Hi Ian,

What a coincidence, you have a touring car and the gentlemen who emailed me also has a touring car and you both have downdraft carbs.
I found the info below on the Chrysler Heritage website, nothing was mentioned about Plymouths of the time but Plymouths were mostly sold out of Dodge dealerships.  Gives one pause to think that maybe a Dodge shop might experiment down the road with a Plymouth conversion.   see link below:

http://chryslergroupllc.extra.chrysler.com/company/Heritage/Pages/Brand-Heritage-1920.aspx

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The downdraft carburetor, first introduced on the 1929 Chrysler and Dodge models, was one of Chrysler's early "engineering firsts." Before that time, carburetors were usually of updraft design — that is, they were positioned below the engine intake. Fuel tanks located above the intake relied on gravity to fuel the carburetor. Those positioned below the intake used a vacuum tank to feed fuel to the carburetor. Locating the carburetor above the engine intake and relying on gravity to deliver fuel to the cylinders seemed more efficient but required reliable fuel pumps for the system to work. Everitt Shepherd, an engineer with the Holley Carburetor Company, approached Carl Breer with a downdraft design in 1928. Breer was concerned about flooding the engine during cold weather starting, but a float chamber developed by the Stromberg Carburetor Company took care of this problem. The new carburetor design brought increased horsepower and speed from a given engine, while improving starting.

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I checked your first post but the picture of the engine is from the other side.  Did you ever post a picture of the carburetor side ?  The picture that I was sent showed a car that had sat in a garage for the past 40 years.   The setup looked like on carb was sitting on top of another and it looked very old.  I will try to add the picture later

Chet...

I recently received an email from a gentleman in Germany who just purchased a 1929 Plymouth touring car.  He has a downdraft carburetor which appears to be sitting on the stock intake manifold which also appears to be installed upside down.   I never thought of doing this but can anyone confirm whether this is possible to do without modification ?  In a prior post Steve talked about a Stromberg Carb and the question came up from Glenn concerning a downdraft to updraft conversion.

If the intake manifold is reversible was this a common practice at the time the industry switched over to downdraft carbs ?

Just curious, Chet...

Hi Ian,

Yes everything you stated makes sense to me.  I understand the method of delivering the hub grease using centrifugal force.  I also understand that a modern car with a grease cap also has a grease port drilled into the center of the axle in order to deliver new grease without removing the hub.  The 29 hub cap is pancake shaped which seems to collect grease in the outer edge of the pancaked front of the hub cap.  Maybe they designed this shape to collect the old grease expelled from the front bearing thus allowing new grease to enter from the supply in the hub.  Either way.., it seems like a ton of grease moving around.  To me, a little over kill but as you stated necessary to produce proper lubrication.

Thanks for the reply.  Chet...

Thanks Ian,

I will check this over the weekend.

Chet...

This is probably a dumb question, but; did the 28/29 Plymouth have grease caps under the hubcaps for the front wheels ?

If no.., has anyone installed grease caps, there seems to be enough room ?

Chet...

Hi Glenn,

All good suggestions.  I thought about machining the mounting portion of the cylinder. 

Yes,  It is only the rubber making contact with the inner surface of the drum.  Mostly with the wheel turning in reverse.  Actually the rubber dustcover is quite thick ?

I thought this might be a quick improvement but if I am going to get this involved I need to do a lot more to the old girl then change the wheels. I think I may let her sit until next summer when my 48 is finally completed, then start a complete restoration.

Chet...

Quote from: frankp on October 07, 2013, 11:37:23 AM
Chet,

I too was concerned about rear wheel.  What if a very thin sheet of brass were placed on axle?  This would enlarge circumference across the width of the shim and prevent wheel from its full inward travel.  Of course there is that pesky drive shaft key/slot to deal with.  Trying a little brain-storming here.

Brother, I do understand about locating those "extra" parts!  Good luck.
frank

Thanks Frank but the taper of the axle shaft and hub are important to produce the necessary "Taper Lock" needed to insure that the hub doesn't slip on the axle.  Nice thought but there is no clean way to move the wheel drum outward on the rear axle.  If I have a problem in the rear I might need to find some old cylinders to rebuild or possibly a shim at the bearing to limit the axle shaft's inward travel.  I seem to remember doing some type of shim adjustment on my 48 Plymouth's rear axle for proper end play.

Chet... 

Quote from: Old Man on October 07, 2013, 08:52:44 AM
I think I mis-spoke or mis-typed. I envisioned the washer on the inside of the drum. In other words in that photo of the backside of the drum, it would have a washer at each bolt station. They would have to glued/epoxied in place. Am I still out in left field or would that not move the drum away from the wheel cylinder by the thickness of the washer? 

