In the MTFCA carburetor book Bruce says the Holley and Ford versions are identical and all parts are interchangeable. Recently I found my first Model F, which I believe is the Ford version of the NH, and discovered a discrepancy. Maybe a carburetor expert can demystify me.
1923 & later Holley NH
1922 & earlier (I think) Ford F
This F has the body for an offset bowl, which leads me to think it's 1922 or earlier, but had the later center drain bowl on it with just the mounting plug and no drain. I assume somebody just put that bowl on because that's all they had on hand.
The discrepancy I'm wondering about is the needle and clamp nut. On the left, from an NH. On the right, what I found on the F. As you can see, the NH clamp nut is really a threaded split sleeve, and the part of the shaft that passes through it to be clamped is unthreaded. The needle I found on the F, with the top of its shaft missing, threads into the nut, which is not split.
Here are the parts in question laid out separately.
So I wonder: Are the needle and nut for the Model F really different from the NH, or are these from some other carburetor, and if the so, what one?
I think the split nut on the left is a modern reproduction so comparing "original" parts may be difficult at best. Ford didn't use the relief cut under the head for the threads. And I recall seeing the nut type on the right on NH carbs. I would think that many replacement parts were available and as we hear on this board, many owners use whatever is available to make it run.
Now I remember. The nut on the right is used on the swivel linkage meter rods. The part that's broken off would have been the swivel U-joint half.
Steve, Perhaps the rounded off nut is the type used on the 26-7 Ts which had the different mixture control and choke mechanism, as indicated by Ken. They are interchangeable, so they are most likely to be able to be fitted to either carb.
Hope this helps.
Allan from down under.
The model F was an early version of the NH, but before they went to the center drain. If you look closely at the bottom, you will note there are no slots for the center drain. I understand during that period, probably 1922, that Holley could not keep up with the demand for carburetors, so Ford had to make them too, and that is what you have. I have several Model F's and like them.
Yep, that's why I knew that center-drain bowl was wrong for it. For anybody who wonders, here's what Larry described.
Offset-drain version, left; center-drain version, right.
Steve,the carb on the right has a crack which can be silver soldered.
A lot of them have cracks where the fuel line screws in, too. Some of those have pretty ugly "repairs".}}