Projects 1948 Plymouth Coupe Custom build

Don't know that I'd call 3/8" of crud "only 3/8"... I think I would figure out a way to REALLY flush that system, with both a pressure washer and a chemical flush. JMHO

 

I have seen pictures of these engines where the crud is higher than the core plugs: 3 to 4" or more.
Anyway, I will clean out the block when I replace the plugs.
Didn't do the compression test today, I got caught up burning my hands, I mean, adjusting the valves, and trying to diagnose a VERY hard to turn rear wheel. Maybe sticking brakes, maybe bad wheel bearing. Didn't get the drum to pop off the hub, so couldn't really make a determination..
Got a lot of fittings greased, fresh oil in the diff and trans. Figured out why the trans only had 1/2 a pint of oil- it leaks like a sive, from front and rear seals. Somehow the shift linkage hardly drips. I guess I will go get my spare trans and see what shape it is in, reseal it and swap it in.

I will put my vacuum wiper motor back together Monday, and NOS heater switch is on the way.

 

The old style axles are a pain.

 

Got a moderate amount done this month, even drove it to work every day last week.
Got rear axle bearing moving free without pulling the axle. Maybe next winter I will rebuild the whole rear end, especially if I can find some 3.55 or 3.73 gears.
Wiper motor leaked vacuum, it is on the way to the Trico wiper guy.
Got brake lights working.
Ordered Brockmans mellowtone steel packs and some pencil tips, have an appointment march 7 to have them installed.
Installed a pair of Aerostar springs, with one coil cut. Found out my shocks were now two piece...got new ones ordered.
Oh, and " Precision Springs" are made in USA # SP08160
Found a pair of the GIANT DeSoto drums for the front. Going to get them all cleaned up and rebuilt.
Got a good deal on the cluster and second gear to rebuild my spare trans with "fast second" 1.55 1940 ratio, vs 1.83 1941-56
Going to send the trans guts and my wheel bearings to New England Gear polishing to be REM polished. Supposed to really slick up the shifts, as well as reduce power lost to the drivetrain. We will see.

 

Nice progress... looking good!

 

Got my mellowtones installed, really pleased with the sound and the look of the pencil tips.
On the drive to work this morning I found that it now surges above 50mph, getting worse if I speed up or go uphill. Not sure if my month old fuel filter has plugged up, or if the switch from turbo mufflers to the steel packs has made it run lean up top.
Meanwhile, been getting my DeSoto brakes cleaned up and ready to go to CH Topping for shoes to be relined/arched and drums turned.
Picked up a nice WA-1 414s carb to try, should be a bolt on swap, I will see if it runs better than the stock carb.

 

The 414s, if properly adjusted, should be better than the Chrysler-designed original carb; however, a much better solution is the Chevrolet W-1 574s (used by Plymouth for a limited time in 1947 when the Ball & Ball plant was on strike).

The problem with using the 574s is that it is SO much more efficient than the Chrysler-designed carb, it is a size 2 rather than a size 3. Plymouth solved the issue in 1947 by recasting the 1938 intake (size 2) with a different part number. The carb could be installed using an adapter, but I really personally don't like adapters when other methods are available.

Strike car owners reported an increase of several MPH top speed, plus a fuel economy increase of better than 25 percent over the non-strike cars.

https://www.thecarburetorshop.com/Carter_574_Plymouth.pdf

Jon

 

Been working on a number of things, trying to take this month to wrap up some of the things I have apart waiting for this or that.
My dual point distributor and WA-1 are both apart, clean, repainted, and awaiting some hardware nitpicking.
My DeSoto drums have been blasted, magnufluxed, repainted, and REM polished bearing races installed, waiting to go to CH Topping to be turned and drilled, but first I have to get my shoes free of the backing plates, so that they can ride along.
I plan on drilling the outside rib of the backing plate while the shoes and drums are being serviced, I can fit roughly 75 .250 holes around each. I have half a mind to send them off to be plated, but think they are too pitted to get a good polish on without major sanding. Not sure when chrome brakes started being a thing.

