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change rear end ratios in our 29


Guest sintid58
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Guest sintid58

Our 29 runs very well but really seems to be running hith rpm at 45 mph and very uncomfortable at 50. It would be nice to have it run a comfortable rpm at 50 or 55 when we are touring with it as we plan.

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I think you will find that all of the Buicks of that era have quite low (numerically high) rear axle ratios. You may have to look at another method of changing ratios - maybe getting something made ? Or adapting something more modern. An aquaintance of mine built a rear end for his 1925 Vauxhall 30/98 using the original case but with a complete modern differential unit inside it. He also added different brake drums with more lining area.

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Sid,

Did you find the old thread about Joe Krepps from Florida was having some gears made. I changed computers and have not yet downloaded all my important stuff from the old unit, or I would have all the information. I beleive he was going back to the late twenties and early

30s. If you cannot find elsewhere, I will look back soon and see what I can find.

John

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Guest sintid58

I have thought about adding overdrive but wondered how much work it will be with the torque tube. I really don't have time to do it myself so would probably have to try and find someone to do it for me.

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My Cadillac has a torque tube, and you can see how it was installed in the photos in my album here on the AACA site. Just pull the torque tube out and mail it to Lloyd, he'll install it and ship it back. Bolt it in, hook it up, and drive. The $2300 or so that I paid Lloyd included installation of the overdrive in the torque tube, and I bet you could ship him your car and have him do the whole job for not a lot more.

I had Jim Capaldi rebuilding the transmission since it popped out of second gear, so they had the torque tube out anyway. You need to drop the rear end to get the torque tube out, but it appears to be a fairly straightforward exercise for any old car shop.

Hope this helps. I'm completely sold on the overdrive. My car will run 60 all day, but right around 52 is a magical sweet spot where it's almost whisper quiet and has plenty of power.

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Sid: Nothing will interchange between a Master and Standard differential. That does not mean it cannot be done - just means it's complicated (read - expensive).

Joe Krepps made (may still have some left) new gears at something like 3.55 to 1 which would be the easiest way to go, I think.

Bill McLaughlin

1929 Silver Anniversary Buick Newsletter

Sid: Email me (bill@29Buick.ca) your email address and I'll send you a Welcome Package for the 1929 Silver Anniversary Buick Club.

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Sid,

In the 1929 Series 116 the Axle Ratio varied between open cars and coupes and the 4 door sedan.

Your sedan should run a 4.9 - 1, I think the coupes ran a 4.636 - 1 ratio and the phaetons ran something taller again but I can't find the exact ratio.

In the 1930 models the 40 - 47 ( sedans ) ran 4.545 to 1, the 46 - 46S ( coupes ) ran 4.364 to 1 and the 44 - 45 ( phaeton and roadster ) ran 4.182 - 1.

Explore the possibility of increasing your tyre size to the next available - I did this on my 1930 Sedan ( mainly by accident as the original size was not available ).

So increasing tyre size and finding a phaeton rear end will help.

A word of caution about uping the highway speed to any great extent!

Your 1929 runs external contracting brakes ( the same as I had on my 1928 Roadster ) and when properly adjusted and using N.O.S. woven type lining material ( not modern HARD material ) they are very adequate.

BUT

As soon as you get water or a lot of dust between the bands and drum they are virtually non existant and it's a frantic grab for the emergency brake which acts on the rear wheels and are protected from water and dust by being housed internally.

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Stuart,

Why would Buick use all those different ratios in the same year in the same series?

Dwight

Dwight,

I don't really know, maybe additional speed on the lighter models to fit the description of Sport Phaeton or Sport Roadster. Here's a copy of the detail from the Specifications and Adjustments 1930 Models.

post-31244-143138735872_thumb.jpg

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Here are more ratios for earlier and later Buick:s.(save it if you need it)

Leif in Sweden.

Leif,

That's interesting.

They list some high speed ratios for some models with special high compression heads!

Anyone know anything about special high compression heads? I don't remeber reading anything about this previously.

