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Messages - chetbrz

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General Discussion / For What it’s worth… RT-08 Brass Bowl Carb
« on: July 10, 2008, 10:33:08 PM »

I spent some time on the phone today with John from “The Carburetor Shop” in ELDON, MISSOURI.  We mostly talked about the Carter Bras Bowl Carburetor RT-08 found on the 29/30-U Plymouths.

Some information from a person who seemed to be extremely knowledgeable about our carburetors.

  • First of all they have original RT-08s fully restored to show quality and in stock for sale and I was told that they are extremely expensive $5,000.00 each.  The reason basically is that the carburetor and its pot metal construction just didn’t survive well after 79 plus years.
  • It is highly unlikely to disassemble these carburetors without breaking the internal components or at least most of the internal jets & parts.
  • Parts are available but pricey.  Idle & high-speed jets are in the $350.00 range per each, $50 dollars for the rebuild kit which doesn’t contain the jets.
  • External acceleration pump may be purchased for $1,500.00 and I was told out of 100 carburetor bodies you are lucky to find two in restorable condition.  He said that the acceleration pump didn’t provide too much benefit anyway and a lot of people use the carburetor without it. 

The gentlemen I spoke with was not trying to sell me anything.   He was nice enough to pass on some information so that I could decide what I would like to do with the two I have in various states of disassembly.   Both of which are floating around in my parts washer for the last 6 months.   Basically he said that this wouldn’t help much because the pot metal expands over time making it impossible to dissemble these without damaging the internal parts or the castings.   This might be a good thing to know before you mess around with your RT-08.

Of course this carburetor was used on other makes at the time like Chevy.  He prefaced the following statement by saying he loves Carter Carburetors.   But in his opinion the RT-08 was the worst carburetor Carter ever made.   He mentioned that a number of people use other carburetors like a Zenith or Tillotson. When they go to a car show after they park they will then remove their driving carb and put on a non-function highly polished Brass Bowl RT-08 just for show.

Don’t shoot the messenger.  I am just reporting on my conversation with someone that is much more knowledgeable then I am on this subject.

28-Q   RJH-08
29-U   RT-08
30-U   RT-08
31-PA   DRT-08
32-PB   BB-Updraft

I hope this info helps and if not any comments would be appreciated.

I am a firm believer in the theory that if it works leave it alone.  So if your RT-08 is working then based on the above I think that you have a very expensive and rare commodity.


General Discussion / 1927 Chrysler owner in Germany
« on: July 10, 2008, 03:31:45 PM »
A colleague of mine from Germany was here at our Virginia office this week.  He is also the proud owner of the 1927 M50 pictured below. Werner Lorenz has owned this 1927 Chrysler for approximately 20 years.   He bought the car in South Africa while on business in Johannesburg.   He states that this kind of car is very scarce in Europe and it is almost impossible to find parts for it.  Even in the States you have to be lucky to find parts. We exchanged some supplier info and spent a lot of time talking vintage WPC stuff.  Hopefully we might be able to get together again this year at Hershey in October.

Yesterday I drove my 29 to work and was able to give Werner a ride in another great WPC car built in the same era.   I believe the 1927 M50 uses the same Maxwell Engine that is in the 1928-Q Plymouth.  The only problem being is that the 27 only had hydraulic brakes fitted in the rear.  Werner was impressed with how responsively my old Plymouth stopped when needed. 

Werner drives his car frequently so if you are in Munich and see this 27 cruise by I would suspect with much certainty that it is Werner out for a casual drive.


Info from the WPC Museum Web Site:

1927 M 50

Engine: Year: Carline: Maxwell / Chrysler / Plymouth 4-cylinder 1927 Chrysler 50 Compression ratio raised to 4.1:1 and output was 35 bhp @ 2200. L-head, 3 main bearings Bore/Bire Range: 3.63 in. Stroke: 4.13 - 4.50 in. BHP Range: 34-38 Cylinder Block: cast iron, deep skirt Fuel System: updraft carburetor Displacement: 170 cu. in.

1929 Plymouth U Motor

Engine: Year: Carline: Plymouth 4-cylinder 1929 Plymouth U L-head, 3 main bearings Bore/Bire Range: 3.63 in. Stroke: 4.25 - 4.75 in. BHP Range: 45-65 Cylinder Block: cast iron, deep skirt Fuel System: updraft carburetor Displacement: 175 cu. in.


    Something I just noticed in the photos on Chet's website, the oil pickup filter is totally different from mine.  Mine is a simple stainless steel open-top, perforated cylinder attached to the drain plug which seems to be magnatized.

