New to me 1948 Desoto Custom Coupe

[Art Bailey]

Hey Folks,

 

I've been lurking here for some time, in anticipation of one day scratching my 40s Mopar itch, reading a ton. After a long search, logging many miles to go look at overpriced rotboxes, I drug home this little beast...a 1947 Desoto Custom Coupe. Pretty minimal rust, straight body and frame, amazingly solid floors and rockers for this part of the world, a paint job that looks ok from 100 ft., not very gross interior from the 80s, the fake wood grain paint is very much intact, and from what I can tell, wear and tear that seems to corroborate the 50k odometer reading. It runs, not great at the moment, due to the wiring under the hood being crap, backs up and goes forward, and after running for awhile, seems to idle nicely with no smoke. I discovered evidence, that my emotions caused me to ignore during the walk-around, of an old fender bender--the hood doesn't close right, and the front clip is out of alignment. It also came with a nice trunkful of spare trim and other parts. Overall, it's a very good starting point, and I'm pretty damn excited--I've wanted a 40s coupe since I was a little kid. After 32 years of driving, this will be the first vehicle I own that's not just for getting my butt from one place to another, on time, in one piece. Hopefully, I can make it do that, too.

 

The guy who sold it to me, who happens to be an old drag racing engine builder, claimed that he rebuilt the engine in '76, and it was never driven, and the current owner let it sit until now. It definitely needs a basic tune up. I'm going to disconnect the entire wiring loom, which is crunchy and scary, and put some temporary wiring in so I can hot wire start it, and move it in and out of my tiny garage. I plan on making my own wiring looms with cloth covered wires (God help me). 

 

Beyond plugs, cables and wires, I think I should also pull the heads, examine the cylinder walls for scoring and ridges, look at the valves, pull the oil pan, clean out sludge. The compression test was a little uneven--the number one cylinder had compression of around 75, the rest around 100-110. We poured a little oil in the number one cylinder, and it came up to 125, pointing to rings?  Would it be a good idea to pull the caps on the crank and examine those, too, and even go so far as to pull the pistons and measure the wear on the cylinder walls, before putting the engine into service? Thanks, looking forward to being here for awhile! 

 

-Art

Edited October 20 by ratbailey

[Knaveofdarts]

Welcome! Nice desoto you picked up - I dig the color.

 

I'm new here myself, but one piece of advice I can definitely share is to, as you stated, drop that oil pan and clean out that cosmic street fudge before you run the motor too much. These engines (or hoods) aren't particularly watertight and if it sat outside for any length of time, it's best to start with known fresh oil.

[Art Bailey]

1 hour ago, Knaveofdarts said:

Welcome! Nice desoto you picked up - I dig the color.

 

I'm new here myself, but one piece of advice I can definitely share is to, as you stated, drop that oil pan and clean out that cosmic street fudge before you run the motor too much. These engines (or hoods) aren't particularly watertight and if it sat outside for any length of time, it's best to start with known fresh oil.

Thanks, man! With my budget, I wasn't expecting to get the body style, condition, AND color, but I hit the trifecta. The oil is pretty fudgey, I'll definitely pull the pan. Luckily, it's all oil and crud, no coolant. The story is that it was inside for most of the last 70 years, and the general condition of things kind of bears that out.

 

The engine builder guy said I should fill the cylinders with PB Blaster, let it sit for as long as I can stand it, suck it out, and then oil it and just run it. I really think the head should come off, and the feeler gauge should come out. 

 

That's not my garage, by the way...

Edited December 21, 2020 by ratbailey

[Knaveofdarts]

I only have a tiny 1-car garage (occupied by my '71 Mark 3) and three project cars, so I know the struggle. All of my '50 Deluxe repair work thus far, including pan removal and exhaust work, has been out in the weather, on a sloped gravel driveway, lying on wet cardboard and cussing. Not recommended!

[Art Bailey]

4 minutes ago, Knaveofdarts said:

I only have a tiny 1-car garage (occupied by my '71 Mark 3) and three project cars, so I know the struggle. All of my '50 Deluxe repair work thus far, including pan removal and exhaust work, has been out in the weather, on a sloped gravel driveway, lying on wet cardboard and cussing. Not recommended!

