linenbaugh Posted January 3, 2016 Report Share Posted January 3, 2016 Hello Ihave an engine from -56 in my -47 Dodge and i need an adapter to make the temp gauge sending unit fit in the head.The newer engines had an electric tempgauge ,and had a smaller tread in the head.Can anyone tell me the tread size in the newer heads, i have measured the treads and found it is 18 tpi taperd tread could it be a pipe tread or NPT ? I do allso need to know the tread of the nut that holds the bulb in place.Any help is greatly appreciated. Anders Quote Link to comment Share on other sites More sharing options...
Don Coatney Posted January 3, 2016 Report Share Posted January 3, 2016 Gland nuts come in many sizes. Most any good auto parts store should have one that will work for you. Quote Link to comment Share on other sites More sharing options...
linenbaugh Posted January 3, 2016 Author Report Share Posted January 3, 2016 Thanks for your answer but it does not solve my problem,The bulb is about the same size as the treads in the head so i need to fabricate an adapter that sticks out a little or i will have to re thread the head,wich will need the head to come off.At this point i do not want to remove the head as there is nothing wrong with the engine .I need to know the tread sizes. Quote Link to comment Share on other sites More sharing options...
Don Coatney Posted January 3, 2016 Report Share Posted January 3, 2016 If the bulb is not inside the head in the flow of coolent it will not read correctly. Follow this link for pipe thread sizes. http://www.engineersedge.com/hardware/taper-pipe-threads.htm 1 Quote Link to comment Share on other sites More sharing options...
linenbaugh Posted January 3, 2016 Author Report Share Posted January 3, 2016 Thanks again but it still dont solve my problem ,i know the bulb has to be in contact with the coolant and i am going to make the adapter that way.I still need the tread size in the newer heads ,as i live in sweden we are metric and do use pipe threads in inch .It would be much easier if someone could tell me the size of threads i have to make so i can find dies or cut the threads in a lathe. Anders Quote Link to comment Share on other sites More sharing options...
James_Douglas Posted January 5, 2016 Report Share Posted January 5, 2016 I just had to drill-tap one head last week for the '49 engine I am doing with a later head. I will take a look in the next day or two and see what tap I used...if I brain fart and don't get to it...send me an email directly to wake me up. James Quote Link to comment Share on other sites More sharing options...
linenbaugh Posted January 7, 2016 Author Report Share Posted January 7, 2016 Hello again I whent to the plumber and bought a bunch of different fittings and made an adapter .The tempgauge works so i guess problem solved. Thanks for your input Anders Quote Link to comment Share on other sites More sharing options...
48ply1stcar Posted January 7, 2016 Report Share Posted January 7, 2016 (edited) I assume you found an adapter, so what was the thread size in the head of the engine and the inside of the adapter? Edited January 7, 2016 by 48ply1stcar Quote Link to comment Share on other sites More sharing options...
Dodgeb4ya Posted January 8, 2016 Report Share Posted January 8, 2016 So what was the thread size? Quote Link to comment Share on other sites More sharing options...
Brent B3B Posted January 8, 2016 Report Share Posted January 8, 2016 So what was the thread size? i'll play along ...........14 or 1.75 18 or 1.5 ???? diameter to be determined by specific application? Quote Link to comment Share on other sites More sharing options...
ptwothree Posted January 8, 2016 Report Share Posted January 8, 2016 My thread checker says it's a 5/8" x 18 tps. This is on my '51 218. Hope it helps Quote Link to comment Share on other sites More sharing options...
Don Coatney Posted January 8, 2016 Report Share Posted January 8, 2016 My thread checker says it's a 5/8" x 18 tps. This is on my '51 218. Hope it helps 5/8" is not a common tapered pipe thread. Check the link I posted earlier. 3/8" pipe threads are 18 TPS. Quote Link to comment Share on other sites More sharing options...
DonaldSmith Posted January 9, 2016 Report Share Posted January 9, 2016 Pipe sizes go by approximate inside diameter, not like a bolt. Quote Link to comment Share on other sites More sharing options...
Dodgeb4ya Posted January 9, 2016 Report Share Posted January 9, 2016 Well I'll supply the final answer hopefully.......and the final answer is... The 1956 electrical temp sender threaded hole size in the Plymouth and Dodge 230 flat head is... 1/4 NPTF The temperature gauge bulb gland nut (1947 Dodge temp Gauge) that also is used on the 1954 and back Plymouth and Dodge (1947) cars is a 5/8" X 18 straight threads per inch size. .625" OD or 5/8". 1 Quote Link to comment Share on other sites More sharing options...
Young Ed Posted January 9, 2016 Report Share Posted January 9, 2016 Well I'll supply the final answer hopefully.......and the final answer is... The 1956 electrical temp sender threaded hole size in the Plymouth and Dodge 230 flat head is... 1/4 NPTF The temperature gauge bulb gland nut (1947 Dodge temp Gauge) that also is used on the 1954 and back Plymouth and Dodge (1947) cars is a 5/8" X 18 straight threads per inch size. .625" OD or 5/8". Do you know of a source for teh senders for the electrical version? Quote Link to comment Share on other sites More sharing options...
Dodgeb4ya Posted January 9, 2016 Report Share Posted January 9, 2016 Did a quick search and came up with this for a 56 dodge....http://www.ebay.com/itm/1955-1956-Dodge-Plymouth-Chrysler-Desoto-Hudson-Nash-temperature-sending-unit-/351452902422 Quote Link to comment Share on other sites More sharing options...
James_Douglas Posted January 19, 2016 Report Share Posted January 19, 2016 (edited) As I clean up from my engine assembly, I found the adaptor that goes into the head and the tap I used for it. It is a 1/2 inch by 14 Thread Per Inch National Pipe. You can see the photo. I sort of remember having to go out and buy the tap for doing another head. James. Edited January 19, 2016 by James_Douglas Quote Link to comment Share on other sites More sharing options...
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