How to find a bad lifter?
How to find a bad lifter? I just completed a head swap on my LS6. I installed TFS 215s and Morel lifters with link bars.
My oil pressure is too low, and but varies. It starts at 10-15 pounds but can reach 50 sporadically. I also have a loud upper engine knock.
I have removed the valve covers and rotated the engine and the pushrods seem to rise and fall okay and none are bent. (Pushrods are Manton Grade 5s and don't bend easily).
Since the motor only has 22k miles and everything was okay before the head swap, I am assuming it must be something in the upper engine - like a bad lifter.
Is there anyway to tell which lifter is bad so that I do not have to pull both heads?
If I do pull the heads and retreive all the lifters how can I tell if one is defective?
My oil pressure is too low, and but varies. It starts at 10-15 pounds but can reach 50 sporadically. I also have a loud upper engine knock.
I have removed the valve covers and rotated the engine and the pushrods seem to rise and fall okay and none are bent. (Pushrods are Manton Grade 5s and don't bend easily).
Since the motor only has 22k miles and everything was okay before the head swap, I am assuming it must be something in the upper engine - like a bad lifter.
Is there anyway to tell which lifter is bad so that I do not have to pull both heads?
If I do pull the heads and retreive all the lifters how can I tell if one is defective?
I still do not know how to test for a defective lifter without pulling the heads, or with the lifters in hand for that matter but,
1. The knocking turned out to be a valve cover clearance issue. The Trick Flow heads are made with extra clearance and are supposed to work with the Jesel rockers with no spacer - and they do. But one of the rivets that hold the baffle inside the valve cover was significantly longer than the others and after idiling the engine for a while left a mark on one the rockers. With that fixed the knock is gone.
2. The oil pressure is apparently a pushrod length issue. I discovered that the custom Manton push rods were not the same length that I expected. It turns out that the Comp Cam adjustable pushrods that i used for all my measurements use a different definition of "length."
Specifically, Comp Cams pushrods (made by Trend Performance Inc.) use "gauge length, which keys off a certain part of the radius on the pushrod ball. Most other pushrod sellers use actual overall length measured from end to end with a 0.100 inch oil hole. In any event, I have now remeasured based on actual overall length using 0-8inch dial calipers which should fix the pushrod length problem. The difference between gauge vs. actual length methods can be anywhere from 0.015 to 0.025 inch. In my case it was 0.020" which is equal to the total tolerance the Morel lifters have on preload (0.030 to 0.050 = 0.020 tolerance).
1. The knocking turned out to be a valve cover clearance issue. The Trick Flow heads are made with extra clearance and are supposed to work with the Jesel rockers with no spacer - and they do. But one of the rivets that hold the baffle inside the valve cover was significantly longer than the others and after idiling the engine for a while left a mark on one the rockers. With that fixed the knock is gone.
2. The oil pressure is apparently a pushrod length issue. I discovered that the custom Manton push rods were not the same length that I expected. It turns out that the Comp Cam adjustable pushrods that i used for all my measurements use a different definition of "length."
Specifically, Comp Cams pushrods (made by Trend Performance Inc.) use "gauge length, which keys off a certain part of the radius on the pushrod ball. Most other pushrod sellers use actual overall length measured from end to end with a 0.100 inch oil hole. In any event, I have now remeasured based on actual overall length using 0-8inch dial calipers which should fix the pushrod length problem. The difference between gauge vs. actual length methods can be anywhere from 0.015 to 0.025 inch. In my case it was 0.020" which is equal to the total tolerance the Morel lifters have on preload (0.030 to 0.050 = 0.020 tolerance).
The manton pushrods machine off 7.5 thousandths on each end. This allows an "oiling" pocket and without it the pushrod would gall the rocker cup. Now with this said realize this that compcam pushrod checking device is said to be 6.800 when closed correct? Well put a caliper on it and measure and you will find it's 6.815 actual overall length. They buffer the 15 thousandths into the measurement number. Thats the same 15 thousandths Manton removes from the ends (combined 7.5 perside). The comp tool does not have the ends machined as it's not going to be used but that does not effect lifter preload values anyway. So in short the comp tool does indeed give you the correct numbers you need. I found this all out thru hands on research if you find anything off let me know please.
