I am questioning my use of factory-length pushrods after installing the AFR 195's. I see the easiest way to measure the existing ones, is to use a black felt marker on the top of the valve. Then put the rocker back on and rotate the engine a few revolutions. The position and the thickness of the mark where the roller rocker hits the valve (and erases the marker black) tells you whether you're running short or long pushrods.

Here's a Holley link off of AFR's website .... with instructions.

My question is this: Are you to rotate the engine by hand, or put the rocker cover back on loosely and crank it with the starter?

My stroker has 20K on it, and it's still quite hard to crank over by hand using the balancer bolt. Guess you pull the plugs out to make it easier? Seems if you use the starter to crank it over faster, the oil would wash off the magic marker from the top of the valve.

Thoughts appreciated

My engine runs GREAT with the heads (I have almost 1500 miles since installing 'em) but I have a LOT of valve noise. I've re-lashed them three times and they always sound the same. So I figure it can't hurt me to check pushrod length and make sure it's correct. I'm using a Crane flat-tappet hydraulic cam.

 

Hmm no takers on this one?

 

Paul from what I have read and understand about the way this works you are correct. I have never done this myself. If I were doing it in my garage I would pull the plugs and rotate it by hand a couple of revolutions and then check the marks. Let us know how it works out.

 

Are you running a hydraulic or mechanical cam? It will vary the technique.
Did you pull all your spark plugs?

In the past I have used an adjustable pushrod with checker springs on both an intake and an exhaust valve. Turned the motor over by hand. Adjusting the pushrod length to achieve the smallest/shortest witness mark in the felt marker dye. I would start with the oem length. Based on wether it is centered on the valve stem or leaning to the intake manifold or the heads will help you determine if it needs to be longer or shorter.

I have never heard of actually running the engine.

 

FWIW, I wasn't asking about running the engine, just trying to decide if the technique was to crank it over with the starter, or pull the plugs and crank it by hand.

I'm still driving it - haven't taken a wrench to it since putting the heads on. When I put the heads on, I used chromemoly standard length pushrods.

It's a Crane flat tappet hydraulic cam and I'm running Crane 1.6 roller rockers. None of that stuff has changed since building the engine a few years back. All I did recently was replace cast heads with AFR Aluminum ones.

At zero lash, I got lots of valve noise, so I rechecked them all. Same noise .... so I gave 'em all 1/2 turn past zero. Didn't affect the noise at all. Last try was 3/4 turn past zero lash.

I am coming to the realization that it's just going to be a lot noisier with the aluminum heads on it. I've built a LOT of engines in my years but the only ones I ever put aluminum heads on, were OEM Japanese stuff. All my previous small block Chevy motors were long before I could afford a set of AFR heads.

My Brother is the automotive engineer of the family and he tells me the noise is normal. He claims that the aluminum heads are going to reflect at least 50 percent more noise than the cast iron ones did. And man, it sure sounds like it!

But back to measuring the pushrods: I want to make sure they are the right length as I don't want make oil-pushers out of expensive heads. I've heard horror stories about valve guides getting all screwed up because of incorrect geometry and I want to get this detail nailed down perfect.

So when I color the tops of the valves and reassemble the roller rocker, do I crank it over by hand? How many cylinders do you check?

 

buy a melling pushrod length checker and be done with it in a minute or two......20 bucks.......

 

That's certainly worth it! How do you use one?

 

you simply put the cam on the base circle of the valve you care to check and slip the tool( looks like a blue plastic rocker) on the stud and if your geometry is right it will rest on the valve tip and pushrod at the same time.....if it sits on the stem and you can move the pushrod up and down, you measure the gap and go longer....if it sits on the pushrod and you have a gap at the valve you simply go shorter....jegs and summit carry them...

 

This is what I used for my motor a few years ago when I put on the AFR heads. I had to put in .100 longer pushrods. I have to check it again this winter when I install the solid roller. I hope I can find the tool. It works very well. I also checked with the felt tip marker after installing the pushrods and it was right on.

 

good for you, it's surprising how much it can be off and yes you must do it again when you go roller which is another great move....valve train geometry is soo important and often overlooked and a real asset to performance and valve guide life too...good luck......

 

Gordon i can mail you mine to use if you cant find yours

 

I rotate mine by hand....remove the plugs if you have to.

Like GORDONM, I used +.100 length pushrods on my AFR 195's......perfect fit.

 

You know I have not seen mine in a year or so. I think I left it at Jays house when we were doing his motor. I'll have to see if he still has it. Probably cost more to mail it to me than buying a new one if I can't find it. I still have some time as I won't need it for a while.

 

Check for an exhaust leak, sounds just like a noisy lifter

 

well you may be right but if you need it let me know