The Ford Barn

russcc · 07-06-2011, 06:25 PM

Hi Fordbarners

Need some guidance on this. I have 59L block '46-48 Ford truck, using a '49-51' Merc. 4" crank, and 8BA rods, do I use 81A mains or 1BA/8CM mains, or are they all they same for a later Merc crank in an earlier block.
Thank you, Russ

Walt Dupont--Me. · 07-06-2011, 07:06 PM

If your useing the 59 block you must use the main bearings that goes with the block, ( 59 mains) the merc crank will fill fit fine. Use the 8BA style rod bearings. Walt

russcc · 07-07-2011, 04:45 AM

Thanks Walt.

GOSFAST · 07-07-2011, 10:14 AM

Just a "tip" here, if you have trouble locating the early mains, especially when certain undersizes are required, you can use the later main set in the earlier application by simply machining .015" off the backside of the thrust flanges.

This is the only difference between the 2 sets!

The dimension between the flanges on the early set is 2.065" and the later set is 2.095". Easily machineable with a decent lathe and a small fixture.

(Add) July 08, 2011, just realized the above dimensions are "reversed" in this post, should read: dimension between the early flanges is 2.095" and the later is 2.065", the machining is still correct, .015" off the late brgs! Sorry!

Thanks, Gary in N.Y.

P.S. I know of numerous sets done this way and out there running with not a single issue!

russcc · 07-07-2011, 07:23 PM

Sponsored Links (Register now to hide all advertisements)

Hi Gofast

Thanks for the tip on the 8BA mains. .015 off the thrust flange is duck soup in my lathe.

regards

07-06-2011, 06:25 PM	#1
russcc Senior Member Join Date: May 2010 Posts: 2,871	Help, main & rod bearings 81A or 1BA Hi Fordbarners Need some guidance on this. I have 59L block '46-48 Ford truck, using a '49-51' Merc. 4" crank, and 8BA rods, do I use 81A mains or 1BA/8CM mains, or are they all they same for a later Merc crank in an earlier block. Thank you, Russ

07-06-2011, 07:06 PM	#2
Walt Dupont--Me. Senior Member Join Date: May 2010 Location: Gardiner Me. Posts: 4,200	Re: Help, main & rod bearings 81A or 1BA If your useing the 59 block you must use the main bearings that goes with the block, ( 59 mains) the merc crank will fill fit fine. Use the 8BA style rod bearings. Walt

07-07-2011, 04:45 AM	#3
russcc Senior Member Join Date: May 2010 Posts: 2,871	Re: Help, main & rod bearings 81A or 1BA Thanks Walt.

07-07-2011, 10:14 AM	#4
GOSFAST Senior Member Join Date: May 2010 Location: Long Island, NY Posts: 1,052	Re: Help, main & rod bearings 81A or 1BA Just a "tip" here, if you have trouble locating the early mains, especially when certain undersizes are required, you can use the later main set in the earlier application by simply machining .015" off the backside of the thrust flanges. This is the only difference between the 2 sets! The dimension between the flanges on the early set is 2.065" and the later set is 2.095". Easily machineable with a decent lathe and a small fixture. (Add) July 08, 2011, just realized the above dimensions are "reversed" in this post, should read: dimension between the early flanges is 2.095" and the later is 2.065", the machining is still correct, .015" off the late brgs! Sorry! Thanks, Gary in N.Y. P.S. I know of numerous sets done this way and out there running with not a single issue! Last edited by GOSFAST; 07-08-2011 at 11:05 AM. Reason: Correction

07-07-2011, 07:23 PM	#5
russcc Senior Member Join Date: May 2010 Posts: 2,871	Re: Help, main & rod bearings 81A or 1BA Sponsored Links (Register now to hide all advertisements) Hi Gofast Thanks for the tip on the 8BA mains. .015 off the thrust flange is duck soup in my lathe. regards