if i go w/ a shorter pushrod to maintain piston/valve clearance, do i lose some cam lift and profile.

 

What cams are you using/planning to use?

 

Is this a troll or are you trying to learn about valve trains?

 

se 257's

 

ok whats a troll...........

 

You will need to understand a few things before any answer will make sense. The pushrods do not affect the valve to piston clearance. The only reason you would change pushrod lentgth is because your cam base circle is different than stock.

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

 

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.

 

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

 

Were they telling you that they were going to use a perfect fit pushrod?

 

If they are using adjustable pushrods it is not a problem. If they are usijng perfect fit pushrods here is what you need to know; the SE257 cam requires +.030" pushrods for stock heads. If your heads are decked .030" and you are using .020" smaller head gasket it more than offsets the longer pushrod requirement (by .020"). I am thinking you would be good to go with stock pushrods.

The lifters have about .200" of travel. You would be preloading your lifters about .020 more than stock.

B