Thanks Mike that's exactly what I needed and very helpful!!!
Normally I would measure the crank, the bearing shell thickness, and have the rods re-sized as a last step to ensure the clearance is to my desired spec, but in this case I am planning to go with new aftermarket rods and lose the control over the re-sizing step and the control it gives me over clearance.
Yes I use a mic on the crank, a ball end mic on bearing shells, and a bore gauge in the rods to determine all this.
Quote:
Originally Posted by mikedsilva
Disclaimer: not an expert, just from my personal experience...
I've used them several times and have had zero issues with them. I usually get rods resized but it all depends on the tolerance to which they are sized.
Bottom tolerance (from memory) is 58.00mm and top tolerance is 58.019.
I have found that the ACL std bearings are fairly accurate and not "thinner" like glyco or AA Clevites. If your rods are sized to 58.010mm then the std bearings should give you a perfect 2 thou or 0.05mm clearance. If they size them closer to bottom tolerance then you might benefit from the larger clearance to get an extra 0.025mm total clearance or you can actually use 1HX shell and 1 STD shell to increase clearance by only 1/2 a thou.... yes, you can mix them.
I'd probably wait till you have your rods so you know where they end up, so you know which set to buy. The good thing is, the ACL are quite affordable.
If you take into account the rule of 1 thou/inch of bore, then technically, a 55mm bore is 2.16 inches, so you should be aiming for 2.1-2.2 thou for the 3.2 rods. I think if you end up with a clearance of 0.05(1.96thou) -0.06(2.36thou)mm you would be fine.
Bear in mind, that your rod journals on the crank will likely vary by a tiny amount too. Are you using a bore gauge and micrometer to determine your oil clearances?
Where do your source ACL bearings in the US?
Curious to hear others experiences or suggestions.
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