Thermocouple Size for Jacobs Port

[BrianJ]

Does anyone know for sure the thread size on the port included on the Jacobs Brake for the pyrometer thermocouple?



I am ordering gauges and need to know the thermocouple size, 1/8 or 1/4.

 

[BrianJ]

Bump...



Anyone know this?



Tried Jacobs, Cummins, and Dodge yesterday... couldn't get through to Jacobs and neither Cummins or Dodge could answer.

 

[nickleinonen]

get the 1/8" npt one... you can always add a bushing to go from 1/8" npt to 1/4"npt

 

[BrianJ]

Thanks Nick...



A tech at Jacobs called me back this morning and they confirmed it was 1/4, however, they said it was 1/4-18 NPTF. Is that compatible with the thermocouple (Westach Duel gauge) thread? All I see for thermocouple threads is NPT. If the thermocouple is NPT, is there a bushing that goes from 1/8 course to 1/4 fine?

 

[Turbo1Ton]

Should be compatible. I only know of one pitch of 1/4" NPT threads and that is 18. It depends on the type of seal of the threads. Check this out for a better explanation.



http://www.cutting-tool-supply.com/TechTips/Tapping/NPTvsNPTF/NPTVsNPTF.htm

 

[nickleinonen]

1/4-18 NPTF

that is spot on... the 1/8" npt is 27tpi i think?



the "F" on the "NPTF" is not fine, it is Fuel... the threads are cut slightly sharper on nptf vs npt and makes it seal better with no thread sealent. they are 100% compatable with each other. .

 

[BrianJ]

Thanks for the replies, and forgive my "rookieness". I got the jake brake yesterday and the gauge and mount are on order. Should be installed next week, can't wait to try out the Jake.

 

[DDahl]

I used a 1/4" Wess. egt probe on my Jacobs port. Worked great!