I'm hoping to find someone who can help me with my issue of correctly measuring my pushrods. I have a new set of Johnson short travel axle oiling lifters, measuring is being very inconsistent. I'm doing my best to follow my builders instructions, this is also my first time doing this.

Im turning the crank to get both lobes of that cylinder at base circle in compression stroke. I start measuring to zero lash. Once I have that measurement I was instructed to add .038" preload to the pushrods and reattach the rockers to confirm length. I was told I should then be getting as close as possible to exactly one half a turn with a ratchet to right. This confirms correct pushrod length.

I believe the problem is occurring during this checking step. The ratchet stops well short of a quarter turn, which means pushrod is too short. I then readjust the pushrod back to zero lash measurement and check by hand. Now there is a ton of play in the rocker. I can now push hard with my thumb on the top of the pushrod and feel the travel in the lifter spring.

I am am uncertain if this is normal or if it should
not be happening. This has happened so far on 5 out of 8 cylinders. Those three cylinders were quick and easy to measure zero lash, and achieved exactly a half turn to tight when checking. After removing the rockers there is no play in those lifter springs.

Im going to include my list of measurements to date. Cylinders 1,3,5,7 were measured last week and all got much longer after the lifters started having travel. 2,4,6,8 were measured today, 4 has travel and will be long like the other head was.

 

 

IIRC, the short travel lifters require a .015" preload setting. Confirm this before you move forward.

Use the Intake Closed, Exhaust Opened method on each cylinder. This means, either the intake or the exhaust valve is fully closed when the other is opened. Then measure the valve that's closed.

When the valve is closed, slip your adjustable pushrod into the bore, tighten down your rocker arm (little over hand tight is ok), and adjust the length checker until the rocker tip has no more up and down movement off the valve tip. That's your "zero lash" measurement.

Now, remove the length checker from the head, carefully. Use a set of dial calipers to measure the length end to end. Take your required preload measurement and add that to your number. That's your total pushrod length.

A full turn on the rocker arm, after setting 0 lash, will measure out to .079" IIRC (confirm this). So if the required preload is in fact .015", your goal is one 1/4 turn.

Hope that helps.

 

The Johnson short travel axle oiling lifters require .035" Pre-Load + or -.005". Additionally, it is possible to get a different measurement from each lifter.

If you are measuring correctly as jayyw has indicated you may need different length pushrods for each lifter.

 

I appreciate the help guys. When I started I was using the method you previously mentioned. I was quickly corrected by my builder to only his methods. He said to add 0.038 preload to each pushrod. I really think the problem lies within the lifters themselves. Some are moving and some are not. I have asked him this question a few times and it hasn't been addressed.

Here is his method thatnhe considers to be rs to be the only right way to do this and I have been following it. I find zero lash, his idea of zero lash is maybe 2 thousandths or less of play hand tight. Once I get there I measure the rod and add 0.038 to it. He then says the correct way to check the preloaded length is to attach the rockers and snug both bolts down hand tight. I should place a ratchet on at 12 o clock and it should get tight and stop at 6 o clock. He said anything between 5:30-6:30 is ok, the goal is a half turn.

Every measurement ive wrote down checks out at a half turn.

 

Assuming there is nothing wrong with the lifters themselves (are they new?) and assuming the pushrod checker has been measured with a dial caliper and assuming each one checks out at half a turn (which is simply a validation of the measurement), then perhaps you simply need to order a different length pushrod for each lifter. As I mentioned, this is very possible and does happen.

 

These are the Johnson ST2126LSR lifters? (necessary for higher open spring pressures.) You're likely going to end up with multiple different lengths of PR's with the short travel lifters, so that is normal.

Those Johnson short travel lifters have .058" of plunger travel as opposed to .201" of the Johnson 2110 drop in LS lifters that I used on my build. The desired pre-load remains the same at .035" +/- .010", but you just have less margin of error on the short-travel lifters.

Also, one of the advantages of Johnson lifters is that you can always call or email them for product support, as well. They were happy to speak to me when I had questions.

sales@johnsonlifters.com or 734-955-6500

 

Yes, these are the brand new Johnson short travel axle oiling lifters under the GMLS category on their site. I fully expect to have several different length pushrods once the measuring is done and correct.

My oroblem i think lies in where the lifters didn't all stay full of oil after soaking for a week prior to install. I believe that's why I can't get an accurate measurement on 5 cylinders.

Any ideas to go get these things full of oil again without pulling heads? Everything is pretty much assembled already and ready for fluids.

 

Ahh no. Don't do that. Did you pump your lifters full of oil or just let them soak? If you just soaked them it is unlikely they actually filled with oil. If they did it will most likely bleed out when sitting anyhow. You soak them for lubrication purposes, not to pump them up. You want the valve lifter plunger in its operating position (not pumped up) or you will cause the valves to open while adjusting.

 

Ahh ok I didn't know that. I thought just soaking was ok. On the 5 cylinders where the pushrods measure long, I can push the on the pushrod with my thumb and feel the travel in the lifter. On 3 cylinders that measured easily I don't get any play at all when trying to push on the rod in the lifter.

Which way should this be?

 

Soaking is ok. You just don't need them pumped up with oil. You soak them briefly before installation for lubrication, not for filling them with oil. Is the valve opening when you push on it?

 

When I'm talking about pushing on the pushrods with my thumb, that's just the adjustable pushrods sitting in the lifters. No rockers on at that point so I can get to the pushrod. Should I be able to do that or no?

 

When the lifters aren’t pumped up you will be able to depress the plunger a bit by pushing like that. When measuring and looking for 0 lash, you need to be careful that you aren’t pushing them down.

 

​​​​​​​Sometimes yes sometimes no. If lifter is filled with oil or stuck then you may not be able to depress it like you are trying. Just get to zero lash and add your preload. Then attach rocker and verify the half turn of the bolt.

 

My dilemma is that I don't know or trust that 5 of these lifters aren't already depressed somewhat and didn't return. When I first measured zero lash and added 0.038 preload to the rod. Then I attempted to verify by getting a half turn and that's what the lifter "loosens up". I can then turn the pushrod back back shorter to the zero lash measurement and have loads of play in the rocker.

Do I need to get these lifters pumped up and can I do so without pulling the heads back off?

 

When the lifters are pumped up once oil pump is primed and motor is turned over all of that play will be taken out. A hydraulic lifter acts like a solid lifter once filled with oil as oil is not compressible. As long as you are sure you are measuring your pre-load from zero lash it doesn't matter about this play. Some of yours might be filled with oil, and some might not be but you don't need to get the lifters pumped up to measure - this is what I am trying to tell you. Just get lifter to base circle of cam, find zero lash and add pre-load. Don't overthink it.

 

Make sure the adjustable pushrod is sitting in the cup and not on the edge of the lifter. This could possibly be the problem you are having. Take a flashlight and look into the bores and you can see if the cups are sitting correctly at the top of the lifter.

 

It almost like the other side has no head gasket or it has a super thick one on one side - all the measurements are like .040-.050 off. Have the heads been shaved or anything like that?

 

Maybe only 1 of the heads didnt get shaved for some reason...

 

I had to work late once again so didn't get a chance to work on the car this evening. Yes, I have been using a light to confirm the pushrod is fully in the lifter cup.

Heads have been shaved to 62.5cc and I'm certain I put both .40 head gaskets on. I didn't check the heads to make sure before we're shaved before installing. I'd be amazed if one wasn't, the builder is meticulous.