The Ford Barn

Flathead · 08-15-2013, 06:55 PM

Why does the Burlington crank standard size journal differ in size from a Ford crank. One or two thousandths difference seems silly. Whats up with this?

Tom Wesenberg · 08-15-2013, 10:06 PM

It that a stated measurement, or what you measure?
Is it more or less than Ford's measurement?
Make sure your measurement is taken with accurate tools.

I measured some cam bearing diameters once and found out the mic I was using was off by a few thousandths.

Flathead · 08-15-2013, 10:11 PM

I am basing this on bearing sizes for inserted engines. They list slightly undersize bearings for the Burlington crank, smaller than for a standard size Ford crank.

PC/SR · 08-15-2013, 10:57 PM

The size is smaller. A friend had a rebuild and had to do it over again because of this. As my guru says, measure everything, twice. And if you have work done by someone else, be sure they and you know and agree on the measurements. Then check his work. This is not a slam on the machinists, who do amazing work and in my next life I want to be one. It is just that stuff happens. Good for you that you caught it early on. Many do not and we hear about the problems here.

BTW, 1 or 2.K is not a silly difference. If you are going with babbitt, give your babbitt guy the crank so he knows the dimensions and be sure he can bore to match. If you are going with inserts, give the crank to the machinist and make sure he knows the dimensions and has insert to match. Then measure it all over again when finished and you are installing it.

Chris in CT · 08-16-2013, 08:36 AM

Hi Flathead, Its not. The original print for the Ford-manufactured model A is for 0.002 under the nearest frractional journal measurement, i.e. the main bearing is 1.623/1.624 NOT 1.625 inch. This amount is easily allowed for in a poured babbitt bearing. It has turned out to be a little more troublesome for insert bearings. My friend Rich Falluca at Antique Engine Rebuilding offers special inserts for the Burlington Crankshaft. I believe they can also be sourced at Snyder's.

When I originally drew the prints for the new crank, I felt it was necessary to assiduously stick to original print specifications. I also did not take into account the degree to which the hobby was changing over to insert-type engine bearings. Hindsight is of course twenty-twenty, and there are numerous things I would do a little differently were I to re-design the crank for today's market.

Thank you for your purchase of a Burlington Crankshaft!

Chris

------------------------------

www.burlingtoncrankshaft.com

Marco Tahtaras · 08-16-2013, 08:37 AM

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Quote:

Originally Posted by Flathead

I am basing this on bearing sizes for inserted engines. They list slightly undersize bearings for the Burlington crank, smaller than for a standard size Ford crank.

That is a misconception. Ford's bearings were fractional at 1-5/8" and 1-1/2". The bearing clearance came from the journals. If something won't fit a Burlington crankshaft then it won't fit a Ford crankshaft.

Flathead · 08-16-2013, 02:01 PM

Thanks for the information. This totally clears up the question I had. I thought that there had to be a reason for this but didn't know the answer. I am thankful that Burlington cranks are available, just wondered about the clearance specs. Thanks again.

08-15-2013, 06:55 PM	#1
Flathead Senior Member Join Date: May 2010 Location: Southern Maine Posts: 1,498	Burlington Crank Journal Size Why does the Burlington crank standard size journal differ in size from a Ford crank. One or two thousandths difference seems silly. Whats up with this?

08-15-2013, 10:06 PM	#2
Tom Wesenberg Senior Member Join Date: May 2010 Location: Mpls, MN Posts: 27,582	Re: Burlington Crank Journal Size It that a stated measurement, or what you measure? Is it more or less than Ford's measurement? Make sure your measurement is taken with accurate tools. I measured some cam bearing diameters once and found out the mic I was using was off by a few thousandths.

08-15-2013, 10:11 PM	#3
Flathead Senior Member Join Date: May 2010 Location: Southern Maine Posts: 1,498	Re: Burlington Crank Journal Size I am basing this on bearing sizes for inserted engines. They list slightly undersize bearings for the Burlington crank, smaller than for a standard size Ford crank.

08-15-2013, 10:57 PM	#4
PC/SR Senior Member Join Date: May 2010 Location: Santa Rosa, CA Posts: 1,279	Re: Burlington Crank Journal Size The size is smaller. A friend had a rebuild and had to do it over again because of this. As my guru says, measure everything, twice. And if you have work done by someone else, be sure they and you know and agree on the measurements. Then check his work. This is not a slam on the machinists, who do amazing work and in my next life I want to be one. It is just that stuff happens. Good for you that you caught it early on. Many do not and we hear about the problems here. BTW, 1 or 2.K is not a silly difference. If you are going with babbitt, give your babbitt guy the crank so he knows the dimensions and be sure he can bore to match. If you are going with inserts, give the crank to the machinist and make sure he knows the dimensions and has insert to match. Then measure it all over again when finished and you are installing it. Last edited by PC/SR; 08-15-2013 at 11:43 PM.

08-16-2013, 08:36 AM	#5
Chris in CT Senior Member Join Date: May 2010 Location: Connecticut Posts: 272	Re: Burlington Crank Journal Size Hi Flathead, Its not. The original print for the Ford-manufactured model A is for 0.002 under the nearest frractional journal measurement, i.e. the main bearing is 1.623/1.624 NOT 1.625 inch. This amount is easily allowed for in a poured babbitt bearing. It has turned out to be a little more troublesome for insert bearings. My friend Rich Falluca at Antique Engine Rebuilding offers special inserts for the Burlington Crankshaft. I believe they can also be sourced at Snyder's. When I originally drew the prints for the new crank, I felt it was necessary to assiduously stick to original print specifications. I also did not take into account the degree to which the hobby was changing over to insert-type engine bearings. Hindsight is of course twenty-twenty, and there are numerous things I would do a little differently were I to re-design the crank for today's market. Thank you for your purchase of a Burlington Crankshaft! Chris ------------------------------ www.burlingtoncrankshaft.com

08-16-2013, 02:01 PM	#7
Flathead Senior Member Join Date: May 2010 Location: Southern Maine Posts: 1,498	Re: Burlington Crank Journal Size Thanks for the information. This totally clears up the question I had. I thought that there had to be a reason for this but didn't know the answer. I am thankful that Burlington cranks are available, just wondered about the clearance specs. Thanks again.