1935 Oil Bath Air Cleaner Installation - Stud Lengths

[Model51]

I'm installing the accessory oil bath air cleaner on my 1935 Truck. I'm wondering if anyone knows if Ford ever included three longer head studs for installing the air cleaner? The base which rests on top of the right-hand head is about 0.15" thick and there isn't the same amount of extra threads on the stud for the nut to fully engage when they are re-installed.

I've never seen any Ford documentation so I just assume the installation is to remove the three head studs, unhook the sparkplug wire and set the air cleaner in place. Then re-torque the head nuts and re-connect the spark plug wire.

Here are some pictures with one showing the amount of "extra" threads on one stud. I just want to be sure I'm not missing something. Maybe I'm just over-thinking it. Ford was often so particular about fasteners it just seems odd there aren't three longer studs. I also realize what a pain removing and installing three new studs would be just for an accessory.

 

[Kube]

Properly installed, there are special shoulder nuts for that bracket. Longer studs are not required.
The relief on the nut is just shy of the thickness of the bracket.

I just last week shipped the last special nuts out to a friend in WA.
Perhaps ask Mike Driskell???

 

[Model51]

Thank you! That's interesting to know. I'll get in contact with Michael and see if he has any.
I wonder what the Ford part number is for these nuts?

 

[nelsb01]

That was my suggestion also.
Years and years ago I purchase a full wooden ammo box of cad plated fasteners.
I may have some of those 'not so tall' nuts.

I will give a look.

 

[Kube]

That was my suggestion also.
Years and years ago I purchase a full wooden ammo box of cad plated fasteners.
I may have some of those 'not so tall' nuts.

I will give a look.

They are same height as the "regular" head nuts. There is a relief on the nut so that it beds down within the hole in the filter bracket.
My photo is terrible but hopefully still a little helpful.
Anyone with a small lathe can make these. The relief is slightly smaller in diameter than the hole in the bracket. The depth of the relief is just a tad less than the thickness of the bracket.

 

[Model51]

Kube,

Now that makes sense. I have a lathe and can turn down some nuts just as you described. I measured the thickness of the filter housing flange at 0.155" so it will be a simple matter of making a few more precise measurements of the hole diameter and double checking the flange thickness.

I've learned my new fact for the day. Thanks!

 

[Model51]

Bruce,
If you have three of those nuts let me know and I'll not spend time on the lathe. f you have them, you could bring them to Hershey.
Dave

 

[Model51]

The inside diameter of my oil bath air cleaner bracket holes is 0.465" and the outer diameter of the head stud threads is 0.435". Cutting a nut down to fit inside the oil bath bracket hole only leaves about 0.015" wall thickness of the shoulder. It doesn't leave much metal for the collar.

I tried this on my lathe with one head stud nut and I'm not sure it's worth the effort. If the holes in the oil bath air cleaner were a bit larger in diameter it might be a good idea, but just using regular nuts to tighten the air cleaner to the head seems to work fine. I had to cut almost to the bottom of the nut thread grooves to make the diameter of the color small enough to fit into the bracket hole.

 

[petehoovie]

The inside diameter of my oil bath air cleaner bracket holes is 0.465" and the outer diameter of the head stud threads is 0.435". Cutting a nut down to fit inside the oil bath bracket hole only leaves about 0.015" wall thickness of the shoulder. It doesn't leave much metal for the collar.

I tried this on my lathe with one head stud nut and I'm not sure it's worth the effort. If the holes in the oil bath air cleaner were a bit larger in diameter it might be a good idea, but just using regular nuts to tighten the air cleaner to the head seems to work fine. I had to cut almost to the bottom of the nut thread grooves to make the diameter of the color small enough to fit into the bracket hole.

 

[Kube]

The inside diameter of my oil bath air cleaner bracket holes is 0.465" and the outer diameter of the head stud threads is 0.435". Cutting a nut down to fit inside the oil bath bracket hole only leaves about 0.015" wall thickness of the shoulder. It doesn't leave much metal for the collar.

I tried this on my lathe with one head stud nut and I'm not sure it's worth the effort. If the holes in the oil bath air cleaner were a bit larger in diameter it might be a good idea, but just using regular nuts to tighten the air cleaner to the head seems to work fine. I had to cut almost to the bottom of the nut thread grooves to make the diameter of the color small enough to fit into the bracket hole.

Hmmm... something seems amiss here. I do recall the collar is not too wide.
For giggles, check this out on eBay.
eBay item number:126283665003

 

[cas3]

The holes in the accessory oil bath do not look as wide as the ford units, just from the pic.

