Cam replacement questions
11-23-2002, 08:35 PM
#1
Burning Brakes
Thread Starter
Cam replacement questions
Hi all, been away from this Forum too long!!
I was investigating why I couldn't seem to keep a good valve adjustment and noticed when the motor (427 L-36) was running (valve cover removed) that #6 exhaust valve spring didn't seem to be going down as far as the rest. This valve also was the one that I suspected as it was difficult to keep in adjustment (flat tappet hydraulic cam).
I pulled the intake today and the #6 exhaust lifter was about 1/4" recessed in it's lifter bore. I pulled the lifter out and the bottom of it had a HOLE worn all the way through it! There was about a 1/4" amount of material worn away as compared to another lifter. Also, the cam lobe is worn away too.
Haven't pulled all the lifters but the two I did looked o.k. I did notice some "blueing" on some of the cam lobes. Not sure if this is normal or not. Also noticed that most of the lifters did not line up exactly over the center of the cam lobe, most were off to the right or left of center. Not sure if this is normal or not. Anybody who can explain please know your help is appreciated.
I was wanting to know what would be the best course of action for me to take?
Should I: 1) Just install a new cam and lifters and hope for the best, knowing that the engine has some metal floating around in it? (I don't drive the car much anyway).
Or, save up some dough and go pull the motor for another rebuild? (Motor was completely rebuilt only 16 months ago).
Also, what causes cam and lifter failure? Would a roller cam help to eliminate the possibility that this will happen again?
Anyway, that's the latest from me. It's always a pleasure to know there is a place you can go to seek help about this hobby/obsession we all share.
Regards, Mark :chevy :flag
I was investigating why I couldn't seem to keep a good valve adjustment and noticed when the motor (427 L-36) was running (valve cover removed) that #6 exhaust valve spring didn't seem to be going down as far as the rest. This valve also was the one that I suspected as it was difficult to keep in adjustment (flat tappet hydraulic cam).
I pulled the intake today and the #6 exhaust lifter was about 1/4" recessed in it's lifter bore. I pulled the lifter out and the bottom of it had a HOLE worn all the way through it! There was about a 1/4" amount of material worn away as compared to another lifter. Also, the cam lobe is worn away too.
Haven't pulled all the lifters but the two I did looked o.k. I did notice some "blueing" on some of the cam lobes. Not sure if this is normal or not. Also noticed that most of the lifters did not line up exactly over the center of the cam lobe, most were off to the right or left of center. Not sure if this is normal or not. Anybody who can explain please know your help is appreciated.
I was wanting to know what would be the best course of action for me to take?
Should I: 1) Just install a new cam and lifters and hope for the best, knowing that the engine has some metal floating around in it? (I don't drive the car much anyway).
Or, save up some dough and go pull the motor for another rebuild? (Motor was completely rebuilt only 16 months ago).
Also, what causes cam and lifter failure? Would a roller cam help to eliminate the possibility that this will happen again?
Anyway, that's the latest from me. It's always a pleasure to know there is a place you can go to seek help about this hobby/obsession we all share.
Regards, Mark :chevy :flag
11-24-2002, 12:11 AM
#2
Burning Brakes
Thread Starter
Re: Cam replacement questions (marky mark)
I did some research on the Comp Cams site and read that a lifter and a cam lobe will fail if the lifter does not rotate in it's bore. Someone else says that you sometimes have to help a pushrod to start spinning on it's own at initial start-up, so as to insure the lifter is also rotating. Perhaps that is what happened to my lifter & cam.
Am I correct in presuming that a roller lifter does not rotate in it's bore? Perhaps that would solve this problem (if that was the actual reason for the failure).
Roller cams for older Mark IV engines: What is required for the retro-fit other than the new roller cam, roller lifters, cam button on new timing chain, etc. Is there some other modification necessary to be done to the block perhaps?
Any help appreciated.
Regards, Mark :flag :chevy
Am I correct in presuming that a roller lifter does not rotate in it's bore? Perhaps that would solve this problem (if that was the actual reason for the failure).
Roller cams for older Mark IV engines: What is required for the retro-fit other than the new roller cam, roller lifters, cam button on new timing chain, etc. Is there some other modification necessary to be done to the block perhaps?
Any help appreciated.
Regards, Mark :flag :chevy