The Ford Barn

32forddump · 07-12-2016, 09:37 PM

Just curious of what the clearance of rod to crank is?

tbirdtbird · 07-12-2016, 09:51 PM

same

Tom Wesenberg · 07-12-2016, 11:15 PM

.001" to .0015"would be good.
When I looked in the Motor's Manual for the rod specs on my 1949 Chevy 216, they said .0005" to .0015", so I set all 6 between .0005" and .00075" and it did fine.

32forddump · 07-13-2016, 07:14 AM

Well it looks like I'm coming in around .003 to .002, i have removed all the shims, so what next? do I have caps ground down to make it tighter?I torqued caps to 30 ft lbs.

John · 07-13-2016, 07:23 AM

OK, something isn't correct. If the rods have that much clearance, 0.070"-0.080" then the crank has been ground undersize too much or the rods were improperly bored. An original standard 'B' crank rod journal should "mike" 1.875" if memory serves me correctly. Mike the crank journal and rod bore and tell us what you have. With that information, we can give you the proper guidance.

Kurt in NJ · 07-13-2016, 07:27 AM

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How are you measuring, .070,.080 is more than 1/16 inch, has the crankshaft been measured ,is it round----.007,.008 is too loose to "just tighten up" by filing the cap , and if done won't last long, there would still be too much clearance at the sides, the "hole" in the rod will be oval

Jim Brierley · 07-13-2016, 09:40 AM

I read his post as 2-3 thousandths. .002" is OK, I run .002" - .0025" on my race engines. You can take off a half thou easily by rubbing the cap on any flat surface, really flat. Use valve grinding compound if the surface is smooth, or none if using you garage floor.

32forddump · 07-13-2016, 11:40 AM

Sorry I was looking at the metric scale first.

Kohnke Rebabbitting · 07-13-2016, 12:03 PM

The Model B rod as Jim said should be set with a clearance of .001-80 to .002-30.

Anything under that you take a chance on smearing the Babbitt, and anything over that is wasted clearance.

216 Chevy rods should be set at .002-3 to .002-80. You can't go by the high or lows of the Babbitt bearing spec. books.

Herm.

07-12-2016, 09:37 PM	#1
32forddump Senior Member Join Date: Jan 2012 Location: Ashby, Mass Posts: 452	model b rod clearance specs Just curious of what the clearance of rod to crank is? __________________ I know I can, I know I can http://www.flickr.com/photos/waltsprojects/

07-12-2016, 09:51 PM	#2
tbirdtbird BANNED Join Date: May 2012 Location: inside your RAM Posts: 3,134	Re: model b rod clearance specs same __________________ '31 180A

07-12-2016, 11:15 PM	#3
Tom Wesenberg Senior Member Join Date: May 2010 Location: Mpls, MN Posts: 27,582	Re: model b rod clearance specs .001" to .0015"would be good. When I looked in the Motor's Manual for the rod specs on my 1949 Chevy 216, they said .0005" to .0015", so I set all 6 between .0005" and .00075" and it did fine.

07-13-2016, 07:14 AM	#4
32forddump Senior Member Join Date: Jan 2012 Location: Ashby, Mass Posts: 452	Re: model b rod clearance specs Well it looks like I'm coming in around .003 to .002, i have removed all the shims, so what next? do I have caps ground down to make it tighter?I torqued caps to 30 ft lbs. __________________ I know I can, I know I can http://www.flickr.com/photos/waltsprojects/ Last edited by 32forddump; 07-13-2016 at 07:25 AM.

07-13-2016, 07:23 AM	#5
John Senior Member Join Date: May 2010 Location: Richmond, VA Posts: 189	Re: model b rod clearance specs OK, something isn't correct. If the rods have that much clearance, 0.070"-0.080" then the crank has been ground undersize too much or the rods were improperly bored. An original standard 'B' crank rod journal should "mike" 1.875" if memory serves me correctly. Mike the crank journal and rod bore and tell us what you have. With that information, we can give you the proper guidance.

07-13-2016, 07:27 AM	#6
Kurt in NJ Senior Member Join Date: May 2010 Location: on the Littlefield Posts: 6,159	Re: model b rod clearance specs Sponsored Links (Register now to hide all advertisements) How are you measuring, .070,.080 is more than 1/16 inch, has the crankshaft been measured ,is it round----.007,.008 is too loose to "just tighten up" by filing the cap , and if done won't last long, there would still be too much clearance at the sides, the "hole" in the rod will be oval

07-13-2016, 09:40 AM	#7
Jim Brierley Senior Member Join Date: Jun 2010 Location: Temecula, CA Posts: 4,089	Re: model b rod clearance specs I read his post as 2-3 thousandths. .002" is OK, I run .002" - .0025" on my race engines. You can take off a half thou easily by rubbing the cap on any flat surface, really flat. Use valve grinding compound if the surface is smooth, or none if using you garage floor.

07-13-2016, 11:40 AM	#8
32forddump Senior Member Join Date: Jan 2012 Location: Ashby, Mass Posts: 452	Re: model b rod clearance specs Sorry I was looking at the metric scale first. __________________ I know I can, I know I can http://www.flickr.com/photos/waltsprojects/

07-13-2016, 12:03 PM	#9
Kohnke Rebabbitting Senior Member Join Date: May 2010 Location: 60615,330th Ave.,Clare, Iowa, 50524 Posts: 1,457	Re: model b rod clearance specs The Model B rod as Jim said should be set with a clearance of .001-80 to .002-30. Anything under that you take a chance on smearing the Babbitt, and anything over that is wasted clearance. 216 Chevy rods should be set at .002-3 to .002-80. You can't go by the high or lows of the Babbitt bearing spec. books. Herm.