well I need new bearings but I don't know which size i should use.
I don't konw if I need more or less clearance.
my mods
street ported
single 60-1 looking for 400 whp.
it's mostly street car..so not really high rpm driving.

ant suggestion?
maybe I should go with medium size..

thanks.

 

I believe the Mazda OEM clearance spec is .0016 (don't quote me on that). So you need to take a micrometer to your Eccentric shaft journal diameter readings and add on .0016"

Scroll to the bottom of the page.
http://www.mazdatrix.com/b4.htm

 

well I already checked Mazdatrix but even they mentioned it's not too much difference between thick and thin one..

I heard if you run high rpm you want thin one...but need more oil pressure.

well I just ordered same ones which were on the engine before..
but I'll check bearing clearance tomorrow.

thanks.

 

I just ordered one from ray crowe a week or two ago, he told me they are so close they almost never matter, and he only stocks 2 different sizes.

 

Mazda doesn't make any difference because they use thesame part number for every one of them (at least FD) I ordered 3 sets recently and got 6 different tolerances, but all 1 off eachother. So I sorted them out as sets with having only one 0.001 off between the 2

 

Exactly, mazdatrix's site basically says the same thing... though, not it lamen's terms.

I got the "loosest" fitting ones. That's what atkins recommended.

 

?. They're not all the same part number... There are 10 different Mazda part #'s for main bearings and 3 for the rotor bearings.

 

The "loosest" would be the .0016 or is an inverse relationship like over-sized bearings for crankshafts...?