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"How fast should I drive it ? " redux...


Guest DeSoto Frank

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Guest DeSoto Frank

I was pondering the ever recurring question "how fast can I drive my old car", most recently surfacing as " 1934 Buick Speed Problem", elsewhere in this department.

As I was driving down I-81 today, in my '97 Jeep wagon on my way to work, I was glancing down at the gauges, and my eye fixed on the tri-colored plastic strip from the speedo of my '41 DeSoto, laying on the little shelf in front of the Jeep's speedo.

This strip has three colored bands, starting with green, going to yellow, then ending with red.

This was to achieve one of the variations of Chrysler Corps' "Safety-Signal" color-changing speedometers, used from 1939 through 1948 on Chrysler, De Soto, Dodge, and Plymouth.

Here's how it looked:

From 0 - 30 MPH, the speedo / needle glowed Green

From 30 - 50 MPH, the color changed to Yellow

At 50 MPH and above, the color changed to "warning Red".

I take this to be a manufacturer's recommendation as to safe operating speed for the vehicle's welfare, as well as legal speed limits / public safety.

Prior to 1950, there weren't that many roads East of the Mississippi that would be conducive to driving faster than 50 mph... one of the few exceptions was the original Pennsylvania Turnpike, from Harrisburg to Pittsburg.

For the most part, I have found that most pre- "Modern V-8 cars"* are happiest cruising at 45-50 MPH ( or less ).

Certain cars may be capable of prolonged higher speeds, but at what mechanical / fuel cost ?

Slow down and enjoy the ride...

:cool:

*( Modern V-8 Cars: '49 & later Caddy & Olds, '52 & later FoMoCo, '51 & Later MoPar V-8, '53 & later Buick, etc)

Edited by DeSoto Frank (see edit history)
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I have been surprised by some of what I have read lately on this subject.

If cars of the 30's and 40's are not expected to be driven over 45 miles per hour or so, I do not understand why the initial December 2, 1927 announcement of the 1928 Model A Ford advertise the car as being capable of being driven at 50 to 60 miles per hour.

My personal experience tells me that a properly restored Model A Ford is capable of routinely being driven at 55 miles per hour.

They will go faster, but 55 mph seems to be about the best cruising speed for my Model A Ford.

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From 0 - 30 MPH, the speedo / needle glowed Green

From 30 - 50 MPH, the color changed to Yellow

At 50 MPH and above, the color changed to "warning Red".

I take this to be a manufacturer's recommendation as to safe operating speed for the vehicle's welfare, as well as legal speed limits / public safety.

Bear in mind what the issues were with the older steering geometry as well as braking limits and more importantly...those skinny bias belt tires and narrow wheels.

But, the 34 Buick thread was mostly about gearing. I am with the guys who don't want to hear a motor scream for extended periods....and many of us are in areas that don't seem to have casual type country roads to use.

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Guest Twunk Rack

how LONG can you drive a Model A at 55 mph without knocking the rod bearings out ? Actually, and here's the irony..probably at least as long as some of the larger, more powerful cars of that day !

The Ford Model A was a fairly light-weight car, so even with its small low-powered motor, it could handle a fairly high rear axle ratio (the Ford buffs will have to straighten me out; i believe most came with around 3.7.). AND, the Ford Model "A" had a fairly short-stroke engine - well "short stroke" compared to the 5" or so of the typical big-engined luxury car of its era.

As I have noted elsewhere, the terrible stresses on a typical pre 1940 car driven at 55 mph are greater than that on a modern car at 100+, not only because of the higher rpm, but also because of the incredibly higher forces on the crank-shaft caused by the longer stroke and heavier connecting rods.

For those of you who think your "poured babbit bearing" equipped pre war car is "happy" at 55 mph, I suggest the following as a tremendous money maker you. If you are correct, the automotive industry world-wide is wasting FORTUNES equipping their car's motors with the much-more-expensive to manufacture "insert" type rod bearings, and the much-more-expensive- to- manufacture combination of a high final drive ratio (meaning low numerically) and multiple speed transmissions. I think those guys should "put your money where your mouths are" and write all the modern auto manufacturers, get your ideas published in the SAE and ASTM publications, and who knows - if they agree with you, they may share the BILLIONS of dollars saved on production costs with you !

