The Ford Barn

Joe KCMO · 12-02-2011, 11:50 PM

Does anyone know the size of the hole in the drivers side head of a 39 ford. And pushing my luck does anyone also know the size of the hole in a 40 cylinder head. Thanks.

flatjack9 · 12-03-2011, 08:05 AM

The size of the hole is the same for both, I think 3/8 IP size. The 39 had a ledge at the bottom of the hole for the capillary tube temp sender and the 40 was drilled straight thru because the electric temperature sender was larger.

G.M. · 12-03-2011, 08:39 AM

The heads set up for a temperature bulb have if I remember correctly a 1/2-20 thread, not a pipe thread. And I believe the sender ones are 3/8" pipe. G.M.

Terry,OH · 12-03-2011, 09:48 AM

If you are looking for the thread size for the 39 with the bourdon tube temperature gauge I believe it is the same for the earlier car 5/8-18
The 40 Ford electric sender is 3/8-18 NPT

Kurt in NJ · 12-03-2011, 01:50 PM

There is an adapter for pipe thread to temp gauge, I think it was used on 60hp cars(at least the 39 my father had used one)---try looking in the "green book"

Joe KCMO · 12-03-2011, 03:42 PM

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I see the adaptor in the greenbook. I have been told try and get one, very difficult. So it either find new heads or make my own adaptor. Right now I have 3/8" pipe and 5/8"-18 for the 39. The majority says that the 40 is 3/8" NPT. I need a majority for the 39 thread size. Then I can make the adaptor.

G.M. · 12-03-2011, 06:49 PM

These adaptors are available from Napa, they have a pretty good assortment. An older Napa store might be better. I know a lot of people jambed pipe thread fittings in the straight threaded holes. G,M,

Bruce Lancaster · 12-05-2011, 07:54 PM

Yes, the adaptor made for installing aftermarket tube-type gauges into pipe holes. Functionalyl right, no idea if appearance is right on. Cheap, often sold in a bag with an assortment of adaptors for various applications. Any company selling about any brand of hotrod gauges will have an equivalent.

12-02-2011, 11:50 PM	#1
Joe KCMO Senior Member Join Date: May 2010 Location: Miami, Florida Posts: 423	Thread size 39 temperature bulb in cylinder head Does anyone know the size of the hole in the drivers side head of a 39 ford. And pushing my luck does anyone also know the size of the hole in a 40 cylinder head. Thanks.

12-03-2011, 08:05 AM	#2
flatjack9 Senior Member Join Date: May 2010 Location: Oshkosh, Wi Posts: 4,527	Re: Thread size 39 temperature bulb in cylinder head The size of the hole is the same for both, I think 3/8 IP size. The 39 had a ledge at the bottom of the hole for the capillary tube temp sender and the 40 was drilled straight thru because the electric temperature sender was larger.

12-03-2011, 08:39 AM	#3
G.M. Senior Member Join Date: May 2010 Location: Florida and Penna. Posts: 4,471	Re: Thread size 39 temperature bulb in cylinder head The heads set up for a temperature bulb have if I remember correctly a 1/2-20 thread, not a pipe thread. And I believe the sender ones are 3/8" pipe. G.M. __________________ www.fordcollector.com

12-03-2011, 09:48 AM	#4
Terry,OH Senior Member Join Date: May 2010 Posts: 4,751	Re: Thread size 39 temperature bulb in cylinder head If you are looking for the thread size for the 39 with the bourdon tube temperature gauge I believe it is the same for the earlier car 5/8-18 The 40 Ford electric sender is 3/8-18 NPT

12-03-2011, 01:50 PM	#5
Kurt in NJ Senior Member Join Date: May 2010 Location: on the Littlefield Posts: 6,159	Re: Thread size 39 temperature bulb in cylinder head There is an adapter for pipe thread to temp gauge, I think it was used on 60hp cars(at least the 39 my father had used one)---try looking in the "green book"

12-03-2011, 03:42 PM	#6
Joe KCMO Senior Member Join Date: May 2010 Location: Miami, Florida Posts: 423	Re: Thread size 39 temperature bulb in cylinder head Sponsored Links (Register now to hide all advertisements) I see the adaptor in the greenbook. I have been told try and get one, very difficult. So it either find new heads or make my own adaptor. Right now I have 3/8" pipe and 5/8"-18 for the 39. The majority says that the 40 is 3/8" NPT. I need a majority for the 39 thread size. Then I can make the adaptor.

12-03-2011, 06:49 PM	#7
G.M. Senior Member Join Date: May 2010 Location: Florida and Penna. Posts: 4,471	Re: Thread size 39 temperature bulb in cylinder head These adaptors are available from Napa, they have a pretty good assortment. An older Napa store might be better. I know a lot of people jambed pipe thread fittings in the straight threaded holes. G,M, __________________ www.fordcollector.com

12-05-2011, 07:54 PM	#8
Bruce Lancaster Member Emeritus Join Date: May 2010 Location: Madison, NJ Posts: 5,230	Re: Thread size 39 temperature bulb in cylinder head Yes, the adaptor made for installing aftermarket tube-type gauges into pipe holes. Functionalyl right, no idea if appearance is right on. Cheap, often sold in a bag with an assortment of adaptors for various applications. Any company selling about any brand of hotrod gauges will have an equivalent.