    I also noted that my brake master cylinder is different, and matched the drawings in my owners manual.  They must have changed the design in '29.  The inlet port on top is not set in at an angle, it enters at a perfect 90 degrees as do the other two fittings, the outlet port and the pressure switch.


Yes.., the earlier 28’s had the Master cylinder you described. 

Also the motors were different from the 28-Q to the 29-U.

1928 - Maxwell Engine 170.3 Cubic In. 

1929 - 175.4 Cubic In.  Plymouth U,  This block is basically the same through the 196.1 ci engine offered in 1930-1932.  Mostly Bore & stroke differences only.  Some new holes added with the fitting of the water pump for the 30-U )



I am going to try plugging off the port that is leaking, but I have a feeling that it will then just pour out somewhere else.


Carter brass bowl carburetors were also used on Chevy’s of the same period.  I was surprised to run across them at a Chevy dealer’s concession at Hershey last year.

I believe that John also mentioned that Modal ‘A’ ford carburetors will also work.

See link to Mikes-A-Ford-able..

Your Carb looks like a Marval:

Anyway, Mike’s has a lot of parts, might find something for your float valve problem.

If you can’t find what you need to get going then try other Ford sources.  If you call or email them they might have a rebuild kit for you present carb. 

I hope this helps…  Chet…


Just an FYI…  The gasket sets for the 175 & 196 ci engines are available.  I believe Gasket City in Canada sells them as well as other venders.

It sounds like you are making good progress with your classic.  As far as the gas pedal goes it is basically a ‘U’ shaped rod that is attached to the fire wall.  I am traveling over the 4th of July weekend but when I get back I will try to take some pictures.  With some measurements you could probably fabricate something if you could find some quarter round steel stock. 

Good luck with the carburetor.



 there is an oil galley plug just above the oil relief valve.  If you draw an imaginary line from that plug straight back to the rear of the engine bock, the oil gage port is located there - at least it is on my engine.    John

Thanks John,   

When I get a chance I will check this out and see if I have the plug.  It would be interesting to check the oil pressure after the valve. 

Interesting hydraulic oil reservoir.  This is the first time I have seen this.  The only other one’s I have seen are the tin can type and the early Chrysler one’s.

Happy 4th.    Chet…

General Discussion / Re: Does anyone know....
« on: June 30, 2008, 02:41:20 PM »
If no one from this forum responds, then try the Plymouth Owners Club Forum.  You don't have to be a member of the POC to join the board.

See link below.

Good Luck,  Chet…

General Discussion / Re: Hand Cranking your Old Car.
« on: June 27, 2008, 03:30:32 AM »

Be careful.., it’s too early in the driving season for any casualties.  Try it with a hot engine first.  It should be easier to start.

Good luck…  Chet...

General Discussion / How Sweet it is... :)
« on: June 25, 2008, 02:54:47 AM »

I drove the 29 to work today, just a couple of miles.  After the oil pressure odyssey I decided to take the old girl out for a spin after work.  I drove a good 35 miles and on the home stretch I pushed her up to 50 mph on the car’s speedometer.  I sustained that speed with throttle to spare for a good 2 or 3 minutes.  Oil pressure was rock solid at 45 psi which in reality is 40 psi.  The engine remained nice and quiet with no bearing nock.  At idle she maintained 20 psi which was telling me that the pressure relief valve was closed and all that wonderful oil flow was going to my engine components.

When I got home I parked her under the shade tree in the front yard and snapped a picture.

What a great day after a very scary time.  I have to admit that Walter P. picked a very hearty engine for his Plymouth line.  After driving a good 40 miles round trip to the car show on Father’s Day with minimum oil going to my engine components and a ton of bearing nock the old girl bounced back in good stride.   It just goes to show you what a great car old Walter P. built in 1929.  As an aside the wife followed me back to our rented garage and reported that I was no longer blowing smoke out of the tail pipe.

How Sweet it is,  Chet…

General Discussion / What I have learned from all of this...
« on: June 24, 2008, 03:34:44 PM »
What I have learned from this adventure...

The pressure relief valve is nothing more then a plug held in place by a spring.  When oil pressure is applied to the plug it will push in depending on the tension of the spring.  When the plug is pushed in.., an outlet to the engine’s oil sump is exposed and excess oil pressure is drained off into the crankcase.

