How much does a lifter compress when not pumped up? I am wondering because I am going to check for pushrod length and I have a hydraulic roller lifter and was wondering if there is a certain amount you can take off after you measure it out for the right size? Has anybody ever messed up and measured with the lifter not pumped out and bought a set of pushrods and was it really off? Thanks for the help guys!

 

you can check it without the lifter pumped up. I check them without turning the motor over.

 

Kens86 how do you check pushrod length without spinning the motor over to see the wear pattern in the valve?

Also would it work to check the length without a checking spring in which would cause the lifter to go down but measuring the amount the lifter moves down and then subtract it from the length of the pushrod? For example my pushrod measured 6.935 ish then I used a dial indicator and checked how much the lifter compressed which was around .120-.128 so roughly .125 can I say I roughly need a 6.800 pushrod seeing the trickflow ones from summit only come in .050 increments? Thanks for the help guys!!!!

P.S. if anyone has ever done it this way and it worked it would be appreciated if you let me know because I am in a pinch to order them soon and really dont have the funds to buy the tools such as checking spring, compressed air adapater to hold valve up, and tool to compress valve spring to do it the other way right now. Thanks again

 

Does anyone know what Kens was talkign about when he said you can check pushrod length without spinning the motor over ? I have never heard of this. Also does anyone think my method of checking pushrod length would work? Thanks again

 

???? anyone.. Sorry to be a pest but I need to figure this out soon. Thanks guys!

 

bump

 

You should use a checker lifter. Either find a solid lifter with the same heel to cup height, or take apart a hydraulic lifter and shim it solid.

 

I understand that getting a checker lifter or making one a checking lifter by takign one apart is the right way but I dont have any hydraulic roller lifters to mess with and for a retro fit into a non roller block they are quite expensive just to buy to take apart. Does anybody think the checking with a adjustable pushrod with the lifter collapsed and then measuring with a dial indicator how much it collapses and taking that away from the length of the pushrod would work to get a close reading on pushrod side?

So my checking pushrod gave me a reading of 6.935 and a perfect wear pattern on the valve and you know the lifter has to be fully compressed there because the lifters are new and I can compress them by hand. So by measuring the lifter at its bottomed out point which was .125 ish I can neglect the .025 for preload and say that .100 shorter then my checkign pushrod should be close to ideal right? So a 6.835 pushrod would be the optimum. If I were to buy them and they go by .050 would I be better to go up or down in size?

 

I assume you have the heads assembled with the springs you are going to use and there fore you can't or dont want to use a checking spring?
This makes it pretty tough to get an accurate pushord length unless you have a dummy solid lifter. You can fill the lifter with oil and hope that the lifter button wont compress as you rotate the motor , but you will induce errors.

ASSUMING also that you have the same exhaust lobe and intake lobe lift AND the same valve stem height intake and exhaust....then....

You need an adjustable pushrod, use prussian blue on the rocker face (carbon paper works) OR...sight down and do the outboard exhaust and the next intake. You need a magnifying glass and a calibrated eyeball to sight well. Once you get the p-rod lengh dialed in by equal movement on the stem by the rocker, subtract about .020" (you do have a 6" to 7" mike or 12" dial verneir ..yes?? to obtain the p-r length dim. U need. Call Smith Brothers and give them the tip to tip dimension you need and specify hard case. They will make them to your dimensions.

After rereading you post...yes you can use a collapsed piece but you have a number of measurments...(the more meas = the more error). Spoeaking of errors you might do the 4 exhausts on each corner. Thats always a fun exercise to see if the machine work on the case is square with the world. I would do every rocker...but most folks dont.

 

Loudpedal you said I could do it with a collapsed lifter and it just takes more measurements. The measurements you are talkign about would be finding out how much the lifter collapses and how much preload I will run because I will need to subtract the preload from the collapsed number and then finally subtract that number from the pushrod length I was using. An example is 1/2 turn preload should be right around .030 and the lifter collapsed about .125 so I should need a pushrod that is .095 shorter approximately then the adjustable psuhrod length I used correct? Thanks again guys.