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Old 06-22-2019, 05:31 PM   #11
orangemonster
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Default Re: Offset grinding crank ?

Maybe for both.About ten years ago I had picked up a crank from a still active today Stock/super stock mopar racer and it was offset ground and hard chromed journals to standard bearing size.
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Old 06-24-2019, 07:35 PM   #12
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Default Re: Offset grinding crank ?

I once did a back to back on a bracket car. 355 vs 383 sbc everything equal. 355 ran 6.80 - 383 ran 6.80. 1/4" made no difference.
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Old 06-24-2019, 10:12 PM   #13
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Default Re: Offset grinding crank ?

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Originally Posted by Daran Summerton View Post
I once did a back to back on a bracket car. 355 vs 383 sbc everything equal. 355 ran 6.80 - 383 ran 6.80. 1/4" made no difference.
I did that in 74 with a 426 street wedge and a 383, same heads, cam, carb and the 383 Torker instead of the 440 Tarantula, the 383 was used after I spun a bearing in the 426 so I could still bracket race every week while I built a new engine. The 383 had almost a point less comp. and about 80k miles on the shortblock, it ran within a tenth and a mph of the average of the 426.
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Old 07-02-2019, 06:52 PM   #14
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Default Re: Offset grinding crank ?

You can weld and regrind the journals to get the stroke you want and keep the standard size. Also we were chroming crank journals back in the sixties.
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Old 07-06-2019, 02:30 AM   #15
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Default Re: Offset grinding crank ?

Take it to a smaller journal size.2.100 to 2" Ect..
I have built many BBC with a 2.100 J instead of 2.2
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Old 07-06-2019, 11:06 AM   #16
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Default Re: Offset grinding crank ?

The .013 Offset only adds a very small amount of displacement!
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Last edited by GTX JOHN; 07-06-2019 at 11:08 AM.
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Old 07-06-2019, 06:42 PM   #17
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Default Re: Offset grinding crank ?

Anyone know the origin or purpose of the .013 rule? (Is it actually .015, .002 to be safe?)
As John implied, the small amount of cubic inches (inch?) gained seems, even though every little bit counts, hardly worth it, unless there's an ulterior motive.
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Old 07-06-2019, 10:50 PM   #18
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Default Re: Offset grinding crank ?

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Originally Posted by Dave Gantz View Post
Anyone know the origin or purpose of the .013 rule? (Is it actually .015, .002 to be safe?)
As John implied, the small amount of cubic inches (inch?) gained seems, even though every little bit counts, hardly worth it, unless there's an ulterior motive.
Dave, Years ago , some crank strokes turned up short in teardown. NHRA decided there might be an advantage in altering the b/s ratio. They decided the limit would be + or - .015.
Of course come crank companies began to offer "rules rider " cranks at + .013..So it began..
Not a lot there, but you might as well take it. Plus, a smaller crank pin can't hurt, can it?
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Old 07-07-2019, 08:12 AM   #19
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Default Re: Offset grinding crank ?

Some makes get to grind crank pin from 2.437 to 2.200 in stock to "fit" the rod.
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Old 07-07-2019, 08:55 AM   #20
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Default Re: Offset grinding crank ?

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Originally Posted by Mark Yacavone View Post
Dave, Years ago , some crank strokes turned up short in teardown. NHRA decided there might be an advantage in altering the b/s ratio. They decided the limit would be + or - .015.
Of course come crank companies began to offer "rules rider " cranks at + .013..So it began..
Not a lot there, but you might as well take it. Plus, a smaller crank pin can't hurt, can it?
Thanks Mark. Still trying to learn something new every day.
IIRC, it was the early 90's? At the time, I remember my partner and I wondering what was up with it. When we ran a car in the mid 90's, if definitely wasn't fast enough to warrant being looked at. lol It was a 440, maybe we were bogus and didn't know it. I know we never checked the stroke. Figured a stock crank was just that.
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