I just brought this home over the weekend. Neat old Mopar that has already had some nice upgrades. It'd been fully rewired and converted to 12v and has a nice front disc brake conversion kit on it. The only thing I'm not real crazy about is the semi-auto trans and the Fluid Drive. The motor runs excellent and it drives pretty decent but it leaks oil from the front crank seal, the oil pan, the rear main, and the side tappet covers which has made an unbelievable mess underneath. Just a lot of 70 year old dried out gaskets and seals. So I think i'm going to go ahead and pull the drive train, clean everything up and put a full gasket kit in it and reassemble. While I'm at it I'm trying to decide to keep the stock trans setup or switch to a regular three speed manual using a Plymouth bell housing, trans, flywheel, shift rods, etc. I know I'd have to move the rear cross member but does anyone know if the column shifter has the positions for a standard three speed?
Try to find a threespeed from a De Soto, Chrysler or Dodge that fit right in. They have longer inputshafts then Plymouths. If i remember right they fit directly to the belhousing for the fluid drive.
I'm definitely leaning that way. Seems like they are cheap and plentiful plus it would basically be a bolt in. Drive it like a standard three speed and use the Fluid Drive for sitting in traffic.
Please don't be too quick to dump the semi automatic transmission... think of it as an anti theft device
Since I'm pulling the motor and trans to fix all the oil leaks, I hate to put the Gyromatic back in without knowing if I can get it to work right. It would suck to have to pull it again if I cant get it worked out.
Started disassembly today. Look like the oil leaks were mainly coming from the front and rear crank seal. The amount of built up sludge under the car is unreal and look like it has been going on for many years. So the plan for the engine is just a good cleaning and replacing all the gaskets as long as the insides look good. I also got this rebuilt 360 with the car but I think I’d rather stay with the flathead as long as it’s in good shape internally. I have to make a decision on a transmission. The clutch surface on the fluid coupling is grooved and cracked really bad. Plus the the Gyromatic didn’t shift right at all so fit now I’m thinking of either a regular 3speed manual Fluid Drive from a Dodge, or switching over to the Plymouth 3 speed manual. I really don’t want a gear shift sticking through the floor so that leaves a five speed swap out. But it was good progress for day 1.
I’m a mopar fanatic...to keep up with modern speed limits... Sell the engine to a restorer and go v8 automatic.. my choice .. is 500 caddy
Nice old Desoto..........whilst you have the engine out I'd at the very least knock all the freeze/core/welch plugs out and stick a hose in the water jacket as well as use a piece of stiff wire poking around to loosen and clean out the water jackets then replace the plugs with brass ones, as far as I know they should be 1 & 5/8th diameter.......if you feel really game remove the water pump and then remove the water distribution tube that is running the length of the block....hopefully it will come out easily and in one piece.......stick hose in there also..........whilst the plugs are out on the other side of the block.......do the water thing before removing the side plates, sump or timing cover etc........once the crud is out of the block then attack the crank seal........generally these will need a speedie sleeve as the pulley will have a groove cut into it, once the speedie sleeve is on install the timing cover loosely then the pulley which you use to "center" the timing cover then bolt on...........give the oil pan a good clean out, pull the rear main to check and replace the rear seal which could be any one of 3 types, don't forget that the seal should also have one of 2 types of side seals......when the pan gasket is installed make sure to have some extra side length protruding over onto the centre rubber pan seal which will compress when bolted down.......as for the side plate or valve cover gaskets a good trick is to completely clean the cover plates then glue the gaskets to the plates to stop them moving when installed.........various companies made cast iron headers like Fenton...........Stovebolt Engineering make Fenton copies, twin & triple intakes were made but can be expensive now..........finned heads also were available but Edgy/ Montana Dodge Boys do both finned heads and intakes..........HEI dissys are available from Stovebolt Eng also...........interesting that it has a ByPass oil filter.......I thought all 25" engines had the full flow filter but obviously not..............regards from Oz.......Andy Douglas
Yeah, I’m going to go ahead and pull it apart. Other than the oil leaks it ran great, quiet, good oil pressure, plugs burned clean; but when I pulled the side covers it had a ton of sludge in around the valve springs. It needs a serious internal cleaning and everything checked.
my 53 Coronet has a 3 speed without the fluid drive .. according to the guys at oldmoparts.com is really rare... which is the bell housing/transmission you need without a whole lot of fabrication.. hit me up after the summer and I will trade ya for a plymouth bell
After finding the flywheel surface of the Fluid Coupling in really bad shape and the seal leaking badly, I decided just to change over to Plymouth parts and have a regular three speed manual.. I'm going Friday to pick up a good running 218 and three speed; will resell the 218.