Theoretically the spring is designed for a defined tension and the adjustment is available for a minor compensation.  I believe when you get into the later 6 cylinder flatheads I was told that the valve wasn’t adjustable although three different spring weights were available.  The springs were color coded

My Observations:

  • The valve is least effective at low rpm which produces minimum oil pressure.  If you wish to increase your low idle oil pressure the relief valve will have little to no affect.
  • The relief valve is designed to drain off excess pressure and is most affective at high rpm when your pump is providing maximum oil pressure to the engine.

From discussing this subject with others who own 28 to 30U Plymouths.  I have founded out that in the earlier modal cars the oil pressure gauge is connected between the oil pump and the pressure relief valve.  On the later modals it is connected to the engine oil path after the pressure relief valve.  In my opinion the later connection between the valve and the engine path is the better of the two designs. 

My suggestions before you do anything.

  • Determine what your problem is before you compensate with an adjustment.  The adjustment may provide a better reading on your gauge but basically may not help your oil problem or provide better oil flow.
  • For high-pressure problems the most likely cause is clogged or restricted engine oil paths.  For low-pressure oil issues you may have leaky bearing caps which are allowing the oil pressure to bleed off or possibly a worn out oil pump.

A good rule of thumb that I have always used in my professional life as well as with my hobbies is “If it ain’t broke…, don’t fix it.  My oil pressure odyssey was started because of excessive and escalating bearing knock and not the gauge readings.   Sorry I don’t mean to lecture just pointing out that this is an area that should be very rarely played with.

What I have learned and been told by others during the course of my trouble shooting.

  • Pressure between the pump and the valve should be no more then 45 psi at high rpm.
  • Pressure in the engine path should not be higher then 40 psi and could be as low as 28-30 at high rpm.
  • Since the low pressure reading isn’t affected by the valve I have been told that pressure as low as 10 psi with a hot engine at low idle was acceptable and presented no problems.
  • Don’t trust your old gauge.  After 70+ years of service it stands to reason that it wouldn’t be dead accurate.  Hook up a new modern high quality auto gauge to evaluate your actual pressure readings.

Adjust for maximum pressure at high rpm.  Whether the oil is cold or warm the Maximum pressure should not exceed 45 psi before the valve and 40 psi after the valve.  Probably checking the adjustment with a warm engine might be best but shouldn’t matter, pressure is pressure at any temperature.  Turing the screw in will increase the pressure reading and turning the screw out will decrease the reading.  Feeling little resistance against the screw is normal and not a problem.

My thanks to everyone who provided information and discussion points to this topic both from this site, through email, and from the POC forum. 


Thanks John for the information, that was very helpful,

The point I was trying to make previously is that when faced with oil pressure problems adjusting the pressure relief valve is not the correct answer or wasn’t in my case.

The problem I was having was that my oil pressure was too high and by lowering the pressure without resolving the reason for the high oil pressure, especially in the 28Q & 29U which measure oil pressure before the valve, is a major mistake.   

As discovered over the weekend the oil path in my engine was gummed up and restricting the flow of oil to the bearing caps.  This was the reason for the high-pressure reading between the pump and the valve.  With the restricted oil flow going to the bearings all the pressure was applied against the only other path.., the pressure relief valve.   By lowering the pressure to minimum I still couldn’t get the operating pressure range correct.  (Never could get the pressure below 35-40 psi at slow idle) But by adjusting the pressure down I was in effect starving the bearings of what little oil they were getting.

Over the weekend I cleaned out the oil path as best I could with out removing the main bearing caps.  Through the use of high-pressure oil & air flow I was able to restore good flow through the engine.  I am still not 100% sure that all restriction has been removed.   After washing out the clog I was able to adjust my pressure relief valve quite a bit in from the minimum pressure setting I had prior.  (which is screwed out to the point that one more half turn and the Carter pin would no longer fit into the pin hole)

After some experimentation I was able to read 45 maximum psi (with a modern gauge) between the pump and the pressure relief valve both at medium and high rpm.  The pressure relief valve is now set at a more reasonable mechanical position and is neither at Max or Min but someplace in the middle.  The old gauge in the car reads 50 psi to the modern gauge’s reading of 45 psi. 

Current operating conditions using the old gauge, which reads 5 psi high on the high end of the scale:

Straight 30 weight oil

Cold engine slow idle:   35 psi
Cold engine high rpm:   50 psi  ( gauge no longer maxs out )

Hot engine slow idle:   25 psi
Hot engine high rpm   45 psi  ( gauge no longer maxs out )

The probable reality is 30 to 45 cold and 20 to 40 hot.  My engine bearings have quieted down so I think my problem is now finally fixed. 

