So I picked up 2 used engines and started my Inspection. I tore both motors down and found similar issues between the 2. One engine was a 90psi per face engine and the other was 30 to 60 but no dead spots. The rougher engine cleaned up alot nicer both interior and exterior this far. The problem I'm finding is the line the side seal creates on the spark plug side. It creates a groove which can be seen and felt. People mention if its "nail catching " then replace or rework. Not sure what nail catching is as we all are different. The manual states a maximum depth of .0039 in. A straight edge like an metal ruler reveals nothing but how the hell do you jab a feeler gauge into that? The next method I'm using which is giving me results is using a magnetic base with a dial gauge. I zero it on the shoulder (greatest amount of untouched material) and slowly pivot the base with the magnet turned off. Does thos sound right? If so the groove only specs out at .001 to .0015 deep. Numbers say it's good but am I doing this right? Will post pics to follow.

 

The groove



Zeroing


Measurement

 

the factory manual shows a dial gauge just like that. i'm sure you're looking at the same pics...

 

Ok, so the real question is this normal or excessive wear? Would you run these or resurface them based on the visual look and feel of the groove? Doing searches it seems like these would be no good to run cause I can feel the lip of the groove.

 

it is normal for the engine to be worn there, and 0.0015 is well within the spec, so if it was a stockish powered engine, i'd run those. if you resurface they need to be re-nitrided, the iron is too soft to run without a surface treatment, but at that point it is probably cheaper to buy a new one.

there is a difference between feeling it, and actually catching a nail, or being out of spec