Measuring for custom pushrods

[dkbug]

Hello guys. Nice to see you guys still as active as ever.

First off I would like to "warn" you guys that I am kind of new to valve train adjustment. From being an engineering student, I do know the terminology and can understand complicated instructions.

I bought the set of cut to fit chromoly pushrods from 440 source and I am making an attempt to take an accurate measurement of the size that I need.

I have a pushrod length checker that I built out of an old chromoly pushrod so I can increase or decrease the length to get an accurate measurement.

Before, I had solid lifters, and now I have hydraulic. I wasnt completely sure how to check for a precise measurement. What I would do before is I would take a dry eraser marker and mark the tip of the valve and install everything, turn the motor over a couple times, then dissasemble to check the wear on the marked valve. With hydraulic lifters, I assume that they will need to be pumped with oil prior to checking for overall pushrod length.

I have my cam card which has all the lashing specs and stuff on it.

I did a quick search on google and youtube but only found chevy type rocker assy's which may or may not be a bit different process..?

Any possible required info
------------------------
440
906 heads - 3 angle valve job with bigger valves
hydraulic comp cam camshaft .488 lift @ .050 - springs to match
hydraulic comp cam lifters
isky ductile adjustable rockers
Anything else?



Thanks in advance guys,

Dakota

Keyboard warriors don't waste your time replying. The train tracks are a much more efficient place for you to play around.

 

[bOb shingler]

they should have oil in them. remove the valve spring and install a very light spring, something that you will find in the hardware store. all you need is enough pressure to return the valve to it's seat. do the same thing as before. now cutting pushrods is a bit on the tricky side. you will need a large dial caliper, like a 12" one. measure carefully from the ball end to where the cup seats in the tube. cut it a tad longer so you can grind it to the correct length on your bench grinder. go easy and check often.

 

[dkbug]

Right, I guess I need to word this a bit differently. When I put my pushrod length checker in, am I doing the process with the marker correctly? Also, I got word that the lkfter needs to be on the bottom side of the lobe and I make the pushrod larger until there is no play, them make it .020" longer.

 

[TrailBeast]

I'm seeing 20-40 for a 440, but you don't need them full of oil.
Just as long as it compresses the spring in the lifter 20-40 for the preload.

 

[dkbug]

Lost my private messages when the forum switch over. Had a gentleman give me the full correct process to check the length on the pushrods. Anyone else here willing to chime in?

 

[dkbug]

Right, I guess I need to word this a bit differently. When I put my pushrod length checker in, am I doing the process with the marker correctly? Also, I got word that the lkfter needs to be on the bottom side of the lobe and I make the pushrod larger until there is no play, them make it .020" longer.

Now I understand what you said, but knowing how to dial in the correct length is where im lost. Do I adjust the length and just determine the length as to how much the valve opens, or by how the rocker arm rides on the valve tip?

 

[AndyF]

Hughes Engines has a good write up on this subject in their tech tips. They also sell an adjustable lifter so you can measure the pushrod length for a hyd lifter. The key thing is to get the adjuster ball in the correct location first. Once the adjuster ball is properly located then you just measure the pushrod using an adjustable pushrod and you are done.

 

[dkbug]

Hughes Engines has a good write up on this subject in their tech tips. They also sell an adjustable lifter so you can measure the pushrod length for a hyd lifter. The key thing is to get the adjuster ball in the correct location first. Once the adjuster ball is properly located then you just measure the pushrod using an adjustable pushrod and you are done.

I did just this and everything worked out great. I had been looking for a good write up like that for awhile. They do a pretty good job explaining the geometry of your valve train.

I sure do wish that we can have a compiled tech article on these forums. I would be more than happy to code one up.

 

[AndyF]

Good deal. I just finished up checking some new rocker arms on an engine and measuring for pushrods. I do it often enough that it is just a 5 minute drill. I adjust the rocker arm so the minimum number of threads are showing then install an adjustable pushrod that appears to be close to what I need. Torque down the rocker shaft, adjust it to zero lash and then rotate the engine over a few times to check for clearance issues. I always measure the lift so I can confirm the rocker arm ratio and then double check valve to piston clearance while I'm in there.

 

[dkbug]

The only thing I was unable to do is check piston to valve clearance. SUPER hard to accomplish an accurate measurement while the motor is still in the car. I am running a bit bigger valves, and I know I was cutting it close before with the closed chambered heads. I installed a set of 906 open chambered heads and a thinner gasket so I knew that I was ok. Just got done breaking in the motor. I had quite a bit of valve train noise but that was to be expected with new lifters/cam and it was my first time with adjustable rockers. Quite a learning experience I must say!