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Fluid Drive, Conversions, and some thoughts on it.


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Hi All,

 

After looking into my specific needs for the upgrading of the 1947 Desoto Suburban, I have decided to not change the current arrangement of using a Fluid Coupling, the Three-Speed and the Borg-Warner overdrive.

 

I had thought about buying the plate from the Gary Stuaffer to use a Torqueflite in the car as the push button version with a rear pump would work well for my cross USA needs.

 

However, I ran across an interesting article that has lead me to abandon that idea. Buried in the SAE Conference Presentation when Chrysler came out with the Powerflite the lead Engineer stated that they purposely picked less stall speed on the converter as they had issues the engines thrust bearings failing.

 

It is interesting to note that when they came out with the Fluid-Torque drive that they changed the design of the rear main bearings and insisted that all Fluid-Torque drive cars get the new not the older designed bearing.

 

The SAE presentation did not go into much detail other than to state the increased offline torque was hammering the bearing. With my heavy car, I don't want to go there as this car will see us through as out MAIN car and also driving around the USA in retirement.

 

Yes, there are some things that I could do to "help" the thrust bearing issue, however that plus the other issues in my specific case tell me to leave well enough alone.

 

The total costs to convert, and do it will all new parts in a first class way, was starting to hit in the $7K to $9K range. A fully new 727, plus the adapter, plus a custom torque converter to make sure the curves work for a six, plus the Gear Venders Overdrive and then all the fabrication and welding. In the end the Benefit-Cost ratio is not there. Yes, I would get better off the line acceleration and 6 forward gears to match the torque of the six and the weight of the car going over the mountains.  The cost to do it "correct" is not worth the benfit.

 

Since my three speed is all but new with about 50K miles on it, I suspect it will last a good long time. I also have a complete second three speed with a known good Borg-Warner Overdrive.  I can rebuild that one and put it in a crate.

 

The big issue is the fluid couplings. I do not want to get hung out someplace with one leaking or failing when we driving around the USA. I also have the '49 to keep on the road.

 

So, instead of spending a fortune on changing a system that works...I am going to invest in making a jig so that I can properly rebuild two or three fluid couplings.

 

What I am doing is securing a NOS late type sleeve and other parts to the fluid drive seal assembly. I am talking with my machinist about spending the time to draw the things up so they can be made in his CNC. I am talking with American Graphite about reproducing some new manufacture Carbon Seals. I am talking with a couple of spring companies on making the spring. The seals and gaskets are not going to be an issue.

 

We are going to make up a jig so that the fluid couplings can be cut open and the bearing replaced and then welded back together while maintaining the alignment.

 

I think that I would rather spend my time and money on this path then the conversion path.

 

James.

 

 

 

 

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I’m sure whatever you do will be done properly. These cars were driven cross country when they were new so with everything rebuilt you should have no issues. If you can figure out how to rebuild the fluid drive unit you’ll be helping a lot of us that have them. Keep us posted.

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I think maybe the wisest piece of advice I ever received in my whole life was "If it ain't broke,don't fix it!".

 

You made a good call!

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One route you might choose is the "delete" fluid drive option.  This consisted of a long throw out bearing sleeve, a long input shaft and a standard  flywheel.

I never knew this existed until Leroi "Tex" Smith bought a Yellowstone Park 48 Chrysler limousine which was so equipped.    another use for this equipment was in 54 V-8  Dodge cars which needed the deep bell housing used by FD cars to fit the engine into an engine compartment designed for the six.

The advantage to using such equipment is that all the levers and controls stay the same and the original cross member remains intact. 

 

I am not offering to part with the items I have, but it gives you a path to explore.

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2 hours ago, dpollo said:

One route you might choose is the "delete" fluid drive option.  This consisted of a long throw out bearing sleeve, a long input shaft and a standard  flywheel.

I never knew this existed until Leroi "Tex" Smith bought a Yellowstone Park 48 Chrysler limousine which was so equipped.    another use for this equipment was in 54 V-8  Dodge cars which needed the deep bell housing used by FD cars to fit the engine into an engine compartment designed for the six.

The advantage to using such equipment is that all the levers and controls stay the same and the original cross member remains intact. 