In the meantime, I got the wild hair to tear out my upholstery and fix several things that were bothering me, although stopped short of having the seats and headliner redone.
I started by adding sound deadening mat (Silus brand 50mil) inside the doors, then inside the body by rear seat area. Then I got a box of 80mil and did the floor, rear wheel wells and some of the trunk floor. I still have one tile, that I plan on sneaking up under the headliner. I then added a layer of "reflectix" insulation to the floor, and a layer of foam carpet pad before laying down new carpet. I also installed new rubber draft seals around the pedals.

I got the rear area back together today, adding heavy plastic between the body and the upholstery card, something that hadn't been done before, causing the door cards to get moisture damage. I also added a layer of the carpet pad to the inside of the upholstery card, and behind the rear seat back, to hopefully absorb some more sound. It isn't much, but I had a whole roll of it in my attic, so may as well use it.
If the weather holds out this weekend, I will get the door panels and kick panels in, and be ready to pull back the headliner to put the deadening in, few layers of the reflectix for heat, and get the sun visors installed.

On the test drive around the neighborhood, I noticed it was running fairly hot, but without any signs of boiling, so I need to check the accuracy of the gauge (some aftermarket one, cut into the stock dash) but it may be time for me to flush my block and install the new radiator I bought several months ago.

Lots to do still, but starting to come together.

 

You don't have to worry about putting on a rad cap with a higher pressure. The rad is vented to the atmosphere.

 

It is the whole radiator that is the problem- half plugged up and leaking cracks all around the tank.
Water pump and t-stat are new. Fan is unshrouded, may make something simple down the line if it has problems in traffic after radiator swap.

 

Got most of the interior back together, need to make a new door card for driver side. PO must have noticed that the bottom of it was going bad, so instead of adding a plastic weather barrier to to the door, he just cut the bottom of the door card off and used paint stir sticks to tack a new bottom on.

Working still on prying the spindles/brakes/backing plates apart. Going to take my drums to be turned today, and hope to get shoes sent out next week.
I was going to use CH Topping for brake work, but found that Porterfield lines and arcs shoes for not much more. I am going to try thier RD-4 "vintage road racing" compound. In doing this, I am not going to have the drums cross drilled like I had planned, but just stick to the more conventional backing plate drilling

 

You go man , go .

 

Killer coupe. I thought I had seen all the old p15 customs but that Bob Alexander coupe is slick!

 

Instead of doing much productive on my car, I drove two states over to snag up a deal on this bw R10G1 overdrive transmission with all the bits and pieces, as well as some extras.

 

I use Kilmat works well.

 

Been a while since I updated proper.
Been driving the car to work around once a week for the last few months.
Slowly getting work done on it. I work a lot, so it is easier for me to refinish or make parts ( on lunch breaks) than it is to have time to install them.

Car was seemingly a little sluggish, so I decided to do a tune up. Clean points, check dwell, bump timing a little.
Instead...


Found that my refreshed distributor had its vacuum can give up, so figured it was easy enough to swap in the '54 IAT I had rebuilt with dual points and a Terrel rebuilt vacuum can.
For some reason I hadn't set the point gap on the bench two months ago, so spent some time getting it set.
As I was swapping my plug wires over to the new cap, I realized what bad shape they were in. Luckily, the set I had pulled off my '54 engine were in pretty good shape.
After a couple cranks, my battery went from full power to totally flat, like a light switch. After blaming the solenoid, starter, switch, I finally realized the battery was to blame. An hour on the charger and it was back to cranking strong. Well for 4-5 starts as I was setting the points. Then back "off" without warning.
I figure a fresh battery is in order.

While I had the hood up, I finally addressed the terrible placement of the throttle return spring. It had been run to the vacuum advance line, and barely had enough tension to pull the throttle closed. I had an original head bolt (from the '54) that has the screw in tab, so, with no regard for the safety of my headgasket, I swapped it in.



Hoping to finish tuning this afternoon.

 

Anyone have any words of wisdom in regards to setting the dwell on a dual point distributor? Other than "don't do it"

It is a "Dynaflyte" aftermarket plate, points are NOS autolite (pn:IGP3028ZS)
When I follow the directions I can get 38* on the set furthest from the lead (matchbook in between the points of the other set)
I can get 38ish with the other set, but it seems that adjustment comes opposite of the norm: more gap equals more dwell.
And together I have 35*. Opening both sets up I can get as high as 41 together but I am having to bend the points out more that I should, and gap is around .030" on each set. Something isn't right.
Are the instructions wrong? It says set farthest from the primary terminal is the opening, timing set, but looking at it, they open and close after the primary side.
What am I missing?


