Topic: Why different size temp senders?

[MustangAndFairlane1867]

I'm trying to research when/why the temp senders on 289, 4-barrel intake manifolds went from the small size temp sender to the large size temp sender.  And did the manifolds that took the smaller sender have corresponding smaller threaded holes, or did they have the larger holes that required a reducer adaptor (brass?) to hold the smaller temp sender?  Thanks, Ron

[67gta289]

Have you looked in the small block Ford book by Bob Mannel?

[67gta289]

Page 6-15 talks about the larger size manifolds included three reinforcing ribs which provide additional support form potential over torquing of the larger sensor.   There are pictures of both and it is difficult to tell but it seems that the holes are different sizes.

[MustangAndFairlane1867]

Thanks, John.  I'll pull the book out this evening and take a look at those pages.  I noticed earlier today that on page 141 of the 2018 NPD catalog they show both sizes of the senders, and they say the smaller one is pre 9/1/1965, and the larger sender is after 9/1/1965.  Interestingly, my intake manifold (January 5, 1965) has the larger, threaded hole with a brass reducer that accepts the smaller sender.  That would seem to answer one of my questions, but for some reason the NPD catalog doesn't list the brass reducer for sale anywhere in the book.  Unless, of course, I missed it.  Always a possibility.  Anyway, I'm going to keep researching it to see if I can come up with a clear answer.  Thanks, Ron...

[markb0729]

Yes brass.  Let me know if you find one of those brass reducers.  I never found one when I was looking although you can probably make one out of a brass fitting.

[MustangAndFairlane1867]

John--that info on page 6-15 in Mannel's great book is a discussion of 1966 intakes, which is of no help to me.  I need to find some literature talking about the early and late 1965 intake manifolds.  That's apparently the year when the transition from the small to the large temp senders took place.  Thanks, Ron

[67gta289]

Sorry about that. Your original post did not indicate the year so I flipped the book to 66 and found the reference.  Since it was there I assumed it met the need. Since you have the book let us know what you find

[jwc66k]

Lets think "service". If you had a factory engine with a manifold that had the smaller tapped hole, you got the smaller sensor. Ford enlarged the tapped hole for a larger diameter sensor, and used an adapter to accommodate the smaller sensor in the larger hole for assembly line use until all the smaller sensors were used. Then they were ready for "the big one" (it's a California earthquake saying). If yours failed a decade later, you either got a new small one, or a new large one depending on the original intake. No adapter was needed as a service part.
That's the reason. I know it still does not answer the "when", but that was an engine assembly plant determination, not car assembly line determination.
Jim

[CharlesTurner]

Previous discussion on size:

http://www.concoursmustang.com/forum/index.php?topic=7801.msg44639#msg44639