MTFCA Forum

Looking for pictures of pouring jigs and boring setups for cam bearings. Anyone have any to share? Thanks Dan

I have found that the biggest issue regarding repouring cam bearings is finding good shell cores that don't have the parting line worn down so that the OD is not round.

Have you seen these?
http://mtfctulsa.com/Tech/cam_bearings.htm
http://www.mtfca.com/discus/messages/41 ... 1416772968
http://www.mtfca.com/discus/messages/25 ... 1342157696

The link to Mike Bender has some good advice, but the “issues” he describes with reproduction cam bushings currently is not a factor. There is a different manufacturer within the last couple years and his cam bearings are good and sold thru the major vendors.

As far as rebabbitting your own... about 90% of the shells are worn undersize and can’t be re-used.

I heard a rumor that the new bearings are only made in std size. So if You have a undersized cam you are out of luck. That is reason looking to pour cam bearings. Dan

Adam,
Could you elaborate on what you mean by "worn undersize"?
Are you talking about the thrust?
If so, I am also interested in how others are pouring the thrust surface?
Are people machining material off the thrust end to get and adequate amount of babbitt on the end?
If so, what thickness is needed? Are they using anchor holes?
Harry Lillo
Calgary

Adam is correct that the bearings are much better in construction and don’t present the problem I was addressing.
There has been a vendor change in the last year or so.

But all that are listed is Std bore. What about undersized cam shafts? Dan

Dan, I have a cam that is well under size bearing grind and new bearings are machined bearing bronze, I've done this on a couple of Honda OHC' bikes that had sized as well and they pull 5 times the revs of a stock T.

If the break line on the iron casting looks like a break and is not worn, you have good candidates for rebabatting. The fixture in the picture gives you enough babbitt to cut to any size you want. Call if I can help or answer questions, Bob @ nine o 3-824-194nine. PS some bearings were iron, with no babbitt, if you have them you’ll have to bore them to make room for the babbitt

Harry Lillo wrote: ↑

Tue Mar 30, 2021 1:06 pm

Adam,
Could you elaborate on what you mean by "worn undersize"?
Are you talking about the thrust?
If so, I am also interested in how others are pouring the thrust surface?
Are people machining material off the thrust end to get and adequate amount of babbitt on the end?
If so, what thickness is needed? Are they using anchor holes?
Harry Lillo
Calgary

They are worn undersize on the outside diameters of the cast iron shells. It’s pretty common to see them .005” smaller than the smallest acceptable diameter according to the Ford print.

I was thinking the same thing about the outside diameter. Then too, I have seen cases where the hole in the block is worn. Even if the OD on the bearing was correct, the hole was still too large esp the front hole from the bearing not fully locked in place.

We are working with wear limitations to get a GOOD ENOUGH outcome with these bearings, weather rebabbited or whats available new. As just mentioned "wear in the block". In many cases the optimal way, or only way to compensate for wear, is to hone the block & make custom bearings.
McMaster carr sells cast iron rod stock (done this) run in cast iron. Or make from bearing bronze like posted pix (beautiful work).

What is OD on Ford print? Thanks Dan

Reading this post with interest. I have a 25 block that the front cam bearing hole is center punched all the way around. A few years ago there was a post on the forum about using a thin sleeve or bushing to bring the hole back to spec. Seems like that would work.
Anybody done that?

John, the first T I ever bought turn out to have the bearings shimmed, It ran fine for about 15 years and then flogged the brass shim out. I thought the engine had done a big end it knocked that bad, Would I do it myself on a re-build, the answer is no, I keep a selection of bearings to make sure I have good fitting ones on re-builds, the bearings do vary in OD as do the block holes.

Does anyone know or have the OD from the Ford drawing? Thanks Dan

The Ford drawing for T-411AR Front Camshaft Bearing shows the OD to be 1.372-1.373.

Respectfully submitted,

Trent Boggess

However, the factory drawing for T-412-B Cam Shaft Bearing (Center) show’s the OD as 1.369-1,370. The center cam shaft bearing is slightly smaller than the front.

Respectfully submitted,

Trent Boggess

Trent Thanks that is info I need. Dan

Dan This Is the fixture I use to Pour and Bore Model T Cam Bearings.

When I posted above about the OD not being round, I should have stated "not round and undersize". If there is parting line wear, the OD of the shell becomes an oval. Trent posted the Ford print dimension and I'm surprised its that small. In my experience, you will find few blocks that don't measure at least 1.376 in the front bearing bore and slightly smaller by usually .002" or so in the center bore. Ideally you want a light tap fit between the bearing OD and the bore. Shimming the bearing OD is a short term band aid solution in my opinion. Suppose I'm getting a little off topic here but it does come back to the issue of having unworn or almost unworn shells to begin with, because the end goal is to have a cam bearing that is not swimming around in the block. 100 year old iron does have its challenges as we all know.

I have some NOS bearing that I plan to rebabbit. Thanks for the info. Dan