The second cam journal is slightly out of alignment. I had to chamfer the edge of the cam bearing to insert the cam. Once install, holding onto the t.gear, it was stiff to turn with two hands. Am I making a mistake by proceeding with this engine as is?

 

Yup. Do over time.

 

Can you hear me shouting and stomping?

 

I feel your pain. I had to re-do my cam bearings (shop installed) because I couldn't turn the cam by hand after installation. I bought the tool, new bearings, and did them myself. Much better result the second time - but I was not happy that it was necessary to do over. Good luck!

 

Thanks for the reply. Two different sets of cam bearings have been installed in this block with the same result: on #2 journal the bearing has to be chamfered and sanded or the cam hits the bottom of the bearing and will not enter. That seems fairly conclusive to me. I have another block with 40k miles on it. I am going to ream the ridges, run a hone through the cylinders, and swap everything over to the other block. I think the first one is an anchor. What a shame to waste all that machine work on a junk block.

 

Ouch! Well, I can't relate there. I was able to use the block.

Crazy thought... did you confirm that your block is really the problem and not the cam itself? i.e. the #2 ?journal? on the cam is not off-center/damaged/etc.?

I can think of two quick checks; 1) put the 1st and 4th cam journals on v-blocks and a dial indicator on #2. This should confirm if the #2 journal is centered.

2) insert your camshaft into the block, one journal at a time, and try rotating by hand. For example (assuming #4 is at the rear of the engine), insert the cam journals #4 and #3 into the block bearings #2 and #1 respectively. Next would be to insert journals #4, 3, and 2 into block bearings #3, 2, and 1 respectively. Does it still rotate freely or bind?

If your #2 bearing on the block is really the problem, wouldn't it already "catch" and bind in the scenario above? i.e. I would imagine the #3 journal also catching on the #2 block bearing as you are trying to insert the cam?

Just my thoughts. But anyways, my condolences for the issues you are facing!

EDIT: on second thought, it looks like you already did this - but maybe I'm misunderstanding your original post. You had to chamfer the edge and sand to insert the cam, meaning #4 and #3 journals on the cam were also catching during insertion?

 

Make sure your cam isn't warped. Lots of issues with warped cams and bad blanks. Only way to tell is on a machinists table.

 

I'm a bit loopy due to meds for a finger infection, but will answer best i can. Only #4 journal on cam has difficulty entering #2 block journal. Once it is through, the other cam journals enter fine. Done this with two sets of bearings, two cams, Isky and crower.

 

The block of the engine I'm working on only has a thousand miles on a re-bore. This engine in a different form, with a different bottom end, lost oil pressure after only a thousand miles. That's why am being very careful as I'm putting it back together in the same block. Today I removed the camshaft and experimented a little bit whether it. I tried it in three journals and spun it, then did the same and only two journals. What I noticed was that the camshaft seemed to get tight or difficult to turn as it entered the rear of a couple of the journals. So I pull the cam out and I took pieces of four hundred grit wet and dry sandpaper and soaked it in WD-40, put down a couple of rags to catch any particles that may come off inside the block, and I gently sanded the journals a bit on that back edge. And I took the rags out vacuumed inside the block added lubricant to the bearings again, and slid the cam into place.. After I did that the cam spun freely. It seems to be touching 360° in each journal. I don't feel bad about doing that in the bearings because four hundred wet and dry sandpaper is what machine shops use and on their little belt sander when they polish cranks. The four hundred wet and dry puts a mirror shine on crank, then it should be all right on a bearing. Anyway, the cam is spending freely now and I have it all buttoned up back into place. It does freak me out a little bit because this block lost oil pressure in a different build, so I'm hoping that nothing I did hear is going to cause that to reoccur.

If anybody has a reason why I should not proceed with this engine, with this block, with the cam as it is, I'd really appreciate a response. Thanks.

 

I'm not an expert on machining, but could a machine shop hone the cam tunnel or something? Poorly installed bearing or bearing defect? Cam defect?

Also when power nation built their motor they said due to the 300s length and weight when assembled on an engine stand the engine can bow and throw clearances out. They built the engine on a steel table, I did the same but I don't have a stand anyway lol

Just thinking out loud