The Ford Barn

Walt Dupont--Me. · 02-16-2014, 03:12 PM

George, if your block was the 40 Ford block with the .040 thick steel sleeves, and they removed the sleeves they would have to bore the block .075 to use the 3-3/16 + .030 pistons. I've removed a lot of those sleeves and bored .045 to 3-3/16 8BA std. pistons. Probably another .030 won't hurt it. Walt

Walt Dupont--Me. · 02-16-2014, 03:16 PM

Quote:

Originally Posted by JWL

Regarding the crankshaft----it will be worn on the bottom side of the journal. Tell the shop to move the stroke out .010 and it then wil clean up at .030. And, it will close up the deck clearance to a more reasonable dimension. I have only done this on about 200 crankshafts so it probably will work in your situation.

JWL I like that idea, I never thought of it. That will only pop the piston up .005 Walt

Ken/Alabama · 02-16-2014, 08:11 PM

I've got some .040 rod bearings with the flange. I've seen people use them in the later engines by machining off the flange.

JWL · 02-16-2014, 10:28 PM

How ridiculous is that to worry about flexing the crank?? All the 4 1/8" strokers were cut .138 undersize and used with everything from blowers to nitro season after season of competition. Many of those old cranks have been in service, after their days of racing, and are still going today.

Ol' Ron · 02-16-2014, 10:43 PM

I have several 4" Merc cranks stroked to 4 1/8 running around this place and one is in an Ardun along with those 21A rods. Not a problem The 296 is over 10 years old.

scooder · 02-17-2014, 05:49 AM

Sponsored Links (Register now to hide all advertisements)

Thanks for the explanation of why you'd be nervous about. .040" under cranks and. bearings. I do believe your worrying about nothing. The posts from Walt, Jwl and Ron should put your mind at rest.
Nothing wrong with. 040" under.
Martin.

Cool Kat with Hot Car · 02-17-2014, 12:26 PM

If one was to have a 4 inch Merc. crank offset ground to make a 4 1/8, is there a maximum size on the original 4 inch journals before it can not be used?

f1builder · 02-17-2014, 08:06 PM

great info guys. i will talk to bob at pro machine in rapid city tomorrow and see what he says. i did find .40 rod bearings here, will just confirm the size tomorrow. i have had 5 or 6 merc 4" cranks in my cars and never had a problem with them but .40 would be my biggest cut. i was told the canadian merc cranks had better steel which is why i hung on to this one. anybody know anything about that? thanks to all for input.

02-16-2014, 03:12 PM	#21
Walt Dupont--Me. Senior Member Join Date: May 2010 Location: Gardiner Me. Posts: 4,200	Re: +40 bearings George, if your block was the 40 Ford block with the .040 thick steel sleeves, and they removed the sleeves they would have to bore the block .075 to use the 3-3/16 + .030 pistons. I've removed a lot of those sleeves and bored .045 to 3-3/16 8BA std. pistons. Probably another .030 won't hurt it. Walt

02-16-2014, 08:11 PM	#23
Ken/Alabama Senior Member Join Date: May 2010 Location: Alabama Posts: 3,455	Re: +40 bearings I've got some .040 rod bearings with the flange. I've seen people use them in the later engines by machining off the flange.

02-16-2014, 10:28 PM	#24
JWL Member Emeritus Join Date: May 2010 Location: Fitzgerald, Georgia Posts: 2,204	Re: +40 bearings How ridiculous is that to worry about flexing the crank?? All the 4 1/8" strokers were cut .138 undersize and used with everything from blowers to nitro season after season of competition. Many of those old cranks have been in service, after their days of racing, and are still going today.

02-16-2014, 10:43 PM	#25
Ol' Ron Senior Member Join Date: May 2010 Location: Chester Vt Posts: 8,985	Re: +40 bearings I have several 4" Merc cranks stroked to 4 1/8 running around this place and one is in an Ardun along with those 21A rods. Not a problem The 296 is over 10 years old.

02-17-2014, 05:49 AM	#26
scooder Senior Member Join Date: Jul 2010 Posts: 2,597	Re: +40 bearings Sponsored Links (Register now to hide all advertisements) Thanks for the explanation of why you'd be nervous about. .040" under cranks and. bearings. I do believe your worrying about nothing. The posts from Walt, Jwl and Ron should put your mind at rest. Nothing wrong with. 040" under. Martin.

02-17-2014, 12:26 PM	#27
Cool Kat with Hot Car Senior Member Join Date: Jul 2010 Location: NorCal Posts: 305	Re: +40 bearings If one was to have a 4 inch Merc. crank offset ground to make a 4 1/8, is there a maximum size on the original 4 inch journals before it can not be used?

02-17-2014, 08:06 PM	#28
f1builder Senior Member Join Date: Jan 2011 Posts: 554	Re: +40 bearings great info guys. i will talk to bob at pro machine in rapid city tomorrow and see what he says. i did find .40 rod bearings here, will just confirm the size tomorrow. i have had 5 or 6 merc 4" cranks in my cars and never had a problem with them but .40 would be my biggest cut. i was told the canadian merc cranks had better steel which is why i hung on to this one. anybody know anything about that? thanks to all for input.