The Ford Barn

kurt v · 01-10-2023, 03:26 PM

I'm putting a 53 merc crank in a 1940 block, which main bearings 38 t0 48 or 49 to 53, do i go by the crank or by the block ?

thanks kurt

Tim Ayers · 01-10-2023, 03:59 PM

block for mains. Rods need insert bearings for 8BA-style rods.

Mart · 01-10-2023, 04:29 PM

Yes, as above, mains always go with the block. FWIW for anyone with a French block, even though produced after the 8BA series, the mains are the 59A type.

Ken/Alabama · 01-10-2023, 06:41 PM

If your installing a Mercury crankshaft in a 40 block it must be bored to 3 3/16” or the rods won’t fit down the hole.

Bored&Stroked · 01-10-2023, 09:17 PM

Also, change the pot-metal rear-main seal retainers to the later ones . . . as you now need the rope seal. It may or may not have the correct plates (top and bottom). As Ken noted, it is best to bore the block to 3.187 - so the later 8BA rods fit through the bores - otherwise it is a considerable main to try to put the pistons/rods in from below and then attempt to put the crank in!

36coupe · 01-10-2023, 10:32 PM

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Without boring the rods will be very close to touching the bottom of the bore. I think it is recommend to remove 1/16” x1” from the bottom of the bore if you don't bore it 0.125
My 81A block was real close to touching after boring to 3.187.

kurt v · 01-11-2023, 10:47 AM

I intend to bore to 3 3/16 and use the 8ba rods

busmania · 01-11-2023, 10:51 AM

I am building basically the exact same engine (40 block, merc 4” crank, 3 3/16 pistons). What can and carbs will you be running?

Bored&Stroked · 01-11-2023, 01:52 PM

Quote:

Originally Posted by busmania

I am building basically the exact same engine (40 block, merc 4” crank, 3 3/16 pistons). What can and carbs will you be running?

Whatever makes you happy! I tend to run dual Stromberg 97's on this combination - probably with an Edelbrock Slingshot manifold -- so I can run the generator in the stock location.

36coupe · 01-12-2023, 05:35 AM

Quote:

Originally Posted by Bored&Stroked

Whatever makes you happy! I tend to run dual Stromberg 97's on this combination - probably with an Edelbrock Slingshot manifold -- so I can run the generator in the stock location.

That’s exactly what I'm doing but I have Stromberg 48s with 97 tops and bottoms and an Iskey 77B cam which should be pretty close to stock 8BA cam. I also have a late merc 8BA cam modified to fit an early engine for a letter build.

deuce5wndw · 01-12-2023, 10:00 AM

Just to add to the discussion, the front and center main is the same 8ba or 59a it is the rear one that is different.

01-10-2023, 03:26 PM	#1
kurt v Senior Member Join Date: Sep 2021 Location: summerton, sc Posts: 360	main bearings I'm putting a 53 merc crank in a 1940 block, which main bearings 38 t0 48 or 49 to 53, do i go by the crank or by the block ? thanks kurt

01-10-2023, 03:59 PM	#2
Tim Ayers Senior Member Join Date: May 2010 Location: NJ Posts: 6,274	Re: main bearings block for mains. Rods need insert bearings for 8BA-style rods.

01-10-2023, 04:29 PM	#3
Mart Senior Member Join Date: May 2010 Location: Solihull, England. Posts: 8,798	Re: main bearings Yes, as above, mains always go with the block. FWIW for anyone with a French block, even though produced after the 8BA series, the mains are the 59A type.

01-10-2023, 06:41 PM	#4
Ken/Alabama Senior Member Join Date: May 2010 Location: Alabama Posts: 3,281	Re: main bearings If your installing a Mercury crankshaft in a 40 block it must be bored to 3 3/16” or the rods won’t fit down the hole.

01-10-2023, 09:17 PM	#5
Bored&Stroked Senior Member Join Date: Jan 2011 Location: Central Ohio Posts: 5,248	Re: main bearings Also, change the pot-metal rear-main seal retainers to the later ones . . . as you now need the rope seal. It may or may not have the correct plates (top and bottom). As Ken noted, it is best to bore the block to 3.187 - so the later 8BA rods fit through the bores - otherwise it is a considerable main to try to put the pistons/rods in from below and then attempt to put the crank in!

01-10-2023, 10:32 PM	#6
36coupe Senior Member Join Date: Oct 2012 Location: Eastcoast Posts: 867	Re: main bearings Sponsored Links (Register now to hide all advertisements) Without boring the rods will be very close to touching the bottom of the bore. I think it is recommend to remove 1/16” x1” from the bottom of the bore if you don't bore it 0.125 My 81A block was real close to touching after boring to 3.187.

01-11-2023, 10:47 AM	#7
kurt v Senior Member Join Date: Sep 2021 Location: summerton, sc Posts: 360	Re: main bearings I intend to bore to 3 3/16 and use the 8ba rods

01-11-2023, 10:51 AM	#8
busmania Senior Member Join Date: Oct 2022 Location: Denver metro Posts: 361	Re: main bearings I am building basically the exact same engine (40 block, merc 4” crank, 3 3/16 pistons). What can and carbs will you be running? __________________ 40 ford coupe Build -https://www.jalopyjournal.com/forum/...coupe.1277406/

01-12-2023, 10:00 AM	#11
deuce5wndw Senior Member Join Date: May 2010 Location: Liberty, KY Posts: 915	Re: main bearings Just to add to the discussion, the front and center main is the same 8ba or 59a it is the rear one that is different. Last edited by deuce5wndw; 01-12-2023 at 01:53 PM.