1951 DeSoto Q&A

[RamblinMan63]

Hello all, it's been a while since I've posted. I ended up disassembling the 251 for my S15. I took it to a machine shop to have it worked on. I had the cylinder head milled, bored .30 over, crank and camshaft reground, rods re conditioned, etc. The machinist is installing the cam bearings, cam and valves/ valve springs for me. I will be putting the rest of the block togther myself along with a friend whose done small block fords before.

I also located a fluid coupling for my car earlier this year. It came out of another '51 DeSoto. I got it from hidden valley auto parts in Arizona and had it freighted to the Sawmill I work at.

DodgeB4ya you were confused by my original post. I had meant it is drivable in the sense that the car is structurally solid and can be put on the road again fairly easily but when I bought it I bought it as a non running project. I should have been more clear on this. For me functionality is more important than appearance. The car is a tad bit rusty but that wont matter when she's going down the highway again.

Ive put together most the brake parts I need for the car. I have also been killing and sealing the rust. It is coming together, slowly and surely.

Is there a way to delete my other two threads? I started two other unnecessary threads on the same car lol. Might as well just have the one thread.  

[James_Douglas]

Be careful with the little flywheel on the fluid couplings. Make SURE you make 3 or 4 little wooden wedges with a slit across the end. Tap them LIGHTLY between the flywheel and the coupling housing so that the flywheel cannot rock. Use bailing wire around the wedges to keep them in place. Once installed into the unit with the transmission input shaft in place, then and only then cut the wire and remove the blocks.

 

ALL fluid couplings should have this done BEFORE a trans is removed. If the plate is allowed to flex about 50% of the time the carbon seal will get cracked. Often the problem does not show up for a few months after the whole thing is running and then you start to get a leak.

 

James.

[RamblinMan63]

On 7/21/2020 at 8:38 AM, James_Douglas said:

Be careful with the little flywheel on the fluid couplings. Make SURE you make 3 or 4 little wooden wedges with a slit across the end. Tap them LIGHTLY between the flywheel and the coupling housing so that the flywheel cannot rock. Use bailing wire around the wedges to keep them in place. Once installed into the unit with the transmission input shaft in place, then and only then cut the wire and remove the blocks.

 

ALL fluid couplings should have this done BEFORE a trans is removed. If the plate is allowed to flex about 50% of the time the carbon seal will get cracked. Often the problem does not show up for a few months after the whole thing is running and then you start to get a leak.

 

James.

I have been nothing but the most careful with this part James. I have wedged it firm for the time being.

On these transmissions does the bell housing bolt on before the coupling or after? The coupling has studs on it, do bolts go on the other side of the crank shaft?

 

 

[MarcDeSoto]

Yes the fluid drive does have studs on it.  Yes I think the bell housing goes on before you install the fluid drive because the bell housing is what supports the back part of the engine on the frame.  Bolts, what bolts?  The fluid drive doesn't have any.  It has studs.  The studs go through the crankshaft holes and nuts go on the studs.  You tighten them gradually going around from stud to stud to 55 to 60 foot pounds.   Of course, you can't get a torque wrench in there because it's too tight.  I have special long Miller wrenches for this job that you tighten to what feels like 55 ft. lbs.  It's been a long time since I've done this so I would like DodgeB4ya to verify my statements.  

 

 

[RamblinMan63]

I meant nuts not bolts sorry. Does anyone have any experience with the pre molded rocker panel replacements you can find on ebay? The rockers on my "51 are rusted out on the passenger side.

[RamblinMan63]

Update:

The machinist is getting close to being done with my block. While I'm not going for a full on restoration I'm heavily considering pulling the body off the frame for rust killing/sealing. Not to mention it'll make all the under chassis components I need to work over more accessible.

I've also been blind sided with a free 1959 Thunderbird my friend and his dad gave me lol. Instead of buying rocker moldings I might use the Bondi glass and work it over while the front pans will absolutely be replaced.

[42 DeSoto Fifth Avenue]

On 7/23/2019 at 10:28 AM, RamblinMan63 said:

 

 

Marc I do have the M6 transmission. Unfortunately I do not have a fluid coupling unit to go with it. The PO sold the fluid coupling out of my car to a local shop who's working on a '49 DeSoto. The shop swapped the coupling because it leaked but now it doesn't and they still have the coupling (out of the '49) laying around.

 

My plan is to get them to sell me the fluid coupling so I can keep it original. The back up plan, If I can't obtain the coupling would be to get the trans out of that "48 Plymouth. Correct me if I'm wrong but I felt it would bolt up easy and I'd still be keeping it mopar without any fabrication. 

 

My landlord has a '46 fluid drive desoto. Its totally rotten but its drivetrain is complete. Unfortunately he thinks he's gonna do something with it and I know he won't. The right amount of money might pursue him though to sell me the parts out of it.

Plymouth  never had the Fluid Drive, only a regular clutch with the standard 3spd tranny. That was an option on the 51 DeSoto. You can use that and ditch the FD/M-5 set up. You could add to that a 50s Borg Warner OD for highway cruising. Lots of of folks on this site have done that and there's info in the technical section. . My master parts list (4.1.55 version) list this part number for 'Fluid Drive w/clutch driving plate" 1320 563. It is listed as fitting 41-53 6s. The same number is listed for 41-54 Dodge  6s and 41-53 Chrysler 6s. A different part number is listed for 52-53 Hemis. Looks like your landlord 46 DeSoto is the best fit donor.

[42 DeSoto Fifth Avenue]

On 7/14/2019 at 1:33 PM, Dodgeb4ya said:

That's a late 1950 on up M-6 Transmission.... Dodge DeSoto and Chrysler.. all the same except for the U-Joint  output flange .

The M-5 slightly different was used from late 1942 TO 1948 DeSoto and Chrysler.

You can see the date on it and Model prefix at the beginning of the # which I cannot see from the pic.

Do you have a source for the info that the M-5 was used on 'late 42-48 DeSoto and Chrysler?

[RamblinMan63]

56 minutes ago, 42 DeSoto Fifth Avenue said:

Plymouth  never had the Fluid Drive, only a regular clutch with the standard 3spd tranny. That was an option on the 51 DeSoto. You can use that and ditch the FD/M-5 set up. You could add to that a 50s Borg Warner OD for highway cruising. Lots of of folks on this site have done that and there's info in the technical section. . My master parts list (4.1.55 version) list this part number for 'Fluid Drive w/clutch driving plate" 1320 563. It is listed as fitting 41-53 6s. The same number is listed for 41-54 Dodge  6s and 41-53 Chrysler 6s. A different part number is listed for 52-53 Hemis. Looks like your landlord 46 DeSoto is the best fit donor.

 

I did source a fluid coupling assembly and clutch from a '51 DeSoto out of Arizona. The machine shop is now done with my 251 flat six. Bored .30 over, crank and cam shaft ground, re conditioned rods, new pistons, rings, bearings, water distribution tube, valve seats, valve stem guides, valves ground, cylinder head milled, hot tanked, cleaned, rings and piston fitted, wrist pins fitted, valves and valve springs installed and painted hot rod orange! The rest of the assembly I'm doing myself.

[Dodgeb4ya]

2 hours ago, 42 DeSoto Fifth Avenue said:

Do you have a source for the info that the M-5 was used on 'late 42-48 DeSoto and Chrysler?

Ed....The M5 was not used in late 1942 cars... only the piston type M-4...my mistake.

It has been corrected above in my original post....thanks for noting.