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Overdrive speeds


ThriftyT

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4 hours ago, James_Douglas said:

I have run my 5000 pound 1947 Desoto for 15 years with a 251 engine, a fluid coupling, and the three speed stick with BW overdrive. I have used the 4.1 gears and the 3.9 gears. I go down the highway at 65 all the time.  On hills, I usually have to drop it out of overdrive. The car is just to heavy compared to most running the six.

 

As far as I know there is no overdrive that was made to mate with the M5/M6 transmission. I do know you can go get a gear vendors OD unit and splice it into the driveshaft. At a cost of about $6K by the time you are done. I know guys with Packard's and the like from the 1930's that have done that.

 

James

Some Volvos have a similar OD that can be adapted in that same fashion. 

 

Or, if your desire is great and your pockets deep enough there's always the Hone-O-Drive. 

https://www.ebay.ca/itm/HONE-O-DRIVE-Overdrive-Baldwin-Motion-Yenko-L88-ZL1-Shelby-Mustang-Comaro-K-Code/233646184478?hash=item366665d81e:g:docAAOSwR9BfEi-i

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I had a 30 over 57 model 230 in my 48 Plymouth coupe with Edgy head, Offenhauser intake, dual Carter Webbers, cast iron headers and Langdon's HEI distributor all in front of a 53 model R10 with 3.90 rear. I also had Rusty Hopes disc brakes. I made multiple round trips from Dallas to SW Missouri which is an 800+ mile round trip with the majority of it on multi lane highways. Would cruise at 70 all day long with no issues. Drove the car short distances of 4-5 miles on the Dallas North Tollway where if you are doing 70 you are getting ran over or receiving lots of a finger up rather than thumbs up. 

 

Only problem I ever had with the car on the trips to Missouri was a broken alternator bracket near Vinita, OK on the Will Rodgers Turnpike. A heavy screwdriver and two pair of vice grips got me the last 60 miles or so to Joplin where I could get it welded. 

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On 8/3/2020 at 4:03 PM, harveyspoint said:

Gentlemen...I had a '48 P15 Coupe for 42 years....Stock engine, 15" wheels and I put a '52 Plymouth overdrive into it..I put 25000 miles on it and was very pleased

with it...I could   run down the road just like the newer cars... It seemed like it was just above idle at the speed limit...2300 RPM was 65 MPH...1900 RPM was 54 MPH...

You multiply your rear end ratio by .7 and this is your O.D. ratio...3.9, which was the standard '48 Plymouth rear end =2.73 with O.D....You can manipulate the governor

with a toggle switch and you have a 5 speed tranny....Those old engines have plenty of torque, unlike the new short stroke engines...That's what you call cruising...

in 2014, I was going to repaint the '48 and the kids said 'Grandpa , you shouldn't be painting that car at your age, this new paint s deadly, why don't you find one that's

already painted and ready for the road?'  So we looked on the Internet for a while and found a beautiful maroon '47 coupe, with a '53 engine and a split manifold....

So, I took the O.D. out of the '48 and installed it into the '47, and gave the '48 to my Grandson, who had grown up riding around in it...I'm 87 now, but one of the best things I ever did

was to put that O.D. in that car....Makes a world of difference, so, go for it ....

Back in 72 I found an R10 OD 3 spd tranny for my p18 for $75. If you can find one now itll set you back 2 gr or more. Because these OD trannys are getting so rare now Im leaning towrards a 3.55 rear end for next years project

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1 hour ago, michaelmarks697@yahoo.com said:

Back in 72 I found an R10 OD 3 spd tranny for my p18 for $75. If you can find one now itll set you back 2 gr or more. Because these OD trannys are getting so rare now Im leaning towrards a 3.55 rear end for next years project

 

I paid $150 for my R10 with a 218 attached about 6 years ago. 

 

Saw an Ebay add for a Plymouth Flathead and Transmission. I just about went right past it because his photos on the ad were pretty dark and hard to see, but I caught a glimpse of what I thought was governor on the side of the transmission. The auction had only about an hour left on it and he had received no bids. Sent him a message to ask if it was an overdrive and by the time he got back to me the auction had ended with zero bids. 

 

He verified that it was an indeed an overdrive and that it and the engine were from a 53 Suburban that he was putting a new Gen III Hemi/Automatic in. Said if I wanted I could have it for $150 but had to take both the engine and transmission. He was in Denver and Amarillo was as close as I could get inside my sales territory for work so arranged a business trip to Amarillo and rented a pickup for the week. Made a few customer calls a couple days then that went to Home Depot to buy some lumber to build a cradel for the engine/transmission. Wednesday I drove to Denver, picked it up and drove back to Amarillo. Thursday I drove back to Dallas with a couple of customer visits on the way home. 

