TheSamba.com :: View topic

Fri Nov 21, 2008 9:48 am

I have a crank bearing in hand with the following marking:

"0.5/STD Ga"

It is has a KS logo and what looks like a KS part number (74475701).

My understanding is this means the crank journal has been machined down 0.5mm. What I am looking for help with is identifying if the case has been align bored and the bearing has a larger outer diameter than STD? Would the bearing marking indicate this, perhaps something like "0.5/0.5"?

Fri Nov 21, 2008 10:06 am

Give Dan Hall a call. He is in your phone book. Maybe Dan Hall Automotive Machine or something like that.

Fri Nov 21, 2008 10:36 am

I had Dan do my flywheel resurfacing, so I know exactly where he is and would use him again! I was just wondering from more of an academic perspective if the bearing markings will indicate if the outer diameter is non-standard?

Fri Nov 21, 2008 2:13 pm

The crankcase bearing numbering convention is:

First is the OD, or case bore size. Cases are bored oversize in 0.5mm(.020") increments.

Second is crank main journal size. Cranks are ground undersize in 0.25mm(.010") increments.

So your bearing is for first oversize case; standard crank.

The crank main bearing size is not the rod bearing journal size. Rod journals are ground in the same 0.25mm increments, but independently of the main journals, so they must be measured separately. Rod bearings will have "Std.", or an undersize in 0.25mm increments stamped on the back of the half-shells.

Fri Nov 21, 2008 2:28 pm

Thanks tencent. Exactly what I was looking for. I had it backwards. The rod bearings are marked STD, so the crank appears to have avoided machining so far.

Fri Nov 21, 2008 7:02 pm

Yeah well good luck getting those oversize case bearings.