Eta: It looks like the secondary points rubbing block barely touches the cam. They are all the way open in the picture

 

Prop one set of points open with your match book and set the dwell on the other set of points to what ever the individual set of degrees dwell setting for a 6 cylinder with a dual points dist is suppose to be. Then move the match book to prop the other set of points and set the dwell on the first set to the same correct degree setting for a single set in a dual point 6 cylinder dist..

One set opens and closes before the other set, but between the two sets, it increases the dwell time for better spark at higher rpm. That is why you need to set the individual dwell on each set of points then get the combined dwell number for the dual point dist for that 6 cylinder..

 

Thanks.
I suspect that a bulk of the problems I am having is due to bad condensers. The first (NOS Autolite) gave up at the end of the first day. Tested and swapped in a USA one from another distributor, drove around the block, and it gave up in my neighbor's driveway.
The process you describe is what I was trying but the total dwell is LESS than either of the points single. I am still baffled. I got both sets of points to hit the rubbing block evenly. Also Reducing points gap Reduces Dwell. That doesn't seem right. Could it be possible that my dwell meter (1980s craftsman USA made) is reading wrong due to 6v positive ground?

I ended up just setting both points to the specified gap and giving up on the meter, but was stymied by the condensers.
I have swapped my stock unit back in, and will just plug the vacuum coming off the carb for now.

Fortunately, Mopar flatheads use a tab to drive the distributor, so they are very easy to swap distributors on.
However, I do wish both distributors were the same model, so that the distributor cap could remain wired up and in place.

 

A 12 volt negative ground meter won't read a 6 volt positive ground electrical system correctly.

Dwell is the degrees of directional rotation between the time the points open and the time they close. Closing the point gap will reduce the dwell.

If your 6 cylinder dual point dist has 6 cam lobes to open the points, one of those sets of points is suppose to open and close a few degrees before the other set opens and closes. If you somehow managed to get both sets to open and close at the same time, you have defeated the purpose of the dual point dist.

The concept with the off set points was to build more time to create a spark as the rpms increase.

 

Around a month ago I was doing my regular search of Craigslist for old Mopar stuff. I stumbled onto a flathead 6 core "dodge" engine, for way to much money.
But it was only a couple hours from me, and I still had a few minutes of my lunch break to kill.
As I scrolled through the pictures, I realized it also included some pretty expensive new parts, and was actually quite a good deal.
An email and some phone calls, and the owner kindly agreed to hold it for me till I got time to get it.
I picked it up yesterday. It poured rain on the way home, so I didn't get a chance to look it over very well.
It is a grimy Yellow, industrial 251. I am not sure what it is out of, brass tag has the Chrysler pentastar, so must be '60s.
It does not have the pad for full flow oil filtration.
At a glance, the exhaust valves are standard, not sodium filled.
Rear sump oil pan.
Turns smoothly 270* then stops hard, has at least 1 stuck (open) valve, but need to pull the tin off to see what's up. A rebuild is planned, so likely no big deal.


Head is off, and has been milled an unknown amount. Most likely cut to up compression.

Also included was a new Asche supplied cam regrind, marked 380, split exhaust manifolds, and an unused AOK triple carb setup, linkage and carbs all complete, but linkage is set up for a truck.
Anyone know if I can just flip this over and make it work for my passenger car linkage?


I belive the cam is their Isky 3/4 race clone, which is their recommendation for trucks and cruisers that want more power, but don't actually want to deal with the hassle of a big cam.


I am not sure why I thought this was a good idea, but here I am.

Anyone have a link to a good write-up on how to fit the 25" engine in place of the 23" in '48 Plymouth?

Hey Canadians:
What years did y'all get the 25" 218, and what did the compression get up to?
If they kept up with US improvements, a early to mid '50s head should be around 77-84 cc, which would yield almost 9-1 on this 251.
On industrial engines, how did the crank case get vented? PCV?

