Projects 1948 Plymouth Coupe Custom build

Thanksgiving morning I purchased a '48 Plymouth club coupe. It is an older restoration, all stock except '50 Pontiac tail lights and dual exhaust. I will post my progress here, this first post will get caught up to where I am currently.

I have 2 young sons, 5 and 1, so my goal is to have this car reliable and (reasonably) safe to take the family on cruises and to car shows so that they can grow up with good memories and productive hobbies, even if the rest of the world is on fire.

Car runs and drives fairly well, but needs some electrical work, a thermostat and most maintenance to be done. Horns were disconnected, and sound when connected. Relay is dangling with one wire broken off where it goes into the bottom of steering box.
Once I got it all hooked up, horns gave a few half hearted 'toots' then sputtered and stopped.

Heater, radio and clock don't work.

Brake light was replaced with an LED one, but never wired up. It is 12V unit, it seems the company that makes them are out of business. I installed the sedan bezel and light that came in my box of parts to find that 1. It fits terribly 2. Brake light switch is bad. I found an adequate Coupe bezel on Craigslist out of state, and a good friend of mine picked it up and shipped it to me.
I haven't installed the switch yet, but will do it very soon, when I flush out the muddy river water that is serving as brake fluid.
I have gathered some wiring diagrams and bakelite terminal blocks, and will be organizing the underdash wires and getting the brake lights run through the blinker switch-making my taillights also serve as stop lights.

While I like the look of the pontiac lights, they don't leave room for the stock style reverse light. I will have to see if car is wired for one, but I would like to have something to indicate to others I am moving backwards...maybe a beeper!:lol:
Any ideas of how to add a nice looking revers light?

The Mopar style wire wheels with shorter radials are very nice but car also came with a set of original wheels with good radial white walls that I actually like the looks of better. I will run the aftermarket 'Lancer' style caps that came with the car.

My box of parts also included a piece of trim to shave the hood ornament with (bolt on replacement). I guess it is a 'JC Whitney' type piece. Unfortunately it doesn't fit very well, and paint under hood ornament was never buffed and looks bad.
I have been trying to decide if I like the fronts of these cars shaved and decked or not.

The package shelf behind the rear seat had been covered in black vinyl when the car was restored in the mid-late '90s. Rear window gasket looks to have been replaced at the same time, but had split at the bottom middle where it had been bonded together, and leaked. This ruined the cardboard under the vinyl.

I took it to work and was able to whip up a fresh cardboard card for it, plush it up with some sheet packing foam, and get the vinyl wrapped back around it. It seems that one of the layers was possibly the original cover, it was a light colored, woven fabric with a soft fuzzy feel to one side. I left it out, due to how deteriorated it was.

Got it installed when I got home, and filled the gap in the rear gasket filled with some black RTV.
Went and picked up the spare engine/trans that came with the car. Unfortunately, no overdrive other major goodies, but has a clean carb on it, all the oil filter tubing and bracket I was missing, and a very clean fuel pump. Cylinder head is cast in 1952, #1405849-10 but engine number is p15 798272, scratched into the pad. It doesn't look like the number stamping on the other engine. Engine is painted silver, but in the grime under the valve covers the block is blue, oil pan is black. After a little investigation and a chisel to the number pad, the tinfoil And Bondo came off to reveal a different number-p24*i6364i*
A 1953 Plymouth engine. Should have stronger camshaft and 7.1 Cr head. A good core for my future 230+" build.

While trying to fit a thermostat, I started down the " this needs fixing too" rabbit hole, finding the generator slide bracket cracked, the belt frayed, the water pump nearly
seized, the lower generator mount missing a bolt ( no wonder it was wobbly), may as well get fresh radiator hoses, gee that radiator has some cracks....
Most of the bits are now bead blasted clean and repainted, waiting to be installed, But...

So, with coolant out, I should just pull the head to have it milled for compression, right? It would be nice to have the T-stat pad milled clean as well...what do y'all think?
Risk taking apart a running engine?

I am planning on pulling the oil pan and valve covers to dump out the sludge before installing my new old stock Purolator oil filter and switching over to detergent oil.

Oh and late January I have a dual carb intake set-up coming, from one Mr.Asche.

To be continued.

 

These are nice old cars. I have had two the first a 48 Business Coupe and the last one a 48 Club Coupe. Had a 383/727 in the Business Coupe but a built 57 model 230 and 53 model R10 OD in the Club Coupe. The Plymouths were far ahead of the Fords and Chevys of the day with independent front suspension and better braking.

On the Club Coupe I did a stock rebuild of the front suspension and added a Rusty Hope disc brake kit. With the hot rod 230 and OD it would cruise at 75 all day long. Made multiple 800+ mile round trips in the car from Dallas to Joplin for the HAMB Drags and to visit family in SW Missouri. Wish I still had it.

 

Nice looking car. I've had mine for a half century now. Back then, parts were easier to find.

 

Look forward to the build. Always loved the 48 coupes.

 

Nice car.

 

Nice car. A '48 Club Coupe is on my wish list. I really like the dash/interior in them. JMHO, but I prefer the stock Plymouth taillights.