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Dear Matt,IMHO 55 in a Model A is OK till you HAFTA stop.I believe the mechanics are fine for stopping as long as EVERY car on the road is a Model A,a NEW car stops short and you are going to be looking for a ditch to dive into.The problems are the width of the brake shoes and the size of the tire patch on the road.Our family has owned a 1930 Briggs bodied 4 door sedan since 1967.diz

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Dizzy,

I have owned a early 1931 Briggs bodied Town Sedan. I understand your concerns about the brakes on that.

The much lighter 1929 Phaeton, with properly restored brakes, stops without problems.

Twunk Rack,

I have driven multiple Model A Fords for thousands of miles and haven't had any babbitt bearing problems yet. Feel free to provide me with any advice or preferably data to support your thoughts, but the sarcastic tone does not help convince me.

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Guest Twunk Rack
Dizzy,

I have owned a early 1931 Briggs bodied Town Sedan. I understand your concerns about the brakes on that.

The much lighter 1929 Phaeton, with properly restored brakes, stops without problems.

Twunk Rack,

I have driven multiple Model A Fords for thousands of miles and haven't had any babbitt bearing problems yet. Feel free to provide me with any advice or preferably data to support your thoughts, but the sarcastic tone does not help convince me.

you apparently did not read, or did not undertand my "post" above about Model A Fords.

let's try it again. I noted that a Model A Ford can handle 55 mph at least as well as the big expensive luxury cars of its era, and I will again repeat the reasons for those who werent able to comprehend what I was explaining the first time.

Again, the Model A was a very light-weight car, so, even with its small low-powered motor compared to the big cars of its era, it could handle a "high" (meaning relatively low numerically) gear ratio. Again, I am not certain, but again, think they usually came with around a 3.7 rear axle.

So, right off the top, they have MUCH less stress running at 55, much less engine rpm, than a typical "big" car of that era.

Then you add to that fact that they had a relatively short stroke, much shorter than the big-engined cars of that day. The shorter the stroke..even a quarter of an inch..for example ( but I understand the Model A stroke was as much as an INCH shorter than some of the big "super cars" of its era) the MODEL A would enjoy MUCH less stress on its connecting rod bearings, meaning, again...it could survive 55 mph at least as long, if not much longer, than much more expensive cars.

Bear in mind that as good as the "Model A" was - certainly a tremendous buy for the money, my recollection is that with the higher speeds possible in better roads coming in, starting with the 1930's, Ford elected to turn the "Model A" motor into what, when I was a kid, we called the "Mexican Jaguar"..meaning, a fully balanced crank-shaft with full pressure oiling, and at some point in time, that engine got "insert" type rod bearings.

You Ford experts will have to take over from here - I am no Ford expert, but I have to admit, again, Ford made damn good cars for the money.

Edited by Twunk Rack (see edit history)
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I understood the first part of your post and had no objection to it at all.

This is what you said that I did not appreciate...

For those of you who think your "poured babbit bearing" equipped pre war car is "happy" at 55 mph, I suggest the following as a tremendous money maker you. If you are correct, the automotive industry world-wide is wasting FORTUNES equipping their car's motors with the much-more-expensive to manufacture "insert" type rod bearings, and the much-more-expensive- to- manufacture combination of a high final drive ratio (meaning low numerically) and multiple speed transmissions. I think those guys should "put your money where your mouths are" and write all the modern auto manufacturers, get your ideas published in the SAE and ASTM publications, and who knows - if they agree with you, they may share the BILLIONS of dollars saved on production costs with you !

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The sales manager for Bentley in England had a wide experience of all types of cars including the most luxurious. But he was impressed with the Model A when it first came out.

It happened that he had to make a long journey to a business meeting. He made the journey with a friend in the friend's new Model A. While it did not compare to a Bentley in performance, he felt the car had a lot to offer and was impressed with the feeling of untiring stamina it gave cruising at 45 to 50 MPH.

