1940 and up big port OHV intake manifold nuts

[Jerry Wieland]

Yesterday I was putting a non chrome intake manifold with PEEK seals on the 1940 EL I recently bought and reminded myself of something that I had noticed years ago but had never gotten an answer for. Pictured are the 3 different styles of that intake nut that I am aware of. In general these were used on 1940 to 1954 OHV's and 1952 to 1956 K's and maybe WR/KR type bikes.

The one on the left is the original one that came on the 40 EL although it is chromed. I have other examples of this nut and in my collection of intakes is a 1940 only intake that has one like this one and one like in the middle. This nut is also identically cut to all 1936 to 39 OHV nuts that I have looked at except it is slightly bigger.

The one in the middle is identical to the ones on my original 1948 FL. When you see this one NOS and packaged it is usually in a manilla envelope.

The one on the right is the same as what is on my friends 1955 KH and when you see this one NOS is usually in a plastic bag as shown.

My question is - Does anybody know or have bikes that will layout a better timeline as to when these changed.

Usually this type of thing has only a passing interest for me because I am more of the attitude of - 'Lets just ride them' but for the last 6 weeks I have been laid up with a herniated disc in my back and my Doc says I cannot lift anything more than a full coffee cup. Needless to say I am running out of things to do that fit this regiment.

Jerry

[Chris Haynes]

The third one with the double bevel appears in my 1952 factory photos. 52FL1001 doesn't have them but 52FL70## does. The thought is that the double bevel was there so thay would fit the "K'S".

[Jerry Wieland]

Thanks Chris - the late ones being cut for the K's is kind of what I thought. Saw an 'original' 1944 F at the Viking Chapter meet but silly me forgot to look close at the detail of the manifold but here is the best picture I took of the left side. They appear to be the middle version.



Jerry

[Rubone]

Jerry,
My '40 only loose manifold and my '42FL (three owner) both have the 2nd version. I have not found any of the first version in my stuff. My '55 KHK has the 3rd.

[Jerry Wieland]

Robby I have an loose original 40 intake and it has one of each. Maybe it changed right a way. I know of a couple of high numbered OEM 40's to look at but they are quite a distance from me. An OEM 41 would be nice to check.

The 40 that the chrome intake was on is a low numbered one - 40EL140x

Jerry

[oldsouthmcy]

Jerry, Robbie,

Below is a closeup from a factory photo of a 41 prototype built around a late 40EL. It has the 2nd version nut.

While it does not establish when the 2nd nut was introduced for production 1940 models, I believe it is safe to say that it was used on all 1941 & later models until the substitution by the third type in 1952.

Bruce

manifold nut.jpg