The rear bearing determines how far the wheel and drum will sit on the axle shaft.  The race for the rear bearing is inside the hub.  Works the same as the front bearing only the inner race sits against the axle rear flange.  Washers on the bolts that hold the drum to the wooden wheel will only move the drum closer to the cylinder not away from it.  If you consider the wood wheel and the brake drum as a single unit it might make more sense.  Thanks for the response.

Chet...

Quote from: imoore on October 06, 2013, 11:55:10 PM
Hi chet
I have an original wheel cylinder if u want me to measure diameter.
Ian

Ian,

If that is easy for you to do it would be helpful.  I think the front wheels can be easily solved.  I am more worried about the rear, since there is no option for outward adjustment. 

Chet...

Quote from: frankp on October 06, 2013, 01:31:12 PM
Chet,

Short note.  I purchased new cylinders from Andy B many years ago to replace my pitted ones - exact same problem and had to return them.  Even though claimed to be for 1929, his cylinders' outside diameter were too large and rubbed on the drum.  The original cylinders were sleeved with stainless steel locally at almost the same cost as the new ones.  Also did the master cylinder.  You might want to look at this option also.

frank

Hay Frank,

Since I generally never throw anything away I might still have them.  It's finding them that's the problem.  If I can find a proper spacer I think that would do the trick in the meantime.

Ths,  Chet...

Quote from: Old Man on October 06, 2013, 09:33:03 AM
Chet I would just build out the drum/wheel with washers. We don't drive these things fast and furious enough to worry about it. If the shoes don't overhang the drum by any amount I don't see a problem. I would epoxy heavy washers at each bolt and install. Can't see any downside except slight change in front track. But that won't change alignment just max. steering circle I think. And the washers will be too close to center of mass to affect balance of wheel/tire assembly. This is what I would do. How fast can wheel speed be at 45 mph. on 19" wheels?

I think I have just the opposite problem.  The Drum is to far inboard.  In order to move it away from the cylinder I would have to put a 1/16 or 1/8" spacer between the axle rear bearing stop and the rear bearing.  This is the only way to move the drum away from the cylinder.  It doesn't have to move that much and there is plenty of room on the axle to accommodate the shift.  It turns forward OK but grabs the rubber in reverse motion.   I think a 1/16" spacer would do the trick.  Or maybe a new rear bearing ? What do you think ?  See picture below.

Is it an updraft Carb.



If it looks like this I believe the bottom T screw might be the mixture.  I have a universal carb that looks similar and the instructions say to turn in the mixture screw until it starts to effect the idle then open it a little ? (1/4 or 1/2 turn) If it doesn't feel right at top end open it a bit more ?

PS... Make sure you remember how many turns you move any screw so you can get back to where you were !

Chet...

Quote from: SDGlenn on October 05, 2013, 06:04:24 PM
Hey Chet, Still working on the ole girl hey?  What is original on the 29U? My 29 Coupe has the 20" wheels...   I notice the brake drums on mine are pretty squared, looking along the brake shoe surface to the surface that bolts to the wood spokes.  Maybe the Brake shoe surface on mine is a bit wider than the one you show a picture of. Maybe the brake cylinder is a bit too large?   
Glenn

Glenn,

The 20" wheels are the correct size but mine need to be respoked. (an easy $1,200+) So I decided to see if the 19" would work to save a couple of bucks.  The drums are the same because I took the drum off my 20" wheel and installed it on the 19" wheel and had the same problem.  1/16" stop washer on the axle would move the wheel out just enough or maybe new bearings. 

Does the brake cylinder look correct to you ?  I think it is a bit to large.  I will have to see if I kept the original parts when I fixed the brakes back in 2004.   I got them from Andy before he sold the business.  I think they are for a PA and he said they would work fine.

Chet...

Chet...

I tried installing the 19" Plymouth wood wheel on the front driver's side of my 29-U.  What appears to be happening is that the drum installs slightly further inboard which I believe is because the new wood spoke assembly may be just a hair larger then my old 20" wood wheels.  Looking at the pictures below it appears that the rubber dust seal is rubbing on the inside of the drum.  I guess I am not buying new tires just yet.  

Any advise



The picture below shows how far the cylinder sticks out past the brake shoe.


You can see the scrap marks below.  I even changed the drum with my old car drum.


Really wanted to buy tires at the Hershey Show on Friday I would expect a good show price.

Chet...    

Tks, 

This is all good info so that someday I might be able to undo some of the things that have changed over the past 80 years.