 

I am not offering to part with the items I have, but it gives you a path to explore.

Learn something new every day. Any photos of the parts it takes to do this?

James.

 

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Start with something like one of these...

20201118_111407.jpg

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On 11/18/2020 at 11:53 AM, Adam H P15 D30 said:

I know you have already decided not to go with the conversion but you could've cut your costs / complexity by a lot if you used an A500 or A518 overdrive TF instead of the Gear Vendors OD.

Of course I could...but...I do not want to go to any kind of floor shift and the electric power steering assist makes a column shift a non-starter. Hence a push button 727. Also, for the weight of the car I was interested in the gear splitting that the GV unit gives you. Just an overdrive is what I have now so why bother for just that. Also the 1963 and 1964 727 has a REAR pump on it so it will compression stop going down a hill.

 

The real nail in coffin however was the technical discussion of the thrust bearing issues when these engines were subjected to higher off the line torque of a torque converter.

 

Lastly, one more thing. Since we will be driving this car a lot of miles...gas mileage is an issue. A non-lockup converter is going to slip about 6% while a fluid coupling is going to only slip 1% to 2%. If we do a lot of miles...better mileage with the fluid coupling.

 

Of course with the 5000 pound weight, I would have liked the torque multiplication to get the thing moving...but...I guess people will just have to wait as a slooooly accelerate!

 

Everything is a compromise and in the end I felt the benefit for the costs did not win out. Not to mention my back sucks and that would be a fair amount of work.

 

James.

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22 hours ago, Loren said:

I've always liked the Fluid Drive idea.

There is a spare seal kit on eBay right now.

Best of luck with this project!

 

There are two different post WWII seal assemblies. The early one with the bellows have a bad habit of cracking and leaking. That is why Chrysler came up with a new design.

 

I have the factory service bulletins on it. I have secured all the parts for the later version and did it for about $300. Chris at AndyB wanted $500 plus. The problem is that there are seven parts to the seal assembly. Non of the parts are compatible with the earlier ones. It is all or nothing.

 

I have 4 coupling not counting the ones in my cars. I plan on tearing them down and if I am lucky, some of them have the later assembly. 

 

It will be interesting to see what my machinist wants to draw up the sleeve so it can be made on the CNC. The material cost is nothing. Once a computer file exists, the cnc can spit these out in short order as there is not much to them.

 

James.

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Hi James,

I was in the business of reverse engineering expensive replacement parts for Diesel Turbochargers.

Much of what I did was precision cylindrical grinding.

If you get stumped or want a second opinion, I love such projects.

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I know a lot of people aren't into the whole You Tube video thing.  To be honest I don't know how all these guys ever get anything done.  It would be so time consuming starting and stoping work on a project to set up cameras and doing mutiple takes etc.  Then add on all the editing which would also be time consuming.  If I'm doing a project on my car I need to concentrate and focus.  It's beyond me how youtubers do it.

However,,,,,,  On the other hand,,,, what you propose would make fasinating video knowledge.  So it would be really nice to see the whole process start to finish documented on video.

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On 11/19/2020 at 6:23 PM, Loren said:

Hi James,

I was in the business of reverse engineering expensive replacement parts for Diesel Turbochargers.

Much of what I did was precision cylindrical grinding.

If you get stumped or want a second opinion, I love such projects.

Loren,

 

I will keep that in mind. Interestingly...I was going to but a turbo on the new engine and use the holley 2BBL sniper. But all the turbo plumbing....

 

I think I am going to source a Mac VS-57 Supercharger instead of a turbo. The V-57 was designed with that pulley that changes size and keeps the thing at about 5 pounds of boost. That is a good thing so that I do not need an air cooler and detonation should not be an issue.

 

My calculations on 5 pounds of boost on a 265 with VE of 70% tells me I should hit about 140 to 150 HP. Hopefully that will help move the thing over the mountains.

