How inportaint is it.....

To get the pushrod length just right? I mean suppose I have the cam I want, the lifters springs and valves, got the rockers I want, I have checked the P to V clearance and used an adjustable pushrod checker to get the length, what if pushrods don't come in the exact length I came up with, do I just use the closest one I can find or what? no I have not done it yet but I am just seeking information, also ford pushrods are 5/16 diameter right?
If it's not the correct length it will throw it off a bit right...how much is ok?
Prolly gonna get to it this weekend sometime and want to know what I'm doing at least somewhat.
Say mine are 7 11/16" (7.6875") but no one has that size.

 

Use the next closest size.

 

Ok longer or shorter closest size? I assume longer but I don't know.

 

what RPM range you going to turn this motor?

 

Not a drag race motor, just a little street car, prolly never see over 5000 rpm, at least not until I get the money to stroke it out.
Actually looking at another F4TE block to do that too while I drive with this one.

 

I guess it depends on where it would put the pattern on the valve tip.

 

Try smith brothers...They can make pushrods in any length you want....Crane cams will do the same as will many cam manufacturing outfits...

It is important since valve giudes and valve stems tips can get ruined by wrong geometry.

 

For a street engine, it's not really critical to be exactly perfect. Do your length check and then look at what is available. Usually in .050 increments.

http://www.karlperformance.com/subCategory.cfm?subCat2=1020&subCat=821&cat=49

Set your checker to the length longer and check it, then do the length shorter and check it. Buy whatever leaves the narrowest pattern closest to the center of the valve stem. I use a sharpie to mark the top of the valve stem each time to check the pattern.

If it's hydraulic cam, it will never be perfect anyway, if it's a solid cam, factor in your clearance.

SPark

 

I guess I didn't say did I lol.........it a hydraulic roller cam, roller rockers 1.6 ratio.
Also looking into a B303 cam, gotta check P to V clearance first on the cam I have and see if I have room, but may just save that for the stroker.

 

As Mavman already pointed out.. proper geometry is VERY important to logevity. I use Smith Bros on all my custom builds and being even .050 off one way or the other can make measurable differences in rocker tip sweep. But bigger lift cams are usually far more picky than smaller ones.

http://www.lunatipower.com/Tech/Valvetrain/HowToVerifyValvetrainGeometry.aspx

First thing you'll need to do is either get yourself a solid lifter.. or at the very least.. use a very soft "checking spring" to avoid collapsing the hydro lifter during the check.

 

A solid lifter would be much easier on me, where can I get ONE?

 

Get an old hydraulic roller lifter, take it apart, fill it in with washers and make a solid lifter.

 

I guess a trip to the junkyard is in order then.

 

FYI, I have NEVER done that, it is just what literally popped into my head.

 

It will be a little more difficult to see the pattern if you use a checking spring I would guess. I've never done it that way. And as stated above, I also use a sharpie.