kloneoner

Hey whats up guys

I recently bought a B18C Type R motor that was "freshly rebuilt" which after tearing it apart i found out was true.

BUT a valve retainer broke in half dropped the valve and destroyed one piston sending fragments all throughout the motor.

bored the block .5mm to 81.5 and polished the crank and replacing the head completely

the motor had main King Bearings marked 0.25 MN M5259L AM
and rod King Bearings marked 0.5 AN C4287 AM

plastigauging the clearances they were all either close to spec or a little tight

i decided i wanted to use OEM honda bearings

But after Micing the crank and only getting to one rod journal on the connecting rods before getting aggravated i noticed:

all the main Journals on the crank shaft are very close to 2.1547

and the rod journals on the crank shaft are all very close to 1.7057

after dial bore gauging one connecting rod big end journal i got 1.8545!!!?

im using a fowler xtender calibrated with a micrometer, i understand that to a machinist Fowler is crap but its all i could afford right now

ROD BEARING MATH

1.8545 - 1.7057 = .1488

.1488 - .0015 = .1473 (desired oil clearance)

.1473/2 = .07365 (bearing half) !!!?????

when i mic the old bearing i get .0681

i dont mind being bashed just really need help

maybe my dial bore gauge is not calibrated correctly?
to get my bore gauge measurements i am doing one of two things

either zeroing gauge taking measurement and subtracting it from the anvil i have in the gauge or

zeroing the gauge while taking the measurement and then zeroing the gauge back in a micrometer

please tell me i am doing something wrong instead of hitting a dead end

thanks alot for the help in advanced

00b18b

Assuming you calibrated the bore gauge and mics correctly. Your figures for the crank main journals is only off by ~.01 (2.1644-2.1654) and for the crank rod journal you are a lot off by ~.07 (1.7707-1.7717) per helm service limit(new). Your rod big end is actually tighter by ~.04 (1.89) I assume aftermarket rod. So it looks like the crank spun a rod bearing and was turned+mircropolished at some point. You will need a thicker rod bearings since oem bearings only go up to ~.059. I would find another crank if I were you.

kloneoner

thanks alot

Muckman

iTrader: (2)

This is why I platigage for a sanity check after measuring. For the time you spent on this you could have thrown in a set of bearings and platigaged it.