Let's discuss cam bearings

Tom Righter · Jan 12, 2022

Jim Weise said: ↑

Rich,
I have no data to support the idea that the grooves in the front bearing won't supply enough oil to the driver side lifter galley. Built well over 100 motors with them now, and a lot of them have had very quiet valve-trains. Even at 600 rpm idle speeds.

I think if you do the math, on the two back grooves, vs the one cam journal groove, the two back grooves in the bearing actually provides more square inches of passageway for oil. And behind the bearing, it is not subject to trying push the oil against the spinning camshaft.
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As far as coatings going, I have used them in the past, and continue to use them, but aside from the piston skirt coating applied by Line2Line coatings out in MI, that is used for sizing needs, I have yet to see any bearing coating that simply does not wear off in the contact areas. I have used all the major coaters, plus done it myself in the past.

Bottom line, I am not having any bearing issues, so I am not looking for solutions. Sure the "top" engine builders all use it.. I has a wonderful profit margin, and is the easiest sale in the world.

You may call me jaded, but I prefer the term realistic. Most of my peers in the industry do not use coated bearings, unless they are trying to maximize the profit margin on each engine. And the majority of them will give you the same answer as me..

Yes, they can be helpful during initial startup and break-in, but they are not required.

I have built dozens of Buick 455 based engines from 350 to nearly 1400 HP, and have not had a bearing failure issue. Dozens of these engine were Hi spring pressure solid flat tappet or solid roller cam 600+ race motors, with the buick cam tunnel.

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Tom, I am curious.. I assume your using the BT-9 bearing from Durabond.. Or are you having the BP-9's coated individually.

As far as oiling, you say your putting oil in at the 7'oclock postion? There might be a hole there, but I really doubt it will actually oil there. 5-7 is the highest point of contact, and the hydrodynamic wedge is under the greatest pressure there. I very much doubt that 70psi of oil pressure will break into the wedge there. I assume your drill another hole in the bearing to do this? and then using the larger hole drilled by durabond to line up with you hole drilled into the driver side galley.

Your must be putting quite the groove in the front journal, to get oil around there fast enough to go all the way down the driver side lifter galley, and feed the cam bearings thru a .062 hole.

I can see all kinds of situations where this could be problematic, in relation to cold engine oil viscosity slowing down the oil feed to the bearings.

You must have to be awful careful about oil temp with that setup. I can see where a coated bearing would be required here. Intermittent dry lube conditions are the best reason to coat bearings.

JW[/QUOTE hi Jim, I was going through my drill bits to get ready to do a 430 block and I realized I miss spoke about the whole I drill in #2 thru 5 its 1/8 inch
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Mart · Feb 13, 2022

Tom Righter said: ↑

I have a tool that draws them in so I can be very precise at where I locate them ....
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I use the draw bearing in place method myself. Doesn't distort bearings at all.

BQUICK said: ↑

I just found a box of like new but previously installed teflon coated cam bearings and I had marked it "cam too tight". I seem to remember either using a different coating or non-coated and also had to polish the cam journals down some to finally get cam to turn freely......
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I've found drawing, instead of pounding bearings in, eliminates the tight cam issue above unless cam is slightly bent. Usually something isn't right if you have to resort to scraping bearings or polishing cam journals down to get perfect alignment "spin".

avmechanic · Feb 19, 2022

Mart said: ↑

I use the draw bearing in place method myself. Doesn't distort bearings at all.

I've found drawing, instead of pounding bearings in, eliminates the tight cam issue above unless cam is slightly bent. Usually something isn't right if you have to resort to scraping bearings or polishing cam journals down to get perfect alignment "spin".
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What kind of tool setup do you use to draw the cam bearings in?
Greg

Mart · Feb 19, 2022

avmechanic said: ↑

What kind of tool setup do you use to draw the cam bearings in?
Greg
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Custom made deal, made before I retired.

Mart said: ↑

Looks similar to my home made model. Mine pulls the bearing in, no hammering or drifting. The o.d. has to be about. 004 smaller than i.d of bearing to allow for crushing after install or you'll scratch up bearing i.d. trying to remove it after installing. The blue delrin threaded spacers hold the threaded rod true and centered to block cam bores. The large flat washer goes against the block while you turn the nut and pull the shell in. Works slick. Rear cam plug has to be out to use it for all the bearings. Don't know if TA bearings, (cause they are wider), will fit without crank or rod removed to sneak them into position.
All i.d.'s are threaded and concentric to o.d.'s. Never have had a cocked or distorted bearing using this contraption, so no i.d. reaming ever necessary.

You're on the right track!
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ronbz455 · Aug 1, 2022

I've been running stock cam bearings for years without a problem. Now don't know about getting the TA or not. One thing I noticed in the stock bearings is the McQuay Norris front bearing has an oblong hole and a small hole and the newer ones have 2 oblong holes.

TimR · Aug 28, 2022

I don't pretend to be anywhere near the level you guys are at, but I made my own tool for drawing in cam bearings and it works like a champ. This was done after a go around with a local machine shop. I've used it 4-5 times (one engine on stand currently) with no issues. Maybe somebody might be interested in the specs. The o-rings really aren't needed. I thought the nylon idea that somebody did was a good one too. And wow that was a long time ago when I made that page!!!LOL Cheers

http://fixjet.ca/bearingtool.html

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Let's discuss cam bearings

Tom Righter Well-Known Member

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Mart Gold level member

avmechanic Well-Known Member

Mart Gold level member

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