I just finished degreasing my bare 1918 block and, besides all the "regular" rebuild problems, I discovered the rear cam bearing (bushing) is missing a big piece! I'm assuming this is some sort of iron or bronze bushing, pressed into the block.
I know the suppliers carry the center and front bearings but does anyone carry this bushing?
Cancel that.......I found it in one of the suppliers websites, staring me right in the face!
The new bushing will probably need to be reamed to size. It takes a special tool - basically a dummy camshaft with a reamer on the end.
I suspected as much......thank you Bob. I have a good metal lathe and might be able to bore it to size before installing.
I believe by '18 they had gone to cast iron.
No George you can not bore it to size before installation, it need to be pressed into place then align reamed. A tool is made for that purpose.
Jack is correct, as two things happen; the bushing is reduced in size by a little bit from the press fit, and the hole in the block isn't necessarily aligned with the cam bearings accurately.
This is the proper tool for align reaming.
I might also add that you want to purchase a properly made "brass" bushing with the oil groove - not the "sintered" bronze one - not all vendors carry the same !
Because of how few of those reamers are out there bet most cars just get the bushing reamed.
Most all cars that are getting an original cam installed (reground or other wise) the KR Wilson or other ream cuts the bushing to original stock size and does not allow for rear cam journal wear.
You might find all goes together without reaming the rear bushing. Mine did. It does not need to be line bored, like main bearings. You can likely just ream it to size letting the reamer follow the existing bore of the new bushing. You should be taking out only a few thousandths, just keep your reamer parallel to the camshaft axis. If you need to remove a lot of material then a setup like Steve shows would be quite helpful.
I had multiple removable reamers ground for undersized cams - it is common to find the rear journal worn a couple thousands under.
Before you posted that info, I was thinking along the same lines.
My bushing does indeed look like iron, but I'd prefer brass. What is the harm with sintered bronze though? I've used it in many projects with running, oiled fits.
Well, I had intended to bore it slightly oversize internally to allow some compression when pressed into the block. Believe it or not I've done this before and gotten away with it.
In this case however I think I'll set up an expanding reamer on a shaft in order to insure alignment.
Thanks everyone...it's amazing what you forget (or never learned) on that T build 40 years ago!
I think the rear cam shaft bearing is one of the places where you can save money on expensive special reamers by first fitting the new bushing to the cam, then making it a little undersize for the block and glue it in place with loctite or some epoxi while the cam holds it in alignment.
The other places on a Model T I use this method are the spindle bushings and the front bushing in the driveshaft tube.