FE Power Forums
FE Power Forums => FE Technical Forum => Topic started by: FElony on October 09, 2015, 01:56:24 PM
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What is typical for a final crank journal polish, grit-wise? Does anyone finish up with liquid polish, or is it all dry?
Oh, let me add another question while I'm at it. Can a stock FE crank really be turned down to use Ford 400 rods or BBC's with no issues? That's a lot of meat to take off. What does a grinder usually charge? Local crank guy here charges by the .010" shave, hate to see price for .130.
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Hi Felony---
From my own observations, a strip of crocus cloth is used for polishing purposes. And done dry. My most recent crank jobs were done by Moldex and the charge was by the job.
KS
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It's dry. Some guys do it on a lathe, some guys do it on a crank polishing machine.
As for the rod journals, yes, it's possible for an FE rod journal to be taken down to a BBC size. However, a lot of crank grinders can't or won't, because you end up grinding a lot more than journal surface. You have to widen the journals as well and that eats up a lot of grinding stone.
Find out if your guy can do it first off, then get a price. It will be more expensive than the old 10/10 deal.
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I just had a 2U crank turned 10/10 by a local shop, looks like they polished the rods but forgot to polish the mains. The mains had ridges enough to catch your fingernail on. I figured no big deal, brought it in to work one evening (a metal fab/machine shop) and chucked it up in the lathe. Bought some 400 grit paper and a shoelace and went to town on it, inspired by this video:
https://www.youtube.com/watch?v=j7DZxqPUQto
It took longer than I thought it would but the results were very good. Didn't loose any more than 0.0002" if that, and most only 0.0001" using 400 grit paper and PB Blaster. It's installed in an engine but not running yet. I think the journals look just as nice as any other normal machine shop finish.
-Jake
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Love pb blaster. Great stuff
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I just had a 2U crank turned 10/10 by a local shop, looks like they polished the rods but forgot to polish the mains. The mains had ridges enough to catch your fingernail on. I figured no big deal, brought it in to work one evening (a metal fab/machine shop) and chucked it up in the lathe. Bought some 400 grit paper and a shoelace and went to town on it, inspired by this video:
https://www.youtube.com/watch?v=j7DZxqPUQto
It took longer than I thought it would but the results were very good. Didn't loose any more than 0.0002" if that, and most only 0.0001" using 400 grit paper and PB Blaster. It's installed in an engine but not running yet. I think the journals look just as nice as any other normal machine shop finish.
-Jake
That's the vid I was thinking about, also. I have some cranks that have light surface rust on them that probably don't warrant sending out for machining. It seems to me that 400 grit might still be to rough. Not sure on that, hence the question. Could certainly progress to a higher number, but at what point are you just wasting your time?
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Love pb blaster. Great stuff
Ever try Gibbs? I learned about it from the gun forums. Got some and it works pretty well. I have also tried the Acetone/ATF mix found on the 'Net. That may work the best. I put a 50/50 mix into a glass jar and observed that the two took the better part of two weeks before they starting blending with each other. So, if you use it in an opaque dispense, be sure to shake it up a bit before squirting.
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How bout Kano- Aero Kroil or Schaeffer- Penetro 90?
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I just had a 2U crank turned 10/10 by a local shop, looks like they polished the rods but forgot to polish the mains. The mains had ridges enough to catch your fingernail on. I figured no big deal, brought it in to work one evening (a metal fab/machine shop) and chucked it up in the lathe. Bought some 400 grit paper and a shoelace and went to town on it, inspired by this video:
https://www.youtube.com/watch?v=j7DZxqPUQto
It took longer than I thought it would but the results were very good. Didn't loose any more than 0.0002" if that, and most only 0.0001" using 400 grit paper and PB Blaster. It's installed in an engine but not running yet. I think the journals look just as nice as any other normal machine shop finish.
-Jake
That's the vid I was thinking about, also. I have some cranks that have light surface rust on them that probably don't warrant sending out for machining. It seems to me that 400 grit might still be to rough. Not sure on that, hence the question. Could certainly progress to a higher number, but at what point are you just wasting your time?
Well I also bought some 600 grit paper when I got the 400, but when I used it I couldn't tell that I was accomplishing anything. IMO the 600 was a waste of time.
-Jake
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Well I also bought some 600 grit paper when I got the 400, but when I used it I couldn't tell that I was accomplishing anything. IMO the 600 was a waste of time.
-Jake
I was wondering if I should buff it to the point I could shave in the reflection. Of course, my face would be distorted in the curvature, but I'm used to that. Born with a distorted face. My father used to call me Funhouse FElony when I was a little kid. A story for another day.
Thanks for your feedback!
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Well I also bought some 600 grit paper when I got the 400, but when I used it I couldn't tell that I was accomplishing anything. IMO the 600 was a waste of time.
-Jake
I was wondering if I should buff it to the point I could shave in the reflection. Of course, my face would be distorted in the curvature, but I'm used to that. Born with a distorted face. My father used to call me Funhouse FElony when I was a little kid. A story for another day.
Just a thought...
....if your face is already distorted and you stare into a polished curved surface there is a small chance that the reflection may straighten itself out like a fun house mirror and you may actually look normal...but as I said...Its a small chance