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Speed and towing


48rob

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Hi,

 

 I'm considering a 1946-49, and maybe 50-51 as my next old car.

 

I enjoy touring (long distance) and camping.

I want a car that will run 65+ all day, and that can pull a 2500 pound low profile camper.

Tongue weight of 300 pounds or less.

I really want to keep the rpm's in the "relaxed and easy" range, not screaming and shaking...

 

A long time ago I owned a 1950 Dodge sedan. As I recall it would cruise at 55 or 60 mph, but my memory can't distinguish between top speed and comfortable rpm's.

Most of the other old cars I've owned were in that same range of 50-55 comfortable cruising speed, though some were perfect at 40mph...

 

What are these cars like? Any of the models come with better highway gears?

Would a BW. overdrive be the answer?

 

Thanks,

 

  Rob

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those cars came with the BETTER gears for the time it was built..today they just come with better highways..you will more than not want to change rear ratio and or go with the OD unit..or a combination of them both...consideration for later model tranny would be food for thought..as the cars got new..the highways faster and the improvement gas quality...car crusie speed were on a steay uphill climb...rear gears were often one of the first things that got factory altered for these higher sustained speeds as basically only things that changed engine wise was a slow increase in CR which related to slightly higher HP..

 

assuming you staying stock with the engine...you never mentioned anything here...the flattie built its max torque in/about 1200 rpm so basically you have your full twisting strength at very low end..why I suggested later wide ratio 5 speed tranny...due to the lower ratio of the lower two gears will allow you to change the rear ratio and still have stock performance in 1 and 2...3-4 streetable and 5th for cruise.

 

Do a search on these pages..(upper right hand corner of the page)..be sure you are at TOP OF FORUM and not within just this thread...there are pages upon pages of those folks reporting back here with the changes they have made...yours for the reading..will get you up to speed fast in what is available and may help you decide you ultimate end goal build..

 

as for tongue weight and trailer..I recommend a later style receiver hitch mounted and tie to the frame and not just one hung across the rear flimsy factory tie bar that at best maintained separation of the frame rails.  Also be sure to displace rocking on stop/takeoff to a point along the frame rails forward of the rear mounting point...frame stress will result otherwise and possible early failure of the metal..and your rear spring mounts need to be in great condition..the shackle bushing are soft rubber here and very spongy even when new..poly bushings from a later A body will help with this..body sway is bad even without a towing load..look to a panhard rod for better control while towing..

Edited by Plymouthy Adams
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PA,

 

  Thank you for the detailed information!

 

I'm good with the stock engine, just trying to reduce rpm and gain decent highway speed.

 

I'll start reading the mods other members have done.

 

What is the average comfortable cruising speed with these cars, stock?

 

Rob

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Peak HP was at 3600 rpm.  Cruising speed at 80 to 85% of that rpm can be maintained in normal conditions at normal altitudes.  So take your gear set, and your tire diameter and dial up one of the several online calculators that will convert that rpm to road speed based on the gearing and tire variables.  I have 225 75 15 radials on my car and 62 mph is 3280 Rpm with my 4.11 rear.  We have done several trips of over 500 miles with naught but a broken fan belt to side line us.  This with a trunk load of traveling supplies, tools and baggage.  Check with your insurance carrier to assure they do not have restrictions concerning antique cars and trailers, some specialty companies in the collector car field will not cover damage if / when a trailer is attached.  Do not forget to considered upgraded brakes and or trailer brakes as you research your vehicle.  I think Dodge or Chrysler fluid drive might be and advantage to towing.

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as Greg points out, the fluid drive would be an asset while towing especially on areas where you may have to stop on an incline...no need to clutch..just hold the brake and rev and pull away safely..as it is just a coupler, there is no torque multiplication...do not consider this device a torque converter

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With a fluid drive there is limited engine compression braking and when parked there is no engine compression braking. So a good working emergency brake that will hold the load on a hill is a must.

 

If you install a Mopar built overdrive transmission there is NO compression breaking as the unit will freewheel when the over drive is engaged. As was mentioned earlier if you upgrade to a 5 speed overdrive manual transmission such as a T-5 you will have compression breaking in all gears.

 

Front disc brake conversion is inexpensive and easy to do and I would recommend it especially if pulling a trailer. A differential swap from a later model vehicle can offer a better final ratio and  improved emergency brakes.

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With a fluid drive there is limited

engine compression braking and when parked there is no engine compression braking. So a good working emergency brake that will hold the load on a hill is a must.

 

If you install a Mopar built overdrive transmission there is NO compression breaking as the unit will freewheel when the over drive is engaged. As was mentioned earlier if you upgrade to a 5 speed overdrive manual transmission such as a T-5 you will have compression breaking in all gears.

 

Front disc brake conversion is inexpensive and easy to do and I would recommend it especially if pulling a trailer. A differential swap from a later model vehicle can offer a better final ratio and  improved emergency brakes.

If you install a simple toggle switch to override the governor you can compression brake with an overdrive all the way to stalling it out.

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If you install a simple toggle switch to override the governor you can compression brake with an overdrive all the way to stalling it out.

 

I used a momentary switch on the shift knob. It would do this but you had to hold the button.

 

Normally you would just coast without compression braking unless you held the button.

