Cam bearing let down

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jeffnmo

Just another Mopar Maniac
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Hey my FABO friends I need a little help. About six months or so ago my son and I took my 340 apart, intake, cam and heads well my back has been shot for years but with meds I was doing OK, and then bam it went out for good ( reason for the six months ) but I've had surgery since and today was the day to put it back together. I got a set of LA-X heads from IMM and a Lunati Voo Doo Hydraulic flat tappet cam, any way when I started cleaning everything up I noticed the cam bearings are shot, I've never changed cam bearings before, how hard will it be to do with the motor in the car, I have access to the proper tools. How I didn't notice them before, I don't know. Thank You very much for any help given.

Jeff
 
how hard will it be to do with the motor in the car

You can't. There is a plug on the cam end on the back side of the engine that has to come out....then you need room to get the removal tool in there to drive the bearings out.

Unless there is another method that I'm unaware of.
 
You can't. There is a plug on the cam end on the back side of the engine that has to come out....then you need room to get the removal tool in there to drive the bearings out.

Unless there is another method that I'm unaware of.
And REALLY not with a bad back!!!
 
I have the install tool if you're in Missouri....but your location says otherwise, Jeffnmo...
 
OP, in what way are the cam bearings 'shot'?


That's what I'd like to know. I've used some really bad looking cam bearings without issue. With pretty much stock stuff there isn't that much load on them.

One Pontiac 400 I was screwing with have 2 cam bearings that were actually cracked and the rest were marginal at best. The owner said run it. So I swapped cams and made not of it on the invoice. Ran it for a year, cam back in for more cam and a gear change. Bearings looked the same. So I did the swap.

He drove that thing for years. Until about a week before he died. Had to put 50-60k on those junked up bearings.

Seen it many times. Sometimes you just don't need to screw with it.
 
I'm going bet if the cam bearings look that bad you might wanna take a look at the rod bearings too.
 
That's what I'd like to know. I've used some really bad looking cam bearings without issue. With pretty much stock stuff there isn't that much load on them.

One Pontiac 400 I was screwing with have 2 cam bearings that were actually cracked and the rest were marginal at best. The owner said run it. So I swapped cams and made not of it on the invoice. Ran it for a year, cam back in for more cam and a gear change. Bearings looked the same. So I did the swap.

He drove that thing for years. Until about a week before he died. Had to put 50-60k on those junked up bearings.

Seen it many times. Sometimes you just don't need to screw with it.
Yes, I have raced a few k-miles on a rally engine with some reeeeally loose cam bearings....like .008" clearances, where it was supposed to be .003". Not that I should have LOL, but it was nary a problem. 8k rpm all the time. 4 banger, cam-in-head. So I'd like to see/understand the exact nature of this issue. If there are many big chunks gone from the babbit deteriorating, then probably needs to be done. If it is one limited sized chunk missing, then probably not. And, of course, what the OP is comfortable with.

I imagine that they can be gotten out in-car.. but the old ones are going to want to fall into the crank case when removed. And you gotta get the news ones to stay on the tool while you carefully get them into place to then drive them home. Gotta makes sure #2 and #4 get driven in the right way to line up the holes at the top, to send the oil to the rockers. Getting a mirror in there to double check may be possible.
 
The last 340 we just did had a wiped lobe when it came here. My son was just going to install a new cam. After he took the cam out he saw the bearings were flaking apart he pulled the motor and talked the guy into a rebuild. If that is the problem with yours. Install new bearings.

The flakes coming off have to go somewhere. And once you have it apart and reinstall the cam. They just disintegrate twice as fast. Ask me how I know? I didn't listen to my dad years back. That was the end of that motor. That is a good reference above that rusty added from Krazycuda I would use it.
 
Make sure you use high quality bearings. The last bearings I put in my 340 were a standard quality 1484M and when I pulled it apart this year , one bearing started to show signs of breaking up. This time I've got High Performance SH875S MAHLE/CLEVITE SH875S Camshaft Bearing | RockAuto
IMG_5400[1]_1280x960.JPG
 
how.....HOW have I never seen this series? !!!
Thanks....and thanks @krazykuda

Jeff

Jeff if you look in that same section, I have two how tos on cam bearing installation. One for a 383 and one for the slant six. You needed the small block, which Karl did.
 