 

[Kube]

The holes in the accessory oil bath do not look as wide as the ford units, just from the pic.

CAS3, you have good eyes my friend!
I went just moments ago to measure the holes in a NOS filter unit like the one being discussed in this thread. The holes in mine are .565".
Why the holes are so small in diameter in the posters unit is beyond me.

 

[mercman from oz]

Detailed Engine in Dave's 1935 Ford Model 51 Truck

 

[Model51]

I have several 51-9625 accessory oil bath air cleaners and the Ford Engineering drawing for this part. The drawing specifies three 15/32" (0.468") punched holes in the mounting flange and I measured them at +/- 0.465". With the 7/16" head studs, there's just not enough space between the stud threads and inside diameter of the hole to require a shouldered nut. When I put the air cleaner on the engine, without the nuts, it didn't wiggle much so I just used the original nuts and all seems well.

There are multiple versions of this air cleaner so maybe there's a version with wider holes that needs the shouldered nut to lock the air cleaner in place?

 

[Kube]

I have several 51-9625 accessory oil bath air cleaners and the Ford Engineering drawing for this part. The drawing specifies three 15/32" (0.468") punched holes in the mounting flange and I measured them at +/- 0.465". With the 7/16" head studs, there's just not enough space between the stud threads and inside diameter of the hole to require a shouldered nut. When I put the air cleaner on the engine, without the nuts, it didn't wiggle much so I just used the original nuts and all seems well.

There are multiple versions of this air cleaner so maybe there's a version with wider holes that needs the shouldered nut to lock the air cleaner in place?

I will admit, I know very little about the 35 / 36 model year trucks. Makes me wonder if Ford changed the design to utilize the shoulder nuts a little later. What ya think?
My filter appears nearly identical to yours. The holes were definitely punched.

 

[Model51]

What is the diameter of the holes in your air cleaner mounting flange?

I think this style air cleaner came out in 1932 and carried through the 1940's. I've seen various versions of this air cleaner but admittedly never paid any attention to the mounting hole diameter. I sort of ignored anything other than the one pictured.

 

[petehoovie]

I have several 51-9625 accessory oil bath air cleaners and the Ford Engineering drawing for this part. The drawing specifies three 15/32" (0.468") punched holes in the mounting flange and I measured them at +/- 0.465". With the 7/16" head studs, there's just not enough space between the stud threads and inside diameter of the hole to require a shouldered nut. When I put the air cleaner on the engine, without the nuts, it didn't wiggle much so I just used the original nuts and all seems well.

There are multiple versions of this air cleaner so maybe there's a version with wider holes that needs the shouldered nut to lock the air cleaner in place?

 

[Kube]

See post #12.

I went just moments ago to measure the holes in a NOS filter unit like the one being discussed in this thread. The holes in mine are .565".

 

[Model51]

Life always gets interesting, so too Ford parts. Thanks for the reference to post 12. I missed that. Can you post a photo of your air cleaner? With that hole diameter, shouldered nuts makes sense.

I did a bit of research and found a very similar air cleaner 79-18205 but with a flat top and maybe a different head attachment arrangement since the water jacket connection is in the center of the head. I also found and another tall cylindrical oil bath air cleaner released for 1934 Ford with Part No. B-9600-B but it's different and looks like it was intended for 4-cylinder vehicles. I can't find any others and now wonder why Ford would have two versions, especially since the Ford Engineering Drawing clearly shows a 15/32" hole diameter specification.

 

[Kube]

Life always gets interesting, so too Ford parts. Thanks for the reference to post 12. I missed that. Can you post a photo of your air cleaner? With that hole diameter, shouldered nuts makes sense.

I did a bit of research and found a very similar air cleaner 79-18205 but with a flat top and maybe a different head attachment arrangement since the water jacket connection is in the center of the head. I also found and another tall cylindrical oil bath air cleaner released for 1934 Ford with Part No. B-9600-B but it's different and looks like it was intended for 4-cylinder vehicles. I can't find any others and now wonder why Ford would have two versions, especially since the Ford Engineering Drawing clearly shows a 15/32" hole diameter specification.

I have the later version atop a '40 Ford.
The older version... I wonder if perhaps it was produced later than '36 for service and the change in hole diameter was done at that time either by design or simply "done" by the company that made them for Ford.

Oh, kinda / sorta related... in late '39 the location of the ground strap to the engine was changed. Prior to that a longer stud was specified for the (strap) head stud.
Sorry to possibly add to the confusion.