Bearing Spacers

Rogue Racer

Bearing spacers for V8 blocks to use 6 cylinder size main bearings with cut down V8 cranks. Do the math.

fifesjeep

Ahhhh yeah... I'm drawing a blank... Any pictures, drawings etc?

jeep_man_401

Why? :oops:

Rogue Racer

1. Ability to save some 390 & 401 cranks. 2. Reduce bearing friction on race engines. 3. Reduce weight of crankshaft.

jeep_man_401

Wouldn't turning them down that much weaken them.

jeepsr4ever

Something has to be done!! Many bearing mfgs arent even making .030's anymore for any AMC application.

Rogue Racer

Well, let's think about this. AMC V8s all use 2.75" main bearings, the same size as big block Chevrolets, Hemi MoPars and big Block Fords that displace up to 800 cubic inches and make 1500+ hp. Small block Chevrolets commonly use a 2.45" main bearing in engines that make over 1000 hp. Small block Fords use a 2.25" main bearing and there are also bizarre power combinations from them. Yes, it will weaken the cranks. Will it weaken them to the point they are so fragile you can't use them? No. Reher-Morrison built Pro Stock big block Chevy engines in the 1980s using spacers to reduce the main bearing size to 3.500". Most Pro Stock engines today utilize small bearings. NASCAR proved you could run a Honda or Toyoto rod bearing for 850 hp, 9000 rpm and 500 miles. It will work. And it just so happens that the AMC 6 cylinder main bearings are 3.5" but exactly the same width as the V8 bearings. Piece of cake. I made some spacers out of .060" under Ford FE bearings, but it is a pricey deal and very labor intensive. Machined-up spacers would be nice.

jeepsr4ever

I am not sure how spacers are made but I believe they are stamped out using combination tooling.

Rogue Racer

MC - Here are some things to tickle your imagination.

http://chucker54.stores.yahoo.net/mabesp.html

http://www.moparmecca.com/DrillDown/Details/Bearing%20Spacer.htm

http://www.speedwaymotors.com/pl/111,533_Main-Bearing-Spacers-350-Crank.html These are made from a set of stock 400 bearings that have been reamed or honed to the correct diameter.

http://www.compcams.com/technical/Catalogs/106-07/325.pdf

http://hoffmanmachine.biz/wst_page2.html

http://www.competitionproducts.com/prodinfo.asp?number=5620

http://oldsperformanceproducts.com/products.asp?menulevel=Bearings

jeepsr4ever

I have built a few 377's so I am familiar with thicker bearings and bearing spacers btu the ones without a notch scare me. What keeps them from spinning?

Rogue Racer

You can either Loctite them in place with Stud & Bearing Mount, or pin them.

Rogue Racer

Rogue Racer wrote
Reher-Morrison built Pro Stock big block Chevy engines in the 1980s using spacers to reduce the main bearing size to 3.500". . . . . . the AMC 6 cylinder main bearings are 3.5" but exactly the same width as the V8 bearings.

Those numbers should be 2.500", not 3.500". Don't know what happened there. Maybe a slipped brain cell.