verano29

I'm in the process on installing heads (dart pro1 205) and cam (comp 228/231 .571/.573 112) on my 98 vette and I'd like to order the new push rods ASAP. What lifter preload are you guys running and what do you recommend?

GuitsBoy

iTrader: (4)

.080 to .100 is the norm. If youve got everything mocked up, use a PR length checker and find out how long the PRs would need to be for 0 preload, then add .080.

vettenuts

iTrader: (4)

I ran your numbers based on your measurements, looks like 7.425" is the ticker. I PM'd you the calc's.

verano29

Bump. What lifter preload are you guys running?

Fratsit

iTrader: (1)

.100 for me.

R/

Frat

verano29

Seems that .100 is quite common. Has this proven to be too much for anybody? Any valvetrain issues associated with running such a high lifter preload?

verano29

Anybody have valvetrain geometry issues and/or other valvetrain issues running .100 or over on lifter preload?

vettenuts

iTrader: (4)

Pushrod won't affect geometry, only preload. They come from the factory with 0.100".

verano29

Yeah, I suppose it wouldn't affect geometry. I didn't know that they come from the factory with .100" preload. Is that common with roller lifters on stock setups?

grinder11

iTrader: (1)

Vettenuts, NOT TRYING TO HIJACK, but I am also FINALLY getting my motor together, and this thread also apllies to me, and, many others, I'm sure. Again, NOT trying to hijack, but with some of the reported failures of the Caddy lifters (Which I am running!), is this pre-load applicable to the Caddy lifter, as well? Talked to Katech today, and was told to go to ls1howto.com and look for lifter install. I have had no luck finding it....yet. This thread would be the perfect one for someone to post up on just where this "lifter install" is, and maybe a link, to help any of us who might need it, get there. Thanks.

verano29

hehe just kidding...cool icon!

grinder11

iTrader: (1)

Anyone know where this link is? I am trying to find out the pre-load on the caddy lifters, and Katech told me to check out the ls1 how to, but can't find the lifter install link/story he referred to. HELP!!!! Thanks, guys. (Sorry verano, but....did I do it again??!!!)

vettenuts

iTrader: (4)

LS1howto didn't use Caddy lifters (it pre-dates them), is your question specific to installation of lifters or preload on the Caddy lifters?

HEMIETR

iTrader: (2)

I'm running the Johnson Hylift lifters. Recommended .020-.030. I'm at .026

grinder11

iTrader: (1)

FWIW... W2W recommends only around .025 preload when the (STOCK) motor is HOT. I would imagine that with all that aluminum expanding, when the motor is cold the preload would be quite a bit more, say .040-.050 (If it is .025 COLD). In talking to Kurt Urban@ W2W, he said that they usually shoot for about one full turn down from zero lash when the motor is cold. The rocker bolts are M8-1.25, which means when you make one complete revolution of the bolt, it will travel about .050". I know that on the "traditional" small block motors, a lot of us (Me included) would loosen the rocker until it JUST started "ticking" and then we would tighten down the rockers only about 1/4-3/8 of a turn, which would make the engines rev a little higher and make a little more power on top end. This setting allows the lifter to not have to "bleed down" as much as a higher pre-load setting would do. Hope this helps!

ONEBADWS6

iTrader: (22)

The Caddy lifters suck. You need .160 preload not .060 like SDPC says.

Fratsit

iTrader: (1)

I have always been under the impression that lifter preload is a function of push rod length on a non adjustable valvetrain. If that is the case then why do I always read about people going "(a set amount of turns) passed 0 lash". How are they able to get the preload right and still torque the rockers to 22 ft lbs?

For me: I used an pushrod length checker and when the lifter was on the base circle of the cam, I turned until she was just snug. I did the math from there and added in my desired preload.

So far so good and valvetrain is quiet. Am I just not getting it?

Please explain...

Thanks,

Frat

verano29

For non-adjustable rocker arms that is the technique I used. I turned out the pushrod until I couldn't feel it "click" then I added .075" to that. It's not an exact science but I'm sure I'm within +.025 of that. So I know that my preload is somewhere in the neighborhood of .075-.100, which seems to be what everyone is recommending.

PREDATOR-Z

Counting turns on non adjustable stock rockers, just lets you estimate your preload.
Rockers have to be tightened (22>24 lbs) while p-rod is on base circle.
While tightening to 22 lbs, one can count the number of turns and that gives that person an idea of preload value.
Stock rockers are NON adjustable, they just have to be tightened to 22>24 lbs, that is it. The pushrod length is what will determine the preload increase or decrease.

Fratsit

iTrader: (1)

Exactly what I thought. Verano and Pred...... thanks for the feedback.

R/

Frat