badazz81z28

iTrader: (6)

Not the 228R.

Fast98Z28

Well, I just pulled the pushrods and they "checked out" There was some wear on the top where it would meet the rocker. Im going to double check. How do I check lobe lift at the top of pushrod? Im really hoping I don't have to take the head off to replace a lifter, and if I do, my engine only has 2k miles on it, would I have to replace the cometic head gasket? Would there be a way to tell thickness with it still on? or after it has been removed? because I do not know what thickness they were.

03Sssnake

iTrader: (20)

Some wear at top of the pushrod where it meets the rocker is normal. From the video it did not sound like you had a collapsed lifter either, that is pretty damn noisy when it occurs.

Just check your preload. A push rod length checker would be the best bet. However if you don't have one, count the turns it takes to run that rocker bolt down from 0 lash to 22lbs. The longer the pushrod=more preload and will take more turns to reach 22lbs. You want about 1 full rotation to reach 22lbs, mark your socket to gauge this. Make sure you are on the base/heel of the cam for the particular valve you are on when you go to torque down.

great video skip ahead a few minutes to pushrod length check and counting turns etc...

Fast98Z28

thanks, it would just make me wonder why it would make the noise after 2k miles.... because if it happened after 2k? what could have caused the noise to start if it wasn't the lifters?

intenseblue

iTrader: (1)

That cam does have a smaller base circle

Fast98Z28

When a lifter goes, will it be consistent with rpms?

Fast98Z28

Well i checked for proper PR length last night. I bought a Comp Cams 7702-1 checker tool. Used my calipers to check at 7.35, and only got about 3/4 of a turn before 22ftlbs from "zero lash".
I then made the tool to 7.375, and then got about 1/2 turn from zero lash before 22ftlbs.
Then i took my 7.4 pushrods, and checked from zero lash and got about 1.5 turns to 22ftlbs. Which ultimately if i did this process right, the 7.4's would be correct.

i used this method:

The TDC method is NOT always accurate. Try the EO/IC method to check pushrod length. I have posted directions on this forum numerous times... Here it is again:

FWIW, EVERY cam install I have done using the LS7 lifter with a cam with greater than .600" lift (read smaller base circle) AND stock heads w/GM MLS gaskets has taken 7.425" pushrods for ~.050"-.060" preload. We measure lifter preload on each and every cam install we do. I have never had a lifter failure nor do we end up with the dreaded "sewing machine" noise.

Its very simple, If you change ANY of the following:
valve sizes, valve job, head milling, thinner/thicker head gaskets, decked block, cam with an altered base circle, etc... YOU MUST CHECK FOR PROPER PUSHROD LENGTH.

I have helped countless numbers of individuals with this process over the phone, via email, and PM's. I've posted the process on at least 3 occasions.

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.

If you are not familiar with the EO/IC method for determining valve events in a 4 stroke engine, its very simple:
For a given cylinder as the Exhaust valve is Opening, the intake lifter will be on the base circle of the cam and lash/preload should be checked for that intake valve.
For a given cylinder as the Intake valve is Closing, the exhaust lifter will be on the base circle of the cam and lash/preload should be checked for that exhaust valve.

THIS METHOD ALWAYS WORKS!!!

Check it using the above method and see where you are.


any input? This all started out after hearing a ticking noise... thinking my PR's were too long, and the noise did not start untill about 2k miles. I was thinking maybe too long of PR's could have collapsed a lifter. After looking at all the rockers/springs/PR's it seems everything is fine. So what could this ticking be? So confused. I just wanna drive.

Fast98Z28

Anyone know what this noise could be?

SladeX

It's a collapsing lifter. My stock ones did that after a cam install. I went through all that crap of measuring pushrod length, replacing with correct ones, ensuring all within 1 1/2 turns etc. Once replaced with new lifters, sound was gone.

Fast98Z28

That's exactly what I was thinking.... What lifters did you end up getting?

Fast98Z28

Today, I put everything back together and the noise went away. I used my mechanics stethoscope and noticed "ticking" from the lifters on BOTH sides. but standing there I could not hear it with out the stethoscope. Could this mean I may need longer pushrods for a bit more preload? They could have been "ticking" the whole time I just could not hear it.