Pushrod length measurement for Newbs w Girly Roller Lifters

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NewbVetteGuy
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Pushrod length measurement for Newbs w Girly Roller Lifters

Post by NewbVetteGuy »

Application: SBC Gen1, Retro Hydraulic Roller, short travel slow bleed-down lifters, CompCams push rod checker (push rod cut in half with threads added to make it an adjustable length), 1.6 Comp Ultra Pro Magnum rockers; 5/16" pushrods/guideplates


I'm looking for advice on how to accurately measure my pushrods using the comp pushrod checker (note: I've never done this before).


Specific questions/restrictions:
  • I do NOT want to buy a solid version of my hydraulic lifters just to measure pushrod length
    I'm not super in love with the idea of taking one lifter apart and shimming it with washers, if I don't have to
    How do I accurately measure the pushrod length and account for the fact that the hydraulic lifter will be collapsed?



Idea: Can I just use my distributor hole-based oil pump shaft and an 18v drill with a zip tie over the trigger (1,600 RPM) to adequately fill the lifters to help get an accurate measurement?

-My springs are 145# closed, 350# open- can I measure push rod length with these springs installed or do I need checker springs to avoid collapsing the lifters even with the drill prime hack?

Note: I have short travel, low bleed-down rate Johnson (now Scorpion) lifters- I'm kind of hoping that this may help the drill prime solution to work.


Is there a better method? -Should I just forget all this stuff and just ask Johnson how much extra length to add to my measurement to make up for the lifter being collapsed and forgot all the drill or shim funny business?!?



Thanks!
Adam
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Re: Pushrod length measurement for Newbs w Girly Roller Lifters

Post by 77cruiser »

Put a couple of checking spring on that are light enough so your lifters won't collapse.

https://www.youtube.com/watch?v=o5is9BsH5OU
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Re: Pushrod length measurement for Newbs w Girly Roller Lifters

Post by CGT »

Checking springs for sure. I have even had the checking springs get sketchy on a hydraulic lifter.
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Re: Pushrod length measurement for Newbs w Girly Roller Lifters

Post by groberts101 »

Imo.. Shimming a pair of lifters would be easiest in the whole scheme of things. Otherwise next best and even easier.. is to just order same lifter but in solid design. Just make sure seat cup height is the same and you could use any similar solids too.
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Re: Pushrod length measurement for Newbs w Girly Roller Lifters

Post by treyrags »

groberts101 wrote: Tue Mar 20, 2018 4:34 pm Imo.. Shimming a pair of lifters would be easiest in the whole scheme of things. Otherwise next best and even easier.. is to just order same lifter but in solid design. Just make sure seat cup height is the same and you could use any similar solids too.
This. Or use a stiff spring and adjust all the travel out of the plunger. When you find the length you want subtract the thickness of oil you want underneath the plunger from the pushrod length
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Re: Pushrod length measurement for Newbs w Girly Roller Lifters

Post by 77cruiser »

Or you can get a cheap stock style lifter & shim, as you can't take link style apart to shim. Just have to take in account the difference in seat height.

https://www.ebay.com/p/Engine-Valve-Lif ... 0005.m1851
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Re: Pushrod length measurement for Newbs w Girly Roller Lifters

Post by cjperformance »

Measure lifter plunger travel with NO oil in the lifter.
Check pushrod length with the lifter plunger bottomed.
Decide where you want the plunger to be an subtract the excess plunger travel from your checked pushrod length.
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Re: Pushrod length measurement for Newbs w Girly Roller Lifters

Post by groberts101 »

Duh.. sorry for the slow uptake here. Short travel lifters don't have enough pluger travel even when full compressed to worry about skewing the roller tip sweep pattern by large enough amounts to throw off final pr length choice all that much

Can't remember what I've measured in the past but iirc it's not much more than .040" or so till fully seated. Just factor that in when adjusting sweep patterns and making final pr length estimate, is all. I'd surely call the mfgr to confirm plunger travel number.
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Re: Pushrod length measurement for Newbs w Girly Roller Lifters

Post by travis »

What about a Manley pushrod length checker...the one that sort of resembles a plastic rocker arm? I have used mine on dozens of sbc’s over the years as a sanity check against a “real” PR length checker (check twice, order once) and it is surprisingly accurate. I’ve never used it with a roller, but lots of hft and sft cams and it works
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Re: Pushrod length measurement for Newbs w Girly Roller Lifters

Post by ProPower engines »

Why not just prime the engine while checking the PR length???
That way you will have a real world location of the plunger and if they are short travel lifters you will only need to ad the recomended preload to the OAL of the PR when done.
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Re: Pushrod length measurement for Newbs w Girly Roller Lifters

Post by cjperformance »

ProPower engines wrote: Wed Mar 21, 2018 4:30 am Why not just prime the engine while checking the PR length???
That way you will have a real world location of the plunger and if they are short travel lifters you will only need to ad the recomended preload to the OAL of the PR when done.
If you were only checking PR length on the base circle, had the rockers position for correct geometry established and were simply using a checking pushrod to gauge length from rocker to a pumped up cup then a primed lifter is fine, no reason why not but its not at all necessary.
Most of the time I am checking for pushrod length I dont even have a pump or pan on the engine.
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Re: Pushrod length measurement for Newbs w Girly Roller Lifters

Post by MadmanMark »

One option is to tighten the rocker until the pushrod-checker bottoms out (before the valve moves) and measure how far it compressed. Once you get the pushrod size with minimal sweep on the valve, subtract the amount the lifter compressed less whatever preload you want.
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Re: Pushrod length measurement for Newbs w Girly Roller Lifters

Post by R.Olds »

Man you guys complicate things....LOL....If you dont have enough feel or talent to adjust an adjustable push rod without collapsing the lifter....you probably shouldnt be working on engines to begin with... :wink:
Dont forget to add in the lifter preload you intend to use, to the length of the push rod....meaning if you have a 7/16 stud and plan to use 1/2 turn preload, that equates to an additional .025 push rod length you will need.
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