Overdrive Question

Pat/Ohio said:
Vic, I have been watching this thread with interest as I want to do something with my '40 Ford Conv. I would love to have a Columbia set-up, but locating all the parts along with the cost compared to other options puts it on the "back burner!" I was thinking Mitchell for a while (and still am), then I purchased a 3:54 gear set from Speedway for $350. It is still sitting on the bench as I type.

I have a 3:54 gear in my '32 5-W. It works great! I generally cruise around 55-60. That's fast enough...especially with the mechanical brakes etc. of the '32.

Let us know what you decide....can't wait! :)

Good luck, Pat
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Hi Pat, at this point I'm leaning toward the 3:54 gears as they are a lot less expensive... Vic
 
Butch11443 said:
Vic, you might also look for an overdrive transmission out of a 40's Zephyr. It would work great for you also.
Butch
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Butch, I have a Columbia for our '39 Zephyr, but for the '39 Ford, I don't think the '40 Zephyr OD transmission would work without a ton of modifications, and that's more work than I want to get involved in, but I appreciate the suggestion. Vic
 
Lincoln did not have an factory installed overdrive transmission in 1940 outside of the Columbia overdrive. 1941 started Lincoln adding a factory installed Borg Warner overdrive unit to their cars.
 
copperpenny said:
Lincoln did not have an factory installed overdrive transmission in 1940 outside of the Columbia overdrive. 1941 started Lincoln adding a factory installed Borg Warner overdrive unit to their cars.
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I wasn’t sure if it was '40 or '41 when Lincoln went to the BW OD unit. As I said, I have a Columbia for our '39 LZ. When I said it would require a lot of modification I was referring to installing a BW OD unit in the '39 Ford, not an easy task it at all possible. Vic
 
Vic, the big issue is: do you want to chop the floor up to fit in the Mitchell? I don't know about 39s, but most of the earlier V8s (except pickups, etc.) require non-trivial floor mods. John
 
John, No:eek:, I don't want to have to modify the floor in the '39 Convertible Sedan. If that has to be done, that's the end of the Mitchell for me; I'll go with the 3:54 gears. Vic
 
Vic you change the rear gears and it will hurt take off from start and use more clutch to get going.With Mitchell you can use it in any gear.And you do not have to redo the floor as I put a complete Bradley floor in my 40 conv.That is why I used the cable shift Don
 
Vic,
Since you have not received a report from someone who has a 39 CS, call Sue at Mitchell. She may be able to put you in touch with someone who has put a Mitchell in a 39 CS.
John
 
John, I think I'll give them a call however, after all the responses I've had; I'm leaning toward the 3:54 gear set...:confused: We'll see. Whatever I do, I'll try to make the conversion while you are down here. You know we could use your supervision...:D Vic
 
flatmotor40 said:
Vic you change the rear gears and it will hurt take off from start and use more clutch to get going.With Mitchell you can use it in any gear.And you do not have to redo the floor as I put a complete Bradley floor in my 40 conv.That is why I used the cable shift Don
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Don, that's good to know, now I may shift (pun intended) my attention back to the Mitchell OD. Vic
 
I have both the 3:54 & the B-W overdrive. 3:54 in my 34 pickup & B-W in my 31 chevy done by Mr. Lloyd. With the B-W you will not need to pull the differential or engine to work on clutch etc.Mr. Lloyd's setup has it set up so you can remove the overdrive by it self thus allowing you to remove tourque tube, ****** etc.
 

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I doubt you are as silly as I, but one solution might include simply upsizing wheel and tire size, providing clearance exists. Going from 700 x 16 to 750 x 17, I found there was a gain in road speed per RPM of about 12 1/2 percent, largely because the sidewall was greater in its width. At this moment, a question occurs to me along these lines. I wonder why a tire manufacturer does not make a tire with extreme sidewhall width, retainining the 16 inch inner diameter but increasing the outside diameter substantially. Maybe it would look too strange or something? Of course, speedometer is going to off if this is done this way.
 
Perry, I must be silly as well because if I'm planning to do any long distance driving in my '35 sedan w/4.11 gears I put 750 x 16 tires on the rear. Helps me keep up with the big boys without over revving my little stock 221 engine.
 
Perry, when I got the '39 CS (20+ years ago) it had a set of Goodyear 650X16 tires on it and they hit the front fender when turned sharply so, I replaced them with 600X16's and over the years I've had several sets of bias ply and now I have a set of 600X16 radials that give a much better ride and handling. Vic
 
I bet it does ride nice, Vic! I recall changing my 69 Chev 4wd from belted tires for
radials back in the day. It was unbelievable the smoothness in ride I gained! I would offer one more thing, though, Vic. Maybe better to ask the guy who has done it, but
I calculated a rather miniscule gain in Velocity per RPM when changing ring and pinion on a Model A Ford -- from 3.78 to 3.54. Seems like it was 6 percent or something. Seems that would be only a three mph increase when cruising at 50 in the latter case versus the prior case, i.e., 53 vs. 50.
Perry
 
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Perry, there is a lot to consider on both sides so I'm going to do more research before I make a decision. Vic
 
Correct, but some look more at reducing engine "strain". As speed increases the percentages stay the same, however at 70 mph the numbers get larger. Rpm drops from 2964 to 2766 with a 30 in. tall tire. I think the O.D. add much more flexibility. JMO
 
Vic,

One other thing that you might consider if you install 3.54 gears.

Don't know what gears you have in your transmission, most likely a 28 tooth cluster/16 tooth main drive gear.

Swapping that out for a 29/15 combination would give you a 1st gear close to the standard 28/16:3.78. That CS is heavy and the 3.54 MAY require more clutch slip and low gear lugging than you'd like.

Just put the 29/15 gears in a '36 4dr that had a 3.54 rear, and the take off was improved.

Kinda the opposite of Lincoln Zephyr gears that require a gob of low end torque.

(Of course, 3rd gear is straight through like all gear sets.)
 
flatmotor40 said:
Vic you change the rear gears and it will hurt take off from start and use more clutch to get going.With Mitchell you can use it in any gear.And you do not have to redo the floor as I put a complete Bradley floor in my 40 conv.That is why I used the cable shift Don
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Don, What gear ratio are you using with your Mitchell? And, Which Mitchell gear are you using? Any problems installing the Mitchell in the '40 Conv.? I am thinking that Vic's '39 CS is close to the same weight as the '40 Ford Conv. Pat
 
I put the 36% and I have a 3.78.When you leave OD in and you start off it is a little soother than with the 3.78 but engine RPM is down.Works great and if you see a big hill you just clutch it shift in non OD and get it done Don
 
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