My first Plymouth - 1950 Dlx Business Coupe

[jclars]

Last September, while still on vacation, a friend sent me a pic of a business coupe for sale.  I recognized the place immediately and regretted I would not be home for a couple of days.  But it waited for me!  It has a bit of history.  Owned by famous Mopar sponsored drag racer Dave Wren, it was one of two drivers he used before passing away the year before.  As it turns out he had about six of them scattered over his farm, most of which looked like a parts source for the others.  They sat out in an open field with many of his 70's era racing cars.  I was lucky enough to get one that had been indoors for awhile at least.

 

I got it running within a couple of days, but when I replaced the water pump, the extra flow blew out a weak spot in the head gasket.  It went downhill from there, with 3 head bolts removed, 3 broken off and 18 still stuck in the block.  Anyway, I haven't decided fully what to do with the thing as it came to me unexpected.  For the 1 mile I was able to drive it, it sure glided along!  These have always been an attraction to me reminding me of those little armored sowbugs that seemed to float along as they moved.

 

My first question is how these business coupes were outfitted for the travelling salesman.  I cant find any pix or examples.  I understand there were even shelving systems available like for a cargo van.  And in relation to that, what was their payload?  Is this stated on a published spec sheet?

 

Thanks in advance,

John

 

 

[Kilgore47]

Just keep working at it.  You'll eventually get all those bolts out.  Heating - soaking - hitting the head of the bolt.  All these help.  Sometimes a little turn clock wise before you try to take it out will help break them loose.  

[jclars]

Thanks for the encouragement!   After twisting off three almost flush to the block surface, I decided to drill the heads off the rest.  Giving me at least a shank to work with.  These are the most stubborn I have ever faced, and so many.  There is evidence of some sort of gunk on the three I got out - Loctite?  But so far no progress.  I will also be looking to weld oversized nuts on the heads to give something to grab onto.

 

I was actually not looking for a project as I have one I am in the middle of.  But when it actually started I thought it would be fun to drive around.  Now I can't even move it easily!  And I have a new water pump, head gasket and bolts already invested in it.  Oh well, I keep doing those things you mention in passing, as I putter on the other project.

 

A pic of the car, as I found it.  Almost looks like a staged barn find, except this was a typical scene throughout this mans hoard.  

 

 

 

Edited February 2 by jclars

[Los_Control]

12 hours ago, jclars said:

what was their payload?

I always thought it was moonshine ..... cool cars I love the body style on them.

 

As far as those bolts goes, I'm guessing heat would be best. Possibly welding nuts on them and really crank up the welder and give them extra welds ..... might be enough heat to break them loose.

Possibly cutting them down shorter so the threads will get maximum heat penetration when the nuts are welded on?

 

A oxy/acetylene torch would be ideal ..... I'm guessing you already know this ..... I'm not allowed to play with them though  

[Doug&Deb]

The gunk on the bolts is thread sealant. All of the bolts go into the water jacket. Remember to use sealant when you install the new bolts. Also after installing the new gasket you need to re-torque the bolts after a few heat cycles. 

[jclars]

Good info!  But every bolt??  Oh well, It was not a runner when I got it, and quite frankly, my intent was a different powerplant anyway, so low probability that this motor will get revitalized.  It was only because it started up so easily that I pursued what I thought would be a few quick fixes for a runner.  At $1250, I guess I was expecting too much!

 

I take it that there is no official data on what makes a business coupe a hauler?  Any extra payload given all the added cargo area?

[Doug&Deb]

I don’t believe there’s extra payload. They were designed for door to door salesmen so more volume than weight. If your engine still turns freely a new head gasket and bolts may be all you need to get it running again. Not overly expensive.

[jclars]

Thanks - I have both gasket and studs waiting in the wings.  Its the stuck studs that worry me, especially the three broken off at the head surface which may need drilling.  And what if there is more to come?  Not expensive if I can do it myself, but how to hit dead center on drill out?

 

So payload might be in line with the passenger + cargo of a 4 door sedan.  At least 500# extra, plus the difference in wheelbase.  I think they both had the same frame and drive train from what I've studied, but no weights listed in the sedan category either.

[Sniper]

Induction heater, probably help with exhaust manifold nuts too.  Lots of options on Amazon.