 

*******

On the sleeve, my main concern is to figure out what they made the things out of. The spring (NOS) is on my desk and I think any decent spring company can make those. The snap ring is likely something that I can get that is a stocking item. The copper sealing ring will be a litter harder to deal with, although perhaps the ones that I get from Aircraft Spruce can be had in a larger size.  The spring retainer and the sleeve is the hard parts. American Graphite can make the seal and there is a guy on ebay that seems to have a lot of them...

 

I had an email from the production engineer who is with the "new" company that that got the old Gyrol line from Howden. He was helpful in telling me how to approach the balance issues. Interesting that Rawb sent me emails with the photos of the ones he has cut open. It used a FAF bearing which is the Timken "low line" economy bearing line. So the Chrysler engineers did not worry to much about the bearing quality. I find that very interesting. I winder if one of their better bearings would yield any power gains....

 

So much fun when we start re-engineering things!

 

James

 

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Hi James,

I do enjoy your posts!

It may be ignorance but I've never understood why folks have had balance issues with re-assembled FDs.

But then I've never understood the need to slice them open either. On a torque converter you have a sprag clutch to replace and sometimes the snout and they do lots of them. A much more complicated piece yet it's almost routine.

Ball bearings are thought of in industry as "commodities" with different grades of materials and fits. Most of the replacements are better quality than the originals they replace. You can't go wrong with SKF brand ball bearings or Timkin brand roller bearings. Other brands can be hit or miss and there are some I'd never use such as BCA or anything Chinese.

 

Blowers have the design advantage that they are in a constant drive ratio so they produce power right away. Having a variable drive makes them somewhat like a turbo...a little less at low end and much more at the top. (unless its designed to lower the boost at the top)

A slow speed high torque engine like a long stroke flathead definitely benefits from a blower while a turbo would push it in directions it doesn't really want to go.

5 psi of boost is pretty safe in an overhead valve engine. I think you can go higher in a flathead as there is so much surface area to cool the incoming charge. When you get to 10 psi that's when the performance gets "eye opening". The issues we had with the 1978-80 SAABs had to do with exhaust valves heating up and causing a "ping" on steep hills. Since they started with sodium cooled valves the solution was a thicker head on the valve. That engine was limited to 6.5 psi. Later engines had charge air coolers and knock sensors before ultimately going to 4 valves per cylinder which ended the exhaust valve issue even with 10 psi and 10 to 1 compression ratio.

The design of the Chrysler engine makes it a great candidate for a blower.

The water distribution tube, the wide space between the cylinder bore and the valves are very helpful. The fact you can get sodium exhaust valves is helpful too. Since the engines where sold to Forklift makers you can get a gear driven cam then drive a blower off that gear in the place of the hydraulic pump. I am not sure but I think that's how Graham drove their blower on the Continental engine. They had a right angle drive so the carburetor sat right on the inlet of the blower.

Again I enjoy your posts and have used some of your information on my project.

Thanks Loren

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One of the things I have been thinking about is the efficacy of building the jig then seeing if we could use some of the "high end" sonic tools to determine the state of the bearing in a fluid coupling. I know it is used in industry all the time. If one could find a way to see if the bearing was still good without opening it up that would be a big deal.

 

I know of two coupling personally that had bearing failures. Both of these were high mileage cars that were driven on a daily basis in and around the greater San Francisco Bay Area. In one case it was a person that used the car for their job and it was her only car. I got a call from the one shop in town I trust if I don't want to do something. They said she was screwed and wanted to know if I had any spare couplings. 

 

I had one that was "rebuilt" by a company years ago before they went out of business. I sold it to them at my cost so they could get her back on the road. You should have heard the racket when the bearing starts to go.  I have that old one and it is first up on the cut open list.

 

I have a few others and like I said above, if they was a way to check the bearing without opening it up, that would be a good thing.

 

***************

As an aside, in an indirect response to the current thread on the fluid. I do not understand the mentality of telling people not to drain and put new fluid in the couplings.  The factory never intended for the units to run forever. The VP of Engineering at Gyrol told me that the additives break down in 5 to 7 years even in the cans. The unopened can I had analyzed showed that the additives had broken down. The couplings have air in them and as such the fluid will foam without the additives and foaming lowers the power transfer. The anti-rust will die and the moisture in them will slowly eat at the bearing.  I just don't get it.

