Hi all,

I'm new to the forum. I've got a '76 F-150 with a 300 i6. I started rebuilding the engine recently. When I went to put the new camshaft in, it kept getting stuck at the 3rd bearing (all are new). So stuck I needed a hammer and a block of wood to free it. The bearing was the correct I.D. and the cam journal was also in spec. I replaced the bearing again and it got stuck again. The bearing it got stuck in would fit over the journals once I pulled it out again. I don't think there is an issue with the block because when I pulled the camshaft it came out easily and this engine never had any issues in the 5 years I ran it. I used a cylinder hone and sand paper to make one of my surplus bearings slightly bigger to see what happens. With that one in the block the camshaft fits better but I would still need a hammer to get the cam journals through that bearing. I also know it's not a problem with the camshaft since I used a micrometer to ensure it is the correct size, and I tried with both my new camshaft and the one that was original to the truck to fit through the bearing. It doesn't matter if I try to put the camshaft through the front or through the back of the block, it gets stuck at the number 3 bearing.

I am pretty much out of ideas. Any help would be greatly appreciated.

Thanks

 

How did the old cam bearing look? Did it have more wear say on the top? Maybe indicate block shifting. Are you sure you are installing the bearing square in the block. Try the old cam see if it goes in and spins freely. Maybe the new cam is bent. Good luck

 

Agree that the new cam is bent. Cut yerself a couple "V" blocks from wood, set up a dial indicator on the journals and check the run-out.

 

Sorry for the confusion in the first post I did try the old cam and the new one. I will still check the run-out to be sure and I will inspect the old bearing more closely but from what I could tell it was worn fairly evenly. It was worn quite a bit though. What is the best method for measuring if the new bearing is set squarely? It looks right to me but I guess I better be sure. Thanks for the help.

 

Let me begin by saying that you should post in the inline six chapter of this forum, or over at ford six dot com. The inline six block is a special beast.

I had the same problem with one of my engines. However, my out-of-alignment bearing was #2. It drove me crazy. I asked everyone, and got the full range of people trying to help, who had no experience with such a matter.

I did a bunch of research and found that at the factory they employ a 'bearing reamer' at such times. Finally, I took it to a machine shop and the guy took some fine w/d sand paper, I believe it was 400 gt., and he 'worked' the bearing until the cam slid right in. Sand, try, sand, try, until it worked.

Or, you could pull another block from the j/y, and lose your machine work on this one.

Good Luck. P.S. I like to chamfer the leading edge of cam bearings.

 

I was afraid to mention reaming the bearing for sounding like a hack. I have seen never done it . But a old timer I knew when I was a kid was building a old flat head engine. He had the same problem. He cut 4 notches in the old cam on the journal that was tight. He put the cam on until it got hard then started turning it cutting the bearing so the cam turned freely. Then took fine sandpaper and polished the bearing. Then test fit the new cam and it spun freely. He ran that engine till he died several years later.

 

Thank you all for the advice. I did get the cam in today. I took about half a thousandth of an inch off the bearing and used fine sand paper to clean it up. Interestingly enough the old bearing was worn more on one side. New ones are just bigger than .070" and the old one was around .064" on one side. I took the new one down to between .069 and .070" and the cam went in easily. If anybody encounters the same issue in the future, I used a cheap cylinder hone on a drill with 2 bearings held together in a vice (since I have 4 extra bearings) to ream the bearing.