[Z06] lifter preload and pushrod length
07-04-2015, 09:48 AM
#1
Melting Slicks
Thread Starter
lifter preload and pushrod length
Discussing some things with a friend and he was mentioning something about lifter preload and pushrod length.
Now I know that if I do my heads I should measure pushrod length so I can use the proper pushrods to get the right valve contact area with the end of the rocker etc. etc.
Here's something he mentioned to me. I should also change out my LS7 lifters and get LS6 or 9 ones since they are better (in what regard I don't know), and depending on where the lifters go in the bores when I check pushrod length I should do all 16 of them and not just one cyl.
His reasoning???? There is a spec for lifter preload and you would like the spec to be on the tight side to quiet down any possible lifter noise (clacking). By only checking pushrod length for one cyl. and using that length pushrod on the other 7 cyl. your lifter preload for some of the other cyl. might be in spec but could also be on the looser side and possibly causing some clacking noise.
In my case my car since new has had a clacking noise (really noticeable in 3rd gear around 2000rpm) and everyone says it's normal (even the dealer when I had the shop foreman listen to it). Car runs strong for the last 5 years even with the noise and when my friend listened to it he feels that's lifter noise and why he mentioned the above.
If I do my heads and put everything back I really don't want to hear that noise again so I'm wondering if what he told me is kinda right or is he smoking too much of the good stuff?
Tony
Now I know that if I do my heads I should measure pushrod length so I can use the proper pushrods to get the right valve contact area with the end of the rocker etc. etc.
Here's something he mentioned to me. I should also change out my LS7 lifters and get LS6 or 9 ones since they are better (in what regard I don't know), and depending on where the lifters go in the bores when I check pushrod length I should do all 16 of them and not just one cyl.
His reasoning???? There is a spec for lifter preload and you would like the spec to be on the tight side to quiet down any possible lifter noise (clacking). By only checking pushrod length for one cyl. and using that length pushrod on the other 7 cyl. your lifter preload for some of the other cyl. might be in spec but could also be on the looser side and possibly causing some clacking noise.
In my case my car since new has had a clacking noise (really noticeable in 3rd gear around 2000rpm) and everyone says it's normal (even the dealer when I had the shop foreman listen to it). Car runs strong for the last 5 years even with the noise and when my friend listened to it he feels that's lifter noise and why he mentioned the above.
If I do my heads and put everything back I really don't want to hear that noise again so I'm wondering if what he told me is kinda right or is he smoking too much of the good stuff?
Tony
07-04-2015, 01:00 PM
#2
The LS9 lifters are what's more commonly called "caddie" lifters, or high rpm lifters. Either LS7 or LS9 will work fine. I'd rather talk you into some Morel or Johnson with the largr .750" wheel, but they are considerably more expensive.
Pre-lode has been debated for...well, friggin ever. Some like it low, some like it high and both camps have good points. I like to set it right smack in the middle of the plunger travel. If the thing moves 100 thou, set it at fifty. That has been working for me for a long time.
When I check length, I'll hit the four corner cylinders, both valves. Make damn sure the lifter is on the cam's base circle though. The bigger the cam, the more important this is.
Pre-lode has been debated for...well, friggin ever. Some like it low, some like it high and both camps have good points. I like to set it right smack in the middle of the plunger travel. If the thing moves 100 thou, set it at fifty. That has been working for me for a long time.
When I check length, I'll hit the four corner cylinders, both valves. Make damn sure the lifter is on the cam's base circle though. The bigger the cam, the more important this is.
07-04-2015, 05:39 PM
#3
Drifting
I'm on my original lifters. Using more preload than some. (I forget the number right now) and my valve train is MUCH quieter than stock. Windows up no ac or radio I can barely hear it at about 2000 rpm.