Lifter Breakin: Same Just for 2 Cyl's?
Thread Starter
Le Mans Master
Joined: Feb 1999
Posts: 8,351
Likes: 75
From: Tampa Bay FL
Lifter Breakin: Same Just for 2 Cyl's?
I am planning to replace the #5 and #7 intake/exhaust lifters when I replace the intake manifold gaskets with Fel-Pro Printoseals (one of my vacation projects this week). I have noted in several pubs that 'cam breakin' should be performed at 2000rpm for approx 15-20 minutes. Is this applicable for just two of the 8 cyl's or can this be performed for a shorter period?
Oh, and this is on the '80 L48.
Oh, and this is on the '80 L48.
Burning Brakes
Joined: Apr 2004
Posts: 847
Likes: 0
From: Des Allemands LA
I would replace all the lifters at the same time. Something happened to cause the other four to go bad. And regardless of how many you change don't skimp on break-in. If you do you may as well put used lifters on a new cam 'cause you'll end up with the same results 
. Just my 2cents.
. Just my 2cents.
Thread Starter
Le Mans Master
Joined: Feb 1999
Posts: 8,351
Likes: 75
From: Tampa Bay FL
Originally Posted by ram82fire
A question here ,,,,,,,,,,what is wrong with the two lifters you plan replacing ??
Geo
Geo
Racer
Joined: Dec 2002
Posts: 361
Likes: 0
From: Toms River New Jersey
Originally Posted by TedH
I'm getting some 'lifter' noise from that area of the valvetrain. My suspicion is one of the lifters has failed. I adjusted the entire bank of lifters/rockers today to 1 full turn after '0 lash'. Quieted down more but still getting some noise that I can actually feel as it 'ticks' through the valve cover. I intend to give the full valvetrain a good review before I pull any of the lifters BUT I have purchased the replacement Energizer Cam/lifters (same as the one I have in the engine) as a precaution.
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Thread Starter
Le Mans Master
Joined: Feb 1999
Posts: 8,351
Likes: 75
From: Tampa Bay FL
Originally Posted by Not2New72
Did you check your exhaust manifold/header bolts? Notorious for ticks.
Roy
Roy
Thread Starter
Le Mans Master
Joined: Feb 1999
Posts: 8,351
Likes: 75
From: Tampa Bay FL
Originally Posted by BacaBill
1 FULL TURN??? NO, NO,NO, no more than 1/2 turn after reaching 0 lash
Safety Car
Joined: Aug 2000
Posts: 3,711
Likes: 43
From: San Antonio TX
Spec for a non-anti pump up lifter is .060" of preload. (1” / thread pitch x rocker ratio) will tell you mathematically how much pushrod movement occurs at the adjustment nut. Using the smallblock stud pitch of 24 threads per inch and the stock rocker ratio of 1.5: 1” / 24(threads per inch) = .0416” per full turn, multiplied by the rocker ratio of 1.5 = .0625.” So, one full turn of the adjusting nut on a stud that has 24 threads per inch and a 1.5:1 rocker ratio will result in .060~ preload.
Spec for an anti-pump up is usually at .020" preload.
There is nothing wrong with setting the preload the way the engineers intended it to be. It doesn't matter whether you're talking old or new lifters.
And surprising no one has mentioned that the "break in" is for the cam lobes. You can put new lifters on an old cam and just drive the thing. It's done routinely and there is no break-in period in this situation.
Whether new lifters will help your valvetrain tick or not is another question and is anyone's guess. If the old lifters are bleeding down excessivly or are not feeding oil properly into the plunger, perhaps. If the lifter face is concave instead of convex, then you likely also have some lobe wear too and a new lifter won't fix that.
Spec for an anti-pump up is usually at .020" preload.
There is nothing wrong with setting the preload the way the engineers intended it to be. It doesn't matter whether you're talking old or new lifters.
And surprising no one has mentioned that the "break in" is for the cam lobes. You can put new lifters on an old cam and just drive the thing. It's done routinely and there is no break-in period in this situation.
Whether new lifters will help your valvetrain tick or not is another question and is anyone's guess. If the old lifters are bleeding down excessivly or are not feeding oil properly into the plunger, perhaps. If the lifter face is concave instead of convex, then you likely also have some lobe wear too and a new lifter won't fix that.
Le Mans Master
Joined: Mar 2002
Posts: 7,456
Likes: 2
From: Coming home from Luckenbach Texas
GM factory service manual says 1 full turn. Why do people usually recommend less than this?
BTW: I would be concerned that the lifter replacement is not going to solve the problem. Hate to say it, but pulling the cam (and likely replacing it) may be the thing to do...
Melting Slicks
Joined: Jan 2004
Posts: 2,672
Likes: 1
From: New Cumberland PA
Originally Posted by gerry72
(1” / thread pitch x rocker ratio) will tell you mathematically how much pushrod movement occurs at the adjustment nut.
Look at a 1.5 ratio rocker. The length from the push rod to the nut is 1 and from the nut the the valve stem is 1.5. It doesn't matter if the lengths are inches or feet. It's the ratio that is of concern. So in a 1.5 ratio rocker the over all length is 2.5. The far end of the rocker will move 2.5/1.5 (or 1.67) more than the nut. Use the 1.67 in place of the rocker ratio for the calculation.
Increasing the rocker arm ratio decreases the amount the push rod end moves versus the nut. For a 1.6 ratio rocker arm, the ratio is 1.625.
Race Director
Joined: Sep 2002
Posts: 10,362
Likes: 5
From: San Diego - Deep Within The State of CONFUSION!
Sounds like it's a simple math calculation using the rocker ratio. However that's not how it works when calculating how much the push rod end of the rocker moves when adjusting the rocker nut.
OMG!! You guys are giving me a headache! 
OMG!!
You guys are giving me a headache!
Racer
Joined: Apr 2004
Posts: 401
Likes: 0
From: IL
I think you need to rethink those math statements. Your both only half right. Regardless, he's over compressing the lifter which is causing the tick. And could lead to premature cam wear.
What you really need to do now is check for a bent Pushrod! In your other posts you've stated that you tighented 1.5x's past zero lash. If the Pushrods are straight reuse them. Next check the "old" lifter bottoms for wear. Lube them up and reinstall. But this time use the half turn past zero lash method. If nothing else, you'll get could practice before installing the new cam/lifter set. Same with the Intake post you have going.
Later.
What you really need to do now is check for a bent Pushrod! In your other posts you've stated that you tighented 1.5x's past zero lash. If the Pushrods are straight reuse them. Next check the "old" lifter bottoms for wear. Lube them up and reinstall. But this time use the half turn past zero lash method. If nothing else, you'll get could practice before installing the new cam/lifter set. Same with the Intake post you have going.
Later.
Le Mans Master
Joined: Mar 2002
Posts: 7,456
Likes: 2
From: Coming home from Luckenbach Texas
I don't get it. The GM shop manual and Chiltons say 1 full turn. (GM book even says this centers the lifter plunger). Haynes says 3/4 turn.
So where did the 1/2 turn specification come from?
(Not trying to be difficult, just curious...)
So where did the 1/2 turn specification come from?
(Not trying to be difficult, just curious...)