 

So, I was able to expense the trip to go pick it up as well giving me the R10 and a spare engine for a total of $150. 

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I am talking with a guy in Tucson that has what he says is the complete drive train pulled from a 51 Plymouth for sale.  Someone pulled it to hot rod the 51 with a V8.  It is complete, from front engine mount plate to oil bath air cleaner to emergency brake on the tailshaft.  I am awaiting a shot of the engine number before I get serious though and I have a couple car friends in Tucson that can take a look see for me.  I plan to take the company truck all the way to Tucson to get it if the deal works out.  I get to use it for personal use, I get charged a flat fee of $160/mo, and they pay for everything else, including the gas.   I rarely use it for personal use since it is a monster that I hate parking in town.  2019 Silverado 2500 4x4 long bed, yeah it couldn't get bigger.   My other option is the Cambridge, which I much prefer around town but it's not going to carry that back from Tucson.

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OD reducesengine rpm at highway speed. The governor controls the cut in and cut out speed typically around 35 mph to engage and similar or slightly lower for drop out. Depending on tire diameter and rear end ratio this reduction is around 900 to 1000 rpm. So at 60 in direct drive engine room will be in the 3100 range, when in overdrive rpm will drop to around 2300 rpm.  Makes high way cruising.  You can also use it in city driving by leaving the trans in second gear and using it as a two speed. If your car is still wired as from the factory, the is also a kickdown function if hill climbing acceleration or passing is desired to automatically drop out of OD.  In the downloads section of the website there is a printable guide to operation and maintenance.

 

In both second and third gear the transmission will freewheel under 30 mph meaning engine compression braking is not available.

 

If your car is stock, pushing in the control cable engages the OD and it's electrical controls.  Note it is not recommended to select reverse gear with the cable in.  Some say there is an internal control which desserts OD if reverse is engaged but I have found mine doesn't work. So cable out when reversing.

 

To use the OD push in the cable, drive and shift normally, (except for the freewheeling bit) until you are at speed in excess of the cut in speed.  Lift of the gas pedal briefly then press down evenly this should trigger OD engagement.  You can feel when it cuts in and hear feel the decrease in rpm. To disengage floor the gas pedal to trigger the cutout switch or just slow down till rpm drops under the governor's set speed.

 

My governor is set a bit high and doesn't engage till about 45 mph so I only use mine when I am on the highway.  The governor provides the ground path that allows the solenoid to engage.  At a minimum before you try to use it, a check of the wiring and the connections to assure everything is clean and tight and that the fuse in the OD relay is in properly and of sufficient amps for the circuit, 20 amp if I recall correctly.

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19 hours ago, Sniper said:

I am talking with a guy in Tucson that has what he says is the complete drive train pulled from a 51 Plymouth for sale.  Someone pulled it to hot rod the 51 with a V8.  It is complete, from front engine mount plate to oil bath air cleaner to emergency brake on the tailshaft.  I am awaiting a shot of the engine number before I get serious though and I have a couple car friends in Tucson that can take a look see for me.  I plan to take the company truck all the way to Tucson to get it if the deal works out.  I get to use it for personal use, I get charged a flat fee of $160/mo, and they pay for everything else, including the gas.   I rarely use it for personal use since it is a monster that I hate parking in town.  2019 Silverado 2500 4x4 long bed, yeah it couldn't get bigger.   My other option is the Cambridge, which I much prefer around town but it's not going to carry that back from Tucson.

He shoots, HE SCORES! dam do you mind if I ask what hes asking for it?

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5 hours ago, michaelmarks697@yahoo.com said:

He shoots, HE SCORES! dam do you mind if I ask what hes asking for it?

 

He's asking $1500 but it supposedly recently rebuilt.

 

What I'll pay though, remains to be seen.  He has just sent me the pic of the engine number, it is not out of a 51Plymouth and it is not a 218.

 

It's a D42, a 230 I may have scored here as I have been looking for a 230 and even core 230's are not cheap, ~$500 is what I have been seeing on the low end.  Mind you this is a complete drive train take out, see pic.

D42.png

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If the 218/230 difference is important to you, and impact the price you would pay, be sure to check the actual stroke.  Since it has been rebuilt, especially if done by a commercial rebuilder, not a shop, the block and crank may not match.  Really common practice to just use whatever is available to build to order.

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