How does fresh air come in? The oil fill tube had a sealed cap.
Will a 23" oil fill tube swap on?


If i want to run sodium valves, are the larger diameter valve guides available? Or can the old ones be drilled and reamed?
Any reasonable way to convert this block to full flow oil filtration?
My 217 runs well, and I have more pressing things to fix, so I am not going to be in a hurry to swap this in.

 

The 25" engines were on practically everything except for the convertibles and wagons that were imported from South of the border. Been a long time and can't remember that stuff.

 

Kroil, a little plastic deadblow and a pair of channel locks got the valves all going up and mostly down, pistons all move as they should, can make complete rotation now.
This motor is reasonably clean, likely just oil residue, carbon and time making things sticky.
Good enough to tear it down.
Going to get it apart, clean, magnuflux and measure before making a plan with my machine shop.
I will definitely be putting a lot of weight on the suggestions laid out in Tony Smith's engine build tech article.
The 380 cam has 242* of duration, and makes peak power around 4500rpm, so I am going to be giving a good bit of attention to the health and safety of the rods and crank.
Yesterday I got the head cleaned up a little and took some measurements.

Deck is nice and flat.

Chamber is .420" over intake valves, and .408 over exhaust.

Rough Chamber volume was 84cc. Need to drill the hole in my measuring plate bigger. Spark plug I had handy sat a good ways down in the head.

I will work to find a plug that sits more flush.

Piston tops are around .012-.015 below deck.

With current bore size this combo would yield around 7.7-1 compression.

With likely machine work needed ( .040 overbore, pistons .020 above deck) this will yield 8.4-1.



I am surprised, as this is originally a 6.8-1

Industrial head, best I can tell.



I am getting head sandblasted now, going to check it for cracks before doing more work to it.

I belive there is flow to be had at the back and roof of the chamber, as well as in the transfer area. I am thinking about making a shop vac powered flow meter to research this.

 

Well it looks like i need to take the time to fix my gas gauge...

 

For years I ran mine w/o a working gas guage, an Olds 455 & an 11 gallon tank. Eventually went to a 331 hemi & a 16 gallon tank. Never did have a working G.G.

 

Or record the mileage every time you fill it with gas.
I fill it with gas, then write down the mileage reading on the odometer. If you know how big your gas tank is, and you have an idea what your gas mileage is, you can stop and get gas before you reach the miles at which you run out.
If you ran out of gas, it shouldn't be hard to figure out how much gas you can use out of your tank. This may be more accurate the knowing the number of gallons the tank holds, sometimes you can't use the full amount in the tank.
Once you have determined how much usable gas is in your tank, then its simply a matter of how far you go on a gallon of gas, and how close you want to push the limits. If you don't know what mileage you can get out of a gallon of gas, I might suggest you fill your tank at every 100 miles for 3-4 tanks filled up. That will give you a ball park idea of your actual mileage, and will give you a number of miles you can go between fill ups. Sometimes gas mileage varies do to weather, where you drive, and how full you got the tank the last time (I suggest you quit putting gas in as soon as it shuts off rather then to round it up to the next what ever). I always leave myself about 30 - 40 miles from running out, some times gas stations are not as close as you would like them to be.
I ran out of gas one time with my coupe, about 2 weeks after I started driving it, and I have driven it nearly 100,000 miles since then. Working gas gauges are nice, but not required.

 

Thats what I have been doing the last 2 years. I usually aim for every 150-200 miles.
I have been using the Plymouth to get to work this last week, and monitoring the miles didnt cross my mind until I felt that first stutter pulling onto the highway.

 

I would think 200 miles would probably be OK cruising down the highway (at 55-60), but might be pushing it with stop and go city traffic. With the drive train that is in my coupe (no where near OEM) the difference between highway (cruising) and city (stop and go traffic) is 5 mpg on the gas mileage, that is an 80 mile difference on a 16 gallon tank. My coupe will go 250 miles on the highway (you better be finding gas soon), but I fill up at 150 when I drive it around town. My gas gauge works great until it gets down to about 1/4 tank, then its pretty flakey. That is why I record the mileage with every fill up.

 

While out at the park with my family, a young man approached me. He had taken this picture of my car a few weeks ago, while it was out on the town.