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Guest kencary
I was pondering the ever recurring question "how fast can I drive my old car", most recently surfacing as " 1934 Buick Speed Problem", elsewhere in this department.

As I was driving down I-81 today, in my '97 Jeep wagon on my way to work, I was glancing down at the gauges, and my eye fixed on the tri-colored plastic strip from the speedo of my '41 DeSoto, laying on the little shelf in front of the Jeep's speedo.

This strip has three colored bands, starting with green, going to yellow, then ending with red.

This was to achieve one of the variations of Chrysler Corps' "Safety-Signal" color-changing speedometers, used from 1939 through 1948 on Chrysler, De Soto, Dodge, and Plymouth.

Here's how it looked:

From 0 - 30 MPH, the speedo / needle glowed Green

From 30 - 50 MPH, the color changed to Yellow

At 50 MPH and above, the color changed to "warning Red".

I take this to be a manufacturer's recommendation as to safe operating speed for the vehicle's welfare, as well as legal speed limits / public safety.

Prior to 1950, there weren't that many roads East of the Mississippi that would be conducive to driving faster than 50 mph... one of the few exceptions was the original Pennsylvania Turnpike, from Harrisburg to Pittsburg.

For the most part, I have found that most pre- "Modern V-8 cars"* are happiest cruising at 45-50 MPH ( or less ).

Certain cars may be capable of prolonged higher speeds, but at what mechanical / fuel cost ?

Slow down and enjoy the ride...

:cool:

*( Modern V-8 Cars: '49 & later Caddy & Olds, '52 & later FoMoCo, '51 & Later MoPar V-8, '53 & later Buick, etc)

Hey we flathead guys feel left out of that Modern V8 statement you made!!

Pontiac flat head straight 8's lasted through '54 and most of these cruise very nicely at 60-70. I even sometimes spin the tires by accident if I let out my clutch too fast on a hill. The previous owner of my Pontiac drove 80MPH on the interstate at times.

Personally I like to stay on the slow side not because of power, but because of the limitations of steering, brakes and tires of my old '51. Maybe with a set of wide whitewall radials I'd feel better, but for now 60 and under feels good.

Ken

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Guest DeSoto Frank

Ken,

I'll bet your straight-eight Pontiac has Hydramatic ? (Auto tranny & fluid-drive cars tolerated taller final gears...)

I used to drive my '48 New Yorker (3.36 rear) 65-70 MPH on the interstate on four-hour trips between school & home while finishing college in the late '80s, with no seeming ill-effects.

Put over 40,000 miles on it, retiring it at over 106,000 miles.

I also "killed" a number of stove-bolt Chevy sixes (couple insert-bearing 235s and some babbit pounder 216s) by trying to drive them at 55-60 MPH for prolonged periods, back before I knew any better ( These were in 4.11 cars and 4.57 trucks).

When Detroit made the switch from long-stroke, L-head engines to short-stroke overhead-valve V-8s, between 1950 and 1955, they also really began to embrace the true "modern" automatic transmission, and with the burgeoning interstate highway system, all-day cruising at 60, 70, 80 MPH (or more) w/o destroying the engine became possible, and even common.

With their "valve-in-head" design, both the Buick and Chevy in-line engines were pretty advanced as far as breathing and performance were concerned, especially prior to WWII; it's kind of a shame they clung to poured bearings for so long.

As for the Model A, I'm supposed to be taking delivery of my '28 Special Coupe next week, and I hope to get some road-time in before PennDOT lets fly with their "Car-B-Gone"...

So, I will be getting some hands-on experience with my own 80 year-old Babbit-mobile.

The Ford does have a lot going for it, with its relatively light weight and 3.7 gears.

Just to be clear, my original point was finding a practical ceiling speed for prolonged, repeated cruising in a pre-1955 car... my '50 Chevy Fleetline would do a short sprint of nearly 80 MPH for a brief period, but it was happiest at 50 MPH or less.

I think there's an engineering component behind Chrysler choosing their color-coded speed zones the way they did... ( Green to 30 MPH, Yellow from 30 to 50, Red at 50 & above.)

