The Ford Barn

Don · 10-13-2016, 03:14 PM

This engine did not have the small piece of pipe connected to rear main cap.This is a 37 -21 stud engine and wondering if it should be there ? If so ,how long and thread size? What is the purpose?

David J · 10-13-2016, 04:15 PM

Yes you should have one . The tube is meant to have it's lower end submerged in the oil . Do a search on this and you will find MANY opinions on it . I always use one . Pics are a 33 but yours will be similar = no rear seal .

jetmek · 10-13-2016, 05:19 PM

The ford service bulletins state that when using the later style oil pump (one with large separate pickup and screen) to NOT use a drain tube on the rear main.

Brian · 10-13-2016, 09:45 PM

David J [whom is is wealth of knowledge on real early Fords, and whom I admire greatly] and myself disagree on this point. A 1937 V8 engine came from the factory without that tube. Sure, the cap is tapped, but a tube wasn't fitted. Therefore, not needed, nor original.
I think the tube was done away with in 1935 with the advent of positive crankcase ventilation. Prior to that, ie, 1932-34, those engines could [would] blow oil outta the rear main bearing by virtue of the crankcase pressurisation.
However, I think it was David J, in an earlier discussion about this very topic, who showed that 1938 Big truck engines were equipped with the tube?? So what do I know? FWIW.

David J · 10-13-2016, 11:09 PM

Brian ,
Thanks for the nod but I don't deserve it . I definitely don't know all .

On the pipe it is 81A 6326 and is for all 38-42 90 and 100 HP V-8's . Pass , Comm and truck . Page 130 Orange bible .

Earlier pipes are 18-6326-AR [ 32 only with 30* oil hole ] , 18-6326-B [ 32-34 with 45* oil hole . Page 31 28-34 parts book effective 3/5/34 .

18-6326-B is listed as 32-35 models BB,18,40,46,48,50,51. Page 38 parts book effective 6/35 . Some check ball ones listed also .

Can't find the 36 or 37 books but this is the same info I posted last go .

Probably not a huge deal but they came in all cars I like and unless you screw it in way too far and make a dam out of it I see no harm in it . I also like the idea of the labyrinth seal breathing on it's own - not through a huge hole in the bottom .

Terry,OH · 10-14-2016, 07:45 AM

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Below is a photo of 81A-6326 used on 85 & 100HP 1938-42. The steel check ball type 40-6328 is for special equipment, one such type is the grain dumps truck where the entire truck was upended to dump the contents, the ball prevented the oil from flowing back using gravity. Very unusual.

jetmek · 10-15-2016, 09:12 AM

See February 1936 service bulletins Pg 364 fig 529 while its not proof positive ALL of the non babbit engines ive disassembled have no oil tube installed.

10-13-2016, 03:14 PM	#1
Don Senior Member Join Date: May 2010 Location: Ashland KY Posts: 1,159	Drip tube off rear main This engine did not have the small piece of pipe connected to rear main cap.This is a 37 -21 stud engine and wondering if it should be there ? If so ,how long and thread size? What is the purpose? __________________ DON P

10-13-2016, 05:19 PM	#3
jetmek Senior Member Join Date: May 2010 Location: albany Posts: 468	Re: Drip tube off rear main The ford service bulletins state that when using the later style oil pump (one with large separate pickup and screen) to NOT use a drain tube on the rear main. __________________ engine and component overhauls my specialty! Website- www.godevilgarage.com

10-13-2016, 09:45 PM	#4
Brian Senior Member Join Date: May 2010 Location: Masterton, New Zealand Posts: 3,848	Re: Drip tube off rear main David J [whom is is wealth of knowledge on real early Fords, and whom I admire greatly] and myself disagree on this point. A 1937 V8 engine came from the factory without that tube. Sure, the cap is tapped, but a tube wasn't fitted. Therefore, not needed, nor original. I think the tube was done away with in 1935 with the advent of positive crankcase ventilation. Prior to that, ie, 1932-34, those engines could [would] blow oil outta the rear main bearing by virtue of the crankcase pressurisation. However, I think it was David J, in an earlier discussion about this very topic, who showed that 1938 Big truck engines were equipped with the tube?? So what do I know? FWIW. __________________ Unfortunately, two half wits don't make a whole wit! Last edited by Brian; 10-14-2016 at 01:01 AM.

10-13-2016, 11:09 PM	#5
David J Senior Member Join Date: Jun 2010 Location: St Croix Falls WI Posts: 2,080	Re: Drip tube off rear main Brian , Thanks for the nod but I don't deserve it . I definitely don't know all . On the pipe it is 81A 6326 and is for all 38-42 90 and 100 HP V-8's . Pass , Comm and truck . Page 130 Orange bible . Earlier pipes are 18-6326-AR [ 32 only with 30* oil hole ] , 18-6326-B [ 32-34 with 45* oil hole . Page 31 28-34 parts book effective 3/5/34 . 18-6326-B is listed as 32-35 models BB,18,40,46,48,50,51. Page 38 parts book effective 6/35 . Some check ball ones listed also . Can't find the 36 or 37 books but this is the same info I posted last go . Probably not a huge deal but they came in all cars I like and unless you screw it in way too far and make a dam out of it I see no harm in it . I also like the idea of the labyrinth seal breathing on it's own - not through a huge hole in the bottom .

10-15-2016, 09:12 AM	#7
jetmek Senior Member Join Date: May 2010 Location: albany Posts: 468	Re: Drip tube off rear main See February 1936 service bulletins Pg 364 fig 529 while its not proof positive ALL of the non babbit engines ive disassembled have no oil tube installed. __________________ engine and component overhauls my specialty! Website- www.godevilgarage.com