soloman369

iTrader: (13)

cool thast sounds awsome

brad8266

iTrader: (23)

Ok let me clear the comp "r" lifter preload issue. the correct lifter preload warm on these lifters is .002-.004 as per Comp instructions.
http://www.compcams.com/Technical/In.../Files/160.pdf

transam69230

iTrader: (49)

I am doing a H/C swap and i bought the LS7 caddy lifters, and i have stock length pushrods, will these lifters rock with stock rockers arms on a ls6 block.

jegten

iTrader: (22)

thanks for the info.

but, my engine will be cold when i set the preload. is that when i use the .008-.010"?

thanks

brad8266

iTrader: (23)

If I were you i would call Comp and verify what the cold preload should be since they dont say in their documents.

jegten

iTrader: (22)

yep, that sounds like a good idea. thanks, brad.

jegten

iTrader: (22)

i just spoke to compcams help techline.
"set to zero lash to warm the car up. the engine will expand, and create a .008 of preload on the lifter. go back in, and set to zero lash, and add .003" of preload on the warmed up engine."

verbatum what they told me.

BOWTIE

OK, here is the problem with using Comp R with the stock pushrods... Not every valve is going to be exactly the same and when you are trying to set preload to such a small value .002-.004 (damn near zero), it makes it a little difficult when you may have valve setup heights that vary by more than that. This combined with the fact that most blocks are not perfectly square much less have exactly the same deck height from side to side means you would basically need to set up every valve and neasure to get the right length pushrod and you would most likely end up with between 4-16 different length pushrods. Then as if that is not difficult enough, most off of the shelf pushrods will come in lengths varying .025 in lengths. This will not be accurate enough to use those lifters so you will end up spending a bunch of money getting custom sized pushrods made for your application. Or you can just get the ones that get your geometry right, and use adjustable rockers to set your preload the correct way.

brad8266

iTrader: (23)

Who said anything about them using stock pushrods with them? All you have to do is use a pushrod checker to get your measurement and then add preload to get the new PR length needed.

brad8266

iTrader: (23)

There ya go man.

jegten

iTrader: (22)

thanks, brad.

well..this just occurred to me. since i am using the PR length checker, and will use this
"Count how many rotations you made with the checker. Each spin is .050. the checker is 6.8, # spins x .050 add .080 for lifter pre-load."

example of a 228/232, .588/.595

9.25 spins on the intake and 9.75 on the exhaust side.

9.25x.050 = .4625+6.8+.080= 7.3425
9.75x.050 = .4875+6.8+.080= 7.3675

for a PR length of 7.35

i got this info from someone. is it possible he is using OEM lifters?

and,
9.25x.050 = .4625+6.8+.003= 7.2655
9.75x.050 = .4875+6.8+.003= 7.2905

this last is replacing the "high" preload of .080 with R lifters of .003"

are there such short PRs out there?

brad8266

iTrader: (23)

If both the exhaust and intake cam lobes are the same lobe type ie XE or XE-R or LSK then all lobes will take the same size pushrod. On a cam where the lobes are different you will have to measure both.


Your first example is on a stock lifter, .080 preload.

You can have custom length pushrods made if they arent a normal stock size.

jegten

iTrader: (22)

my lobes are a littel more than XE-R and not as high as the LSK, .612/.600, so i was thinking of using the same length for both intake and exhaust.

just trying to figure things out. i am planning on milling the heads to 62cc from 64cc, so maybe that would put the PR length on a more "normal".

you know, i really wouldn't have to worry too much about what compcams said if i just use the checker formula with the .003 preload, then, i just torque the stock rocker arms to 22lbs, and am done, right?

brad8266

iTrader: (23)

Is your cam a 230/214?

Milling down the heads will mean you will need a shorter pushrod.

If they say .003 warm then you first want to warm everything up. So you could probably get away with using like a stock rod for just long enough to get the engine a bit warm, then take them out and use the checker to go zero lash, then add .003.

jegten

iTrader: (22)

it is a 228.232.

yes, i realize that now. lol

yeah, i guess you are right. just have to go through the whole thing to get it done right the first time, correct? lol

God knows i have waited long enough, so, what's a couple more for this.

brad8266

iTrader: (23)

228/232 .612/600 does not match up to any of Comp Cams lobes. Who made that cam for ya?

jegten

iTrader: (22)

it is not a compcams lobe.

Flowtech Induction, Ed Curtis

brad8266

iTrader: (23)

Oh ok.

jegten

iTrader: (22)

i am really excited about it. i did soooo much research, and changed cams 3 times before finding this one!! lol
mind you, changed cams before even installing them! lol

i am hoping for a lot of power, good manners, and hopefully good numbers.

warp_6

iTrader: (2)

+1. You will need to use adjustable rocker arms. Use your checker to find zero lash. That will be the length of your new push rods. Then you will set your pre-load with the rockers.