DIY crank polishing, or just Pay?

[MrSony]

Anyone ever done it? Crank is in good shape. Has some very faint scoring, from dirty oil i assume. No spun bearings, crank spun like butter. Was wondering what I could use to polish it myself and take the glaze off. Or should I just pay my local machine shop the ~50 simoleons to do it for me? I was thinking a soft rag (lint free microfiber?) and some metal polish with the crank set on some V notch wood chocks. What say you guys?

 

[pagrunt]

Safer just to have a shop do it, just had the crank for my 350 cleaned & polished. Got the vets discount of $40.

 

[-83MONTESS-]

No sense and risking it for the measly $50 or whatever shops charge. Save the hassle and the headache and do it right.

 

[pontiacgp]

for the cost of the metal polish, set up time and the time you spend polishing it spending $50 for a better job than you can do is more than worthwhile

 

[Kwik_Cutty88]

I’ve “polished” the journals of my crank with emery cloth and a little motor oil just to clean them up a bit. Haven’t had any issues.

Probably not as good of a job as a professional with machines/proper supplies will do, but hey, it seemed to work.

 

[Texas82GP]

I saw a guy polish a crank for a 2 cylinder small gas engine with Emery cloth for my dad. It looked great but we didn't put a mic on it or plastigauge it. It went back together and back into service.

 

[pontiacgp]

I would be concerned with the scoring

http://www.autoserviceprofessional.com/article/92691/Inspecting-crankshafts?Page=3

General tips

1. If the journal surfaces are damaged (scratched, scored, gouged, burnt), further inspection is required. If the scratches are light enough, the journals may be saved simply by re-polishing with 400 grit, followed by 600 grit abrasive paper. This should be done on a dedicated crankshaft polishing stand, where the crank rotates at a slow speed while an arm-mounted abrasive belt is lowered onto the journal. If the surface damage cannot be eliminated by polishing, the journals may need to be re-ground with an abrasive stone wheel on a crankshaft grinder.

 

[fleming442]

You realize it will still be stock, right? Offset grind it for MORE STROKE!

 

[vanrah]

Good Morning Guys; Since my education was auto engines & did work in an engine shop years ago, I'll toss in my $.02 cents. Polishing a crank is used to describe taking near nothing (.00001") off to as much as a half thou (.0005"). And even dedicated equipment can add eggggg (run out). So be very careful if you decide to do it yourself. Make some V blocks from a 2 x 6 or what ever. And I wouldn't use anything courser than 900 grit at home. Even the shop equipment can add egg polishing, operator plays a major roll, at least on older equipment that I'm familiar with. If the 900 grit doesn't clean it up & use a new strip on every journal consider taking it to a shop. And if ya got steady hands consider chamfering the oil holes before ya have it polished. And when ya get it back (done), CLEAN, CLean, Clean it. Get some small brushes & run them through the oil holes more than once. Soap & warm water, lots of it, rinse & spray while (water) wet with oil including oil holes displacing the water. Make sure that ALL the water is off before ya Bag it until time for use. Plastic gage at assembly, know your clearances. Good luck, Ole' Bob

 

[Texas82GP]

I saw a guy polish a crank for a 2 cylinder small gas engine with Emery cloth for my dad. It looked great but we didn't put a mic on it or plastigauge it. It went back together and back into service.

I meant to add, in the case of building an engine for a car or truck, something I cared about, I would have it professionally polished.