Hydrive

[Loren]

I was on facebook the other day and saw a post by a guy with a 49 Dodge.

The car didn’t come to him with a engine just a whole bunch of parts.

In one of the photos there was an engine with what looked like a torque converter with a small clutch on the end and no bell housing.

To be sure it was a torque converter I asked him what the oil pump looked like. He put up a photo of the oil pump with its signature pressure relief.

A Plymouth HyDrive.

The factory material on the Hydrive says it can’t be retro fitted to another Plymouth because there’s just too many special parts.

However, I supposed that if the Dodge had Fluid Drive, the HyDrive might fit ( engine and transmission of course ).

One’s imagination takes hold and you start to thinking about it. My auntie had a HyDrive Plymouth and she was still lovingly talking about it into the 1970s!

I found a newsletter online of the Cascade Pacific Plymouth Club ( of which I am a member ) from 2016 written by a long term owner of one.

I highly recommend it if you like obscure engineering.

www.cascadepacificplymouth.org/509PhilHallHyDrive.html

If this link doesn’t work just google: Plymouth HyDrive and the Cascade Pacific Plymouth Club article will be very close to the top.

The HyDrive name has nothing to do with Oregon Weed, its a reference to shifting the transmission into high gear and leaving it there.

The engine developed 117 lbs feet of torque, then the torque converter multiplies it 2.6 times! Which is a pretty respectable number.

Anyway its a fun thought exercise, enjoy!

[Doug&Deb]

If I’m not mistaken the Dodge Gyro-torque transmission that was offered in 53 is the same setup. Basically the M6 with a torque converter instead of a fluid coupling. You would need both engine and transmission as they shared oil.

[greg g]

The hydrive was basically a three speed you drove around using third gear, using the clutch only to change in and out of reverse.  The engine, torque converter and transmission shared engine oil. So you need to have the block with the plumbing to support that circulation.  Allpar.com has a good piece or two regarding this mash up of pieces parts.  It was only offered from late 53, when the 230 got put in Plymouths though 54.  55 got the powerflyte 2 speed automatic.

[Doug&Deb]

Greg I stand corrected. Thanks for the information.

[Plymouthy Adams]

the hy-drive was a true torque converter as compared to a fluid coupler.  The hy-drive was offered with the 218 as a boost in performance as the torque was multiplied and the result was so good that they offered better gearing in first, second and a bump in higher ratio in the final drive.  Win win across the entire line up save for the shared oil.  The 54 model year in mid production saw the 230 installed in the Plymouth and was coupled solely with the Powerflite trans.  55 model year saw the 230 across the board in Plymouth and the 218 was history.  1954 was the only year Plymouth offered the flathead 6 in two different displacements thus a diamond was added to the engine block ID plate to denote the 230 from the otherwise plain jane 218.