I get a inquiry once in a while about what to do about a engine that has new cam bearings installed and then the cam wont go into the engine because the bearings are too tight..... The simplest thing that I have done is to take a old cam and with a straight edge mark a line in the center , all the way down all of the journals,,,, then I take my dremel tool and a abraisive wheel, and cut down about 1/4 in. on the marks.... next i grind the right side off out to the edge of the journal and smooth it up with wet or dry sandpaper so it dont scratch the new bearings... this gives you a L shaped cut in each journal .... you want your L shaped cut to face to the right.... so you can put a cam bolt into the nose of the cam and turn it to the right with your long rachet and socket..... With the new bearings installed , squirt some atf on the lobes and start the cam into engine and turning to the right , work the cam all the way down into the engine... the cam/reamer will do a good job of reaming excess material from the new bearings... when the tool turns easily and smoothly , remove it and finish the bearings off with 4 ought steel wool and clean solvent.... leaves a beautifull bearing finish.... Will one of you guys sticky this for me please..... Doc
I comment on making this a sticky. I thought I was crazy when I put in new bearings and the cam did not fito No: but after writing our good ole expert Doc I again got a good answer and help. Thanks Doc, I owe you one:TU:
Here's the one I made. It did take some effort to turn the cam while shaving the bearings. I went slow and stopped often to blow out the shavings. Doc, do you put in a straight cut or angle it like I did? My machine shop wanted to polish down the cam journals for a proper fit.... but I wanted the bearings correctly sized in case I ever change the cam! I did call the manufacturer of the cam bearings, Durabond, and they gave me the ok to use the cutter method.
I went with the straight line method, Walt.... I think probably either one....point is , this works and allows anybody to do the cam bearings at home...:laugh:
Here's a link to a Nailhead rebuild that goes through all of the steps if installing and reaming new cam bearings for a nailhead. Just like Doc told you to do, but for those of us who are visual learners, this is very helpful. This is only one of about 15 separate articles (about 10- 12 pages each) on the rebuild of the nailhead. Some items I don't agree with - installation of hardened valve seats - but it's pretty thorough. If any of you nailhead gurus (Doc - Tom - et al) have time to read this completely, I'd like to know if there's anything that you disagree with. Plus there's an lot of additional articles on nailhead related stuff. The first link is the cam reamer, the second link is the index to all of the nailhead stuff. Thanks, Ed http://www.webrodder.com/article.php?AID=457&SID=4&CID= http://www.webrodder.com/index.php?page=showStories&search=nailhead
Seeing that it has not been mentioned. Before a person goes in and reams their bearings to size, make sure you have the right bearings to do this. For example, Clevite's B-1 series bearing has a .020" rabbit overlay and they will size out nicely. The AL-3 series bearings are a harder aluminum base material and are not intended to be resized. The compromise is that the B-1 bearing only has 1800 psi load strength and the AL has 5000 psi. The B-1 has better embedability, but will not withstand higher spring loads. Never finish a bearing surface with a vetrified abrasive, especially babbit. It will embed into the material and wear anything against it's surface. Use Scotchbrite or similar...or nothing at all. With babbit, it will polish itself. A few reaming lines may not look pretty and shiny, but it's way better than contaminating the bearing surface with abrasive.