Trending Topics
The manton pushrods machine off 7.5 thousandths on each end. This allows an "oiling" pocket and without it the pushrod would gall the rocker cup. Now with this said realize this that compcam pushrod checking device is said to be 6.800 when closed correct? Well put a caliper on it and measure and you will find it's 6.815 actual overall length. They buffer the 15 thousandths into the measurement number. Thats the same 15 thousandths Manton removes from the ends (combined 7.5 perside). The comp tool does not have the ends machined as it's not going to be used but that does not effect lifter preload values anyway. So in short the comp tool does indeed give you the correct numbers you need. I found this all out thru hands on research if you find anything off let me know please.
Since then I established that: (a) my 6.80 Compcam adjustable pushrod measures 6.820"; (b) the Comp Cam literature states flat out that its measurement is "guage" length which is not used by other companies; and (c) the Compcam adjustable pushrod installed with +11 turns (7.350 gauge length) does NOT give the same clearances at the rocker as the Manton pushrod (7.350 actual length).
Terry Manton sent me one of his checking pushrods free of charge and I purchased a some 0-8 inch dial calipers to sort all this out. I verified that I get zero lash at 7.32 inches (actual overall length) whether I use the Compcam or the Manton adjustable pushrod. The trick is to measure overall length and ignore gauge length UNLESS you are going to order Comp Cam pushrods.
I believe the only reason this does not come up more often is that the more commonly used lifters have much broader preload windows such that the difference between gauge length and actual overall length is not significant. But on lifters like Morels it can be a critcal difference.
Last edited by Darkman; May 20, 2010 at 09:13 PM.
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 So if you closed the comptool and went with the 6.800 measurment (it's actually 15 or as you found 20 thous longer) and ordered a Manton overall pushrod length of 6.800 you will come up with different preload figures? Wether that extra 15 or 20 thous is there on the comptool or not does not change the area on the ball end that contacts the lifter cup or rocker arm. If for the hell of it you took the comp tool and machined the ends like a regular pushrod I dont see it changing the actual preload values. I am not challenging your findings this is GREAT information and I spent a **** ton of time sorting this out and spoke with Terry on the phone more than once as well. Thanks for the discussion
So if you closed the comptool and went with the 6.800 measurment (it's actually 15 or as you found 20 thous longer) and ordered a Manton overall pushrod length of 6.800 you will come up with different preload figures? Wether that extra 15 or 20 thous is there on the comptool or not does not change the area on the ball end that contacts the lifter cup or rocker arm. If for the hell of it you took the comp tool and machined the ends like a regular pushrod I dont see it changing the actual preload values. I am not challenging your findings this is GREAT information and I spent a **** ton of time sorting this out and spoke with Terry on the phone more than once as well. Thanks for the discussion
So basically in short what you are saying is add the .020 to what the Comptool's regular "turns" measurement comes up with? So fully closed= 6.820 overall length in a Manton PR?
Yes, except from what you reported there may be instances where the 0.020 inch difference maybe on 0.015 based on the length of the Compcam adjustable pushrod. Those may not vary that much during current production, but there may be an earlier "vintage" of those that have a different overall length. The Compcam literature shows an example in which the difference is 0.017 inch. In theory, since the gauge measure is based on a constant 0.140 inch assumed tube diameter the actual value would vary with pushrod diameter. So it comes back to "It is always best to measure."
Bringing this topic back up. It interested me enough to order a measuring device from Manton. The Comp Cam device (7702) and this Manton device do not have the same ends on them. The Manton tool is indeed machined flat on the ends just like a production pushrod from him. The CompCam tool is not machined flat it is a complete spherical end.
