02bluess

iTrader: (18)

Brian, Joseph, and Spectacle,

Think I speak for everyone when I say THANK YOU for taking the time to discuss this topic in a manner us weekend mechanics can understand.

As Brian said, I know I've been pulling my hair out trying to figure out the best way to address the issue, and I'm sure I'm not the only one

Paul...

Country Boy

iTrader: (24)

Then it wouldnt be as fun now would it

Country Boy

iTrader: (24)

Basically, what what you want for preload. I had Rs on stock preload and spun 7100 once or twice and didnt have a problem, but the valvetrain was extremely noisey. If someone (ARP, GM, Comp,) give a spec on their product, its there for a reason. If you want to follow that or not, then its up to you and dont cry foul when something goes wrong.

Chicago Z06

my heads have been milled .015 and i am running stock rockers with the hardened push rods and my motor sees 7000 quite often with no issues as of yet.. i too was worried about this and was going to go to custom push rod length until i took everything apart last night and noticed very little pre load.. so i am leaving it alone until an adjustable rocker becomes available without having to remove the heads and machine a bunch of areas, or i go stroker and the heads come off again. my setup has been going for 6000 miles with no issues... so it is up to you on what route you go. FYI Harland Sharpe has a good deal on their rockers... if your heads are already off GO ADJUSTABLE!!!! you just spent 2k plus on your top end.. DON"T GET CHEAP NOW... this is why parts fail... people not doing it right the first time.

the MFG has specs that give them an out if things are not followed. this is HP not a stock vehicle.. parts fail... and most of the time it is the knuckle head in his garage with a brand new set of craftsman's finest and his wideband internet connection. and that is the extent of his knowledge of the internal combustion engine and engine management. you have to go with what you know works and what you can get away with as well as the risks involved.. if you do not have this knowledge take it to someone who does. saving a few dollars in installation costs will cost you more once you strip that bolt, break that bolt, overtighten this or undertighten that or whatever the case may be... good luck!!!

Wes

Unaffliated Racing

iTrader: (15)

The comp pro mags dont require anything to be done to the heads..they bolt right on
The driver side valve cover..the baffle has to be removed and the support ground down..but its very minor

SSEUL8R

Im puttin a TSP228 in my car soon, will I have to worry with ANY of this if I stick with stock lifters and rockers? Say I sometime get some better rockers, will I then? Also, how do you check preload? do you stick a feeler gauge between the rocker and the valve, doh! no that's how you check lash on a solid roller. I guess my question is will I need to worry about preload with stock rockers and lifters? And how do I check preload? Thanks

02bluess

iTrader: (18)

Shouldn't have to worry with stock rockers/lifters. Just torque to spec and go

SSEUL8R

Can you tell me how to check preload just for future reference?

-Joseph-

iTrader: (12)

Here's a quick way to check preload that I use when I do cam swaps, you can use a dial indicator, as I always do with new engine buildups (no oil in lifters):

When your done installing the camshaft and timing gears, rotate the crankshaft and camshaft to where both of the timing marks are at the 12' o clock position. This is the TDC for #1 cylinder in the firing position, when both valves are shut. When the dots are lined up dot-to-dot your on #1 cyl TDC on the start of intake stroke FYI. Now install your rockers loosely on the #1 cylinder and tighten the rocker arm bolts by hand until you feel slight resistance. The slight resistance will be 0 valve lash, you can verify this by spinning the pushrod as your tightening the rocker bolt also. Now comes the easy part, from there, tighten and count how many 1/4 turns before the rocker bolt will hit the 22lb ft torque spec. Each 1/4 turn of the rocker bolt until it bottoms out and torques the bolt is about .012" of travel on the lifter plunger. (1.25mm thread pitch on rocker threads x 0.03937 = inches per 1 complete turn) *1.25 x .03937 = .049" travel per each bolt revolution or .012" preload per 1/4 bolt turn.

You can also use the much more accurate dial indicator to measure preload (measurement taken on pushrod side of rocker arm), but if you don't have one, this simple method will get you by.

SSEUL8R

So thats where they run into problems with Comp R's, they require so little preload that you cant get the rocker bolts tight without shimming or adjustable rockers. The light has finally come on. lol

michael101

iTrader: (21)

I just finishished my cam install last night using the Comp pro mags. They sure make life simple compaired with trying to get the stock stuff right.

My setup is using LS6 heads with Crane dual springs, Comp 'R's, and the FM11 cam. These springs require a taller installed height which was killing me with the stock rockers.

The Pro Mags are the most adjustable rockers by far and the most forgiving for different setups. Wish I would have just bought them with the cam instead of waisting a week with the other stuff.