Rob94hawk

iTrader: (1)

Winter's over so it's time to get back in the garage and put this engine where it finally belongs.

I have the Comp Cams pushrod checker my question is can I do it with the Patriot double springs on the heads?

And, do you guys still soak the lifters in oil for a few days?

Thanx

RamAir95TA

iTrader: (2)

I would take out the inner spring on one of them while measuring.

Are these new LS7s or what? If they are new LS7s/replacement lifters, just clean off the cardboard lint, a quick dunk in oil, and you're good to go. There is no need to soak the lifters for a few days as they are already prefilled with a light oil. If they are used or otherwise, an hour or two in oil won't hurt.

Rob94hawk

iTrader: (1)

The heads are bolted on so what's the right tool?

And yes they are new LS7 lifter.

gregrob

iTrader: (8)

Use a test spring!

wrd1972

iTrader: (12)

A couple of years ago, I tinkered with this in depth and this is what I found.

First off the best way to check PR length is to use a solid lifter or convert a hydro lifter into solid for testing purposes. I tried the soft valve spring and it always gave inconsistent results because the piston in the lifter would always move some tiny amount. IMO, its worth pulling the intake and using the solid lifter to ensure the measurements are spot on accurate. I remember way back, when using the soft spring testing, the 7.050" PR length looked to be correct for my motor. When I did the solid lifter testing more recently, the ideal PR was 7.150" and that is what I am running today with great results.

Second dont use a Sharpie because the markings dont wipe off easily enough to reveal the pattern. Instead, use a dry erase marker (whiteboard marker) and the patterns will be much more clear and readable. The best stuff to use IMO is ring and pinion gear pattern grease because that stuff provides the best pattern period but not everyone has it sitting in the toolbox.

Third the ideal scenario is to have the sweep pattern as thin as possible and dead center on the valve tip. You will quickly learn that this is not easily achievable so one must compromise. I personally believe that thin sweep slightly trumps being dead center because the bigger the sweep, the more parasitic loss (friction) at the rocker roller thus robbing power. Also you dont want the pattern to be too close to the edge of the valve or you risk excessive valve guide wear due to the valve being biased when moving up and down in the guide.

IIRC, my current roller sweep is around .040" with the pattern being around .030" off center on the valve. If I run the pattern dead center of the valve, the sweep increases to around .090" or so. Without some serious mods to the heads and valvetrain, it is impossible IMO to have .040" of roller sweep while having the pattern dead centered on the valve so again, you must compromise. I have also gotten the sweep down closer to .020" or so but the pattern was dangerously close to the edge of the valve.

My 2 cents.

93BlackZ28

iTrader: (5)

^agreed

sweetbmxrider

iTrader: (13)

I did mine with the patriots and a sharpie without a problem. I had a converted ls7 lifter while doing it.

Rob94hawk

iTrader: (1)

Intake is still off so now all I need is how to do the solid lifter mod.

RamAir95TA

iTrader: (2)

Take apart one lifter (snap ring), remove the guts, replace the plunger with something solid (I used a cut-to-size small bolt). Put a piece of electrical tape or equivalent around whatever you stick in there to keep it from scratching up the cylinder walls, then reassemble it. Don't forget which one you modified, and don't forget to reassemble it the right way!

I went out and bought a single lifter to use for this purpose (labeling it of course) because I didn't feel like taking apart and rebuilding one I was planning on using. Keep in mind a single lifter is $40 though...

wrd1972

iTrader: (12)

Yeah what Joe said. I used a little soft wood insert that would re-expand a bit after being crushed to ensure a very solid lifter.

gregrob

iTrader: (8)

I don't know how you were compressing lifters with a soft spring. When pumped up they're almost impossible to budge.

sweetbmxrider

iTrader: (13)

One rolled off the bench on me and had a slight mark in the body so I was forced to buy a single ahahah. I just used a bolt that I had to remove a little material from and then labeled it.

wrd1972

iTrader: (12)

If they are totally pumped up, they should in theory be impossible to budge.

IMO the lifter check valves slowly bleed the oil down inside the lifter bodies once the motor is turned off. Some bleed down faster than others and I have seen this in new lifters as well as old ones. The stronger springs accelerate the bleed down process as well.

I got a wider range of readings when using the soft test spring when measuring PR as a result of the piston moving in the lifter once the lifter had bled down either partially or completely. When I did the solid lifter, readings were much more precise and consistent. Although it is more work to do it like that, there is nothing that should skew the readings.

Rob94hawk

iTrader: (1)

Would it be a bad idea to modify an old stock LT1 lifter?

wysemunky

iTrader: (2)

If you want the most accurate and optimum results you should mock up using the parts your gonna be running. The newer LS7 lifters are supposed to have the same plunger depth as LT1 lifters so if you have a set of original LT1 lifters and a set of LS7 lifters you could check if they are the same from the tip of the roller to the part where the pushrod sits. If it is then there should be no problem using an old lifter and converting it solid to check with.

gregrob

iTrader: (8)

I'm going to be measuring one of my old lifters very carefully, and comparing them to my new Morels to see if the cup height and more specifically the relationship from the roller tip to the cup is the same.

If so, I'll make a solid test lifter. I will not however tear apart one of my Morels to do so lol.

wrd1972

iTrader: (12)

I closely compared the LT1 lifter to the LS7 lifter even going as far as taking them apart and analyzing the internal parts. I only found one thing obviously different between the two lifters.

The "pushrod cup" on the LS7 lifter sat about .020" deeper in the body compared to the LT1 lifter. Another way of saying it, the machined inside diameter slot that is used to capture the retainer clip, was machined .020" deeper in the body. The overall size of the the LT1 and the LS7 lifter bodies measured the exact same. I completely believe that this change was intentional (reason can be debated) and not a result of acceptable machining tolerances.

I will speculate that this was done to make the LS7 lifter more robust as to reduce the chance of breakage at the end of the body where the pushrod cup and the retainer slot are located. I will further speculate that GM expected the LS7 lifter to endure more abuse from the higher performing LS platform so beefing it up would not hurt. I saw no evidence of anything else different with the lifter roller or other internal parts.

Just an observation above. Will the .020" difference really matter? No.

Big Al

iTrader: (1)

I always use one of the springs out of a master cylinder. Use it as the valve spring. Set the lifter just like you would, no lash then down a 1/2 turn, 1/4 turn or whatever you think is best. I use the lifter just as it comes from the factory. Then do the "crawl" test. Just pay attention to what's going on.

You can cut an old push rod, put a long piece of small threaded rod inside with a nut on it. I thread the inside of the top of the push rod, but it's not that important, you can just bottom the threaded rod out in the top of the push rod. Adjust the rod to the the perfect length, remove it and measure it. I've worked on some engines that are next to impossible to get right and then fixed it by adding lash caps. Whatever works.

As I read through this, I noticed some were saying the LS7 lifter does not bleed down. That might be true if you run gear lube for engine oil, otherwise it's not true I can hold pressure on the back side of the rocker for a while and feel them go down. The key here is time, it takes a while. High performance lifters bleed down much quicker than regular lifters. That's why they recover from a "float" so much quicker.

Al

Rob94hawk

iTrader: (1)

One more ?, if you're gonna use a "solid roller lifter" then why use a lighter spring? Wouldn't leaving both inner and outer springs bring more accuracy?

Big Al

iTrader: (1)

If you're doing a cam swap there are other things you need to know, like piston to valve clearance, rocker arm bind, installed valve spring height, and so on. Using a light spring makes it so easy.

Al