Hey Brian, which cam are you going to use? I need one for my red Caif car...it has one bad lobe. Car was getting a 4 speed conversion, figured I might as well pull the motor to give it a once-over. It might be escalating into a full rebuild, tho! .....I have a bad case of the 'might as wells'......
Well, this engine is being stubborn! I just spent all afernoon honing the #2 cam bearing so the cam would go in the engine. It was about .003" too small. I guess that is the downside to having the cam bearings put in before you buy the cam.
When I rebuilt my first nailhead, the machine shop 'align-honed' the cam bearings...I have no idea how they did that, or if it is common practice on any other engine... I've heard of builders 'scraping' the bearings to fit them also... Brian, what did you use to hone your bearing?...A 3-stone wheel- cylinder/brake hone?
Carmen did a set for me once, and he scraped the high spots and that cam then fit like a glove. Now I am wondering if NAPA honed mine or what they did......I swear he said "hone"......here I go again!:af:
I guess i need to ask, are you guys saying that the cam bearings dont fit out of the box and that they have to be hand fit to each specific cam bearing journal?. that sounds pretty scary to me
The way I remember Carmen explaining it to me was that the bores in the block may not be perfectly lined up. All I can say is that so far each time I had new cam bearings installed in my Nailhead there was a problem with them being too tight. Once in the past I pressed a set in myself and had to hone them to fit......I had to remove a LOT of material doing that........that's when I had Carmen do them over. The block I have now is a different block, and I had NAPA do those......they were a little tight when I went in to get it, and I made them loosen them up a little. They were still much looser than the ones were in my first motor.......I had to nearly hammer the cam in they were so tight...(no, I didn't really do that.....just a description) that's why I had to custom fit them. I think if the bores are on the small side, the bearings crush when you install them. I wonder if the Chebby and Ford guys have this problem?o No:
That is what I did--honed them with a 3-stone wheel cylinder hone. Took quite awhile because I had to keep stopping and scrape the babbit/aluminum material off of the stones as they gauded up. The cam wouldn't even go in the engine at all, so I got out the calipers and found the culprit--#2 bearing was about .003" too small for the cam to fit through it! Machine shop installed them--they usually do the honing/fitting if there is a problem, but this time I didn't have the cam yet when they put them in. It is correct that they crush slightly when you press them in if the hole in the block is a little undersized.
3 thousandths seems like an awful lot, but it wouldn't surprise me. When Carmen did mine, he started by doing the rear bearing first, making sure it fit well before doing the next one. Each bearing after that was fit one at a time and the front bearing was done last. You would think that this job would not be so difficult, but for some reason these Nailhead blocks must be tempermental I guess.
I am making progress now--.0015" clearance on mains and .0015" clearance on the 3 rods I have in so far. Tonight I will install the remaining pistons/rods and degree in the cam.
