Vette58

Top Speed for '39 Special all standard

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On ‎2‎/‎9‎/‎2011 at 4:23 PM, Mark Shaw said:

question if a Mitchell overdrive made for a 4 cyl Ford would work for an 8 cyl Buick...

I have a Mitchell in my 1925 Pierce 80 (70 bhp) and have one in stock for future installation in my 1934 Pierce 8 (140 bhp).  Friends have successfully used them in a 1933 Pierce 12, a 1937 Packard 12, and a 1939 Cadillac Series 75 V-8.  The late Mr. Mitchell beta-tested his OD in a Chevy 454 dual rear wheel pickup, and couldn't break it.  The unit is certainly robust enough!  I have no connection with Mitchell Manufacturing other than as a VERY satisfied customer.

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We have a Borg Warner overdrive in our 38 Buick Special. It requires modification of the torque tube but is a worthwhile upgrade. Lloyd Young in Ohio did the torque tube modification and I did the install back in Las Vegas, best thing I ever did for the Buick. I had to ship the torque tube to Lloyd and he shipped it back with a Borg Warner overdrive bolted to it. Our car cruises along at 65 or 70 at the same speed the engine would be turning at 45 to 50 without the overdrive. As far as keeping the car original with modifications that were available when the car was manufactured the Borg Warner overdrive was available in 38 and could have been installed by an independent shop or even a Buick dealer if the customer wanted it. In those days it was rare to have that done as the roads were not like today and most cars rarely went faster than 45 or 50 mph. The good thing about an overdrive is the car can be used just like a late model car and driven daily if wanted and on hi ways and freeways for long distances without hurting the engine life or being a hazard to others on the road. The car still has enough power to climb long grades or steep hills and the motor loafs along in overdrive on the flats and the more normal grades. We only have a Special, it would be even better for a Century. We use our car weekly at the minimum and almost daily in the winters here in Vegas. We have driven about 6000 miles since I installed the overdrive with no mechanical problems, we did have to replace an electrical 6 volt overdrive relay with a brand new one about two weeks after the initial installation, since then it has been flawless. The Buick motors of 38 and 39 had babbit rod bearings and the motors have a long stroke with high piston speed, they are torque motors and should not be driven at high rpm's for any extended period of time. In my opinion the motors should stay under 2700 rpms at cruising speeds. Perfect for their day but not so good for today.

 

 

 

Edited by LAS VEGAS DAVE (see edit history)

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On 11/12/2017 at 8:35 AM, Ben Bruce aka First Born said:

What the heck was under the chevy hood?

 

  Ben

Who knows.  I do remember the hood was off and two boys were in it.  It couldn't pass us.  My Dad finally gave into my Mom's loud demands to "quit it, Earl, have you lost your mind?"  haha

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I have some factory documentation somewhere that says the top speed of a '41 Century with 3.60 gears is 108 MPH, and that car was about 60 horsepower stronger than a stock '39 Special and the Special probably has 4.10 gears. I don't know the official figures, but I think getting a '39 Special to run faster than about 85-90 MPH would be a real feat and its longevity at that speed could probably be measured in minutes...

 

I'd also like to amend my earlier post in this topic and say that if I were doing an overdrive in an old car again, I would go with Gear Vendors instead of trying to make the Borg-Warner unit work. Many others have had success with the B-W unit (sadly, the one in my '29 Cadillac has proven to be problematic), but for about the same money, I'd much rather have the modern unit that doesn't have free-wheeling or finicky electrics. I'm strongly considering installing one in the Limited while I've got the rear end out of it for a rebuild.

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Matt, be aware that the gear vendor overdrive does not raise the ratio nearly as much as the borg warner. I have one in a 78 Ford pick up truck. The finicky electrics you refer to are not finicky at all if you have the new overdrive relay that is now being made and is available in 6 volt or 12 volt and your wiring is correct and proper size with good connections.

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On 11/13/2017 at 1:50 PM, Matt Harwood said:

I have some factory documentation somewhere that says the top speed of a '41 Century with 3.60 gears is 108 MPH, and that car was about 60 horsepower stronger than a stock '39 Special and the Special probably has 4.10 gears. I don't know the official figures, but I think getting a '39 Special to run faster than about 85-90 MPH would be a real feat and its longevity at that speed could probably be measured in minutes...

