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37 special max speed


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Whats  the maximum  speed  that I can reach on a 1937 buick special series 40      of course with a original  248 ci  engine ?   I  started this topic last year , thinking that something was wrong with my car . 

I had a lot of  help and answers .  But all of them tried to   resolve the problem  with a tune up , spark plug . fuel filter  etc .    Well,   now after talking to a few buick owners  around jersey  ,  I come with a question : 

   Is there anything wrong with my car to  begin with ?    Not according to   a few buick owners !   they said that   35 / 40  mph is the maximum speed I can get .    I would like to get some input from you gentleman .

                                                          Best regards

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I don't know what the maximum speed would be but I have driven mine at 75 mph and it could have gone faster. Your engine will be spinning about 3700 rpms at 75 mph with stock gearing. Whoever says that 35 or 40 is all they can go is wrong. With stock gearing your car will be happy cruising all day long at 50 mph. We drive our Buick almost  every day and ours has the same engine and transmission and rear axle as yours. We have installed an overdrive in ours but we don't use it at speeds less than 50 mph.

Edited by LAS VEGAS DAVE (see edit history)
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I can cruise my '32 at 50-55 without too much strain.  While the gearing is low, it could use an extra gear, but I am fine.  Have you verified the speedometer accuracy?  Maybe some one has the wrong size tires.  Do you mean it will actually not exceed that speed, or do you mean the engine is really "wound up"?

 

John 

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Even if it has 14inch wheels and small tires which it probably doesn't  it should be fine at 50 mph. The smart thing to do would be to take Daves advice and hook a six volt tach to the coil and drive the car at least 3000 rpms and see what your speedometer says. What size are your tires? No 1936 or later Buick will only go 40 mph, some will go 100mph.

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 what I mean by rev the engine is that in neutral the rpm s go up !     and I checked to see if I'm really engaging  in 3rd

​ gear  and it looks like I am ,  you can tell the   difference .    the only noticeable  thing here is :    the gears are very  veryvery    ​   very   very   low ,    all 3 of them .    This car is completely  original  but I'm gonna have to check the rear  diff size   .

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My stock geared 1937-41 was cruising all day at 55-60 when we drove to Nashville last Sept. Over 1,500 miles. No more than 55 up hill and tried to keep it a 60 down hill. And yes it is a workout for these cars. It is much happier at 50-55.  I know the feeling that at 35 mph the engine revs sound as if the car is waiting for you to shift to the next gear. A little faster and all feels in harmony..... I love it.

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I've found that my GPS gives me a more accurate indicator of speed than my speedometer.  I also don't have to try to communicate with someone behind me in a different car trying to match exactly the speed I'm trying to maintain.

 

If you look at the newer hi-tech aftermarket speedometers, most of them are now GPS driven rather that through gears and cables.  You don't need to worry about tire pressure, tire size, worn magnets or anything else.  I get a nice digital screen with numbers on it, not even a needle to misread.

 

It doesn't even need a power source; it will run on its internal battery for quite a while.

 

Worth a try.

Edited by RivNut (see edit history)
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My stock 4.44 gearing that should be the same as yours doesn't feel to low for the power the engine has. All the 37 BUICK SPECIALS had 4.44 ratio rear ends.  I don't think there were any ring and pinions made that would give it a lower gear ratio than the 4.44 ratio. There was a set offered by Buick that would give it a higher ratio. A larger rear axle housing would be necessary to fit a set of gears that would give it a lower ratio. Maybe someone put a completely different rear axle housing in your car for some reason but I doubt it, that would require a lot of work with no gain. I think your engine is not even getting 3600 rpm for some reason. 

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RiveNut   i dont think i can tell if im going 35  or 31  mph ,  but im pretty sure  i can tell the diff  between  35 and 55 .  So my problem is

not in what speed im going but why im going so slow .    And Las Vegas Dave i think thats what im gonna have to do....    first find out

whats the rpms  at the highest speed  that I'm able to go.  tx

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here is something simple to check...

 

When I first re-assembled my '38 (basically the same car as yours), the linkage to the carb was way out of adjustment.  When the gas pedal was mashed to the floor, the throttle plate was only about 2/3 open.  Have someone hold the throttle down, while you look down the throat of the carb (engine off).

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If it was a slipping clutch, your nose would alert you to that in a very short while, unless the clutch was completely gone, and then it would be difficult to get the car to move at all.

 

As a very long shot, can you actually go through the 3 gears as you accelerate?

 

It is virtually impossible to put the transmission together incorrectly

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Can we clarify?

