Cam Bearing Advice

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BHB4408

BHB4408

BHB4408
Joined
Aug 29, 2022
Messages
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Location
Edgewood, WA
I'm ready to start building my .40 Over 440 w/440 Source 512 Kit, Trickflow 270 heads, 12.1 Compression, Edelbrock Max Wedge Single Plane Manifold, 1050 Holley, etc, you get the picture...100% Drag Car, with maybe 600+ HP. The Block is all machined, and I need to install Cam Bearings. Can you advise me on whether I want fully grooved, partially grooved, or any other advice you have to make sure I order what is best for my application?

Thank you,
 
BHB4408 said:
I'm ready to start building my .40 Over 440 w/440 Source 512 Kit, Trickflow 270 heads, 12.1 Compression, Edelbrock Max Wedge Single Plane Manifold, 1050 Holley, etc, you get the picture...100% Drag Car, with maybe 600+ HP. The Block is all machined, and I need to install Cam Bearings. Can you advise me on whether I want fully grooved, partially grooved, or any other advice you have to make sure I order what is best for my application?

Thank you,
Click to expand...
I run a coated bearing.
I'll see if I can find the box with the part number tomorrow
 
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Number 4 bearing is the only bearing grooved IF you want full time top end oil and did all the oiling mods with an external system. even then oil is taken away from the bottom end.
In general you don't need a grooved bearing.
 
You can groove the #4 cam brg in the cam using a Dremel. That is how I do it; no need to pay extra for special brgs.
I used to use Dura Bond brgs, but with the last couple of sets, I found the cam was tight, so I no longer use them.
 
Big blocks have a problem with the #4 cam journal due to the factory machining which makes having the bearings broached after installation a necessity.
Ask @Oldmanmopar
 
The cam fitting tight isn due to and undersize cam journal
Mr. Sinister said:
Big blocks have a problem with the #4 cam journal due to the factory machining which makes having the bearings broached after installation a necessity.
Ask @Oldmanmopar
Click to expand...

You have to open up #4 cam journal a few though on most blocks I have messed with or the cam turms hard or will not slide into #4 at all. The correct method is adjusting the journal size. If a person doesn't have the necessary means to do a job such as that they break out a bearing knife which is more for tractors and heavy equipment in the field but it works.

I can't imagine doing any type of close tolerance work with a Dremel tool especially when you can easily chuck the camshaft in a small lathe so tolerance can be maintained. If you already spent the money to get a roller cam and all of the necessary hardware; not grooving number four when the cam is made is like stepping over a dollar to pick up a dime.
 
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Jeremiah (jd) said:
The cam fitting tight isn due to and undersize cam journal


You have to open up "4 can journal a few though on most blocks I have messed with or the can turms hard or will not slide into #4 at all. The correct method is adjusting to journal size. If a person doesn't have the necessary means to do a job such as that they break out a bearing knife which is more for tractors and heavy equipment in the field but it works.

I can't imagine doing any type of close tolerance work with a Dremel tool especially when you can easily chuck the camshaft in a small lathe so tolerance can be maintained. If you already spent the money to get a roller cam and all of the necessary hardware; not grooving number four when the cam is made is like stepping over a dollar to pick up a dime.
Click to expand...
It’s not the journal size it’s a factory machining alignment issue. And you don’t use a bearing scraper or knife to do the job either. And it’s thousandth in measure.
 
Jeremiah (jd) said:
they break out a bearing knife which is more for tractors and heavy equipment in the field but it works.
Click to expand...
I use an old camshaft with a few pie cuts on the journals to dress the bearings., stick it in and spin. lol
Mopar cam bearings are thinner than most, they get boogered up and distorted a little when installing.
 
Mr. Sinister said:
Big blocks have a problem with the #4 cam journal due to the factory machining which makes having the bearings broached after installation a necessity.
Ask @Oldmanmopar
Click to expand...
Not all big blocks, I've never had to even fiddle with any of the big blocks I've installed cam bearings in, and as a matter of fact I had to redo some cam bearings for my boss once because he couldn't get the cam in, the cam went right in after I did it. Problem I usually see is the installer or installer operator.
I have seen them need broached though, not in person
 
The best thing the OP can do is look up the Herb McCandless big block oil mods. do's and don'ts need mods.
 
