Author Topic: Scat Crankshaft block interference - Subtitle “why can’t anything be easy"  (Read 4622 times)

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DuckRyder

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I seem to recall someone else having this issue, question is, how critical and will it affect the balance? Can I just make a couple of blocks to spin the crank on and decrease the outer diameter using a file of un married parents and then clean up the shavings really well, or do I need to seek out a machine shop to fix it?

Robert

philminotti

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I had that exact problem.  Pond block and Scat crank.  I had the oil slinger flange turned down a bit on a lathe.  No problem.  But I do suggest doing it right, ie. on a lathe.  Pretty common area of interference.

philminotti

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And one more thing... In my limited experience of building two FE's with nearly all aftermarket parts, nothing EVER fits like Legos.  Everything needs to be massaged.  Intake to oil pan, balancer to bellhousing!  Good luck.

DuckRyder

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I’d be nice if something went my way every once in a while...

I guess I will go throw myself on the mercy of the only decent machine shop I know Monday, I expect he will be nonplused that I got this crank somewhere else, but maybe he will do it for me before christmas...
Robert

My427stang

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I had one like that too, if you think you can shape it, go for it.  It's so close to centerline that the small amount you remove won't change balance

As I turned mine, the slinger was egg shaped, I wonder if they had a run that wasn't machined properly
---------------------------------
Ross
Bullock's Power Service, LLC
- 70 Fastback Mustang, 489 cid FE, Victor, SEFI, Erson SFT cam, TKO-600 5 speed, 4.11 9 inch.
- 71 F100 shortbed 4x4, 461 cid FE, headers, Victor Pro-flo EFI, Comp Custom HFT cam, 3.50 9 inch

DuckRyder

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I actually think mine is egg shaped too... It’ll spin 3/4 turn...

If my guy will do it that is probably the best... you know I’m fumble fingers and that could be bad...
Robert

cjshaker

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Since you'll be removing the same amount of material around a 360 degree radius, it shouldn't affect balance at all.
Doug Smith


'69 R-code Mach 1, 427 MR, 2x4, Jerico, 4.30 Locker
'70 F-350 390
'55 Ford Customline 2dr
'37 Ford Coupe

My427stang

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Since you'll be removing the same amount of material around a 360 degree radius, it shouldn't affect balance at all.

They aren’t too big, they aren’t machined round, which means metal has to come off one side...after balancing.  Not enough to matter that close to centerline anyway
---------------------------------
Ross
Bullock's Power Service, LLC
- 70 Fastback Mustang, 489 cid FE, Victor, SEFI, Erson SFT cam, TKO-600 5 speed, 4.11 9 inch.
- 71 F100 shortbed 4x4, 461 cid FE, headers, Victor Pro-flo EFI, Comp Custom HFT cam, 3.50 9 inch

DuckRyder

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Now that I'm actually looking at it, its obviously egg shaped, egregiously so...

I make the slot in the cap 3.48-3.50 and the slinger in the 3.30... range... but being off center... well you know the story...

If I have him turn it to the lowest spot it is going to be a vestigial oil slinger (in other words quite small) and I'm not sure if that is going to cause me any issues or not...

I suppose if I take 3.30-3.35 or so and cut it in half that will give the the radius and that amount from center line should work while leaving it egg shaped...

In other words small and round or somewhat larger and egg shaped.?.... Which is preferable...?

Bonus points if you can tell me how they get like that, seems like it would take real work to machine it elliptical... <shrug>

Robert

My427stang

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As long as it doesn’t hit at either end of thrust it will be fine
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Ross
Bullock's Power Service, LLC
- 70 Fastback Mustang, 489 cid FE, Victor, SEFI, Erson SFT cam, TKO-600 5 speed, 4.11 9 inch.
- 71 F100 shortbed 4x4, 461 cid FE, headers, Victor Pro-flo EFI, Comp Custom HFT cam, 3.50 9 inch

philminotti

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If you're anything like me, your rear main seal will leak either way. ;D
Seriously though, I noticed your crank is knurled... Did it come that way?  I bought my Scat crank in 2006 and it didn't have that.

Phil

DuckRyder

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lol,

Yeah, I it didn’t leak a drop before so I’m sure it will this time.

It did come knurled so I guess that went my way...
Robert

Falcon67

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And one more thing... In my limited experience of building two FE's with nearly all aftermarket parts, nothing EVER fits like Legos.  Everything needs to be massaged.  Intake to oil pan, balancer to bellhousing!  Good luck.

LOL, not just an FE thing either.  One of the reasons when I decide to update the rotating assy, I'll buy the whole deal from a known vendor. 

pbf777

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If I have him turn it to the lowest spot it is going to be a vestigial oil slinger (in other words quite small) and I'm not sure if that is going to cause me any issues or not...

    No problem, as the slingers' intended propose was engineered in the time of the "rope" seal era.     ;)

Quote
In other words small and round or somewhat larger and egg shaped.?.... Which is preferable...?

     I would prefer to prior, particularly as the machining effort to the block, producing a professional and accurate result would be more difficult.      :P

Quote
Bonus points if you can tell me how they get like that, seems like it would take real work to machine it elliptical... <shrug>

      No, it's just Chinese   ::) 
   
      I imagine that the seal diameter may not be elliptical, but perhaps just machined off center from the main journals, as this surface is machined earlier in the roughing process, and apparently the crankshaft is re-fixtured for the cutting/grinding of the mains, and not replicating the previous effort.      :o   


     Scott.

frnkeore

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What needs to be done here, is to take the crank to a regular machine shop and have them put a 20 deg chamfer, on the back side (flywheel side) of the slinger, of about 1/2 the width of the slinger.
Frank