Depending on your crank you may not be able to use acl bearings due to the clearances required. If you have a crank with C's or D's for your crank journal codes, I dont think acl will fit properly. On the crank in my motor, the smallest journals are D's, at 1.8889 inch. According to Acl the smallest crank journal you should run with their bearings is 1.8890. However when I used the black honda bearings I get proper clearances using a plasti gage. Honda bearing give you alot more flexability in getting proper clearances, however you will most likley have extra after the build is done, however they are fairly cheap. I personaly would rather have proper clearances and extra bearings than the other way around.

Here are hondas sizing charts for your viewing pleasure.

 

The actual clearance isnt as important as all the bearings being with-in a couple 0.0001's of each other.

You wont see much difference between a motor built at 0.0015" and one built at 0.0025"

 

Interesting, why do you say that?


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Let´s say I go ACL and check clearance before I mount them. What if one of them are to big/small, should I use OEM then? Guess it´s a bad idea to mix ACL and OEM?

On the other hand, ACL is a big brand and if they think you can use the same size at all mains I guess it will work?

Thanks for the info guys!

 

Totally forgot, thanks Alloy, really helpful info!

 

Anyone?

There´s also a ACL race bearing with "extra clearance", can this engine handle that without dropping in oil pressure?

 

you dont want the extra clearance bearings..those will put the clearance at 0.0030 or more.. wayyyyyy too much.

the reason you want them all close is so the oil pressure across all 5 mains and 4 rods is close to the same. If you have one main at 0.0010 and one at 0.0020, they are all in "spec" but thats just too big a difference. 0.0010 would be happy with 20 weight oil, where 0.0020 works better with a 30 or even a 40 weight.

From what I have seen acl race bearings are pretty consistent, but they can be different enough to play with the clearances. the last set I had varied by about +- 0.00015

Here is a bearing thickness chart

http://www.laskeyracing.com/shop/bearingthickness.htm

 

Thanks Jason, great info as usual.

Hmmm... Sooo, if I go ACL and they are too big/small I have to sell them and buy OEM?