 

I like it. I have one that's similar.

 

Nice looking car. Try p15-d24.com for more info. I’ve got a 48 business coupe that maybe i’ll get finished some day.

 

It can be wired to give you 3 brake lights. The front chrome looks good stock. Shaved looks bad IMHO. I did see one that they had replaced the wide pieces with the thin ones, looked like an improvement.

 

Thanks for the kind words guys.

Struggling to find a suitable thermostat-
Rock auto sent me a standard one, it fits but blocks off the external bypass.
O'Reilly's got me one, but it was missing the "0" ring that seals the thermostat to the inside of the housing, so they got me another one, then another. A total of 9 without the inner seal that it must have for bypass to work.
I took T-stat housing off car, found that also the brass adapter doesn't for up into it like it should, but one of the ones they send in did. Unfortunately I returned them all, figured I would get everything from someone else.
Napa 155 works according to the P15 forum. Got one. Has seal. Brass doesn't fit.
Got one on order from AutoZone, we will see today.
If I can't find another brass part to fit, should I Dremel open the housing?

 

Great looking Plymouth. Always liked those body styles. Kinda ahead of their time in relation to the Fords and Chevies (JMHO) of that time period. Looks like a lot of fun for you and the boys going forward. Good luck.............Don.

 

Independent front suspension, parallel leaves in the rear and the canted B pillar and grill looks way better than the competition, but no V8.

 

Sorry I can’t help you with that the HEMI in my car uses a chevy thermostat

 

..........Always loved that grille and canted B pillar. Yes, sadly, no V-8, but those old Flat sixes though down on power, were some true workhorses that seemed almost indestructable. Thankfully, there is/was some great dress-up and speed equipment to make 'em some cool little engines.

 

Growing up the next door neighbor had one for 20 + years. He drove that to work when everyone else was rockin 60’s muscle cars. The car was his calling card of sorts, and I am sure his girls now have fond memories of riding around in it although at the time we’re probably embarrassed by it. If I had room and $ for one I would choose it as my tail dragger custom.

 

Thanks for all the responses guys.
Made some progress this weekend. Still no thermostat that fits. Bought a NOS Napa one.
Also have a 4 core aluminum radiator on the way. I put everything together so I could get antifreeze in the block so it wouldn't bust during this cold spell. I will just run it as is till I can get some other stuff caught up.
While I had everything apart, I took the time to clean and scrape off a lot of the scruffy red paint and repaint it with the stock silver. Looks a lot better. When I have to oil pan off I will do the same to the underside.

Waiting on my fuel pump rebuild kit, and now that I moved the coil, I have no spark. Coil is dented and ancient, plug wires are ratty old lacquered cloth, and distributor cap looked like the rotor has been grinding the hell out of it.
Grabbed the distributor from my spare engine, a '53 unit, IAT-4101. I found a NOS Dyna-Flite dual point conversion kit and a pair of NOS autolite points for it, and have them on the way. I still need to figure out what coil will perform best.
I know most of y'all wouldn't mess with points, but if I wanted electronics, I would drive a new car.

I also made 'conceptual' progress- I came across a early '50s custom that gave me a lot of ideas for how I want the car to turn out: the Bob Alexander coupe.
I am not planning on the front end mods, just the shaved handles, deck lid and modified trim. May fill and peak the hood down the road.

 

Don't know if you are aware of this place. Lots of parts for old Mopars. A thermostat is listed for your car.https://www.oldmoparts.com/search/?...UeOahGowFf7nz0MCivOJ0h0Xi_UFiEwQaAjH_EALw_wcB

 

I have seen that suppler. The thermostat they have is the OG bypass type, with no given temp rating. Likely 160*. Obviously better then nothing ( what I currently have) but I am wanting a 180*. The NAPA 155 is basically a brass adapter, a modern thermostat, and a wide, square O Ring. I have seen pictures of ones fitting fine, but suppler must have changed in recent years. I am hoping to track down the # for the modern thermostat and o ring so in the future I don't have to go through this and also so I can try a 195* stat.

 

If your looking for flathead parts or most things drivetrain related for your 48 Plymouth, www.vintagepowerwagons.com will be your friends. They are one of the biggest reproduction or oem parts companies dealing with any thing late 30s - late 50s Dodge/ Plymouth replacement pars. They specialize in vintage Power Wagons and military truck parts, but have a lot of stuff that will fit your Plymouth. Those military guys are pretty stickler or oem replacement parts, especially motor and drivetrain stuff.

The next option is www.robertsmotorparts.com. They also have a lot of stuff reproduced. I don't think they are as active as they used to be, but still a good option. Gene

 

Got my dual point conversion kit, found it is missing some small pieces. Got the old grease cleaned out of it and the distributor it will go in pretty well cleaned up, but have a bad vacuum advance, so off it goes to Terril machine to be rebuilt.
Since that will take at least a couple months, and I am still hunting a couple small components to install the kit I figured I would pull the distributor out of my car, clean it, and fix whatever was causing the rotor to hit the cap.

Turns out it is a different model than either of my other distributors, and was in total shambles. Vac canister totally blown out, advance plate locked up. Weights sticky and covered with rust. Points covered in carbon. Connecting wires inside wrapped in tattered electrical tape.