Been there! I've worked on my car in winter, in the street in NYC with cars whizzing by my head, but at some point I decided I was too old for that s$&t. My 19X19 unheated garage is a palace compared to that.

Edited December 21, 2020 by ratbailey

[Sniper]

Pouring some oil in a valve in block engine may also seal the valves so it's hard to say why the compression came up.  Though your numbers look much better than mine, about 50 in all of the cylinders, but it gets me around. 

[Art Bailey]

I guess the numbers back up the rebuild story--I think it's supposed to be 113 from the factory. Honestly, I would've been happy with 60 p.s.i., but I'm pretty thrilled the guy wasn't yanking my chain about the condition.

[Sam Buchanan]

Nice score! I would not pull the head unless the flattie is begging for it. I agree with just driving it for awhile to find out the true condition of the engine, these engines are amazingly resilient even after sitting for many years.

 

Decent compression...not smoking.....no bad rattles or smells.......DRIVE IT!

 

Spend your time and $$$$'s on brakes....that'll keep you busy for awhile. 

Edited December 21, 2020 by Sam Buchanan

[keithb7]

Something to think about: Opening up the engine will likely lead you to much contemplation and decisions. One decision compounds another, and another, and another. Or you can pretend you'll didn't see what you found, button it back up and putter around like @Sniper does with 50 psi in the cylinders.

 

If the car is new to you and you want to just drive it,  I'd drop the pan, valve covers and oil filter.  Clean all the sludge out of those areas. Install modern detergent oil. Pull the head. lap the valves. Set the valve lash. Forget about any top ridge, cylinder taper or out of round at this point.  Just get it running. Drive it for a while.  Tune it up. See how it performs. Hows the water at operating temps? Oil leaks? Oil burn? Enjoy it for a while. Sort out the bugs. Then decide how far you want to go with the powertrain. Make a plan, a budget. Start squirrel-ing money away. 

 

It's early in this honeymoom stage. Resist the temptation to pull and tear the engine down at this point. Because...Then there's always the clutch, tranny, park brake, trunniuons, diff, axle bearings, brakes.... And it hasn't even turned a wheel under its own power yet. Go enjoy the car. Pick away at it and drive it. That's what I did and I loved every minute of it. Its winter #2 here now for me and my honeymoon stage car , and guess what? The pic says it all.

 

 

 

 

 

 

[Sam Buchanan]

Also, put at the top of your list a peek into the fuel tank. A rusty fuel system will have you chasing problems that won't go away until you have a clean tank and lines.

[knuckleharley]

5 minutes ago, Sam Buchanan said:

Nice score! I would not pull the head unless the flattie is begging for it. I agree with just driving it for awhile to find out the true condition of the engine, these engines are amazingly resilient even after sitting for many years.

 

Spend your time and $$$$'s on brakes....that'll keep you busy for awhile. 

Couldn't agree more. Why tear down the engine when you don't have to?  Drive and enjoy the damn thing for a few hundred miles. Put some heat and wear on the engine with new non-detergent oil,and you might be surprised at how well it starts running after a half-tank of gas or so.

 

After all,you can always tear it down later IF it needs anthing.

 

MY number 1 rule of mechanikin is "If'n it ain't broke,don't fix it!"

[Art Bailey]

2 minutes ago, Sam Buchanan said:

Nice score! I would not pull the head unless the flattie is begging for it. I agree with just driving it for awhile to find out the true condition of the engine, these engines are amazingly resilient even after sitting for many years.

 

Spend your time and $$$$'s on brakes....that'll keep you busy for awhile. 

Hmmm...I'll try to resist my urge to pull everything to pieces   I just hate the thought of being the guy to wreck something that was perfectly good all this time. My only other experience with something this old was a total garbage '52 flathead Ford  that apparently couldn't be killed, so yeah, I hear what you're saying. It needs plenty, so I'm not worried about wondering what I need to do next besides engine forensics.

[Los_Control]

The rings will/can stick from sitting for several years without running. Good chance with a few heat cycles the rings on the low cylinder will loosen up and compression will rise to match the rest.

 

I have similar issue with mine, #1 cyl was 75, #5 was 90, rest were over 100. I kept adding marvel mystery oil in the cylinders let it soak and then run it.

