[Scott Stoneburg]

In looking to buy cam bearings for my 535. I am considering the Luhn grooved bearings. But am not sure if they are necessary. Is getting coated bearing worth the extra money? I have always just had standard cam bearing in all my motors. Im not going with 55mm, the cam will be larger than any i have used before so more srping pressure. ( big roller. 280@.050 .450 love lift )
What are your thoughts and why?

[Mike Davis]

I have been running the Durabond coated cam bearings for a few years. My cam is a 274/280@.050 with 700lbs pressure over the nose. The bearings looked good when I had to pull it apart for a piston problem. Noticed a difference in the bearing with less wear at the 5 and 7 oclock positions over previous non coated.

[tom s]

My thoughts about Marks grooved bearing.Its like giving a dead man a enema,cant hurt!Tom

[Scott Stoneburg]

I can get the uncoated grooved bearing from Luhn for $94.00 or a coated set ( not grooved ) for $85.00. what would be the better option

[Dragncar]

Cam bearings can take a beating. I don't think Marks bearings are a bad idea, just not need for most and who knows at what level you put them in. Its not like those bearings on a std journal cam will make it any stiffer like a 55mm will do. Or make your valve springs last longer like a 55mm will do.
I bought my std cam bearings for Jeff at KRE. Asked about the special bearings and was told they just never have any cam bearing issues with basic bearings. If they don't why would I have any issues ?
The folks at Luhn are fantastic. Building my oil pump pickup around their suggestions. The guys at Steffs asked if I wanted their matching pickup but thought I would just finish the one I started for the Canton pan for the Steffs.
Maybe they can grove some babbit bearings for the 55mm cam engine.

[steve25]

The aftermarket blocks have much improved oil flow over a factory block, so I really don't see the need for anything fancy here, but the basics need to right where as the Cam Bearings are set in there Bore perfect without any cocking up or down, or left and right.

The only type of Cam installation tool to use is the kind that pulls the Bearings in, not the type of tool that drives them in.

The pull in type of tool requires access to both the front and rear of the block to do the install right!

[Scott Stoneburg]

The only type of Cam installation tool to use is the kind that pulls the Bearings in, not the type of tool that drives them in.

The pull in type of tool requires access to both the front and rear of the block to do the install right![/QUOTE]

I will be having the machine shop do the install as I do not have the tools to install the bearings. And they will be completing the bore/hone process for me. . I will inquire as to which type tool they use. The shop is one I trust and has a good reputation here.

[slowbird]

Originally Posted by steve25

The aftermarket blocks have much improved oil flow over a factory block, so I really don't see the need for anything fancy here, but the basics need to right where as the Cam Bearings are set in there Bore perfect without any cocking up or down, or left and right.

The only type of Cam installation tool to use is the kind that pulls the Bearings in, not the type of tool that drives them in.

The pull in type of tool requires access to both the front and rear of the block to do the install right!

Why?
We've been using the drive in tool for 30 years and no issues.

[Half-Inch Stud]

Let's pass Physics together: ungrooved Cam bearings sound better for film float stability, and self-feeding for a few more milliseconds upon oul pressure loss. Oh, and the surface area spreads the load for...float.

Reality, lets' be real: Key aspect to babbit Cam Bearing life is DIY, R&R cam as you go to check and assure no-bind. no honing to fit. Much happiness.

Fun comparator: Full grooved rod bearings, for you know full oil distro. Practiced? Diesels? i dunno, but a runway groove(s) is interesting.

[slowbird]

The grooves on the inside of the bearings or the backside? I thought they wer grooved on the back??

[tom s]

They are on the backside connecting the oil holes.Tom

[mysticmissle]

do you think there will be hp cost associated with 4 point oiling on the journal? I can see the longevity benefit, assuming the unsorted channel hads no effect on the load bearing capacity of the cam bearing.

