Measuring lifter pre-load
Thread Starter
TECH Fanatic
iTrader: (1)
Joined: Sep 2003
Posts: 1,009
Likes: 0
From: Chesapeake, VA
Measuring lifter pre-load Sorry if this has been asked before.
I have read through many threads on determining the amount of pre-load with a gauge, but have yet to read what kind of gauge or where to purchase. Can someone direct me to a brand/type/place etc... to get one?
I am trying to track down some valvetrain noise and just shifted to Comp pro-magnum 1.75 rockers (cam lift .575/.576 w/1.7). It's noise above the normal sewing machine sound. This is tap. I installed them, adjusted for zero lash, then added 1/2 turn, then locked down the fastners. The noise changed, but didn't get much better. So I readjusted to 1/4 turn. Again the noise changed some, but still present. My next step will be to go to 1/8 turn, but without a gauge it will be a little hard to be precise. How much pre-load "should" I have?
At what point do I need to consider replacing the lifters? I just had my motor built and had new Melling lifters put in, but up until now, it still had the stock rocker. My motor has 400 miles on it.
I have read through many threads on determining the amount of pre-load with a gauge, but have yet to read what kind of gauge or where to purchase. Can someone direct me to a brand/type/place etc... to get one?
I am trying to track down some valvetrain noise and just shifted to Comp pro-magnum 1.75 rockers (cam lift .575/.576 w/1.7). It's noise above the normal sewing machine sound. This is tap. I installed them, adjusted for zero lash, then added 1/2 turn, then locked down the fastners. The noise changed, but didn't get much better. So I readjusted to 1/4 turn. Again the noise changed some, but still present. My next step will be to go to 1/8 turn, but without a gauge it will be a little hard to be precise. How much pre-load "should" I have?
At what point do I need to consider replacing the lifters? I just had my motor built and had new Melling lifters put in, but up until now, it still had the stock rocker. My motor has 400 miles on it.
On The Tree
Joined: Aug 2004
Posts: 150
Likes: 0
You want .030" preload. Sometimes new lifters, or old lifters that have been out of use for sometime, will loose or not gain full prime. Take the adjustment to zero lash with no preload and lock it down and run the engine for about 15 minutes. Readjust to the 1/2 turn(.030") preload and that should get it.
TECH Fanatic
Joined: Jan 2002
Posts: 1,205
Likes: 0
From: harrisburg, pa
NOT TRUE!! You want .008-.010 Preload with comp pro magnums (cold)
1/5th of a turn is just about perfect but using a dial indiactor will get it right on.
I called Comps tech line...have had no valvetrain issues..and others here that went .008-.010 had had no issues that I know all...guys with more preload have had issues.
Call Comps tech line if you have doubts between us.
1/5th of a turn is just about perfect but using a dial indiactor will get it right on.
I called Comps tech line...have had no valvetrain issues..and others here that went .008-.010 had had no issues that I know all...guys with more preload have had issues.
Call Comps tech line if you have doubts between us.
Thread Starter
TECH Fanatic
iTrader: (1)
Joined: Sep 2003
Posts: 1,009
Likes: 0
From: Chesapeake, VA
Originally Posted by SAM98WS6
NOT TRUE!! You want .008-.010 Preload with comp pro magnums (cold)
1/5th of a turn is just about perfect but using a dial indiactor will get it right on.
1/5th of a turn is just about perfect but using a dial indiactor will get it right on.
TECH Fanatic
Joined: Jan 2002
Posts: 1,205
Likes: 0
From: harrisburg, pa
I do have Comp Rs...missed your Melling.
Call the tech line and get the recommended answer for your lifter...you obviously want to run as little as possible with maximum reliability.
Any dial indicator with a probe and magnetic base. mount it at zero lash..tighten until the rocker pushes the recommended distance. Summit sells them...Harbor freight
Dont listen to any of us..you have melling lifters and comp rockers...how could we possibly have the right answer for you?
Call the tech line and get the recommended answer for your lifter...you obviously want to run as little as possible with maximum reliability.
Any dial indicator with a probe and magnetic base. mount it at zero lash..tighten until the rocker pushes the recommended distance. Summit sells them...Harbor freight
Dont listen to any of us..you have melling lifters and comp rockers...how could we possibly have the right answer for you?
Thread Starter
TECH Fanatic
iTrader: (1)
Joined: Sep 2003
Posts: 1,009
Likes: 0
From: Chesapeake, VA
Originally Posted by SAM98WS6
Dont listen to any of us..you have melling lifters and comp rockers...how could we possibly have the right answer for you?
Trending Topics
TECH Addict
Joined: Oct 2003
Posts: 2,620
Likes: 0
From: Central, MA
Ben, I don't have much of any info to help you... just wondering about that tapping noise. Is it one or two complaining lifters or rockers, or is it the 'whole set'?
I had an unusual intermittent valvetrain noise with my last cam. Stock lifters, stock rockers. It sounded like one, maybe two lifters tapping. I could hear the noise through the firewall when driving, echoing in parking garages or next to cement walls/barriers. It was 'quite' noticeable. Is this what you have?
I had an unusual intermittent valvetrain noise with my last cam. Stock lifters, stock rockers. It sounded like one, maybe two lifters tapping. I could hear the noise through the firewall when driving, echoing in parking garages or next to cement walls/barriers. It was 'quite' noticeable. Is this what you have?
LS1 Tech Stories
The Best V8 Stories One Small Block at Time
6 Common C5 Corvette Failures and What's Involved In Repairing Them
Pouria Savadkouei
Retro Modern Bandit Pontiac Trans AM Comes With Burt Reynolds' Autograph
Verdad Gallardo
Top 10 Greatest Cadillac V Series Performance Models Ever, Ranked
Pouria Savadkouei
Top 10 Most Powerful Chevy Trucks Ever Made!
Hennessey's New Supercharged Silverado ZR2 Has 700 HP
Verdad Gallardo
Coachbuilt N2A Anteros Is an LS2-Powered C6 Corvette In Italian Clothes
Verdad Gallardo
Awesome K5 Blazer Restomod Comes With C7 Corvette Power
Verdad Gallardo
10 Camaros You Should Never Buy
10 LS Engine Myths That Refuse to Die
Verdad Gallardo TECH Addict
Joined: Oct 2003
Posts: 2,620
Likes: 0
From: Central, MA
Dang - I wish I knew what it was.
I drove around like that for quite some time, basically thinking it was rather normal valvetrain noise. It just about completely cleared up about two weeks ago, all on it's own.
The cam was still a little noisey - there was still a small amount of tapping only heard if you listen close outside the vehicle, but it wasn't anything that really raised a flag with me.
I drove around like that for quite some time, basically thinking it was rather normal valvetrain noise. It just about completely cleared up about two weeks ago, all on it's own.
The cam was still a little noisey - there was still a small amount of tapping only heard if you listen close outside the vehicle, but it wasn't anything that really raised a flag with me.
Valve Covers Check the valve covers. With the Pro Mags I had to remove the rear baffle on the drivers rear valve cover. It is a little piece of sheet metal that just hits the rocker.
Thread Starter
TECH Fanatic
iTrader: (1)
Joined: Sep 2003
Posts: 1,009
Likes: 0
From: Chesapeake, VA
Originally Posted by Taphee6
Check the valve covers. With the Pro Mags I had to remove the rear baffle on the drivers rear valve cover. It is a little piece of sheet metal that just hits the rocker.