Some corrections to previous statements.

I guess never say never but before you fool with pressure relief valve settings truly understand what is causing your oil pressure problem.  I believe the setting very rarely changes for no reason.

After further experimentation and observation the vacuum side of the fuel pump presents little affect on the oil pumps ability to provide adequate oil pressure.   My initial theory concerning plugging off the vacuum side of the pump was inaccurate. 


When you have a chance could you provide a picture of where your oil gauge line is attached to your engine.  Hopefully there is a plug in mine that will allow me to measure pressure after the pressure relief valve.

Tks,  Chet...

General Discussion / Father's Day in Virginia...
« on: June 20, 2008, 01:48:01 AM »

This is a continuation of my Post “Any Thoughts”

Cleaning and adjusting the pressure relief valve on the 1929-U was both good & bad.  It was good to clean it but very bad to adjust it and here is why.  (Use the crude diagram below for reference)

The line, which feeds the oil gauge, is between the pump output and the pressure relief valve.  Because of this the pressure relief valve only affects the pressure of the oil going to the motor parts. The gauge reading is only affected by the valve adjustment when the valve is opened to much thus causing a dangerous drop in oil pressure to the motor parts.  My assumption is that this is the reason the Plymouth Instruction Book states “…never to adjust this device…”.  The adjustment will have little affect on the gauge reading unless you completely deplete the amount of oil going to the engine bearings. 

The single eccentric in the oil pump is used to move both oil in the engine and air flow from the vacuum fuel pump.  Because of this, the total pressure out is equal to the sum of both inputs and the viscosity of the fluid.  Since the pump mixes air with the oil…, if the vacuum line is plugged up then no air is introduced to the pump and thus the pump will develop an additional 10 to 15 psi of oil pressure. (reason – air will compress at a much higher rate then oil)    Example:  Take the air out of your brake lines and they work much better.

This is exactly what the problem was with my car.   When I brought the car home it had no vacuum fuel pump and I still have not hooked it up yet.  The point being is that someone plugged the line.   Of course the last owner didn’t have the problem because he had a leaky oil pump cover gasket that introduced the needed airflow.  My problem presented itself after I replaced the leaky oil cover gasket. 

After cleaning and adjusting my pressure relief valve to minimum pressure my gauge was affected by maintaining 35 psi at idle and 50 psi at run.  Good.., absolutely not.  That meant that my engine was not getting the correct pressure at low rpm and probably at high also.   My engine starts to knock when I get into the 40 to 45 mph range and while driving it to the car show on Sunday it was starting to knock between 35 to 40.  I finally discover the above problem after the show.  I drove a total of 35 miles to and fro and most likely took some life out of my bearings.   

I intend to get everything adjusted back to spec before I run the car again.  Hopefully I didn’t do too much damage.  I am glad that the engine pressure stayed pretty close to the same otherwise I probably would have driven the car until I sized it up thinking that I fixed the problem.

The Plymouth manual is correct: 



General Discussion / Re: Hot Days here in Virginia
« on: June 12, 2008, 01:20:35 PM »

I bought it from Steel Rubber.

Seal set, windshield, rubber only, for crank-up windshields. 3 piece set for bottom and sides. Lower strip fits dovetail groove in cowl. Usually for Fisher bodied WPC cars.

70-0016-52.....$ 89.20/set

If you want I can take a picture.  The pieces fit like a glove.  I just had to trim the lengths.  A little pricey but good quality.


General Discussion / Re: Hot Days here in Virginia
« on: June 11, 2008, 04:49:24 AM »

They don't send anything back to you.  When you drive into the park they will ask you if you are pre-registered.  They will have everything waiting for you when you arrive.   I have the 29 in the back porch again while I work on her.  The heat is unbearable in that I get sun in the back from about 1:00 PM on.   I am about a day behind but should catch up a bit with cooler weather.

Since Friday I have completed so far:

- Installed original radiator
- Installed the head, plugs, distributor cap.
- Installed the gas tank
- Installed a new front windshield gasket with tracks.  It now opens & closes real nice.
- Installed new glass on the passenger side door.  Remade the rotted wood pieces and installed new window tracks.

Left to go:   (4 days and counting)

- Button up the cooling system
- Installed the hydraulic rear axel ‘T’ & original reservoir
- Installed the vacuum fuel pump. (with power assist)
- Install the floor covering & pedal trims
- Bring the car to the muffler shop and have a rear tail pipe fabricated.

I think that should do it for now…


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