I have a generic pushrod length checker from Comp, is there one made specifically for lsx engines?

 

Should be 7702-1....been a while since I searched part numbers...but I'm pretty sire this is the one I'm using.

 

7702-1 is the one. If you order from a place that sells "tip to tip" length then you also need an 8" caliper to measure the checker length. I just bought a cheap but decent 8" $30 dial caliper from Grizzly tools.

 

There are two methods of measuring pushrods. See attachment below.

Comp Cams uses the "gauge length" measurement. It's the length defined by a 0.140" diameter gauge at the ball ends. If you use a Comp Cams pushrod length checking tool, it too will give you the gauge length required.

What you're talking about above (in red) is the "theoretical lenght" in the diagram. You can't really measure theoretical length with any tool, since there is no material beyond the flat spot.

Now Manton pushrods measure the length from flat-to-flat (shown as "actual length" in the diagram) ... it's what you could measure with a measuring tool like a larger caliper.

Not that if you measured a pushrod from flat-to-flat (actual length), that the gauge length will be about 0.017" shorter.

 

Humm ... I measured my stock LS6 pushrods at 7.400" (flat-to-flat), which means their gauge length would be 7.385".

Are you sure those were stock LSx pushrods?

 

According to GM, the "universal correct pre-load" would be mid plunger travel.

 

How did you measure them? The 7.385" is what the gauge lenght of 7.400 flat-to-flat pushrods would be. Anytime a pushrod is measured with a caliper from flat-to-flat, that will always be about 0.015~0.017" longer than the gauge length, which is the lenght a Comp Cams pushrod length tool will give you.

 

Here's an example where you could get hosed up. If you used a Comp Cams pushrod length checker and came up needing a pushrod length of 7.425", and then ordered 7.425" pushrods from Manton, then you'd end up with pushrods that were actually ~0.017" shorter than you though you were getting.

That's because the Comp Cams checker tool gave you 7.425" gauge length, and Manton built the pushrods to 7.425" flat-to-flat, which is about 7.408" gauge length ... when you really needed 7.425" gauge length.

Most lifters could probably absorb the 0.017" mistake without issue, but some can't ... especially if you're not pre-loading to near the mid travel point of the plunger.

 

It doesn't surprise me that you get slightly different total plunger travel measurements since it's obvious that all these LS7 lifters are made by different vendors for GM. They are probably made to withing the drawing specs ... otherwise GM wouldn't except them from the vendors.

It does surprise me though that they have more travel then the chart I posted that shows they have 0.166" total plunger travel. That chart was supposedly made up by someone who worked for GM.

https://ls1tech.com/forums/16050470-post56.html

 

salemetro - what's the advertised total plunger travel of the new lifters you've got?

 

This is what I'm saying. If you use the Comp Cams pushrod checker and actually measure from flat to flat with a caliper it will be different than if you added the number of turns to the compressed length(the suggested method from Comp). If you add the 0.017" to the amount of thermal expansion of 0.015" and subtract from the 0.060" preload that most shoot for you get a preload of 0.028". This is 0.028" on a lifter that would be happiest(read quieter) at a preload of 0.080-0.100".

 

According to the manufacturer:

The total travel of your parts are .156". Also, be aware that these parts have the same install height as an LS7 with a standard C-Clip. As you can see our R-Clip reduces the travel some, which places the piston in an optimal position and corrects some geometry. You should need about a .050" longer pushrod.

 

Finally have some pics....everything looks normal. I have decided that I'm going to swap out the springs at this point in preparation for the new EPS cam. I COULD swap them later when they are back in the car, but don't feel like messing with it. Besides, this should have little/no effect on lifter-related noise reduction.

Cam looks fine...



Lifters show no abnormal signs of wear...




Pushrods appear normal as well.....



Swipe pattern appears normal too....



Heads are currently in the machine shop being cleaned up again and re checked for straightness. I'm also waiting for the new springs/locks/retainers to get here sometime next week. Until then, I'll just be cleaning everything up again as time permits.

Stay tuned.....

 

Find anything else?

 

Soooo...a bit of a change of plans. After spending the time pulling the heads, I've come to realize that changing the cam is going to be a major PITA in this car. The front bumper,a/c condenser and radiator all get to come out....in addition to part of the core support. Sooooo....since it's already down for the time being....and I don't feel like doing this again, I'm going to swap everything. List of updates are;

-Fast LSXr 102 intake
-Fast 36lb injectors
-90mm throttle body
-EPS camshaft/double springs
-New lifters
-Dyno tune once it's all back together

Sorry if this leaves anyone dissapointed, as I know that this is not a "Direct" comparison....but with gas the price that it is, I need to stop driving my full-size 454 truck sometime soon.

I'm still waiting for the cam and springs to get here....should be roughly 2 weeks from now. In the mean time, I found another video of the car/noise problems...and thought I'd share. I can't wait to have this done once-and-for-all. I'll post back here with the end results.

http://www.youtube.com/watch?v=M1hzpnLy1zU

 

I don't blame you, it's a lot of work to do most of it twice.

Hopefully all works out well. Keep in mind the Fast intake is likely to add some new different noise all it's own unless they changed something from the 90/92 to the 102 which affects the plunger like sound of the valves closing. If you use the stock style foam on the bottom of the intake it helps keep it quieter.

What cam did you go with?


Want to hear something really strange about pushrods/preload:
https://ls1tech.com/forums/generatio...nd-cammed.html

 

I'm still expecting MUCH less noise than I've been experiencing....and yeah, I'm gonna install the foam pad on the bottom of it.

EPS 218/226 113+2 .6xx....should be here in a week or so now.


Yeah, that's kinda surprising that a .115 preload would cause that.

 

I don't blame you either. But you are never going to really know now.
Cute little cam! That ought to add nice midrange to the Mazda.
And Thunder, good pointer on the foam under the FAST. I will do that to mine as well.
I wonder what the best material will be to handle the heat?

Ron

 

The factory foam is open cell, if you want something that won't absorb moisture then get closed cell foam. Anybody know the size of the factory foam pieces, especially the depth?

 

Yeah, I know what you mean....and I had a really hard time with the decision...I really wanted to make this as "direct" a comparison as possible. However, disassembling the front of the car to do this swap makes it a total PITA.....and it just makes sense to me that more lift & more spring should make life more difficult for a lifter. IMHO, if all is quiet with all the new parts....it should still be a huge statement as to the problem/solution.