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An intact crankshaft????
https://www.slantsix.org/forum/viewtopic.php?t=41717
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Author:  DusterIdiot [ Wed Sep 01, 2010 9:27 pm ]
Post subject:  An intact crankshaft????

Have a new one to ask:

So far every engine I've rebuilt or torndown has had the rear main seal area on the crankshaft is smooth and I've never batted an eye at putting a new felpro seal during assembly...I just went through my pile of cranks and settled on one that looked pretty good...all the journals were round (yes, not even a .001 difference between the cross measurements on the journals-mains and rods...)...While taking the #4 bearing measurement I noticed that the rear seal area on the crank had little diagonal ridges machined into it, I surmise that this was to help scrape the oil off the rope seal and keep it inside the engine...

If this is still intact and I use the newer rubber/plastic rear main seal, are the ridges going to wipe out the seal?

I'll take a picture this weekend before I put the AM Pak engine together...

-D.Idiot

Author:  Dart270 [ Thu Sep 02, 2010 1:22 am ]
Post subject: 

Funny, all of mine have the cross hatches. I think you want to have the crank dude polish them down so they don't mess up the rubber seal. Or, you could probably do it yourself with some crocus cloth or something. Doug recommends this too, I believe.

Lou

Author:  Doc [ Thu Sep 02, 2010 8:53 am ]
Post subject: 

Yes, I hand polish the "cross-hatch" on good used cranks that will run the rubber main seal.
For cranks being re-ground, I tell the shop to polish that area.
DD

Author:  Joshie225 [ Thu Sep 02, 2010 11:23 am ]
Post subject: 

Funny, I've never polished off the seal area cross hatch and always run the rubber seal with no problems. OK, one problem, in High School, but it wasn't due to the crankshaft. :oops:

Author:  RustyRamcharger [ Thu Sep 02, 2010 12:15 pm ]
Post subject: 

Its called "knurling". Its purpose is to help move oil away from the oil seal. Take a close look at the direction of the knurling and the direction of crankshaft rotation and you'll see how it works.

Ken
:-)

Author:  Shaker223 [ Thu Sep 02, 2010 1:05 pm ]
Post subject: 

Quote:
Funny, I've never polished off the seal area cross hatch and always run the rubber seal with no problems.
Same here.

Author:  sandy in BC [ Thu Sep 02, 2010 5:27 pm ]
Post subject: 

moi aussi!

Author:  DusterIdiot [ Thu Sep 02, 2010 9:45 pm ]
Post subject:  Alrighy then!

Purpose was self explanitory, just not sure about the compatibility with non-porous rigid seal...Since I need to shine up the journals with some 800 grit...I'll shine that area with some 400-500 grit and wear it down a bit, then finish with 800, that should take the tops off the knurling a bit to make it somewhat acceptable to the felpro rear main.

Should be done by Saturday, if all goes well...

Thanks, just never seen one of these that hasn't had that area worn smooth, or been polished...

-D.Idiot

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