I was just reading up on how to accomplish this task. Looks like this method is perfectly except able. I watched them use it comp cams site as well. No special tools required.

[Quote = other site]Here it is again in a nutshell:

1. Using the EO/IC method, get the lifter to the base circle of the cam.
2. Using a known length pushrod (7.400" is a good start with stock rockers) run the rocker arm bolt down to zero lash. This is easily done with your fingers "wiggling" the rocker, the point at which the "slack" is just gone is zero lash.
3. Set your torque wrench to 22 lb./ft. Tighten the rocker to full torque and count the number of turns it takes to get there. 1 full turn wtih a stock 8mm X 1.25 bolt is ~.047" preload as measured at the pushrod/rocker interface.
4. I normally shoot for 1 1/4 to 1 3/4 turns with stock type lifters like Comp 850's, LS1, LS7 etc.

For an example, if you use a 7.400" pushrod and come up with 3/4 of a turn, you will need at least .025" longer pushrod to get into range. If you end up with 2 1/4 turns, you will need one .025" shorter...

I might not know everything but I will tell you that this method has worked for me year after year cam swap after cam swap. We average 3 cam swaps a week here so you can do the math.[/quotex]

 

I'm very confused. First you said it's something that you are not familiar with or have the tools for. Then you said you learned how to do it. Then you said you've been doing it three times a week for years.

 

hahaha I copied and pasted that from another site I should have put quotation marks around it or something. Sorry for the confusion that was my first time ever doing something like that.

 

Put, without the x's, [xquote=other site] text you are quoting [/quotex]
​​​​​​So that will look like this without the x's:

 

That is Shane's (mknight759) post on preload, It's been posted numerous times on GM forums.

Thompson Motorsports has a decent youtube how to LS preload. They don't use a pushrod checker because (I'm assuming) they have different pushrod lengths in stock. The turn method is a good sanity check after using the checker to order the correct length.

In the video he doesn't use the EO/IC events to find the cams base circle. I always use the EO/IC method as it's (almost) idiot proof.

The other issue some will argue is that torquing the rocker bolt to spec can move the wrench further than needed skewing the results because you are actually stretching the bolt and NOT moving the rocker/pushrod. The bolt should be turned with the wrench until you just feel the bolt stop when counting revolutions... then if it checks out... torque to the 22 ft/lbs spec.

In the video he torques to 25 ft/lbs... whatever no big deal.

 

I also watched that video before I started. I believe I'll be just fine. I averaged 1-3/4 turns. I got 1-1/4 turns a couple times but I'm sure it had more to do with my ability get consistent zero lash. Thank you