Crankshaft Porn

[motoracer8]

 Sorry gentalmen for the misleading title but I thought I had some photos that I could upload here but they are just alittle too dark for you to see what I'm doing.

I recently repaired a crank and rods for a Vision. I found some Nissan rod bearings that fit with a little mod to the rods.

The anti spin tang is alittle wider than the slot in the rods. The slot in the rods and caps are .115, and needs to be increased to .176, or .061 wider. I did the job with a key way cutter on a milling machine. I know not everyone has a mill in their garage but this is a simple task that any machine shop can do. The cut is toward the inside of the rod. Once this is done the bearings fit like they were made for the rod. The oil hole almost lines up but not quite. One way to fix that is to relive the rod just alittle with a Dremmel, or what I did was put the rod together with it's bearing and run a #49 drill, .176, from the rod side for the oil hole in the bearing. The oil hole in the bearing is very close and reliving the rod in that area would probably work just as well.

The bearings I found are Repco brand, pn#4B2956 std, Cost $24 for the set for 4 rods. OE Yamaha bearings were more that that when you could find them and they were not very good.

I found the bearings in a Clevite77 catalog. They are for a 68 to 73 Datsun B210. Specs for the rod ID is 1.8504 to 1.8514, for the crank pin diameter is 1.7701 to 1.7706, or 44.97 to 44.98mm.

I would make shure your rods ID is correct and that they are round, and the same for the crank pin. A automotive machine shop can measure for you and resize the rods if needed.

If those numbers are met it will give a oil clearance of .0015, and your bottom end will live a long happy life.

Sorry there was no porn, but sometimes the pictures just don't turn out.

Ken G

[Rikugun]

Are these better than the 2002-2011+ Nissan Altima 2.5L, bearings Clevite part number CB-1858AL Rory (RM97) talked about here?
http://ridersofvision.net/rovforum/index.php?topic=14359.20

[motoracer8]

I don't know, I've never seen those bearings. I've seen some Mazda bearings that are much narrower but do fit, and some Opel bearings that do fit the rods but the crank needs to be ground for oil clearance.

The repco bearings fit with a minor mod to the rods that was easy for me to do.

I'm shure any automotive bearing is going to be better than the crap Yamaha was using.

It wasn't just Yamaha, other Japanese makers had bearing probblems during the same period.

[fret not]

Thanks for the Ken.