Now the worst is 95 & rest are over 100. I have not yet started driving it. Was told driving the engine on the road in a decent rpm range will help the rings seat more then just idle in driveway.

[knuckleharley]

3 minutes ago, Sam Buchanan said:

Also, put at the top of your list a peek into the fuel tank. A rusty fuel system will have you chasing problems that won't go away until you have a clean tank and lines.

I am to the point in life where I just automatically assume any old car that has been sitting has a gas tank covered with rust inside,and the first thing I do is order a brand new gas tank for it,replace all the fuel lines with copper/nickel lines or new unleaded gas rated rubber,and rebuild the stock fuel pump or replace it with an electric fuel pump. I do this even before I mess with the brakes. You don't need brakes if you can't drive it anywhere.

 

BTW,the price of a new gas tank ain't that much when you subtract the price of a rollback ride home from the cost.

[Art Bailey]

6 minutes ago, Sam Buchanan said:

Also, put at the top of your list a peek into the fuel tank. A rusty fuel system will have you chasing problems that won't go away until you have a clean tank and lines.

Absolutely--that's almost at the top of my list. There's no varnish stink whatsoever when I stick my nose in the filler, but I'm going to take it out, put a chain in it, and give it a shake 'n' bake, or maybe take it to a rad shop and have them deal. Fuel pump works, too...kind of can't believe it.

[knuckleharley]

2 minutes ago, Los_Control said:

The rings will/can stick from sitting for several years without running. Good chance with a few heat cycles the rings on the low cylinder will loosen up and compression will rise to match the rest.

 

I have similar issue with mine, #1 cyl was 75, #5 was 90, rest were over 100. I kept adding marvel mystery oil in the cylinders let it soak and then run it.

Now the worst is 95 & rest are over 100. I have not yet started driving it. Was told driving the engine on the road in a decent rpm range will help the rings seat more then just idle in driveway.

I suspect it is more of a matter of constant engine heat and hot oil freeing the rings and valves  up.

[knuckleharley]

10 minutes ago, ratbailey said:

Absolutely--that's almost at the top of my list. There's no varnish stink whatsoever when I stick my nose in the filler, but I'm going to take it out, put a chain in it, and give it a shake 'n' bake, or maybe take it to a rad shop and have them deal. Fuel pump works, too...kind of can't believe it.

No surprise. They all seem to work until you are away from home and the old diaphram cracks from being stiff and hard,and then suddenly stressed. Do yourself a favor and NEVER leave home with a car that has been sitting for years if you haven't rebuilt or replaced the fuel pump and every single item related to brakes except for brake lever and pad. New copper/nickel hard lines,new rubber lines,new wheel cylinders,new master cylinder.

 

If you look around,it is cheaper to buy new wheel cylinders than it is to buy kits to rebuild them. 

 

Seriously. When I was rebuilding the brakes on my 1939 IHC PU,the cheapest price I could find on new wheel cylinders for it was right at 90 bucks each,and who knows how long they had been sitting in a warehouse,or what the temps had been in there?

 

So I pulled the hubs,got the parts numbers off of them,and did a web search. Come to find out they were the same wheel cylinders used in 53-54 Corvettes,and I could buy them brand new from amazon for $4.50 each,plus shipping.

 

BTW,for anyone curious,pulling the rear drums from a late 30's IHC pu is the exact same fun process as it is for your old Mopars.

Edited December 21, 2020 by knuckleharley

[Art Bailey]

25 minutes ago, keithb7 said:

Something to think about: Opening up the engine will likely lead you to much contemplation and decisions. One decision compounds another, and another, and another. Or you can pretend you'll didn't see what you found, button it back up and putter around like @Sniper does with 50 psi in the cylinders.

 

If the car is new to you and you want to just drive it,  I'd drop the pan, valve covers and oil filter.  Clean all the sludge out of those areas. Install modern detergent oil. Pull the head. lap the valves. Set the valve lash. Forget about any top ridge, cylinder taper or out of round at this point.  Just get it running. Drive it for a while.  Tune it up. See how it performs. Hows the water at operating temps? Oil leaks? Oil burn? Enjoy it for a while. Sort out the bugs. Then decide how far you want to go with the powertrain. Make a plan, a budget. Start squirrel-ing money away. 

