[rohrt]

I was going to do the Straub method to get my pushrod length. It looks simple enough to do.

In practice this turned out to be a big fail. To establish the 90 deg relationship to the spring retainer there is only a about 1-2 threads left. The polylock is not threaded all the way down, there is a 1/4" gap at the bottom with no threads.


https://www.youtube.com/watch?v=o5is9BsH5OU&t=12s

I guess I need to come up with a plan B

[Gach]

Seriously there’s 50 ways to check Valve train geometry. But here’s The simplest is most accurate way. Get some daikon or black Magic marker and coat top of the valve. Put your adjustable push rod in and your rocker arm on. Set the lash, now turn motor over, the rocker will wear a pattern on top of the valve, I’ll put up a picture. Adjust the push rod up or down until the pattern falls in center of the valve according to the one in my picture. Once you get the correct pattern, Measure your pushrod length, that’s the length you need.

[Stan Weiss]

Originally Posted by rohrt

I was going to do the Straub method to get my pushrod length. It looks simple enough to do.

In practice this turned out to be a big fail. To establish the 90 deg relationship to the spring retainer there is only a about 1-2 threads left. The polylock is not threaded all the way down, there is a 1/4" gap at the bottom with no threads.


https://www.youtube.com/watch?v=o5is9BsH5OU&t=12s

I guess I need to come up with a plan B

Scott no longer works at Straub. But he does post on Yellow Bullet. I am sure he would be happy to answer any questions you about his method.

Stan

[Gach]

You my have to Recoat the valve a couple of times. Clean the marker off with break clean and recoat it. Usually when I’m done, I set up a dial indicator on the retainer and Measure the max lift. Just for peace of mind.

[25stevem]

Correct, that’s the length you need if your valvetrain needs to run WITH lash.

If your pre loading a hydro lifter then that amount of pre load needs to be added to the length of your push rod if you want 100% accurate geometry, no less still have the maximum lift your cam and rocker ratio can provide.

[rohrt]

I see some people use the light spring setup and others used the springs they will run. Does my preload on the lifters make any difference (.030)

My pushrod checker is aluminum so I don't trust its strong enough. I have the light springs to do the job but don't want to pull the heads again;(

Looks like i would need the CC -> 7704-1: Adjustable from 8.800" to 9.800".

The old pushrods were smith brothers 8.75 long with the CC rollers. The Johnson rollers (ST2112OPR) are shorter.
I tried a quick check with those pushrods and as expected the line is way high.


Does anyone make a pushrod checker that is made for high spring pressure?

[Gach]

usually I take a hydraulic lifter, I have a spare and make it into a solid lifter, because if the hydraulic lifter you use isn’t pumped up, your not going to get a accurate reading.

[Gach]

You don’t need to use the light checking spring, and aluminum adjustable push rod is fine, even if it 780 # open. So what type lifters are you using?

[rohrt]

Originally Posted by Gach

You don’t need to use the light checking spring, and aluminum adjustable push rod is fine, even if it 780 # open. So what type lifters are you using?

Johnson rollers (ST2112OPR)

[Gach]

Just make sure that lifter is all pump up and you should be all set. If I remember correctly lifter adjustment goes like this, adjust until there’s no play in push rod, and then go a 1/4 turn. What I used to do with a regular hydraulic lifter, is put it in a can of oil and push the plunger until it’s pump up.

[Gach]

In other words with a lifter pumped up, just set it so there’s no play in push rod, then roll motor over. You will notice with lifter pump up, if you go that 1/4 turn the valve will start to open, specially if you have dial indicated set up on the retainer.

[rohrt]

Thanks Gach,

Working through some confusion here. I thought the Johnson ST were 1/2 turn for the pre load, if the 7/16 studs are .050 per turn, then 1/2 turn is .025. The Johnson preload says .030.

Are you saying 1/4 pre load because you want to be half, of the 1/2 inch preload?




PS - pushrod checker is holding up. Running some test now.


I put a dial indicator on the retainer. I set it at zero lash and gave it a 1/2 turn and it starts bleeding down pretty quick.

The motor is not in the car and I don't have the distributor in...FYI

[Gach]

No The regular old-school lifters required 1/4 turn so your correct Johnson’s could be a half turn.

[Gach]

See you got it figure out

[rohrt]

Tried 8.9", 8.8", then back to the push rods i used with my CC 8.75 last. All with 1/2 turn preload so plunger collapsed.

I don't get it the stock rod length looks the best, but i don't get it, the lifters are shorter.


Does this sound right?

[Gach]

Third picture is perfect

[mgarblik]

Pic #3 is the winner for sure. When you say the old lifter is shorter, is that the overall length or the actual pushrod seat length. There is some variation brand to brand on them.

[rohrt]

Ran another test.

looks just a bit high.

Do I need to take the collapsed plunger into account? Would that essentially lengthen the pushrod .25?

Again with 8.75 pushrod and 1/2 turn preload

[Gach]

I’d say 8.75 is just about perfect. Don’t think you’ll get it any better then that

[rohrt]

SOB!

I only now noticed this.

I think the machined edge would have exposed enough threads for doing the Straub mid lift measurement.