cam lobe, lifter failure
11-15-2010, 10:27 AM
#1
Drifting
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St. Jude Donor '08-'09
cam lobe, lifter failure
I had new LS7 lifters, patriot golds installed not even 8 months ago, and the cam (whiplash cam built by competion cams for England green) now has four worn cam lobes, one of these very bad, three lifters that are flat spot and roller bearings worn badly. The cam has been in the car for over 4years and the original lifters lasted 4 years.
The same thing happened to a tuners car here with a competion cam and on the same lobes. The two on #1, #8.
I have searched on here and have found problems with the hardness of the cams being ordered, LS7 lifters not holding up to high lift cams etc. but havent found anything concrete for the failure.
Has anyone got anything new to add, or a final reason that this combination might have happened?
The same thing happened to a tuners car here with a competion cam and on the same lobes. The two on #1, #8.
I have searched on here and have found problems with the hardness of the cams being ordered, LS7 lifters not holding up to high lift cams etc. but havent found anything concrete for the failure.
Has anyone got anything new to add, or a final reason that this combination might have happened?
11-15-2010, 12:16 PM
#3
Team Owner
First, check the valve springs. If the stiffness and seat values have decreased you could have had a valve control issue and ended up with the issues you have found. I would suspect this first. From there I would move on to hardness of the original parts.
11-15-2010, 05:16 PM
#4
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St. Jude Donor '08-'09
11-16-2010, 10:40 AM
#7
Le Mans Master
was the preload set correctly? ls7s want about .60 dont they? was valve seat hieght checked? pushrod length checked?
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JWM (06-19-2020)
11-16-2010, 11:27 AM
#8
Melting Slicks
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Why don't people understand that the cam lobe is the equivalent of a bearing race and the roller lifter is the roller bearing?
Would you ever replace the roller bearings in your wheel bearings and not change the race?
Changing only one part of a bearing be it the race or the roller is always a bad idea, just because one part is rolling doesn't mean it will not have a distinct wear pattern.
Sorry about the OP's problem but what you have here is a predictable failure.
Would you ever replace the roller bearings in your wheel bearings and not change the race?
Changing only one part of a bearing be it the race or the roller is always a bad idea, just because one part is rolling doesn't mean it will not have a distinct wear pattern.
Sorry about the OP's problem but what you have here is a predictable failure.
11-16-2010, 01:03 PM
#9
Le Mans Master
Why don't people understand that the cam lobe is the equivalent of a bearing race and the roller lifter is the roller bearing?
Would you ever replace the roller bearings in your wheel bearings and not change the race?
Changing only one part of a bearing be it the race or the roller is always a bad idea, just because one part is rolling doesn't mean it will not have a distinct wear pattern.
Sorry about the OP's problem but what you have here is a predictable failure.
Would you ever replace the roller bearings in your wheel bearings and not change the race?
Changing only one part of a bearing be it the race or the roller is always a bad idea, just because one part is rolling doesn't mean it will not have a distinct wear pattern.
Sorry about the OP's problem but what you have here is a predictable failure.
this is very untrue....if you have your valvetrain set up correctly, a cam will never wear out. I took mine out after 2 years of racing and it looked brand new. a lobe on a cam is not a "bearing" that needs replaced. Why do you think everyone sells used cams?
11-17-2010, 11:23 AM
#10
Melting Slicks
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"Valve lifter installation.
Important: When reusing valve lifters install the lifters to their original locations.
If a camshaft replacement is required, the valve lifters must also be replaced."
If a lobe on a cam is not part of a bearing, what is it?
And people sell used cams because other people buy them, some people get lucky and they work fine for a long enough time to dump the car.
Others are not so lucky, you are mismatching micro finishes on high loaded hardened surfaces that run at high relative speeds.
A recipe for a failure.
06-19-2020, 10:05 AM
#11
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06-19-2020, 10:12 AM
#12
Le Mans Master
Well I guess everyone has their own opinion about bearings, so I will defer to the service manual page 6-237.
"Valve lifter installation.
Important: When reusing valve lifters install the lifters to their original locations.
If a camshaft replacement is required, the valve lifters must also be replaced."
If a lobe on a cam is not part of a bearing, what is it?
And people sell used cams because other people buy them, some people get lucky and they work fine for a long enough time to dump the car.
Others are not so lucky, you are mismatching micro finishes on high loaded hardened surfaces that run at high relative speeds.
A recipe for a failure.
"Valve lifter installation.
Important: When reusing valve lifters install the lifters to their original locations.
If a camshaft replacement is required, the valve lifters must also be replaced."
If a lobe on a cam is not part of a bearing, what is it?
And people sell used cams because other people buy them, some people get lucky and they work fine for a long enough time to dump the car.
Others are not so lucky, you are mismatching micro finishes on high loaded hardened surfaces that run at high relative speeds.
A recipe for a failure.
Sounds more to me like the new parts weren't installed correctly. Incorrect amount of lifter preload, or possibly a bad batch of springs.
06-19-2020, 10:34 AM
#13
Burning Brakes
Cam to lifter wear pattern is a very real thing for flat tappet hydraulic camshafts, but new roller lifters can be installed with a used roller camshaft as long as the cam has no lobe defects - its worked for millions of motors since roller valvetrains came into existence.
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JWM (06-19-2020)
06-19-2020, 03:42 PM
#15
Burning Brakes
06-19-2020, 03:46 PM
#16
Le Mans Master
D'oh! (_8(|)
