engine pushrods

[terruscam]

I have an '84 GL 4WD wagon with rebuilt engine, solid lifters. I'm getting noise from there on passenger side somewhere. I have 'several' used pushrods and they seem to be of varying lengths. Should I use all the same length? Does it matter since the valve system is adjustable. Does anyone have a lot of experience with valve systems?

terruscam

[Nug]

I had a nice thing typed out, but I just lost the whole thing.

 

Trying to figure out the length of the pushrod to use? Try this test.

 

Take the rocker arm off. Color the tip of the valve with dykem, prussian blue, a Sharpie, whatever. Put the rocker arm back on. Adjust lash (without screwing up your fancy coloring job. How do you do that, you ask. I'm not sure. Eyeball it. Get it close.

 

Anyway, turn the engine over by hand, for one complete stroke of the rocker arm. Remove the rocker arm again. Look at the tip of the valve. You should have an even mark in your coloring, looking something like this:

 

You don't want it to be uneven, like this:

 

 

If it is all up on one side like the last quality drawing indicates, then your pushrod length is wrong. You could trial and error this with the different pushrods you have, or you could order an adjustable pushrod from Comp Cams or someone. Or you could make one. Figure out how long you want your pushrods by doing the above procedure until you get the pushrod length right, and then order up a set. You will be rewarded by having valve guides last a long time, and less friction. Not to mention a valvetrain that is more likely to hold together at high rpm.

[Nug]

Should I use all the same length?

That depends. If the engine was new, then all the lengths would probably be the same. But if you get into head milling and cylinder decking (which your rebuilt engine might have), the requirements for pushrod length changes. Almost no one checks this stuff, I would guess. But it's important if you want your stuff to run good, for a long, long time.

 

I heard that Formula Vee racers often have an entire engine full of different length pushrods, in an effort to get every valve perfect, in the search for horsepower.

[Nug]

TTT

 

Anyone else have input?

[NoahDL88]

Stick with the same ones that are already in the engine, the two different kinds, not only vary by lenght but also weight, if their weight is different your balance will be off, and thats no good, if you got the steel ones stick with them, although they are heavier they are made for the solid lifter motor, if you are running the aluminum pushrods those are from the hydro blocks, stick with those, cross breeding an engine is rarely a good idea. keep parts as a set. you wouldn't run 2 EA-81 pistons and 2 EA-71 pistons would you?

[terruscam]

Thanks everyone for the input. Since my engine was put together with new parts and old parts and different engine parts I guelss I'll just stick with the ones I have, at least they are all the same length, so I know that part for sure. As soon as I put them back in maybe I'll run tighter valve lash and eliminate the noise. Otherwise, I'll have to go all the way back in.

[Caboobaroo]

if you got the steel ones stick with them, although they are heavier they are made for the solid lifter motor, if you are running the aluminum pushrods those are from the hydro blocks

Well when I pulled my EA71 apart, I found one bent pushrod on the exhaust valve on the drivers side. Mine weren't steel though, they were aluminum. Is this right? I got another set from Mudrat79 that were from another EA71 and those were aluminum too.....

http://usmb.net/gallery/album210/pushrod This is the pic of the pushrod AFTER we tried to straighten it:-\