I'll break out a dial indicator in the next few days and take some pictures of number four being undersized. I have not witnessed an alignment issue. Not saying they aren't out there but making the cam bearing fit correctly has fixed
fishmens67 said:
I use an old camshaft with a few pie cuts on the journals to dress the bearings., stick it in and spin. lol
Mopar cam bearings are thinner than most, they get boogered up and distorted a little when installing.
Click to expand...

I have one of those here. Stopped using it when I purchased a dial bore gauge : D
 
MOPARMAGA said:
Not all big blocks, I've never had to even fiddle with any of the big blocks I've installed cam bearings in, and as a matter of fact I had to redo some cam bearings for my boss once because he couldn't get the cam in, the cam went right in after I did it. Problem I usually see is the installer or installer operator.
I have seen them need broached though, not in person
Click to expand...

90% of my experience is 73-up 400 blocks. We should start keeping track of dates and platforms to see if there is a trend. I find manufacturing history infinitely interesting.
 
fishmens67 said:
I use an old camshaft with a few pie cuts on the journals to dress the bearings., stick it in and spin. lol
Mopar cam bearings are thinner than most, they get boogered up and distorted a little when installing.
Click to expand...
I do the same. Been doing that since I was a kid workin in a machine shop whan I was still in school. It was owned by an old retired Navy machinist. He showed me how to do it. Works great every time.
 
Mr. Sinister said:
It’s not the journal size it’s a factory machining alignment issue. And you don’t use a bearing scraper or knife to do the job either. And it’s thousandth in measure.
Click to expand...

Have you measure the cam journals prior to assembly? If so, what did you use. The alignment issues people speak of, in my experience, is a distorted bearing due to a tight journal. Lastly, the bores I find to be undersized are so by a half a thou to 1.5 thou (.0005-.0015).

Disclaimer : If you aren't measuring with a .0001 resolution dial bore gauge set up with an anvil mic we will probably have different experiences.
 
RustyRatRod said:
I do the same. Been doing that since I was a kid workin in a machine shop whan I was still in school. It was owned by an old retired Navy machinist. He showed me how to do it. Works great every time.
Click to expand...

We have modern tools now. The old ways are doable until you start running roller cam spring pressures and coated cam bearings. Alot of folks including myself used the slittes cam method and scraped bearings for years. We know better in 2025. My 499" intake springs are 300/870psi. I'm not scraping the coating off of the bearings. The proper way to correct the issue is correcting the journal bores to get correct crush on the bearing.

Because....math and science : D
 
Jeremiah (jd) said:
We have modern tools now. It's doable until you start running roller cam spring pressures and coated cam bearings. My 499" intake springs are 300/870psi. I'm not scraping the coating off of the bearings. The proper way to correct the issue is correcting the journal bores to get correct crush on the bearing.

Because....math and science : D
Click to expand...
I don't disagree. That said, I'll never have anything with a roller cam so I'm good.
 
Jeremiah (jd) said:
Have you measure the cam journals prior to assembly? If so, what did you use. The alignment issues people speak of, in my experience, is a distorted bearing due to a tight journal. Lastly, the bores I find to be undersized are so by a half a thou to 1.5 thou (.0005-.0015).

Disclaimer : If you aren't measuring with a .0001 resolution dial bore gauge set up with an anvil mic we will probably have different experiences.
Click to expand...
Yep, then 10ths make a big difference
 
I found the problem with the undersize cam bearing journal in the block, back in the "70's. Found it the hard way when I couldn't get the cam in the block/bearing. I thought the machine shop screwed up when installing the bearings. After that any big block I took to the machine shop for hot tanking and cam bearings, got the rear cam cavity checked, and honed to the correct size. Once and done. Don't have to modify the bearings or cam.
 
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