Georgies

I'm really ticked off guys. Please, chime in if i'm wrong.

14 of the stock pushrods measured at 7.395".
2 of em were 7.390"

My car was all stock with about 17k on the odometer.

TSP states and engraves the kit for my Z calls for 7.400" pushrod length.

All of em are longer. On top of that the stock ones are thicker. They also look better made...

Is it all hype for aftermarket pushrods?

What should I do? Also, some of you may already know but all of the pushrods are super dirty inside. Mineral Spirits and 150 pis of compressed air didn't get the **** out. i'm going to order the comp brush so I can clean them...

Now i SEE this! WTF man, who the hell is doing quality control?! When you machine something and engrave it 7.400, it better be 7.400...

Please guys, correct me if i'm wrong! But I deff need some advise here. I'm not going to tear down in the motor again because some company doesn't take being a machine shop SERIOUSLY

I'm always the first to buy American made...im starting to go

HPS MASTER TECH

just return them. and get a new set.

93Polo

.005 is likely in variance for the manufacturer and your lifter. However, I had a sets of 1 piece Comps and 1piece Trend (Tick) that measured spot on. Mantons are 3 piece made to order. My experience is you get what you pay for.

I would be more disappointed that the new pushrods are thinner.

If this is a street car with OEM or drop in lifter, I'd return what you have and go Comp or call Tick.

neutron82

which brand pushrods did you buy?... the stock pushrods are pretty dinky in comparison to quality aftermarket pushrods so if the stockers look better something is definitely wrong... manton makes very nice pushrods and are great people to deal with, I highly recommend them if you are willing to spend the money... to my knowledge their 11/32 diameter .120 wall thickness pushrods are the largest you can fit in stock heads without any machining for clearance

Georgies

The ones i got are from TSP...heres a link to the thread...go to last page at bottom for pics.

Thanks guys.

https://www.corvetteforum.com/forums...ng-mods-7.html

Georgies

Anyon know which valves are intake and exhaust? Im trying to check lenght.. the fuy at Manton told me to add .05 to my total lenght then to call him back...

Georgies

Im such an idiot...i just followed the runners and see where the go to the intake valves.. theirs a boss in the head for the intake... then i looked a little further.. im a even bigger idiot as the exhaust valves line up to the exhaust ports LOL!

Im learning tho

Sam Handwich

Okay. So do you want to make any changes to your opening post in this thread?
And maybe delete the duplicate post of the above.

BTW - when I get pissed off at a non-responsive vendor, etc. I can go on an extended rant. So I understand your aggravation.

vettenuts

First, 0.005" is the standard tolerance for pushrod length. Second, how are you measuring? The number stamped on the side of the pushrod is the gauge length. You can't measure that value, only overall length (OAL). That is the end to end measurement and it not as precise as the gauge length. The gauge length is measured from a location on the ball end that is 0.140" in diameter. Dirt if the pushrod, although not desirable, is not uncommon. Anyone who takes pushrods from the package and installs them may simply dump a bunch of crap in their motor. You are doing the correct thing, get a pushrod brush and clean them good before installing. Many who don't have problems later and don't even realize why.

Georgies

Vettenuts, i was measuring tip to tip with a vernier. I understand this is the incorrect method. But they should still all be the same right?

I spoke to Manton, he told me to measure push rod length and add .05 when ordering new push rods.

I followed your procedure in another post. When you say to tighten the rocker bolts snug... i tightened down by hand with just a socket.

I put motor at TDC. Cam sprocket mark @ 6 and crank mark at 12.

I then installed a rocker on piston 8 and 4 at 22ft pound to give some stability for the procedure.



I then put tape around the threaded part of the push rod as it would turn a bit when putting in and taking out. The length i measure to get no play at rocker tip is different for intake and exhaust.. is this because im not tightening the rocker enough?


Thanks man

vettenuts

Not necessarily. The different length measurements can be due to different valve stem heights. Depending on the difference, it may not be an issue since hydraulic lifters will take it up. However, having said that, make sure you don't press too much on the lifter while measuring as you can depress the plunger. This is especially true on new lifters that haven't pumped up yet. If you are using stock GM lifters, they are pretty forgiving on preload difference within reason.

As for pushrod length, any vendor will have a tolerance on length. A tolerance of +/- 0.005" is actually pretty good so your longest vs. shortest could differ by 0.010" and still be within specifications.

Georgies

ok so the procedure im doing is correct...should I also check on the other side (cylinder#1) ?

vettenuts

I would, that way you double check you method and get a measurement on the other head.

Georgies

Measuring the Comp push rod checker fully close from tip to tip with a good quality vernier is giving me 6.816".

At TDC on cylinder 6 push rod is measuring

Intake - 7.384
Exhaust - 7.362

These measurments achieve no play (tap) except a little side (left to right wiggle).

I put some electrical tape on the Acme threads of the Comp pushrod lenght checker when i was really close. I noticed the male cap of the checker would screw/unscrew while putting in and out. The tape made it stay still during handeling.

These rusults were produced by tightening the 8mm rocker bolt by hand with a deep socket.

I tried the same thing at 60 inch lbd (5 ft lbs) and it was the same. At 120 inch lbs (10 ft lbs)the exhaust would be tight with 7.384 push rod lenght. (Same as intake)

So to get equal results i needed to tighten the bolt at 120inch pound) for a 7.384 push rod. This deff means theres a difference. Ive never taken off the heads and as far as I know lifters are stock. Stock cam looked good and wear was all even and you could not feel it with your nails (fingers)

Should i stay with tightening by hand?

Im gonna start now on cylinder #1 and post results.

Thanks

vettenuts

That's pretty much right on the money. The Comp adjustable pushrod is 6.800" gauge length when fully closed. The difference between gauge length and OAL (overall length measured between the ends) is in the range of 0.013" - 0.017" so your number is right where it should be.

Georgies

what amount of preload would you add?? the guy at Manto said .05 for a LS6...

I have no idea

vettenuts

Not sure on a stock lifter to be honest and I don't want to steer your wrong (I am running a Morel lifter), might need to do a search to see what others are running. Stock they run at about 0.100" of preload from what I have measured.

Georgies

ok ill check that out. So that number has to be added to the length of the push rod when ordering correct?

Also, should I try the EO\IC method? Or does this only apply when then engine is assembled and no access to cam/crank sprockets?

Georgies

vette nuts, im reading a post you wrote on ls1tech that states you agree that the rocker should be torqued down before using the checker. I'm thinking 15 ft lbs sould be okay not to damge the threads.

My way of hand tightening hte rocker bolts without a ratchet is surely causing a wrong calculations...


https://ls1tech.com/forums/generatio...-question.html

vettenuts

I run it down until the bolt is snug and then snug with a wrench. I don't go to full torque due to the aluminum threads and the number of times required to make measurements. Maybe 1/8 turn or about 10 lb-ft as a guess.