wildcamaro

iTrader: (15)

Hey whats up guys, I just installed a comp cam 224/230 114 .581/.588 with some ported 243's (unshaved) on my car. I hear the dreaded sewing machine noise under my valve covers. I went with 7.4" bc of somebody that is running the same cam.

Anyway i read a gmhightech performance article where they tested the exact same came with stock 241 heads, but they ran 7.35" pushrods. They are usually spot on with their info. But...

I saw a conversation on the forum here where a guy asked the same question i am right now. He got a response (from predator who is real knowledgable) of 7.425" in order to put the correct amount of preload on his lifters. I torqued my rockers at 22 ft-lb, the torqued them again after rotating the engine.

Can anybody take a shot at shedding some light my way. I figured someone with more experience could help me out. Good lookin.

01ssreda4

iTrader: (96)

The 7.425 is quieter IMO for a stock motor. Once you pull the heads, all bets are off. You need to measure. Asking us to "guess" "predict" or "speculate" about what length pushrod you need is like asking a blind person to draw a sunset.

wildcamaro

iTrader: (15)

I'm not as ignorant as you think, i bought a pushrod checker and i came up with 7.4". I was askin if there is a better length in order to quietthe valvetrain and/or increase performance of the engine. I'm not one of these guys that takes this advice as bible I know how to build an engine, the opinions i ask for are experienced based questions not guesstimates.

LilJayV10

iTrader: (39)

Maybe this will help.

https://ls1tech.com/forums/generatio...questions.html

oakley6575

iTrader: (3)

He wasn't trying to "hurt your feelings" wildcamaro. Every set up is different thats why no one here can correctly answer your question. If you used a pushrod checker and you came out with the sewing machine noise, you obviously measured wrong. How much preload do you have measured in to your 7.4 pushrods?

KCS

iTrader: (20)

I dunno, this sounds pretty ignorant to me...

wildcamaro

iTrader: (15)

I meant that I thought I was right in my 7.4" measurment because i knew someone who ran all the same parts and used the same length. I just assumed that the person knew what was going on, but apparently not. I like to do things the "right" way (i.e. minimal valvetrain noise).

Anyway i wasnt taking any real offense to the comments, but sometimes when you get those type of responses it sets off the old defense mechanism.

ok im goin to go back under the valve cover and remeasure, the only thing i think i messed up was the lifter preload that has to be added to the pushrod checker length. I think i used the ls7 lifter preload (smaller) rather than the
stock ls1 lifter preload. Just to double check before i mess up again but stock ls1 lifter preload should be between .060" and .100" right?

Thanks again....it wont be long now before i can go punish these punk mustangs who think that 290 rwhp 4.6's are boss.... (not like i couldnt have done that stock lol.)

94mustang

iTrader: (1)

Always use a pushrod checker BEFORE ordering pushrods. Thats just how it works.

redz_02

iTrader: (4)

But I read it on the internet.

wildcamaro

iTrader: (15)

Ok well now that we got all the smart *** comments outta the way (can't believe people waste time baggin on others).

Does anybody with experience tell me what the preload range is for the stock ls1 lifters? Cause you know if its on the net I'm definately listenin lol.

01ssreda4

iTrader: (96)

I think its around 40-80. Obviously the higher the quieter. Get your feelings off your shoulders dude, we are trying to help you.

wildcamaro

iTrader: (15)

You helped me, but come on those other comments are lame. I'm here to talk lsx and that's it. Anyway thanks to those who helped me. That's why I get on this forum because I like to talk to be people that know what's up, just like anything else the more wrenchin you do one these cars the better and more knowledgable you get.

Can't wait to hurt some mod motor feelings on the street and the track...

01ssreda4

iTrader: (96)

Good luck with your setup...

TTA850

iTrader: (7)

I have the comp XER 224/230 cam though the card says .581/.592 lift with a stock set of 243 heads and went with 7.425" pushrods. I was lazy and didnt measure but went off the fact that 7.400" has worked well for me on stock motors and the cam has a slightly smaller base circle and I calculated that it needed the extra .025" length. It's been running good so far. I also put together a motor for a friend with a comp XER 238/240 cam with .605/.609 lift and out of the box TFS 215 heads which are supposed to use 7.500" pushrods (.100 longer than stock) but when we measured that cam wanted 7.525" and it's been running nice and quiet. So I'd say you likely need a little more pushrod length.

HTH,
Steve

treybadd

Hey guys, new here but have been on ls1gto for about 4 years. I have found some good info here. I recently did my ls3 head/intake conversion with a 220 cam and ls7 lifters. I had the same questions. I could not find a GOOD answer about my question of the proper preload for the ls7 lifters. I am currently running about .095" on the exhaust and .110" in the intakes ( different due to the ls3 intakes being slightly taller) and no problems. In all my searching I found the best answer is to be in the center of the plunger travel. I could still lift the rocker tip up about .125" from the valve stem with rockers torqued so I know the plunger had plenty of travel left.