 

 

[jclars]

Thanks - That reminds me to ask - I did not get all water out of the block - is there a lower drain port I am not seeing?

[Sniper]

Yes there is one on the block down by the distributor

[jclars]

The four sided bung at the edge of the starter?

[Sniper]

Sorry, I got distracted.

 

Went out and looked, it's located low in the block between the distributor and the oil fill tube.  It usually is a pipe plug, that 4 sided bung you mentioned.  I usuallt replace them with a drain cock that has a nipple to attach a drain hose.

[jclars]

Thanks Sniper - No prob with urgency on this one!  It sits right next to the project I am currently engrossed in - a 1961 Volvo PV544.  But convenient enough I squirt some penetrating oil on a few studs, bang on them and go back to work.  And find time to repair my granddaughters bird house.   

 

But draining the rest of the block should help the heat penetration some!

[Saskwatch]

2 hours ago, jclars said:

The four sided bung at the edge of the starter?

I believe that is the oil relief valve ?

[jclars]

Thanks.  No relief needed for sure!  But good to know!

[Booger]

You've got yourself a gem there. It ran before, itll run again. While the heads off you might as well systematically go through the complete check list. New wires and cap. Rebuild the carb. All these components simple and much cheaper than an engine swap. 

[Young Ed]

What all have you tried to remove these bolts? Typically a good impact wrench will buzz them out. Now that you've turned them into studs you need a stud remover that clamps on. I just did a 41 truck engine (technically I haven't verified the engine but it's a 41 chassis) and that one had studs. All of them buzzed right out with maybe 5 pulling the stud itself. For the broken ones welding a nut to the top works way better than drilling 

[Dave72dt]

Weld a washer first for the best weld penetration and heat soak, then a nut to the washer if you have to.  Drilling is always my last choice and can still be done if all else fails.

 

Edited February 5 by Dave72dt

[Booger]

JC get an owners manual for all settings and clearances. They're out they

[RobertKB]

On 2/3/2024 at 2:29 PM, jclars said:

Thanks - That reminds me to ask - I did not get all water out of the block - is there a lower drain port I am not seeing?

I just fully drained my block today. Want to get the radiator checked and change a bad water pump. Drain is between the distributor and oil filler tube. Mine drained perfectly which pleasantly surprised me as they are often plugged with crud. I will add new anti-freeze when I refill the cooling system. 
 

[jclars]

Plugged with crud was my situation.  When I took that exact plug out, there was a dribble, even though I could see water from the block jacket holes.  I took an awl and poked in from below and a screw driver from above and the dribble turned to a 73 year olds piddle stream.  It appears empty now.

 

Thanks for the welded washer tip.  I tried a nut only, and like you say, there was not enough penetration.  

 

The reason I drilled the HH tops off, was the first three twisted off studs were measured to be close to the head surface.  I did not want any more of that.  At least now I can soak them, heat them and weld nuts on without obstruction.  

 

Booger - will an owners manual have cargo weights?  Seems like a basic spec but no one seems to know what it is.

 

Thanks all!

[QEC]

I'd suggest heating the 'studs' with a torch, get them red, then as they cool apply some beeswax or paraffin and the deck. Depending on the amount/type of thread sealant the wax should wick down the threads.  Smacking the top of the stud with a 2lb hammer as they cool should also help break them loose. 

[jclars]

Thanks QEC - I am trying a bit of everything within the suggestions proposed, to see who the winner is!  

 

After finding the sludge in the lower block, however, several things became clearer to me. 

 

One is finding the reason for it running so hot. 

 

Secondly, this block has to come out for a good dip in a hot tank.  Confronted with a complete tear-down of an engine that I was not considering even using in the first place, it may just sit for awhile.  I can think of a lot more fun engines/motors for this thing if they fit without chopping anything, other than a driveline.

 

John 

 

 

[Booger]

JC! Someone up top discussed the cargo weight issue. For the biz coupe Fuller brush man was about volume not tonnage. I suspect there is a GVW somewhere stamped on the fw. The biz coupes wb only a few inches shorter

Same springs and what not. 4 adults and their luggage to the big city for the weekend. (Including hats)

I would say 1000# would be safe