I managed to save the points and condenser, and one cap clamp. Everything else went in the parts bin. What I had been calling my parts distributor I cleaned up, fit the salvaged cap clamp it it, and reassembled. It takes a different cap than what I have, so I will pick up a cap tomorrow and get it back in the car. Hopefully that and a new ignition coil will get my spark back. Should drive a little nicer with a functional advance and one less vacuum leak.

 

I'm glad to see your still in the works. I have always liked your ideas on building your Plymouth Looks good

 

Thanks, I haven’t forgotten about the ole Plymouth but life keeps getting in the way.

 

https://www.jalopyjournal.com/forum/threads/fuel-pump-rebuild-help.1253155/#post-14347342

Got fuel pump rebuilt. Pumping it by hand it moves MUCH more air than an old pump does.l, and if plugged, holds the pressure.
Hopefully will install today and have the car running again!

 

Friday got fuel pump on, thermostat installed, (oh yeah, '90s Napa 155 fit fine) and plug wires run.
Wouldn't catch, even with fuel pump primed, gas poured in float bowl, and starter fluid.
It was about dark, so called it a night. Once inside I had the thought to check my factory manual. Sure enough the diagram I had pulled up online for the firing order showed the distributor turning counter-clockwise, but I had watched it turn clockwise. DOH!
Saturday morning swapped wires around and it fired right up. Until the carb ran dry. Damn.
Ran a milk jug of gas just below the fuel pump and it ran fine. Oh no, the fuel tank must be full of trash and plugged up!
About to give up and go buy a car cover, I figured I would say least LOOK in the tank. Pulled the fuel level sending unit. New.
About 1" of gas in the tank. Well gauge read 3/4 and PO said it was right, but I could see the pickup. Above the fuel. DOH.
Got gas in it, warmed it up ( MUCH faster now it has a thermostat!) and dumped the crude oil it was using as lubricant, and gave it some fresh 10w30.
Tried to set the timing but found it has no timing pointer.
It drives so much better already.
Next weekend I am hoping to get it up on a lift and replace all the other fluids, and plan on pulling the oil pan and adjusting the valves. I will knock the dents out of the pan and wipe it out as well.
Then onto getting wipers and heater 100%.

 

Whatever you do DON"T change to detergent oil. The chances of a leaker and burner aren't worth it

 

Got out to the shed yesterday, got heater switch, defrost switch, wiper motor and linkage pulled to clean up and refurbish. Switches had no wiring to them, so unsure how they hookup. Defrost is more of a mystery- what is electrical that it can control, vs the fan switch?

Wiper will be cleaned and checked, likely rebuilt. I am thinking that while I am working under the dash I am going to install a vacuum reservoir for the wipers, at least until I get my dual action pump rebuilt. Think the little plastic pill shaped can will be adequate?

Did I mention how awesome my neighbor is? They are letting me park the car in their shed/garage (dirt floor garage from the early 1900s) all winter for free.

 

Went to take the coupe to my friends place to put it up on a lift. First time I got up to 60- ding, cling, bing, click, ding, like a bell getting kicked all over the engine bay, then quiet... Looked in rear view to see a plume of smoke so I hit the side of the road, expecting some bad shit.

Got the good open, water dripping from everything. Not water, coolant. Especially the starter. Right above it, a round rusty hole in the side of the block. It had ejected a core plug!

After a quick round of swearing, and a brief explanation to my wife, who I had following me, and have had an idea- expanding core plug. Like the ones I have never understood why anyone would use. Off to the store and sure enough they saved the day!

I guess between the new T-stat and new, higher efficiency water pump, the block saw more pressure than it had in years. Question now is - how do I trust the rest of the plugs?
I am going to do a compression test tomorrow, and make a determination.
I have a spare engine. If I have poor compression, maybe I will see if I can do a quick re-ring and freshen up that instead of installing new core plugs on the engine in the car.
I do not want this car to go full project, but want it daily driver reliable. Thoughts?

I did make it to the shop, and got a number of maintenance things done, and am heading over there now to finish up.

 

Luckily the core plug was easy to get to. Usually they hide 'em behind exhaust manifolds, bracketry or some other 5 things you have to remove to replace!

 

Are you aware of the cooling tube in these engines? Goes in thru the front and runs to the back of the block. They tend to fill up with crud in the rear over time. Several threads here.https://p15-d24.com/topic/35349-cooling-systemrevisited/

 

Yes, when I had the water pump off I looked at it, seems to be a stainless one, didn't look bad, from what I could see. When the core plug was out I stuck my finger in there and there was only 3/8" of crud at the bottom of the jacket. I suspect this engine was rebuilt when car was restored in mid '90s.
I have a radiator to swap in once I have more important stuff caught up. I will consider pulling the water pump back off and pulling the tube out at that time. If engine seems to be in good health I will replace the expanding core plug, and maybe the others. I will flush the block when I do.
When there is coolant in the engine it runs at a good temp- about 175 by the gauge, with a 180* thermostat.

P15 forum said to check that I don't have a modern replacement radiator cap- original was low/no pressure.