***************

James.

 

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Knowing nothing about how the inside of coupler is laid out, I wonder if one could but a small endoscope (optical probe) in thru the drain plug hole and garner any useful information?  We used to use them to inspect bearings on gearboxes in wind turbines, but room to look around was never an issue there.  I know they make them to work with smart phones for pretty cheap.

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20201118_184916_compress85_compress73.jpg.f557c9dd92e05509c225a143800e66f9.jpgThat inaccessible rotated bearing..

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In the November 2020 issue of Skinned Knuckles magazine that arrived in the post today there is an article by a Cam Clayton about servicing Chrysler fluid drive units. It looks like it includes how to dismantle the unit, renew the carbon ring seal, reassemble, etc. along with some tool drawings for specialized tools to perform the operations. I don't know squat about fluid drive units so I am unable to pass judgement on how effective or complete the instructions are but it might be of interest to those who have a vehicle so equipped.

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The hard part is having the Miller tools and....just finding  the correct parts....let alone what if the front bearing is bad or the seal ring surface is worn /pitted or scored.

Not common but I've seen all that.

Best fix... find a good FD coupling.

Generally though FD couplings are very trouble free IMO.

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DISCLAIMER. My fluid drive was not an OD.

I guess I'll throw down the joker option in the deck, to me fluid drive is merely a "gimmick" that I will never truly appreciate. I replaced mine with a standard 3 speed over 10 years ago and never looked back.......no more sluggish rolls from a dead stop and no rowing through molasses from second to third. I know how to hold a standard on a hill so that is no issue either. Now my engine is mechanically attached to the rest of the drivetrain so the E brake is not a huge issue anymore.......I'm very happy without it.

Edited by Frank Elder
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Yea at times I get tired of the Sluggo-matic cars and switch to driving my Plymouth 3 spd OD or better yet my 4 ton Dodge with 13" clutch, a 5 and 2 with no syncro's.

An hour of driving the truck and I'm happy to be back driving the Chrysler's😁

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I have been pondering on replacing my 3 speed with a 4 speed OD, still using the original shifter for the forward gears and using a separate stick under the dash for reverse...I saw it on youtube with a 60's Ford car. Looked real simple to operate.

If I was to convert to floor shift it would be a tremec/getrag 6 speed with double OD and a 3.90 pumpkin, plenty of grunt in the first 4 and steep enough for double  OD. That would utilize all 100 horses nicely.

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I can say that if one drives a '40's car in daily traffic in a Large City like San Francisco that one does appreciate the fluid coupling.

 

When you roll up to a stop sign or light on a hill with people who have zero knowledge of a stick shift and are 2 feet off of your rear bumper...

 

In California if you were to roll back and hit someone, even lightly, you would be at fault, and you would pay a lot to fix their plastic bumpers.

 

Since my back is bad, serious issues with the disc's at L3 & L4, I can get some pretty good pain running down my legs. Pushing on a clutch all time does not help.

 

In my case, the 1947 Desoto IS the car we drive. We own nothing older than 1949.  So, although the standard clutch is superior in power at acceleration and at slip (none) at highway speed, the fluid coupling does have its advantages.

 

Tod, thanks for the hint on the Skinned Knuckles article. I will hunt it down.

 

My plan is to build the jig so that it can be mounted on most larger lathes to take the weld off and then weld it back up. I also plan on loaning it out if anyone else wants to use it. I also have a complete set of fluid drive tools.

 

The only real PITA thing with these units is the bearing inside. Everything else can be had from the outside. Since Chrysler used the "low line" FAF bearings it is not surprising that some of them are starting to go. The best insurance to make sure a good bearing stays that way is to change the fluid every 5 to 7 years. Foaming fluid can have an effect on the lubrication of the bearing. Also, since according to the engineer at Gyrol the housings will allow over years some vapor to get inside, the anti-rust additives are also not a bad thing to get refreshed every now and then.

 

James.

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The biggest problem is having FD vibration/balance issues after the couplings have been cut open and welded  back closed.

It would be nice to see how they were originally serviced....cutting the housing open  welding and jig equipment.

Modern torque converters are easy compared to a FD.

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