And MoPars would keep up with anything else during the "color-coded speedomoter" era (1939-1948).

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Guest kencary

Actually my '51 is a 3 on the tree manual.

Keep in mind, that unlike the Chevy, the Pontiac had a full-pressure oiling system with rifle drilled connecting rods. The Pontiac motto was "built to last 100,000 miles"

I personally don't like to drive this above 60 for a prolonged time.

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Guest Twunk Rack
I understood the first part of your post and had no objection to it at all.

This is what you said that I did not appreciate...

= = = = = = =

RE : MAKING FUN OF THOSE WHO THINK IT IS OK TO DRIVE LOW-GEARED OLD CARS WITH POURED BABBIT ROD BEARINGS AT HIGH SPEEDS...

You have an interesting point. These days, it is VERY important to be "politically correct" and not subject someone's potentially harmful post to a little humor or harsh criticism.

In most parts of the world, you "question" some "politically correct" concenpt, and you will be LUCKY if they dont shoot you or cut your head off.

Here in the United States Of America, we have this very unusual idea of our founding fathers "I MAY DISAGREE WITH WHAT YOU SAY BUT I WILL DEFEND TO THE DEATH YOUR RIGHT TO SAY IT.

Many people want desparately to believe their "politically correct" idea of poured babbit" rod bearings, and the idea that an old low geared car can be "happy" at the speeds discussed here. That is their RIGHT to advocate such scientifically absurd nonsence.

However, in THIS country, it has not YET become the practice to ban, censor, silence those who disagree with some "politically correct" but factually wrong statement.

When you come into a public chat-room, where people are HONESTLY interested in helping people preserve their old cars, you are just going to have to deal with the fact that statements are going to be challenged.

Give it time. Be patient. Each year more and more of our technical expertise type guys are dying off (or getting so disgusted with the "know-it-alls" who think they are smarter than ASTM/SAE engineers, that they just stop coming in here).

Won't be THAT long before no-one is left to challenge the "politically correct".

Edited by Twunk Rack (see edit history)
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You know, 30 years ago when I got my first old car that ran, which was a '37 Buick. My Dad and I had that conversation about speed. That car would go 50 or a little faster very nicely. He pointed out that those cars would go faster for short stretches but that before WWII property rights were respected a little more than they were afterwords and so many of the roads had all sorts of sharp corners that most people really didn't drive all that fast. Plus, there were a lot of other slower cars, and trucks on the road so you had to bear that in mind as you drove as well. Especially at night. He said he almost ran over a guy one night in the middle 30's that was driving a car with carbide headlamps on it! I suppose it didn't have much for tail lights on it. He didn't think the oil they used back then was as good and unless you lived out west (I'm in Iowa) there weren't that many roads you could run down at sustained high speeds. Which he used to say was over 50. Plus, look at how narrow some of those old highways were. We have a few of them around here in North Iowa. They aren't used anymore as main roads, but you can drive down them yet. There were a whole lot of reasons you didn't want to drive really fast 70 years ago.

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Twunk Rack,

It is not my intention to continue a war of words with you. That is not the purpose of the forum. With that said, You don't know me. You are a new guy here. If you knew me, or had read much of what I have posted here over the past few years, you sure would not be trying to accuse me of political correctness.

You seem to be trying to straddle both sides of the fence in multiple posts regarding if a Model A Ford is or is not capable of driving at 55 mph. My experience says that in my case, it is capable of that speed. If you review what I have previously posted, I simply asked for some data, rather than your thoughts that I should accept your statements without question.

While asking for data instead of opinion, I also attempted to ask that you not ridicule others or use a condescending tone about others on this forum.

Feel free to read any of the 1700 + posts that I have made on this forum and you will see that I am about facts, not opinions, and I try to help people, not put them down. I would simply ask that you do the same. That is not political correctness, that is simply civility and good manners.

Now, what data about Model A Ford speed capabilities does anybody have to offer? I only have my own personal experience over a few years with several Model A Fords. If anybody has anything productive to add to the discussion, I am sure others would be interested too.