Not sure if reinventing the wheel is required on a part like this, but i have not had a cam bearing issue since the 80s lol, other mechanical issues sure

[Steve C.]

Stated- "The aftermarket blocks have much improved oil flow over a factory block..."


"There are some subtle differences between stock block oiling and an IA II, but the "oiling circuit", is essentially the same. The drillings from the lifter gallery to the main bearings in a stock block are 5/16", nominal. In an IA II, they were reduced to 1/4" to increase strength in the main web. The IA II has an additional drilling from the outside of the block to the #1 main, capped with a 1/8" pipe plug. Stock block does not have this. It can be used to extract oil for turbo cooling for example, or be used to provide external feed oil to the #1 main. The drillings from the oil filter adapter pad are slightly different. The IA II has "cleanouts", in the center of the block where horizontal and vertical drillings intersect. The stock blocks do not and sharp edges can't easily be addressed. That's the only changes I am aware of."

Source: mgarblik / 2017

Any changes since then ?


.

[steve25]

With a pul in tool you can feel right away if a Bearing is going in cocked, with a drive in type all too many times you don't know the Bearing is even minutely cocked unti you try and get the Cam in.

[taff2]

I prefer to drift the cam bearings in, the only time I've had a cocked bearing is when I pulled them in! If you do get a slightly cocked bearing (whichever method you use) ,put an old cam or piece of correct diameter bar stock in the bush and give it a couple of sharp raps with a copper mallet around it's perimeter - this usually straightens the bush in the bore. We occasionally have to do it in our trans builds ,rather than hone out the bush.

[mgarblik]

I have the Dura-Bond drive in Cam bearing tool kit. It is similar to the ones you see on the Summit site which is essentially a Cal Van tool. The Dura-Bond is made nicer. But the secret to success with a drive-in tool is to always use the centering cone to install ALL the bearings. So that means installing the front cam bearing from the rear using the cone and the rear from the front with the cone. #2,3,4 can be installed from the front or rear. Not saying I have never messed-up a cam bearing. It happens. I probably kill 1 out of 50. Once it's crooked, throw it out. Don't waste a bunch of time trying to save it. The only pull-in tool I have used is the factory Kent-Moore tool for Pontiac V-8's. It's been so many years, I don't remember if I liked it or not.

[slowbird]

Originally Posted by mgarblik

I have the Dura-Bond drive in Cam bearing tool kit. It is similar to the ones you see on the Summit site which is essentially a Cal Van tool. The Dura-Bond is made nicer. But the secret to success with a drive-in tool is to always use the centering cone to install ALL the bearings. So that means installing the front cam bearing from the rear using the cone and the rear from the front with the cone. #2,3,4 can be installed from the front or rear. Not saying I have never messed-up a cam bearing. It happens. I probably kill 1 out of 50. Once it's crooked, throw it out. Don't waste a bunch of time trying to save it. The only pull-in tool I have used is the factory Kent-Moore tool for Pontiac V-8's. It's been so many years, I don't remember if I liked it or not.

X2 centering cone use is a must

[mgarblik]

Originally Posted by tom s

They are on the backside connecting the oil holes.Tom

The GMP-55, 55 MM cam bearings have the backside groove. In a race only application, they are installed BLOCKING the oil feed in the engine block on purpose. This puts the block feed in line with the external groove making the groove and holes in the cam bearing the metering device.

[AC445]

Hello all, at Norwalk I bought a misc. box of rings and bearings. There was an old style box,light brown,of TRW SH292 cam brgs.Upon inspection the I.D. has a small 360 degree oil groove. Any builders have any thoughts +or- on using them? Thanks

[Half-Inch Stud]

Originally Posted by AC445

Hello all, at Norwalk I bought a misc. box of rings and bearings. There was an old style box,light brown,of TRW SH292 cam brgs.Upon inspection the I.D. has a small 360 degree oil groove. Any builders have any thoughts +or- on using them? Thanks

Lucky dog. Sounds like a good find.