jaycenk

iTrader: (1)

Ok so I am trying to measure for the correct length push rods for my Stock rotating/ LE2 head and cam.

I have a set of TF 7.150 push rods from the old engine. I put them in this engine and set the pre load 1/4 turn for lifters and and roller 1.6 rockers. I did a few turns of the engine while I had my oil pump primer running with a gauge and the pressure was at 60psi. I took the rocker off the valve steem I had marked with a sharpy. My swipe was long on the valve stem.

I have an adjustable push rod length checker so I decided to go with a length of 7.000
I assembled the rockers with the test push rod and set pre load again to 1/4 turn. Then I pressurized the oil system to 60 PSi and did a few more turns of the engine to check swipe.
The swipe looks perfect dead center.

My question is should I be doing this swipe test with the lifter pumped up like this or not? I would think since when the engine is running the lifter is going to be pumped up so that's where the swipe should be.

Can someone let me know if I'm doing this right or am I doing it wrong.
Here is a pic of the swipe at 7.000 inch push rod length.

1994Z28Lt1

iTrader: (1)

Doing this test with the lifter pumped up is the correct way to do it. Another thing that some people do is install a light valve spring (one designed for this exact purpose) so that the lifter does not bleed down

Your pattern looks good, I would go with the 7" pushrods although is that a common length for heads that lloyd does? Might not hurt to ask, only reason I say that is because with the deck height on my engine being 9.005 and .017" shaved off my heads I ended up with a 7.150" pushrod, but it all comes down to how the heads were machined up top, and the valve stem length

jaycenk

iTrader: (1)

I'll put an email into him put this is what it seems to want. I figured this was the best way to measure but want to make sure my thinking was correct.
I'm watching the hats of the lifters too as I am turning it with oil pressure at 60 psi and they are staying all the way up.
7.150 was to long on the stem. I tried it again to double check and it came out the same way.
Thanks for the info

1994Z28Lt1

iTrader: (1)

Actually I took another look at my records and I ended up going with 7.1" for my build and the guy that did my heads mentioned 7.050 to 7.150 was the normal range they expect.

Actually another question I have is what kind of lifters are you going with, if they are GM lifters I would tighten them down to 1/2 to 3/4 turn and recheck. If they are some other brand follow their directions, just making sure your covering all your bases.

jaycenk

iTrader: (1)

Gm LS7 lifter so I will do that before I order new ones.

bowtienut

iTrader: (1)

I'd think twice about tightening them down that much if you're going to turn up near 7000 rpm. I'm running stock LT1 lifters at 1/8 turn past zero lash.

If you're not going to spin that kind of rpm and you're certain your valvetrain is up to snuff, then you'll be okay with that much preload. If it's not, the lifter will pump up and you'll hang a valve open.
LS7 lifters are no better than any other hydraulic lifter in that regard.

SS RRR

iTrader: (2)

It's "sweep" and that looks fine. It looks to be a little off center favoring the exhaust side, which is what you want.