I recently bought a set of F9A Durabond cam bearings on eBay and discovered they consist of a wide, single-holed front, and 4 multi-holed center bearings. While I can see that this would cut manufacturing costs, thus making the parts more available, I wonder if the reduced surface area might promote accelerated wear in the 3 journals that need only a single-holed bearing? Has this been an industry standard for very long? (All my parts manual illustrations show 3 different types). Has anyone had a set of these long enough to gauge how they wear?

6 VOLTS/POS. GRD. NW INDIANA

Daniel:

Those are standard issue bearings for a long time.  They'll be fine.  Just be sure all three holes line up with the holes in the block at the center bearing.  Only one hole to line up in the other 4.

John

John - "The Hoosier Hurricane"

Daniel,



When the machine shop installed new cam bearings in my 312 they had a time getting the cam to fit right.

Now this was a quote from one of the shop employees. It would appear that Ford installed the bearings and then line bored them to be straight and true.

In the overhaul manual it states to use the old cam ( if your installing a new one ) cut grooves accross the bearing surface and use this old cam to ream the bearing surfaces for true.



I would have thought the shop would have figured this out. However we don't see many 272 - 312's around anymore. Most of the machinist's weren't born when these cars ruled the streets.



Jim

  Jim Rowe Elkhorn, NE

Jim,



From what I've been reading, if your cam is straight, the need to scrape bearings is usually due to installing them a bit crooked. Since my local shop does not have the equipment to line-bore the block square to the deck, I will likely shlepp it to a place that does, have THEM install the bearings, and get the cam bores done too. I wonder if careless bearing installation is one of the reasons the Ford dealer shops sometimes had to push-start a fresh motor back in the 50s?




6 VOLTS/POS. GRD. NW INDIANA

Daniel : As I recall, it was said in YBM that some replacement Cams are not completely straight, which of course causes a problem. Also, as I recall it was recommended, possibly by John Mummert, to install the front or rear bearing, from the inside. I don't remember which, maybe somebody can can clearify that point. 

Paul

Hi Daniel,  When I was overhauling my 312 I also had trouble getting the cam to fit with new bearings.  Mine are also the Durabond brand.  I brought the block home from the machine shop, and the new cam (Schneider) wouldn't go in.  My old stock cam would go in just fine.  So I measured the cam journals; the stock cam measured 1.915" and the new Schneider measured 1.925".  So there was 10 thousandths difference, no wonder the new cam wouldn't fit.  I cut  grooves in the old cam and tried to enlarge the new bearings, waste of time.  So I took the new cam and the block back to the machine shop and they honed the bearings out so that the cam would fit.  It was a snug fit, but 9,000 miles later it is still doing fine.  My machine shop owner is 60+ years of age, he also said that Ford machined the bearings out after they were installed in the block at the factory.  Anyway I don't think that you've got a crooked cam, it's a matter of larger journals on the replacement cam vs. bearing diameter.  Good luck, Nick

Nick,



The journals on my new Isky cam measure 1.926", but the Durabond bearings are a sloppy, slip-on fit. If the cam bores were aligned, and the bearings not installed improperly, I wouldn't anticipate a problem. I will check the cam for runout to be safe.

I wonder if your OEM cam started out smaller, or could it have lost journal OD from normal wear? Anybody out there have a NOS Ford cam they could measure?

6 VOLTS/POS. GRD. NW INDIANA

Nick:

Did your machinist by chance have your old cam when he ordered the bearings?  This is the reason I ask.  I just looked in my NAPA bearing catalog and found that cam bearings are available in .002, .010, .020, and .030 undersize.  I knew production rebuilders reground camshafts, but I always assumed they only ground the lobes.  Apparently not true.  So if your machinist measured your old cam to buy bearings, and if it was reground .010 under, that's the problem.

I personally doubt if Ford installed semi finished bearings and align bored them in production.  Having retired from the production sector, that would be considered unnecessary extra labor.  Finish bored blocks and precision bearings properly installed would be the norm.  They didn't bore the main and rod bearings after they were installed.  Small block Fords have cam bores progressivly smaller from front to rear.  I can visualize a multi sized mandrel pressing all 5 cam bearings in at once.

John

John - "The Hoosier Hurricane"

Hey John,  No I didn't take the cam with me when I had the block boiled out and the cam bearings installed.  I wasn't aware that cam bearings came in undersizes.  I'm sure you're correct about the Ford engine plant not honing out the cam bearings on each engine, that would be way too labor intensive.  I think the new cam blanks are just finished to a larger size, don't know why.  I know that John Mummert says that all cam grinders get their Y block blanks from the same source.

Daniel, If you are trying the fit of your cam bearings on the cam before they are pressed into the block, then I think they will be loose.  Once they are pressed into the block, they will have a smaller I.D.  Check the fit of the cam in the bearings once they are in the block.  The main thing, if the fit is OK, is to make sure the oil holes are aligned properly.  The center one is the most critical of course, because the oil from it goes up to the rocker arms if it is installed properly.  By the way, my old stock cam with the 1.915" journals only had about 15-20 thousand miles on it, so I think the size must have been close to original.  Engine had good oil pressure.  Good luck, Nick

fellas, I am getting ready to order a mild cam, and I am debating over whether or not to get the 245hp version from Schumann's or if I should get a mild cam from Mummert. I take it I should get my cam bearings from whatever parts man I order from? Would that help the cam and bearing situation?

Dan

Daniel Jessup

Lancaster, California

aka "The Hot Rod Reverend"
check out the 1955 Ford Fairlane build at www.hotrodreverend.com