Sorry I thought it was the front bearing that was scored. Agree with what lamb_daiquiri said - easy way to check is get a straight edge or ruler and place it on the journals - all the lobes should clear the straight edge. If not the lobes will score the bearings as you slide the cam down the cam tunnel. A bent cam would do this too but you would have issues getting it in and out if it were that bent. No doubt this damage was caused by a person and not the engine during running.

I agree that the previous owner caused the damage. I disassembled the engine some time ago and carefully removed everything. I don't recall putting any kind of force on the camshaft when I pulled it out. The engine must of been rebuilt at some point which is when this happened? I received my Clevite bearings this weekend and taking them along with the block and cam to the machine shop. Will post when it's done.

I have another question related to crankshaft end play. It measured .003 in. while I was keeping leverage on the crankshaft which is a little tight. Haynes manual calls out .002 thru .006. Should I have my machine shop shave some of the thrust bearing or crankshaft, or just leave it as is?

If you relieve the leverage on the crankshaft and then measure it, does it keep the .003 in. gap? If it does I'd leave it; it's not right on the edge but close to it. Better than that too loose.

Quote:That's right in between the Haynes specs. I'd leave it be

Nissan spec is: 0.0020 to 0.0059 inch. Again .003 is between these figures

Ok, got my block back with new cam bearings. Camshaft slid in there no problem and spun freely. My only concern is that he didn't line up 3 of the oil passageways 100%. And the outer bearing shows 2 oil passages but only one is lined up with a passageway hole. He said the block only had 1 oil passageway. Someone please tell me that is correct. And should I be concerned with several bearings not being lined up with the oil passageways?

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Well. The word dodgy is the first to come to mind. I'm not sure how bad a partial line up is but one that's completely off would be like running a gearbox without oil right?

DD...do you know if the block has two oil passages for the front cam bearing? If so, a photo of that would be great to pass along to my machinist. Will the camshaft have sufficient oil with several oil passages being partially blocked? I was thinking to possibly use a dremel to grind out the cam bearing and then clean the block.

I do not know, never changed the cam bearings

These are the Sealed Power versions

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Hmmm ... Not sure if Sealed Power's photo is correct. Other photos of 1592M show the wide front bearing with the two holes are offset

Perhaps it is to oil the cam (2nd hole is oil inlet into camshaft?)

The center bearing passes oil to the rocker shaft, it may also have two holes

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Well I have another A15 block sitting on the bench that is partially disassembled. I may end up taking off the timing gears and chain and slide out the cam to see what the front bearing looks like. Unless someone else has a block they are working on and can take a picture and post. Do you see oil starvation issues with partially obstructed oil passageways?