Does a bad lifter HAVE to = a bad cam?
09-14-2011, 07:36 PM
#1
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Does a bad lifter HAVE to = a bad cam? Hello, I have a cammed LS6 and recently it started developing a valvetrain tapping noise. I took off the head today and I found a bad lifter, the roller texture looks pretty bad but the lobe looks ok, a few very minor nicks at worst.
Here's a pic of the bad lifter:
Do I really have to change the cam if the lobe looks ok?
Here's a pic of the bad lifter:
Do I really have to change the cam if the lobe looks ok?
09-14-2011, 08:06 PM
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curious to why the roller on the lifter is pitted? did you bend a pushrod causing the lifter to beat on the lobe of the camshaft? and if the lobe on the cam looks fine i would probably roll with it, good for you though that the roller didnt come apart from the lifter
09-14-2011, 09:00 PM
#4
Going off your info, there is little to no damage to the cam and the pushrod isn't bent, I'd have to say heat treat problems with the roller. Normally I would just call it roller delamination, but yours is more pitted. Not uncommon. The rollers are heat treated to a certain case depth, think of it as a hard candy coat. Improper heat treat caused from many different reasons, create imperfections in the structure of the steel. Usually only at that case depth which is why I call it delamination, it "flakes" off. Anyway, the end result is what you have in your hands.
ETA: In short the higher stress of your cam/springs and age of the lifter exceeded the material capabilities.
ETA: In short the higher stress of your cam/springs and age of the lifter exceeded the material capabilities.
Last edited by Havoc40; 09-14-2011 at 09:34 PM.
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09-15-2011, 04:31 PM
#8
You definitely need to inspect the cam thoroughly. Can you feel any play between the axle and needle bearings? Does it roll smooth? Also, what cam are you running?
If a roller does go undersize, obviously it's going to take away some preload. Looking at the picture I doubt that's your problem, unless you were short on pushrod length to begin with. Say a roller wears .020" diametrically, the preload is only going to see .010" of that. Most rollers will self destruct after they get too small and past the heat treat case. I say most because I've seen some wild hourglass looking rollers.
Time for some new lifters, measure carefully for pushrod length (or verify your existing ones will work), and take a real close look at that cam.
If a roller does go undersize, obviously it's going to take away some preload. Looking at the picture I doubt that's your problem, unless you were short on pushrod length to begin with. Say a roller wears .020" diametrically, the preload is only going to see .010" of that. Most rollers will self destruct after they get too small and past the heat treat case. I say most because I've seen some wild hourglass looking rollers.
Time for some new lifters, measure carefully for pushrod length (or verify your existing ones will work), and take a real close look at that cam.
09-17-2011, 07:55 PM
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So I took a closer look at the cam after I removed the other side head and lifters and I can see enough to tell me that the cam is in fact bad. So I need a new cam....
For those that have done a cam install, is it easier to install a cam with the heads off the car? Or should I put the heads back on after the new lifters are in? I know you don't need to take off the heads for a cam install but will it make inserting the new cam easier at all since the heads and lifters are out right now?
Thanks for everyone's help
For those that have done a cam install, is it easier to install a cam with the heads off the car? Or should I put the heads back on after the new lifters are in? I know you don't need to take off the heads for a cam install but will it make inserting the new cam easier at all since the heads and lifters are out right now?
Thanks for everyone's help
09-18-2011, 02:03 PM
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OK thanks, that's what I was thinking too.
Now on to another question...
I've been reading the forums about scenarios like mine where the cam fails and messes up the lifters and there was mention of cam bearings! Is it possible that my cam messed up the cam bearings as well? I would hate to order another cam and go through this whole process only to find out a month later that cam is toast again because of the bearings.
Now on to another question...
I've been reading the forums about scenarios like mine where the cam fails and messes up the lifters and there was mention of cam bearings! Is it possible that my cam messed up the cam bearings as well? I would hate to order another cam and go through this whole process only to find out a month later that cam is toast again because of the bearings.
09-20-2011, 01:11 AM
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Can anyone help identify these springs?
Will they work with a new cam or do I need new ones?
I would really like to replace the cam only if possible.
I know the pushrods have to be measured in order to get the right length so I probably need a new set. But what about the springs, oil pump, timing chain etc....?
Will they work with a new cam or do I need new ones?
I would really like to replace the cam only if possible.
I know the pushrods have to be measured in order to get the right length so I probably need a new set. But what about the springs, oil pump, timing chain etc....?
09-20-2011, 01:27 AM
#16
take the heads to a machine shop have them pressure tested to make sure they good i dont think a bad lifter would hurt springs but they are one thing i would double check last thing you need is to drop a valve
09-20-2011, 11:56 AM
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Now on to another question...
I've been reading the forums about scenarios like mine where the cam fails and messes up the lifters and there was mention of cam bearings! Is it possible that my cam messed up the cam bearings as well? I would hate to order another cam and go through this whole process only to find out a month later that cam is toast again because of the bearings.
I've been reading the forums about scenarios like mine where the cam fails and messes up the lifters and there was mention of cam bearings! Is it possible that my cam messed up the cam bearings as well? I would hate to order another cam and go through this whole process only to find out a month later that cam is toast again because of the bearings.
Last edited by Jared H; 09-20-2011 at 12:01 PM.
09-20-2011, 02:44 PM
#18
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I doubt your cam bearings are bad ... easiest to look at the cam itself ... inspect the bearing surfaces there for any babit or discoloration. If they look like new you're most likely ok ... good luck! FWIW ... I've been through the same thing but with multiple lifters and I did install a new cam, lifters, ported oil pump, timing chain, and springs ... been fine ever since.
10-12-2012, 09:27 PM
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New to this new guy with new question. My supercharged intercooled zo6 has an emormous flat edge on #4 intake roller, all needle bearings are in pan - but cam looks minorly affected - do i need to replace cam?
