Fixing Big Block Cam Bearings

I need some help, I have a real nice B (400) Block and I need to fix a cam bearing problem. I believe you can go to 54mm Large Hemi core or 55mm cam core.
First of all where should I look for either cam core?
Is there enough material to go to roller bearings in a stock block?
Any help would be gratly appresiated.

What is the cam bearing problem?
I've had to scrape(with a bearing knife) more than one BB Mopar cam bearing to get the bearing I.D. correct for the cams to slide in properly, it is a problem with the factory machining them not big enough I.D.
I would say that 2 out of 10 blocks will need that, you can have the cam bore honed out also to make the bearings fit in them also.
I now install #5 cam bearing first and trial fit the cam and go from there if it fits and rotates
I don't like having to scrape a new bearing but you do what you need to do to make them, I'm sure that is one of the reason the cam bearings are so soft

I use a wheel cyl hone to clean up the bearings.. clean it alot.. use on the ones
that give you a problem.. I also have a cam that has cutter slots in it if I need it

I have done everything with this block, this was the third time it has wipped out cam bearings.
This last time I installed Durabond coated bearings and then measured each cam journal bearing and then the cam. I then cut each cam jounal to give it 0.003" clearance. It turned real nice and I thought I had it finally fixed, NOPE!!!

I'm over it, time to make it work.

What I really need to know is, is there enough room to go to a roller bearing in a stock block?
Also is there a cam core that is avalible for either 54mm or 55mm cam.

I have tried it all and then some, for some reason this block is not happy in the cam tunnel. Time to make it right.

I believe you can run a 55mm cam in those. A call to someone like Ray Barton can confirm/deny this. The cam won't be made from a $2 cast iron chinese cam core so it will cost a lot more money, but you figured that. But it will also be better. I don't believe you want roller bearings.

Yes, I do want roller bearings. I believe it would really fix the problem.

I would suggest contacting someone like Best Machine,,Hughes Engine or other Mopar savy shops and see what tooling they have /use and their opinions on your issues.
Obviously something is wrong.
Not a typical failure in my opinion.

When you say it wiped out the bearings, just some clarifying questions: 1) what does the failure look like ? Camshaft Bearing Diagnosis 2) is it on all journals or is it a repeated failure on just one?

hi

many years back crower made cams with roller bearings to fit stock cam bore , cam had smaller dia jurnal. imperial roller i think it was called i think ? call crower !

Random cam bearings, first time it was on #1 durring a dyno session, second time it took out #2, #3 and #4, this time it took out #2 and maybe some others I can't see it all yet (not taken apart yet).

When it took out #2, #3 and #4 I has to use a slide hammer to get the cam out

I'm telling you Ive have tried everything, I believe the cam bore is offset somehow. The block has been measured a couple times and I was told good to go both times by real good shops.

I'm not looking for the problem anymre I'm just going to fix it.

Well I can tell you this, it is a very typical failure, I have been racing Big Block Mopars for 35 years and when you start pushing the limit of a stock block there are tons of issues. Cam bearing failure is probably the #1 thing wrong with B/RB stock blocks.

Been racing and around Mopars for over 50 years, I can’t remember the last time I saw a cam bearing failure.
Super Stock, Modifed Production, Stockers, even fuel cars.

All using commercially available bearings, with nothing special being done to the bearings or cam.

I thought there were some SS guys running 55MM deals in stock blocks, but don't quote me on that but pretty sure when I was talking to a cojuple of them they said they did as the iron blocks are scarce?!? Is this an oiling issue or?? I mean what else can it be if the cam slides in nice and easy?

How much valve spring pressure opened?

I agree, been messing with mopars since 1974, lost track of how many cam bearings I have sanded and scraped to get the cam to rotate, knock on wood never had a problem either, or seen an engine fail a cam bearing.

The "54mm" roller bearings are really 2.125" INA roller bearings. Ford sells them for their BBF engines. My Hemi block had #1-4 cam bores cut to 2.500". I think most of the SS Hemi guys run all five. For some reason, Joe Allread did my block for the front four and left the #5 as standard. Here is the Ford bearing kit. Pretty good deal compared to buying them individually at the bearing house.

https://www.summitracing.com/parts/...Cld-R6QIVUtbACh2thw3QEAQYASABEgJWffD_BwE

Jegs has them for the same price.

Bearing house price.

https://www.motionindustries.com/productDetail.jsp?sku=02852350

#5 journal is left STD size because the journal boss gets thin and enlarging the bore cuts off the oil passages. It can be done in a stock block but probably costs more than the block is worth.

Pardon my ignorance but how would you know if you have a cam bearing issue unless you find it on inspection? Makes a certain noise(i.e.) screeching,clacking noise?

Same cam each time?

I wiped the inner cam bearings on my tow vehicle 454. Just the inners. What I found was that the cam inner bearing surfaces chattered when ground and you could not see it or feel it. Put it in the lathe and saw 0.001 tir pattern on all the inner cam bearing surfaces. The outer ones did not exhibit any of the chatter and those bearings were good.

Just saying - don't assume or overlook anything............

If you're using the same cam, here's something that happened on a BBC. Plenty of oil clearance, and straight. Ate bearings almost as soon as it fired up. The problem turned out to be tiny heat cracks in the cam you couldn't feel with your hand. Showed up in the polisher. New cam , no more instawipe bearings. I mean smoke coming up through the valve cover with almost. 003 oil clearance. Spun by hand like a top, but as soon as pressure and heat hit it,,,presto saw blade

Thanks for the input, I really do appresiate all the replys.

I'm sure it is a possibilty, at this point it doesn't matter why. My OP was asking if anybody knew there was enough room to install 54mm or 55mm roller cam bearings not "What went wrong?"
I've been in touch with a good friend of mine that owns a real, real top notch shop and we have decidded to install 50mm roller cam bearings. He told me Bullit Cams has cam cores so that is another thing I don't have to find.

Al said I might have an oiling issue and I might, I don't know. This block has lifter bore bushings in all the lifter bores and that has been a topic in the past but that being said I had 50PSI at idle and 85PSI from 3500rpm through 7500rpm (Data logger).

I might make a tube bypass to help the oiling but once again the engine bearings looked wonderful.

The condition I described was one of the weirdest ones I've seen. Plenty oil and clearance, and being able to spin it by hand and have it continue spinning like on rollers was just nuts. Had some bearing material not clung to the cam forcing a polish in the lathe, I dont know if it would have been discovered. That cam became a burr when hot.

If you have room to bore and hone the tunnel to 2.5 a ford roller bearing will get you to a 54.5mm core (BBF), or jesel sells a nice coated babbit for a 60 using that bore size.ive never done a factory block like that, so no idea about available material

Well just wanted to let everybody know I went to a 50mm roller cam bearings to fix the problems I was having with cam bearings in this engine. The cam bores were off, when we cut it it really showed up. Nice and straight now! I got the new cam from Bullet Racing Cams.

Nice!

I have the 50mm bearings in my 48* SB.. I had to do a slight bore job to get the bores right
I really like the 50mm on a SB

I have 60mm roller bearings in my Small Block

I really like them and the cam.

I was going to try 55mm but I didn’t want to weaken a stock block.

Glad you got it sorted out!

That looks awesome too! What would the machining to install these bearings in a block typically cost?

So now that that this hurdle has been cleared what is the plan for the block?

Are all the bearings the same size? Do you need a special cam or does it ride on the bearings?

Put the engine back together and sell it.

All the bearings are the same size (50mm)
I had to get a new cam from Bullet Cams. It's not anything real special just a 50mm cam core. Yes the cam rides on the bearings.