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questionable crank

chevyCowboy

chevyCowboy

I might be crazy but i ain't dumb
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Location
Springfield Nebraska
i was polising the crank with 660grit when i saw this on the rear main journal (not sure if thats the right name. it rides in the rear main bearing)

they apear to be small rust pits?:confused:

they are all bellow the surface. and there are only a couple that i can catch my fingernail in most are to small.

is this something i should be concerned with? should i have the crank turned? my old one would need to be turn aswell so thats out. i have the other complet motor that i could tear down to see if its any good, or i could buy a scat but thats more money. not sure what it will cost to have mine turned tho and then i have to buy new bearings :mad2:

the pics are the best i could get
 

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I would take it to a machine shop and let them check it. They may be able to polish it and it would still be standard. If it needs turning, them you can decide if you want to replace or go with undersize.
 
Usually a polish will put a crank at .001" under. Use bearings sized accordingly. Make sure the journals are *round* still.
 
I think your best bet is take it to someplace the builds engines and get their opinion. If you take it to a machine shop they will say they will have to turn it down and send you a nice bill.
 
Michaeljp86 said:
I think your best bet is take it to someplace the builds engines and get their opinion. If you take it to a machine shop they will say they will have to turn it down and send you a nice bill.
Click to expand...

Maybe I should have said a reputable machine shop. I have taken several cranks to my shop that were only polished - one just recently that I was sure needed turning, but polished up nicely.
 
bobbiemartin said:
Maybe I should have said a reputable machine shop. I have taken several cranks to my shop that were only polished - one just recently that I was sure needed turning, but polished up nicely.
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Thats true if you can trust the guys. Im working on a V4 wisconsin for a trencher. It needed to be sleeved so I took it to a machine shop. I figured about $900 to rebuild it. They cried and wanted to rebuild it themselves for $2700. I said screw that but they said it would be done in 5 days. Since its winter and I dont have a nice heated garage we went with it since the trencer should be used to make money that $2700 would just got into my profist for a while. The 5 days turned into 5 months because there missing some kind of imaginary part that "his guy" said is supposed to be there. And then it turns out their warrenty is a "Im sure it will be fine".
 
I've worked with a lot of machine shops over the years, and I can tell ya that it is difficult for them to polish anything more than .0005" without fighting out of round and taper.

On the other hand, it is also extremely difficult for them to set up and grind less than .002"-.003" radially (.004"-.006" diametral).

I guess the point is, ask them in advance if they can guarantee you a round taper-free journal when they are done polishing. Bearings are available in .001" undersize increments, -and it is possible to use one half of a .001" and one standard to net .0005", -even the factory does that.
 
IMO,i would,nt worry about it to much if the yournal mikes out Ok after polishing.
The pitting is below the surface,there's notting to catch on and the loss of brg surface is neglible
 
bison said:
IMO,i would,nt worry about it to much if the yournal mikes out Ok after polishing.
The pitting is below the surface,there's notting to catch on and the loss of brg surface is neglible
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well thta doesnt help im talking bout a journal ):h couldnt help my self !!!
 
nothing to do with the post but
yelllllllll yumpen yemini yets yll yo yown yo yhe yike ynd yix yhe yeak.
:D:D:D
well jumpen jemini lets all go down to the dike and fix the leak....
wes
 
seriously now do not over polish as the coating on the crank is very shallow
i have used cranks in gassers with deeper rust faults without issues even after 100k miles of use.
wes
 
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