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Your actually are going in two different directions. If you want higher hi-way speeds ODs or a taller rear end is the way to go. But for towing a stock 4.1 is going to be way easier on your clutch. And in a lot of states your are still limited to 55 mph when towing.  For class 1 (under 2 K ) stock brakes will get the job done if they are in excellent condition except for brake fade when used repeatedly like coming down a mountain (first hand knowledge on this issue) so a front disk upgrade is a good call if your towing a lot. At 2500 tow I would stay away from going with a taller rear end and you are also going to need to upgrade your rear springs and shocks (I went with adjustable air shocks) with a 250 to 300 pound tongue weight. The trucks get around the issue by having a compound low (granny first gear) to get you rolling when you have a load to pull. 

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The governor is just a switch that goes to electrical ground somewhere after 25-30 mph, when you slow down past 25-30 mph the centrifugal force can no longer overcome the governors spring and it opens the circuit to ground, this opens the relay circuitry and disengages the solenoid allowing you to freewheel until the spragg clutch catches when the driveshaft rpms match the engines. I prefer to run a wire from a grounded toggle switch to the governor's terminal on the lockout switch, others run it to the relay but i worry about accidental bumping the switch when the overdrive cable is pulled out.

This switch allows you to decide how soon the overdrive can engage or how long it stays engaged, you can turn on the switch at whatever speed you want under 25-30 mph and it will engage, after that speed its moot as the governor has already closed the circuit. If your going down a hill and od keeps dropping out you can hit the toggle switch and override the governor trying to disengage the od.

I also use the switch a lot when I'm testing the overdrives i rebuild.

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Thanks for the safety tips and insurance company warnings, good advice indeed! :)

 

I've been pulling the trailer with a stock Model A for 11 years, lots of fun!

I don't nessesarily want to pull the trailer at 65, but do want the car to be capable when out touring.

 

The 1928 Ford will pull the trailer at about 45-50, and it all stops very well.

The brakes on the car are in very good condition, with adjustments kept up to date, it stops like it should.

After adding 2400 pounds though...it needs help. A 6 volt brake controller runs the trailer brakes.

I don't even bother with the cars brakes when towing, the trailer does it all!

We generally take the combination a hundred fifty miles out to favorite state parks, but I want to go farther. 

If work didn't keep getting in the way, it wouldn't matter, but I only get so many vacation days a year.

 

 

headinghome-1.jpg

trailer1.jpg

 

It sounds like these cars might well be able to do what I'm after.

I'll keep reading the posts and see if someone came up with the perfect combination of modifications.

 

Rob

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I am confused about the claims of freewheeling while in OverDrive. Mine only freewheels when OD selected and under 26 mph...going down hill at highway speeds I can hear the pipes rapping......anyone else notice this....

I'm with you; Don has the symptoms backward.  When the OD is active and engaged you get compression braking; only at lower speeds when the OD is activated but not engaged does it freewheel when you lift off of the throttle.

 

Marty

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If I were you I were you I would get a 48 - 54 Plymouth Suburban. You could put some wood vynle on it and have a matched set. Stock with disc brakes and you will be amazed at what you have. After a few triips you can decide what you want to change. p.s. the sedans and tudors are the same undercarrage. Did you build that 'tear drop"?

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I am confused about the claims of freewheeling while in OverDrive. Mine only freewheels when OD selected and under 26 mph...going down hill at highway speeds I can hear the pipes rapping......anyone else notice this....

 

Mine freewheels in direct drive only, not in OD.  Once I get below 30mph and the relay kicks off it goes back to freewheeling.  With the cable pulled out or od locked out, it will give me engine braking.  At that point

though it is basically a manual 3 speed transmission.

Edited by steveplym
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Thanks for the compliments!

 

Yes, I built the trailer.

 

A "woodie" wagon would look cool, but I really have my heart set on a coupe.

My first choice is a business coupe but reality says I need at least a small back seat for my grandkids, who are with us most of the time and who also love to go camping!

 

Rob

 

For those interested in the trailer...

 

IMGP5704.jpg

hatch2.jpg

pillows.jpg

shower.jpg

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If you are going to tow that trailer, a Plymouth P15  2 door sedan would match the trailer profile nearly perfectly.  They have a large back seat, pretty good sized trunk. They are hard to find as they were the least made style.

 

http://classiccarliquidators.com/photos/1334180519/large/4.jpg

 

 

The business coupe body doe have enough room behind the front seat to modify the area to accept a rear seat.  However the small rear 1/4 glass is fixed.  Could be OK for kids through mid teens.  The club coupe came from the factory with rear seats roll down windows and room for 4 comfortably and 6 in a pinch.  Good sized trunk. 

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Mine freewheels in direct drive only, not in OD.  Once I get below 30mph and the relay kicks off it goes back to freewheeling.  With the cable pulled out or od locked out, it will give me engine braking.  At that point

though it is basically a manual 3 speed transmission.

This is a quote from BW manual

 

When the electrical components of a B-W OD are not functioning this is all that the transmission will do - freewheel. Freewheeling at speed is dangerous and can lead to loss of control due to increased brake use. However a properly functioning B-W OD does NOT freewheel at speeds above 28 mph. In a properly functioning OD engine braking DOES happen. The thought that engine braking is not possible is a major misconception for a B-W OD transmission.

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1941Rick, on 20 Dec 2014 - 11:01 AM, said:

This is a quote from BW manual

 

When the electrical components of a B-W OD are not functioning this is all that the transmission will do - freewheel. Freewheeling at speed is dangerous and can lead to loss of control due to increased brake use. However a properly functioning B-W OD does NOT freewheel at speeds above 28 mph. In a properly functioning OD engine braking DOES happen. The thought that engine braking is not possible is a major misconception for a B-W OD transmission.

Thanks for your correction.

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