valve clearance problems you need to look at different cams, deck or head height, or gasket thickness.
In an attempt to answer your question, you can't change the lift or profile of the cam with the push rod. The profile will determine when & how fast the valve opens, how long it's open, & when & how fast it closes. That will remain the same regardless of the push rod. The lift of the cam will determine how far the valve opens. Shortening the push rod enough to change that will result in a lot of clatter & possibly some serious motor damage.
If you have piston to valve clearance problems you need to look at different cams, deck or head height, or gasket thickness.
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ok thank you, some good info, im having some work done, heads ported, new valve job and heads were decked about 30thou, that would work w/ the 257 cam and raise comp a bit . The heads were done by a good shop who I trust as competent. Assembly is being done by local dealer [mistake]They called and told me they have to use shorter pushrod to maintain piston/valve clearance w/o droping comp [thicker gasket would drop comp] head shop said use 30-35thou head gasket. any coments
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Cruiser
Joined: Dec 2007
Posts: 129
Likes: 0
From: NE Ohio
Pushrods
ok thank you, some good info, im having some work done, heads ported, new valve job and heads were decked about 30thou, that would work w/ the 257 cam and raise comp a bit . The heads were done by a good shop who I trust as competent. Assembly is being done by local dealer [mistake]They called and told me they have to use shorter pushrod to maintain piston/valve clearance w/o droping comp [thicker gasket would drop comp] head shop said use 30-35thou head gasket. any coments
The lifters have about .200" of travel. You would be preloading your lifters about .020 more than stock.
B
Last edited by bwickes; Nov 29, 2009 at 06:50 PM.
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