72Dart360
Well-Known Member
These are photos of my cam bearings after maybe 5000 miles. How could this happen? What steps should I take, such as do another line bore, tear apart the bottom end and go over everything.
What went wrong with these cam bearings?
- Thread starter 72Dart360
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1966 dart wagon
Well-Known Member
I would think it is possible from metal shavings? that would be my first guess, after you line bore or whatever you end up doing(Im not sugesting you do i dont know honestly) but make sure you properly clean the engine and make sure all metal shavings are out. thats mho
AdamR
Big Member
They look like they were to tight
C130 Chief
Mechanical Genius
Bent Cam?
They also look like they got hot. How are the upper halves of the mains? Was the upper valvetrain oiling well? Unless you are running super-mega-monster-stiff valvesprings, cam bearings should last as long as the bottom end.
They also look like they got hot. How are the upper halves of the mains? Was the upper valvetrain oiling well? Unless you are running super-mega-monster-stiff valvesprings, cam bearings should last as long as the bottom end.
64dartwagon
Walking in Circles
Looks like debris in the oil. Open up the filter and check it real good. And make sure to prime the hell out of it when you get ready to fire it up again.
ramcharger
Dismember
Yowwch! Looks like the the oil passages were not brushed and blown out with compressed air before assembley and some grit, crap, silicone, etc. got in there. Looks like a combo of oil starvation and contamination. You did lube the cam journals before sliding the cam in, right? Sorry man. :goodman:
JR
Pissed off senior member.
ramcharger said:
Thats what Im guessing, it looks like something got pushed out of the oil hole and just wiped out the berrings. When I did my 360 rebuild one of the first things I bought when I picked up the block from the machiene shop was a set of bottle brushes in all differant sizes so I could scrub the hell out of all the oil passages. Was the cam new?
demon seed
The Original Demon Seed
Could be all of the above especially contamination. It could also be that when the bearing were installed they were to tight, clearance to the cam, and then the babbit picked up and tore out. Also check that the top half main bearing shells were installed correctly and the crank is OK. Basically start from scratch. Sorry
Terry :goodman:
Terry :goodman:
dodge-n-it
Well-Known Member
next time before you put the motor together use soapy water to clean everything out also. brake cleaner will not clean well enough, it usually causes metal to cling on.
Here's a suggestion from an 80+ year old friend of mine that has rebuilt many engines. When the parts come back from machining, and after everythings cleaned and blown out, coat all the bearing surfaces with Vaseline prior to assembly because in his experince, the most critical time for a rebuilt engine is when it's first fired. Then, a change of oil and filter after the first few hundred miles. 
Captainkirk
Old School Mopar Warrior
First guess, not enough clearance. Second guess, crap in the oil passages. Third guess, no prelube or damaged them while installing the cam. In that order.
ALWAYS check to see if the passages are free and clear and that the holes in the bearings line up with those in the block. Prelube the bearings (I use Lubriplate 630AA or cam lube) and prelube the engine via the oil pump shaft prior to start up. This is critical.Just before you start it for the first time, pull the plugs and coil wire and crank it through until you have good oil pressure indicated. This will prime the pump prior to start-up. The first 3 minutes of a cam's life are the most important!
ALWAYS check to see if the passages are free and clear and that the holes in the bearings line up with those in the block. Prelube the bearings (I use Lubriplate 630AA or cam lube) and prelube the engine via the oil pump shaft prior to start up. This is critical.Just before you start it for the first time, pull the plugs and coil wire and crank it through until you have good oil pressure indicated. This will prime the pump prior to start-up. The first 3 minutes of a cam's life are the most important!
72Dart360
Well-Known Member
Thanks for the info guys. I had a trusted mopar man rebuild this engine for me and I sometimes think that you are better off to do things yourself, so there is no one else to blame. I'll be pulling the block out this weekend and going over a chevvy boys house to break her down and see what else might be wrong. The reason I'm going to take it there is because he is used to seeing engine problems. haha
A
Ace
Guest
Dirty rebuild. You won't see scoring like that without some serious chunks of crap in the oil. Trusted Mopar guy needs to practice better engine hygiene.
:wack:
:wack:
moper
Well-Known Member
Looks to me like they were either tight, or not lined up quite right. I've had issues with passages in the block not lining up just right before. I've had to modify the bearings or block to get the right volume thru them. Also, every time cam bearings get installed, the cam being run needs to be installed and if it cant be turned by hand, you need to clearance them. That's what it looks like. Without enough oil, it's just like any other bearings. Hot spots develop, and the layers de-laminate and come apart, making a bigger mess.
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