Offset grinding crank ?

orangemonster · 06-22-2019, 06:31 PM

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.

Daran Summerton · 06-24-2019, 08:35 PM

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.

Paul Precht · 06-24-2019, 11:12 PM

Quote:

Originally Posted by Daran Summerton

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.

Timetraveler · 07-02-2019, 07:52 PM

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.

Adger Smith · 07-06-2019, 03:30 AM

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

GTX JOHN · 07-06-2019, 12:06 PM

The .013 Offset only adds a very small amount of displacement!

Dave Gantz · 07-06-2019, 07:42 PM

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.

Dan Fahey · 07-08-2019, 12:42 AM

Quote:

Originally Posted by GTX JOHN

The .013 Offset only adds a very small amount of displacement!

The impact is a bit more compression from the added stroke.
Draws .013 more air and then compresses .013 a differential of .026
Plus slightly smaller diameter crank diameter, less parasitic drag.
Most engines it is about 1.5 cuin increase.

06-22-2019, 06:31 PM	#1
orangemonster Junior Member Join Date: Jun 2019 Posts: 6 Likes: 0 Liked 3 Times in 2 Posts	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.

06-24-2019, 08:35 PM	#2
Daran Summerton Senior Member Join Date: Jun 2003 Location: Las Vegas nv Posts: 600 Likes: 18 Liked 66 Times in 37 Posts	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. __________________ 72 cutlass

07-02-2019, 07:52 PM	#4
Timetraveler Member Join Date: Aug 2002 Location: Florida Posts: 103 Likes: 79 Liked 12 Times in 6 Posts	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.

07-06-2019, 03:30 AM	#5
Adger Smith VIP Member Join Date: Dec 2001 Location: Texarkana Ark/TX Posts: 2,446 Likes: 575 Liked 880 Times in 311 Posts	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 __________________ Adger Smith (Former SS)

07-06-2019, 12:06 PM	#6
GTX JOHN VIP Member Join Date: Jun 2009 Location: Boulder City, Nevada 89005 Posts: 2,736 Likes: 2,808 Liked 2,488 Times in 698 Posts	Re: Offset grinding crank ? The .013 Offset only adds a very small amount of displacement! __________________ John Irving 741 Stock 741 Super Stock Last edited by GTX JOHN; 07-06-2019 at 12:08 PM.

07-06-2019, 07:42 PM	#7
Dave Gantz Senior Member Join Date: Nov 2005 Location: Verrry South Jersey Posts: 537 Likes: 134 Liked 251 Times in 125 Posts	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.