 

It's early in this honeymoom stage. Resist the temptation to pull and tear the engine down at this point. Because...Then there's always the clutch, tranny, park brake, trunniuons, diff, axle bearings, brakes.... And it hasn't even turned a wheel under its own power yet. Go enjoy the car. Pick away at it and drive it. That's what I did and I loved every minute of it. Its winter #2 here now for me and my honeymoon stage car , and guess what? The pic says it all.

 

 

 

 

 

 

Good advice. As I mentioned, there is no shortage of stuff to do to make it simply roadworthy. Man, that '38 looks sweet! 

[Art Bailey]

58 minutes ago, knuckleharley said:

Do yourself a favor and NEVER leave home with a car that has been sitting for years if you haven't rebuilt or replaced the fuel pump

 

BTW,for anyone curious,pulling the rear drums from a late 30's IHC pu is the exact same fun process as it is for your old Mopars.

Looks like it's gonna be a new fuel pump, not a rebuild kit...nobody seems to have them. I'll give Antique Auto Cellar a call tomorrow. 

 

Yeah, looking forward to yanking brake drums...

[Sniper]

I may have been puttering around, but I have a plan.

 

I have a core 230 coming that I will go thru and build.  Then I can keep the original engine.

 

You know, I haven't read the compression since right after I bought it.  It runs great, starts right up and has enough poop to chirp second.  Maybe my rings were sticky and loosened up.  I might have to redo the compression check.

[knuckleharley]

3 hours ago, ratbailey said:

Looks like it's gonna be a new fuel pump, not a rebuild kit...nobody seems to have them. I'll give Antique Auto Cellar a call tomorrow. 

 

Yeah, looking forward to yanking brake drums...

I bought a new 6 volt electric fuel pump for my flat 6 51 Ford biz coupe last summer for 36 bucks from Summit Racing. it is an option you might want to consider.

[greg g]

These engines like to get sticky valves when sitting. But it will probably start and run pretty well with one cyl with low compression. In fact a couple runs up to operating temp may encourage self healing..  Leak down testing can confirm a valve not closing all the way.  What drive train does it have.  Dry clutch or fluid drive, three speed manual or semi auto?  For info on fluid drive go to allpar.com and search fluid drive.  For care and feeding of fluid drive go to the Imperial Club website repair section.

 

Go to eBay and get a shop manual and if you can find one a parts book.  The parts books have exploded drawings of assemblies which makes understanding and repair easier to do in the garage.

 

Go to the resources section of this website for fender lists etc.

 

Welcome, good luck and enjoy.

 

And for inspiration, mark your calendar for September of 2021 for our third presentation of the P15 Picnic tour this year in and around Watkins Glenn and the fingerlakes area.

Designed for older Mopars and other orphan brands.  Usually the third weekend in September.  Details will post on this forum.

[Art Bailey]

8 hours ago, greg g said:

These engines like to get sticky valves when sitting. But it will probably start and run pretty well with one cyl with low compression. In fact a couple runs up to operating temp may encourage self healing..  Leak down testing can confirm a valve not closing all the way.  What drive train does it have.  Dry clutch or fluid drive, three speed manual or semi auto?  For info on fluid drive go to allpar.com and search fluid drive.  For care and feeding of fluid drive go to the Imperial Club website repair section.

 

Go to eBay and get a shop manual and if you can find one a parts book.  The parts books have exploded drawings of assemblies which makes understanding and repair easier to do in the garage.

 

Go to the resources section of this website for fender lists etc.

 

Welcome, good luck and enjoy.

 

And for inspiration, mark your calendar for September of 2021 for our third presentation of the P15 Picnic tour this year in and around Watkins Glenn and the fingerlakes area.

Designed for older Mopars and other orphan brands.  Usually the third weekend in September.  Details will post on this forum.

The message board won't let me like your post, I'm shut off for the day...so, *like*

 

Great advice, thanks! I'll research leak down testing. It's a fluid drive, with tip-toe transmission. The shift lever moves hard as hell, but I don't doubt it probably needs lubrication and use--it got that feeling like I'm slogging through some heavy crud when I try to shift. I'll read up at those sources, thanks again. The shop manual, parts book and a Motors manual are on their way.

