Debunking the 10 X 10 Crankshaft Myth for Customers (#5) - Engine Builder Magazine

Debunking the 10 X 10 Crankshaft Myth for Customers (#5)

First of all, in normal use or even high performance use, a used crankshaft will not “clean up” to standard specifications and will usually have to be ground to .010? undersize.  The crankshaft has then remained 98+ percent as strong as new.  The problem arises when “spinning” or “hammering” (knocking) a bearing. 

The crank will not clean up at .010? and must be ground down to .020? or more. A spun or hammered journal causes a crack in the majority of cases, even though it might not appear to be badly damaged.

In order to detect a crack, the crank must be crack checked or “magnafluxed.” Some crank rebuilders do not crack check their product and depend upon the “law of averages.”

The backyard mechanic/racer was right when he found that crankshafts ground past .010? would have a tendency to break, assuming it was because of the reduction in strength and not aware that it was cracked already when it came from the crank repair shop.

Like any other machine in an engine shop, a wet system crank checking set-up is only as good as its operator and only works if it is turned on.

Many thanks,

Fred Geisel

Ocala, FL

Shop Solutions July 2022

When the timing cover or block has no dowel pins, or the dowel holes do not fit snug on the pins. Take an old damper and hone the center so that it is now a slip fit onto the crank snout. Use it to hold the cover in place while tightening the bolts.

THREAD IT TO REMOVE IT

Solid, smaller-sized dowel pins can be stubborn sometimes. One of the most useful ways I’ve found to deal with the really stubborn ones is to start by putting a heavy chamfer on the outside edge of the dowel with a grinder. Then, I run a die on it. In this case, the dowel is 1/4” OD and the die used was a 1/4-20 NC. Run the die on it as far as you can and then remove it. Lay a washer over the dowel, turn a nut on the dowel until it stops. Take the nut back off, add another washer and repeat until the dowel comes out.

Shop Solutions June 2022

I needed a narrow grooving tool to quickly clean carbon from piston ring grooves for an engine restoration project. All the usual grooving tools were too wide.

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