Got the engine all tore down and everything looks pretty good. No sense in not freshening it up with rings, bearing, gaskets and a valve lap while I’m this far. Also going to do a firewall forward clean up; paint the front of the frame and under the hood. Also picked up my Plymouth trans and a good running 218. If anyone needs the motor shoot me a message and I’ll make you a deal.
The good news is, the conversion to regular clutch and 3 spd is an easy deal. Rear clutch housing cross member needs to move forward, clutch throw out fork rod needs to be shortened, but shifter linkage will work just fine. How do I know this, I did the exact same to a 47 Chrysler. With 3.73 rear gears it did alright. It is a lot better outta the whole than a fluid drive and M6. And if you can get your hands in an R10 overdrive direct bolt in as you prolly already know. Some custom intakes like the AoK are nice, some are crap and don't flow well. Mill the head while your apart for a compression boost. As mentioned above a Stovebolt HEI is definitively not needed. An EDGY head good luck on availability on the 25 inch version and price has really gone up. You really don't need it. Good luck on her.
The big Dodge trucks used that engine and had a optional dual carb/exhaust manifolds,I had those parts at one time but sold them since I could not find a decent 2 door to put them on.
Yes they did, but they are scarce and super friggin pricey. Sounds like OP wants stock with exception of getting rid of fluid drive and M6
Yeah, that’s pretty much it; just want to keep her basically stock except for the trans swap. Just want a fun old cruiser that’s reliable without breaking the bank. Finished the tear down today; from here it’ll be degrease, cleanup, paint, reassemble.
When you did your 47; did you cut the crossmember and move it forward or make brackets for the bellhousing to sit on with the crossmember in the stock location?
Done in about 1986 ground off rivets on cross member and moved forward on frame to accommodate clutch housing. On the 47 Chrysler it was pretty straight forward and not difficult to do.
So a couple smaller projects whilst I’m waiting for my crank to come back from the machine shop. First the brakes. One of the previous owners did a disc brake conversion and did the deal where you attach a second master cylinder by running a rod through the first one. Aside from the point that it was leaking pretty bad, it was also sticking up through the floor on the drivers side. So I’m building a bracket to get rid of the original MC and will most likely use a remote reservoir MC or find something lower profile. Next is the seat; this thing was completely junk with the slides broke and most of the springs collapsed. So after searching through the boneyard I found this seat in a 15 passenger Dodge van. I’ll have to lower it but the shape and length look pretty good, I think. I may go back and get a second one out of the same van to use for a back seat if I can make it work. Thankfully the floors have been done and they did a pretty decent job so I don’t have to do any floor rust repair.
Did a massive degrease on the frame with a power washer and several cans of degreaser; now just need to do a little wire brush and some paint to protect it. Thinking about doing a change of direction on the motor. The rebuild cost of the 236 is adding up and I’ve got this 218 sitting here with new valve seats. Seriously considering mothballing the 236 for now and just giving the 218 an exterior cleanup and dropping it in. Could always change back later if I end up keeping it for any length of time.
@falconvan Pat, re’ installing the 218.....I think that is a good idea for now. It should perform quite well in everyday driving. Meanwhile, keep an eye out for a ‘52/‘54 Chrysler Windsor 265”. I put one of those in a ‘51 Dodge Diplomat Hardtop I had some years ago replacing the 230/Gyromatic. At the time I did find an OD trans and it made a great highway cruiser, but even without the OD it was a nice driver. As usual, great progress you are making! Wish I had half the energy and determination you always exhibit. Regards Ray
@falconvan Oh, wait! I just looked at the photo of the 218/3 spd you posted. That trans is the short tail housing version and I think will compound your need for a longer driveshaft.... But, I know you can handle it! Ray
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