 

The consensus seems to be to just run the damn thing. I'm glad I asked you guys, it's good to have a check on my tendency to go overboard and make extra work for myself, thanks everyone. 

 

Maybe I can set a goal of Sept. '21 for the Desoto to make a road trip up to the Finger Lakes! 

[keithb7]

You are likely better off rebuilding the original made in USA fuel pump, versus buying a new pump today that is made overseas. Take your pump apart and look at it. In particular pay attention to the large diaphragm gasket shape. Compare it to pics of pump kits on e-bay or other web sites. You should be able to spot a matching rebuild kit.  Make sure you are not buying a kit or fuel pump for a car that may use the fuel pump action for vacuum wipers.

 

I found that if was difficult to keep the fulcrum pin in place after the rebuild. Several attempts at staking it in place, left me stranded roadside. The pin still found a way to walk out.  JB Weld on both sides of the pin has worked well. 1500 miles and it has not walked out again. Some kits have a machined groove in the fulcrum pin. A c-clip is used to retain the pin. That seems to be the case the with kit shown below:

 

Looks like a pretty good selection here:

https://www.then-now-auto.com/product-category/fuel-pump-kits/desoto-fuel-pump-kits/

 

It's likely this one: https://www.then-now-auto.com/product/fpa48-fuel-pump-kit/

 

Ebay: This will probably be fine as well:

https://www.ebay.com/itm/1941-1942-Plymouth-Desoto-Dodge-Chrysler-NEW-fuel-pump-REBUILDING-KIT-41-42/173237001394?_trkparms=ispr%3D1&hash=item2855badcb2:g:ZUQAAOSw64ha333R&amdata=enc%3AAQAFAAACgBaobrjLl8XobRIiIML1V4Imu%2Fn%2BzU5L90Z278x5ickkSG%2BOFgrj2Yvbvmrj2TAdM7fHpCF4nnDEyxazae7NqCed5ZVRbywI1YMWFoyjZxcQ0EmYGOTq3Uynogg8ijVnr3gMYdArnxrtOSeLSv0C1z2tnfqz3E5JTqDzBeUl1CyWep%2FKJrrX97yBTtIRW7o2PdF0oDn5WdVw2td1lLnk9Ce2AK6cru1xvNGLHIACENN3bkSPKFgRRT5pzaRytvqhGGQgfquLejpDDykqhkUdvmXaHuBgAFSgcN%2BbJanSSDUKs0%2BiWjGKCaH9tCRj1sxh4tWdZw4F2%2FByMSoKYWBUUd1heVSQxP%2F2ixGELlE6bcUv7VI2GE7cio06Vj5BccRF9bzevIoAwLD8Ea3HGGPxAo%2BVGeogHb%2F24oOzMHuCcxXzuLzssyFthN4SwK2EKCXQgNzemMMBoFBGaHEWoJlZ8cYuo63gd0yT1sJ4rO4odXdkgBJ%2BA8MAVedvNN8fVUpfsOGKm1yIh1%2FVXs8jHXsKMupkdyoq0haf8mg3CODRnSp39IWaUltM6NiJZ1ZuLtG0yjtm8gsn9iuRHMIzhltTqqOtBsL%2FpUey26MjhixqLBJPSRISZ8gmFUFVUCDfcwE4WiOYzwnca0HFEBz2D4vPIptM2upJA%2FmlLNEbxSyrNZqDn%2FERdcpEdKkmZOecOvRnNfyHqQfQftnz9TUG9MS7jI7tnbvOa1rm9CMMtvfJvypBcmX%2BZ863ofsb5%2FtrNNnKDMTHyN8E3%2Fxvva7Yd3kGqifg%2F5zXXVd90A0KkqmZrVdGU5WwVAixP8UvTn%2BM7%2BtCrQzvM2HseTBWflWfbPfibXw%3D|cksum%3A173237001394c93b7486192d45acbba4b7b48cfadeab|ampid%3APL_CLK|clp%3A2334524

 

Edited December 22, 2020 by keithb7

[Sniper]

Allow me to introduce a place that takes monster URL's, like the ebay link above and turns them into something reasonable.  www.tinyurl.com

 

this will turn that monster ebay link into https://tinyurl.com/ycoufao5