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Guest sintid58

Thanks for all the information. I may look into having some gears made. I know a couple machine shops in the area that do a lot of special work so maybe someone can work something up for me. I am not interested in getting a lot more speed but to be able to cruise easily at around 50 on dry highways would be nice. With wood wheels and mechanical brakes I wouldn't be comfortable at much more than that. I am used to driving something that requires me to plan all my stops ahead of time anyway to that will help a little anyway. I am hoping we can start to do some prewar tours in time.

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I think you are right Jules in the right application. I wouldn't want to go faster in my '30 Buick, but my '36 International pickup with new hydraulic brakes and steel wheels I would like to go 45-50 and keep the rpms down.

Jay Leno has a little video about them and proper applications.

Gear Vendors under/overdrive, Jay Leno's 1929 Bentley

Dwight

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I still agree with Jules and Dwight. In my '29, it's not about more speed, as with those skinny tires, mechanical brakes, and about 5000 pounds of inertia behind me, I don't want more speed, and it's probably not safe anyway. However, I do want to be able to keep up with traffic on 45-50 MPH secondary roads and not become a rolling speed bump and not feel like I'm abusing the engine. The overdrive makes the driving at, say, 52-55 MPH vastly more relaxing. The engine is whisper quiet and those long rods aren't hammering the babbit bearings to pieces, and it just works so much better as a vehicle. I ran at 55-60 MPH on the highway all the way to the CLC National meet this summer, a round trip of almost 500 miles, and the car didn't miss a beat. With the overdrive, 60 MPH is 2000 RPM according to my calculations, about the equivalent of 42 MPH without the overdrive. As I said, about 52 MPH is definitely the sweet spot. The car just effortlessly glides along and the engine is virtually silent at about 1600 RPM. Think of how well your car drives at 35 MPH and you'll get an idea of how useful the overdrive is.

I'd say for all the effort and money you'll spend retrofitting a different rear gear from a similar car provided you can even find a set, (never mind having one made, which is a lot more than simply cutting it out of some stock--there's heat treating and parkerizing the gear tooth surfaces at the very least), for a 10% improvement is probably not financially wise. My Cadillac also has a torque tube and it accommodated the overdrive without issues and installation was straightforward. The overdrive preserves your original gear ratios, so the car won't feel sluggish at low speeds, which a deep rear gear may not do.

I don't have any connection to any of the overdrive manufacturers, I'm just so darn pleased with how radically improved my car is at normal driving speeds that I think it's by far the best solution. Not more speed, but BETTER cruising and improved engine life, not to mention notably better gas mileage--my Cadillac goes from about 12 to 16 MPG with the overdrive. Still awful, but a whopping 25% improvement!

And for what it's worth, I contacted Gear Vendors about my Cadillac, both by E-mail and by phone and they said they'd have their "old car expert" get in touch with me and he never did. If yours is the first 1929 Buick they've worked on, and you can get them to agree to do the development, expect to eat all their R&D costs in addition to the cost of the unit, which in my opinion is way overkill for a low-horsepower relatively lightweight car. They're nice gearboxes, but you'll likely pay quite a bit more than I did for my Borg-Warner overdrive.

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Guest sintid58

I really am not interested in driving the car at 70 MPH but would really like to be able to get on back roads and drive 50 to 55 with the motor not sounding like it is going to come apart. We will probably look into getting some new gears for it because that would seem like the less expensive way to go. We had a nice little drive with it today and still amazed at how nice it runs and drives.

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Did you read what I wrote? Not more speed, less RPM, exactly what you're looking for. I didn't do it so I could go 70 MPH, I did it so the engine didn't eat itself at 45-50 MPH, which is where I do 85% of my driving. I figured my '29 Cadillac was similar enough to your Buick to be a reasonable frame of reference, and as I said, the difference is simply astounding.

You'll spend at least as much time and effort, and probably a similar pile of money on gears for an inferior result, but meh, up to you. I tried.

Edited by Matt Harwood (see edit history)
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