Good morning guys, first post but I've been reading this site for quite a while. I'm working on my ls1 I pulled out of my old 99ss Camaro. At the point of reinstalling my pushrods and rockers but something seems off. I purchased the comp cam tool to verify measurements and ended up with a measurement of over 7.55 with no lash. From what I've read this seems excessively long, am I missing something here? Stock ls1 bottom end, Thompson Motorsports 243 heads, gmpp mls gaskets, ls7 lifters, tsp torquer v2. Thanks guys any guidance would be appreciated.

 

Can you describe exactly how you are measuring?

Also, with new lifters you have to be very careful you are inadvertently depressing the lifter plunger while measuring. I would start with a pushrod length you know is too short and then carefully open 1/2 turn at a time. Check clearance by gently lifting the rocker tip and checking for a "tick" "tick". Some instructions use the old spin the pushrod but you won't feel zero lash using that method and new lifters.

You have to be very gentle, ask me how I know

 

I used the comp cam tool, ended up with 13 turns or so. I installed my tsp 7.4 pushrods to check and it seemed like a lot of movement on the rocker. I did replace the lifter trays and currently there is no oil in the motor if that could effect it.

 

That looks about .175" too long. I have never seen a set up with stock heads and block use longer than a 7.425".

Are you using a stock GM rocker with stock rocker stands?

 

I'm using stock stand and rockers with a straub trunnion kit. I will have to run through it again tonight and make sure it's not something simple that I screwed up. This is my first go around with this stuff basically just looking to confirm that something is definitely off.

 

dude I feel your pain its so confusing to figure this stuff out for a first time person. lol

 

Think I got it sorted guys thanks for help, I was testing it wrong and compressing the lifter. Second video I watched had a clearer explanation.

 

Can you post link to that video?

 

Very easy to do. I had this issue when my Morel's were new. Had to be very careful when measuring to get things right. Triple check you measurements. You will know if the final length appears to be "off" since you have an idea where you should end up.

 

The problem I'm having is my intake and exhaust measurements are off by about a half turn or quarter turn on my comp measure rod. Should I just average between the two?

Now I am supposed to measure the point in which the tapping of the rockers goes away right, not while they are still tapping? Should I be measuring 1/4 turns, 1/2 turns or full turns of the measure rod? I feel like I'm being too **** but Im not sure.

 

the comp cam tool should be measured with a pair of digital calipers, not by turns.

 

This one seemed pretty thorough https://youtu.be/9sWnhRe8rs4

 

Awesome, thanks just what I was looking for

 

As long as you adjust your numbers for gauge length if that is what the vendor sells.

 

Ok so I went through today and did both measuring methods on all the cylinders I could reach under the cowl.
1) using the comp cams adjustable length checker and consistently measured 9 1/2 turns (calculated 7.350")
2) using the other method of counting turns to to get to 22 ft/lbs and consistently measured 1 3/4 turns (calculated to 7.367")

Which length should I get? 7.350" or 7.375"? Trying to get suggestions of which method they trust more. Thanks ya'll for all your help, sorry OP for highjacking the thread.

 

Did you add the preload to the 7.350?

 

Yes all calculations included preload for ls7 lifters at .050" is my preload incorrect?

 

Maybe not, just seems short with the preload added.

My zero lash measurement came in at 7.353 ( +- .002).

Plus .060 preload, pushrods I got are 7.400.

My 243's are cut .030 and gaskets are .041.

 

I had Texas speed mill my heads to spec with the V2 cam and I know they took a bit off. I don't know exactly how much though.​​​​​​

 

9-1/2 X .050 +6.800 = 7.275, 7.275+.05 (preload) = 7.325"

Not sure how you get 7.367", did you correct for the rocker ratio? What pushrod length was used for this?

Am I missing something?