348 rear cam journal TIGHT

Hobart

Well Known Member
Supporting Member 1
Hi guys. My '58 Delray windowed-delivery project is finally getting close to the end, and I'm putting together my 348 now. Just a stock-type rebuild of a '59 348, cast .030 over stock pistons, stock cam, adding 3x2's though. Anyway, last night I tried to slide the cam in (Sealed Power stock replacement), and when I get to the point of it entering the rear bearing it gets tight - it goes in if you twist it while pushing it in, but it's tight in that rear journal - doesn't want to turn without significant effort. Thinking it could be an issue with the cam, I tried installing the original GM cam - same thing. I removed the rear cam-plug, and tried just sliding the rear journal into the rear bearing, but it's not going to go in without some effort, so I didn't force it. The cam bearings are from Show Cars, and they said that they are most likely Clevite or Durabond, and that they've never heard of an issue like this or had a set returned. The bearings were installed by the machinist who did the bore/hone/etc., and it's the grooved, 3-hole bearing, and the holes look to be lined up properly.

Any ideas? I tried searching the forum, didn't turn anything up.

Thanks!
 

Ronnie Russell

Well Known Member
Supporting Member 2
Not uncommon. My guy won't let the block leave the shop until he has test fitted the cam. Call your machinist and ask for direction. It won't be the first time he has run into that.
 

jim_ss409

Well Known Member
Supporting Member 5
I've had the same thing on a 409 I did years ago, except that mine was just a little on the tight side. Ever since then I've made a point of test fitting the cam BEFORE I installed the pistons etc.:doh

I've never tried it but I've heard of guys modifying an old camshaft to turn it into a reamer. They cut a few thin grooves in a journal, taking care to de-bur the grooves. Then turn it cam with a wrench or the cam gear. Again, I've never tried it so I'm not recommending that method, just mentioning that some people have used an old cam as a poor mans reamer.

Like Ronnie said, it's probably best to call your machinist for direction.
 

64ss409

Well Known Member
Supporting Member 9
I've never tried it but I've heard of guys modifying an old camshaft to turn it into a reamer. They cut a few thin grooves in a journal, taking care to de-bur the grooves. Then turn it cam with a wrench or the cam gear. Again, I've never tried it so I'm not recommending that method, just mentioning that some people have used an old cam as a poor mans reamer.
My neighbor used to do that when he had a tight cam bearing.
 

oldskydog

Well Known Member
Supporting Member 10
He'll probably just take some fine abrasive and shine up the bearing a little...doesn't take much.
 

MRHP

 
Supporting Member 1
I had a tight cam in a 460 ford. Known for cam tunnel warpage. I emeried the bearing and all was well.
 

Hobart

Well Known Member
Supporting Member 1
Thanks guys.

I was looking at it again tonite, and I noticed that on the rear bearing there is a triangular wear pattern, that pretty much seems like it it is tight at the 3 oil holes. My buddy has a cam bearing installer, so we're gonna pull the rear bearing and see how it fits on the cam journal (out of the block), and go from there. I'll keep you posted, thanks again!
 

oldskydog

Well Known Member
Supporting Member 10
Same thing happened to a friend just last week with a 350 sbc build. Took care of it with a little emery cloth.
Maybe the bearing maufacturers are getting sloppy.
 

62impala409

 
Supporting Member 1
My cam bearing were a little snug too. I think they might be getting distorted a bit when they are being installed. I pulled my bearings into position with a threaded rod, others may be driving them into position. I had a few shiny high edges that were easily polished away. Leo
 

Hobart

Well Known Member
Supporting Member 1
I talked to my machinist, he's going to order another set of cam bearings and come out to my house and have a look at the block and go over everything next week. I'll post the results.
Thanks for all of your input!
 

58 Apache

Well Known Member
Supporting Member 2
:cussI have used all theses methods. The poor man's ream only for F**d. A couple of things 1. When you pull the bearing it will be loose on the journal because the bearing is not compressed. The holes are most likely raised and could just need to be burnished or a raised area from the install. Good luck and when installing keep it nice and straight so not to raise the edge putting in.
 
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