Jeff if you look in that same section, I have two how tos on cam bearing installation. One for a 383 and one for the slant six. You needed the small block, which Karl did.

This site is so cool......
God, there's so much help and information here!
I have some good reading to do now!

Jeff
 
how.....HOW have I never seen this series? !!!
Thanks....and thanks @krazykuda

Jeff


I just started doing this series in the past two months or so...

I have more to do, but am juggling work, home, and FABO time...

I try to get one done every week or two when I can.....

I hope to start my next write up on piston installation this weekend or next week if I can get some spare time...

Each section takes me 10+ hours (and 2 -3 days) to sort pictures, highlight pictures with circles and arrows to show where you need to be looking, then write, and proof read...

Keep checking in every 2 -3 weeks for new sections until I can complete the build...

I have a few "holes" that I may just start and post to save the spot until they are in order (namely the one for cam degreeing) and I can finish it after we degree our next cam (which may take till January as my younger son is away at college now and most likely won't be back until Christmas break)... I won't be able to degree the cam on the son's 360 that we are using for our main subject for these builds, I want to show him how to do it on his engine and not do it for him where he won't learn from it, so I have to wait for him to come visit...

I do have some pictures ready for heads and top end that I can use from other builds that I have done and will keep trying to write some more with those...
 
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OP, in what way are the cam bearings 'shot'?


If there are deep gouges or grooves in them... If you can catch your fingernail on it when running it across the bearing "defect", you should consider replacing it...

It also depends on the bearing material... Babbitt is more forgiving that aluminum...

When we installed the bearings at the engine factory, we not only had to measure and meet a size spec, but also had to meet a surface finish spec... You need a special machine with a stylus to measure surface finish that is not affordable to us home builders...
 
I'm going bet if the cam bearings look that bad you might wanna take a look at the rod bearings too.

Also check the oil for any metal flakes... If you find metal flakes in the oil pan, then you should pull the engine and tear it down and start on the first article in the series to clean the block and get all of the chips out of the block and oil galleys so they don't come back and haunt you...

The first article I didn't pull the oil galley plugs as we started out with a running 360 that didn't have many miles on the rebuild... I did find a few assembly issues when we tore it down, that wouldn't affect the oil galley or bearings...

But if you have metal chips in the engine, you should also pull the oil galley plugs and give all the passages a good blast with a pressure washer or take it to the do-it-yourself local car wash to blow them out...
 
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This site is so cool......
God, there's so much help and information here!
I have some good reading to do now!

Jeff


That's part of my motivation to do the series... Where else are you going to find a complete how to series on rebuilding an engine???

This will help make FABO the best Mopar forum on the internet...
 
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The bearings are as some of you say, flaking apart, there are pieces missing from a lot of the edges and chunks out of the middle on almost all of them. I'm going to pull the motor, as hellrats said to check the rod bearings, and I agree, I want to check them all for piece of mind. The motor was losing power and some oil pressure and I wanted a bigger cam any way to go with the better heads, when I pulled the cam some of the lobes were going away, I don't know how I missed the bearings! I gotta say you guys are freakin' awesome, many thanks to all of you, with the help I'm sure I can get this done with no problem. I've never changed cam bearings but I'm pretty good around a motor so this will be a piece of cake. Thanks again to all you fine FABO friends. And if any one is interested, I mentioned my bad back and I know some of you here suffer with it, I'm not talking a back ache, I'm talking serious problems. I was in a car wreck in the late eighties, a guy ran a red light and slammed me in the drivers door. Well as the years went by I've had every treatment in the book and just this least year everything stopped working, so my Doc talked about an Abbott spinal cord stimulator with BurstDr. A unit about a little bigger than a zippo lighter is inserted in my back and a wire runs up my spine, what the thing does is trick the brain into thinking you don't have pain and I have had mine for about a month, my life has totally changed, I went from crying from the pain to just about running around the yard. So look it up or talk to your Doctors because this damn thing works. I think it was crackedback who started a thread talking about his back troubles. Thanks for the help and Thanks for listening.

Jeff
 
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