 

Is the car "hitting a wall" and just will not accelerate past 35 MPH, no matter how hard you push it?

 

OR
 

Does it simply "sound" too busy and you're afraid to go past 35 MPH?

 

If it's the former, then yes, there's something wrong with the car.

 

If it's the latter, it's merely a matter of re-tuning your ear to a car without overdrive, without tall gears in back, with a long-stroke motor, with a mechanical cam, and without a lot of sound-deadening material between you and the engine. If it sounds busy, that's OK, you're not hurting it by going faster. Totally normal on these cars.

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  Dave

   ,lol   I'm gonna check carb  !                                                   

  Matt :    I'm sure I'm going about 35   and theres no way I can get 20 mph on top of that.

 And jeff    I have to agree with Don about that clutch....

   Don  I go thru all 3 gears ,  and whats bugging me is that   they  feel   preeeeety   short  !   All 3 of them .

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On the tach, if you find a 12V it will work if you provide a 12v source inside the car. 8 D cells in series will work fine, the tachs don't pull very much power at all. The line coming in from the distro side of the coil is just a trigger for the tach anyway, the circuitry basically integrates the pulses into an average which is amplified to drive a meter. Or a digital tach will actually count the pulses over a short period, scale them to RPM and present on a display. This one is cheap: http://www.ebay.com/itm/Car-Motor-2-52mm-Blue-Digital-LED-Elec-0-9999-RPM-TACHOMETER-TACHO-GAUGE-7014-/251582177614

 

Cheers, Dave

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It sounds like it has a governor. He goes through the gears but they seem pretty short. Something is limiting RPM. If it's not a governor then maybe the range of motion of the throttle is limited in some other way?

I had an old Ford truck once and a rod in the throttle linkage got bent and it acted like this car.

Dave

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On torque tube cars I use a tach/dwell meter to set my engine rpm at 1000. I then use a variable strobe light and a reflective tape on a rear tire to record it's rpm. The wheel rpm divided into the engine rpm give the gear ratio ( I can't remember if one has to divide/multiply) but it came up 4.44 for my 37 Special. On a different note I went to an open rear end but kept the straight eight engine and learned something: 2.75 gears are too shallow for a straight eight. They did fine around here (Texas) but when we made a trip to the Iowa/Minnesota border there were hills that lugged us down to 60mph so I'm going to stick some 3.36 gears in and give it a try on the next long trip. On level road the 2.75's cruised effortlessly at 75. The 37 has radial tires, power brakes. tube shocks, and large sway bars to make it comfortable in the left lane. Believe in making one handle and whoa before stepping up the "Go". You be the judge on whether or not it looks "butchered".

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On torque tube cars I use a tach/dwell meter to set my engine rpm at 1000. I then use a variable strobe light and a reflective tape on a rear tire to record it's rpm. The wheel rpm divided into the engine rpm give the gear ratio ( I can't remember if one has to divide/multiply) but it came up 4.44 for my 37 Special. On a different note I went to an open rear end but kept the straight eight engine and learned something: 2.75 gears are too shallow for a straight eight. They did fine around here (Texas) but when we made a trip to the Iowa/Minnesota border there were hills that lugged us down to 60mph so I'm going to stick some 3.36 gears in and give it a try on the next long trip. On level road the 2.75's cruised effortlessly at 75. The 37 has radial tires, power brakes. tube shocks, and large sway bars to make it comfortable in the left lane. Believe in making one handle and whoa before stepping up the "Go". You be the judge on whether or not it looks "butchered".

I have an overdrive in mine. With the overdrive engaged the final ratio is 3.73 which is great for flats and small hills. If the hill is long or steep I kick it out of overdrive bringing it back to the stock 4.44 ratio. The 3.36 will probably work 90% of the time but you might have to use second gear if the hills are to steep or to long. I find that the stock ratio is actually great if you don't mind 50 to 55 mph. I only use the overdrive on the freeways and cruise nicely at 65 or 70 mph. By the way, your 37 looks great.

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Clutch seems fine  Bob.  I'm right in central jersey , cranford ,   anybody coming by will be welcome !    we go out for good food and drinks ....      never mind the car !   lets just eat and drink !!!!  

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Swap meets may be a good place to look for a 50's dwell tach unit that will run on 6 or 12 volts.  

 

Failing at that, get a 12 volt tach   and buy a 12 volt battery  for trailer brakes.  I have one rigged to operate turn signals and us it operate LED lights.  A battery tender keeps it charged.

 

Bob Engle

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