[97z28convt]

So I got new heads and am working on pushrod length.. I've got a.checker but only have My hydraulic lifters I plan on using and know I'm getting a collapse when I cycle it. Anyone got a good part number or tip on what solid lifter I could use for this? Don't wanna do the weak spring method as head is torqued down. And I don't have tools for spring dissasembly. Thoughts , help

 

[steveo]

yeah that's a pain; a solid lifter for measuring is usually best.. it might just be best to get the spring tools, or a solid lifter. no big deal already having your heads on, there are plenty of tricks you can use so you dont drop a valve.

in the same token if you know a local machine shop they can probably loan you a used solid lifter.

i think it's possible to do all this as-is if you know the travel of your hydraulic lifter.. and make sure your measurements are done at zero, or whatever.. but that'd probably be sketchy at best.

 

[97z28convt]

Checked and the stock lifters are not hydraulic.. so used them and rod length is 7.3

 

[97z28convt]

Does anyone know if stock lt1 lifters are hydraulic. I tried to compress mine and they don't seem to be.

 

[steveo]

yes they are, absolutely.

if you had a solid lifter valvetrain setup.. well, it's a rare thing, generally race motors only

 

[97z28convt]

Shouldn't you be able to compress by hand.. I stuck a push rod in the end and pressed the open pushrod on My bench didn't compress at all. Then installed in engine and cycled it once. Still no compressing of lifter ...

 

[R3DLT1]

Shouldn't you be able to compress by hand.. I stuck a push rod in the end and pressed the open pushrod on My bench didn't compress at all. Then installed in engine and cycled it once. Still no compressing of lifter ...

Compress by hand no way jose.

 

[97z28convt]

Upon further review it did compress... But only a tiny little bit. Maybe .1 in. Took it apart and stuck a washer in it making it a solid lifter. Rechecked rod length using this solid lifter now. Got 7.3.. I know stock is 7.2. Everyone agree 7.3 makes sense.

 

[R3DLT1]

Upon further review it did compress... But only a tiny little bit. Maybe .1 in. Took it apart and stuck a washer in it making it a solid lifter. Rechecked rod length using this solid lifter now. Got 7.3.. I know stock is 7.2. Everyone agree 7.3 makes sense.

I would wait till u have ur solid lifters in before u determine PR length. Im picky like that but w/e works for u.

 

[97z28convt]

Not going to have solid lifters.. got new hydraulic comp lifters for the engine.. i feel pretty confident with the 7.3 length. Worst case scenario if I'm off by .1 in is it really going to change much? Maybe a couple HP? ... This is My first time measuring rods

 

[steveo]

dont screw it up. measuring pushrod length with hydraulic lifters is sketchy. solid lifter or weak spring.

this isnt a horsepower gain/loss thing we're talking about, there's no power on the table. it's valvetrain geometry. you could break something or cause early wear on valvetrain components.

 

[97z28convt]

Well by taking it apart and reassembling it with a washer instead of a spring ibessentially turned it into a solid lifter. So I don't see where I could be wrong.

 

[Racy Roadmaster]

97Z- Yes you will probably be ok shimming your hyd. lifter,but as you were instructed ,its best not to guess or estimate,there are enough hazy situations when assembling a motor,dont compound it. Get a solid lifter
then you know it is done correctly. Valve train geometry is important,the more accurate you make it, the more reliability you will build into your motor. ed

 

[BALLSS]

"generally" PR length with worked heads (ported and decked) and even more so with a decked block the PR length is shorter than stock (7.200"), not longer

I assume you are marking the tip of the valve stem, lashing the RR and rotateing the engine and them removing the RR to see the witness mark. If it is towards the exhaust side a shorter PR is needed. Closer to intake a longer PR.

you want the witness mark center on the valve stem

you also want a wipe pattern on the valve tip as narrow as possible

 

[FormulaJoe]

When I bought my ls7 lifters I ended up buying 1 extra one from summit to make solid for my PR length checking. I have read of a few people doing this and if done right works perfectly, no "guessing or estimating" to be had. To get the most accurate results you'll need to use the same kind of lifter you are going to be running and use something (like washers) to shim your lifter up so it is solid.

 

[97z28convt]

Yeah trick flow stated they have a thicker deck than stock so a slightly longer push rod makes sense .