 

I'd also like to amend my earlier post in this topic and say that if I were doing an overdrive in an old car again, I would go with Gear Vendors instead of trying to make the Borg-Warner unit work. Many others have had success with the B-W unit (sadly, the one in my '29 Cadillac has proven to be problematic), but for about the same money, I'd much rather have the modern unit that doesn't have free-wheeling or finicky electrics. I'm strongly considering installing one in the Limited while I've got the rear end out of it for a rebuild.

 

     Well Matt, it sounds like you questioning my verascity (spelling).  I know what I saw.  Of course, the speedometer may have been off, and too, I was seeing it from the far right seat.  Even as a kid in 1947 I never forgot the experience.  It was burned into my memory.  The car did throw a rod, but that was in 1952-53 after Dad turned it in on a 1951 Plymouth.  I learned to drive in that Plymouth...ugh! 

     By the way, my blue '39 sedan has the optional 3.9-1 gears and I've had it at 80 more than once I think.  The speedometer needle hangs up at just over 70 and I have to tap on the glass to get it to drop back to zero.  Needless to say, not often, but I have run it 70 many times.  This car also has insert rod bearings since I rebuilt it in '65.  We were on a tour to Williams Grove 10-15  years ago with the yellow four-door convertible.  On the track I got it up to 85 for a very short time, and I think it has the 4.44 to 1 gears, but I really don't know.  I backed it off immediately because it still has babbitt bearings.  Typically I run the yellow car 55-60.  Again, who knows if the speedometer is right. 

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The speedometer in my Limited is accurate at 10 MPH, off by 2 MPH by 20 MPH and reads 60 when I'm going 52 MPH. I cruise on the highway with it indicating 70 MPH which is about 58 MPH road speed and it's happy enough there. Extrapolating from that, an indicated 100 MPH would be going about 82 MPH road speed. If I wanted to abuse the car, I bet I could get that speedo to start a second rotation around the dial by running it flat-out. However, that doesn't mean it's going 130 MPH. It's probably going about 93.

 

I'm not questioning what you saw and I'm certainly not suggesting that you're lying, I'm just trying to help the OP by telling him that the factory listed the top speed of the 1941 Century with 3.60 gears at 108 MPH. Getting a '39 Special to go 98% of that speed with 60 fewer horsepower and 30% shorter gears is extremely unlikely, and that was the question--how fast is a '39 Special? I can guarantee it's not as fast as a '41 Century and +60 horsepower is almost 50% in terms of these cars. Speedometer error is real, and it was real when these cars were new. I don't trust them a bit so I verify with my GPS just so I know how far off they are at various speeds. That's how I know how inaccurate the Limited's speedo is and that it's not a straight X MPH off at all speeds but rather a multiplier; that's why it's pretty accurate at low speeds and gets less accurate the faster it goes. I suspect the engine/transmission are out of a 1941 Roadmaster, which would explain why it is off by almost 20% at 60 MPH.

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Top speeds mean little as it can only be for a short time whatever it is. Cruising speed which is the speed a car can be driven for hours at a time with no damage to the motor is  what interests me and is what normally matters in the real usefulness of a car.

 

 

Edited by LAS VEGAS DAVE (see edit history)
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Okay, agree with all.  By the way Matt, that test '41 Century probably had the all-metal high compression head gasket too.  Most of those are long gone now and replaced by the .050 head gasket, and that reduces compression.  A late friend of mine, a retired line mechanic, was always wanting those metal head gaskets for his '41 Century just in case he needed one to boost the umpf of his car.  He liked fast Buicks.

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On 2/10/2011 at 9:30 PM, soldier said:

I had a 1940 Buick Roadmaster back in the day(1953). I was able to get it to 98 mph on a long flat stretch of lonely road late at night. Back then we had no speed limit in Iowa except a reasonable and proper clause. I'm not sure if I had been detected by the Highway Patrol that they would have thought that to be proper. I was a little disappointed, as a thought the old girl shoud have made the 100 mark. Soldier

 

 

No the Roadmaster could not do 100, that was saved for the Century and is the reason they called it the Century. The only Buick that could do 100 (the century)

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