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With my limited search of the SAE website, I have not found anything in any technical papers to answer my question. I was amused to see that their 2009 Historical Book Guide features a Model A Ford on the cover.

You may think that helping "includes making fun of people", but I have to disagree with that statement.

If you wish to further berate me, please do so by private message so nobody else has to read it. I do not intend to continue this discussion with you publicly.

Edited by MCHinson (see edit history)
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Guest kencary

OK guys I don't know as much as you do about old cars, I am just now getting into '50's cars, prior to this I've been dealing in '60's muscle cars.

I assume all this talk about poured babbit bearings does not apply to most '50's cars. True my '51 Pontiac is not geared as tall as a modern car, but as far as I know it has insert bearings and a full pressure oiling system.

My mom and Dad had a '51 and drove it well into 1964 on the NJ turnpike and other roads at speeds around 60mph the car was sold in 1964 and it ran like a top with 60,000 miles on the clock.

Let's put this panic into perspective for those on the forum. When you say old cars, let's qualify that a bit more.

Ken

Edited by kencary (see edit history)
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= = = = = = =

RE : MAKING FUN OF THOSE WHO THINK IT IS OK TO DRIVE LOW-GEARED OLD CARS WITH POURED BABBIT ROD BEARINGS AT HIGH SPEEDS...

You have an interesting point. These days, it is VERY important to be "politically correct" and not subject someone's potentially harmful post to a little humor or harsh criticism.

Therein lies the problem Twunk Rack....or should I call you PF

Hartman?

Your criticism is not appreciated here. :mad:

You have been banned multiple times, for the same reasons that MC Hinson speaks of. You do not know how to play nice.

Straighten UP!

R.W.Burgess

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Therein lies the problem Twunk Rack....or should I call you PF

Hartman?

Your criticism is not appreciated here. :mad:

You have been banned multiple times, for the same reasons that MC Hinson speaks of. You do not know how to play nice.

Straighten UP!

R.W.Burgess

Mr. Burgess, I've been wondering the same thing. This person has been banned many, many times for the same reasons...rude, condescending, pedantic and insulting posts. Yet...like a bad penny or an adolescent pimple, he just keeps coming back. He just signs up again as a "new" member and persists with the same rude behavior. This person is the reason I, and many others have quit coming to this site as often as we used to.

He seems to be spitting in the face of the moderators here. If someone is banned multiple times, why is he allowed back under a new name?.... we all know who this troll is, and Peter G well knows his ISP...why not just cut the snake's head off?

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I've held back my comments until now, but concur with Matt, and endorse Wayne Burgess' thoughts.

When repeat offenders do not learn -- for the sake of the rest of the decent folks here -- cut off their priviledge !!

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OK guys I don't know as much as you do about old cars, I am just now getting into '50's cars, prior to this I've been dealing in '60's muscle cars.

I assume all this talk about poured babbit bearings does not apply to most '50's cars. True my '51 Pontiac is not geared as tall as a modern car, but as far as I know it has insert bearings and a full pressure oiling system.

My mom and Dad had a '51 and drove it well into 1964 on the NJ turnpike and other roads at speeds around 60mph the car was sold in 1964 and it ran like a top with 60,000 miles on the clock.

Let's put this panic into perspective for those on the forum. When you say old cars, let's qualify that a bit more.

Ken

I think the insert/shell vs babbitt bearing debate has been overblown. No doubt in my mind that replaceable shell bearings are better from an engineering viewpoint. That being said, my first car was a $75 1949 Chevy 2 door fastback (babbitt brgs) upon which I promptly in stalled two one barrel carbs and lost the muffler. Like most teenage boys I flogged that poor car way beyond what it was designed for and it never let me down. My parents had a new 1951 Stude Land Cruiser with the 232 V8 (full pressure, insert brgs) and OD trans. About once a month we would drive from Tulsa to Wichita (+/- 200 miles) to see my grandparents and when road conditions allowed, 65-70 MPH sustained was not uncommon. The Stude lasted many trouble free years.

Also keep in mind that today's oils are vastly superior in preventing wear and failure than what was available when many of our old cars were new.

I remember when 50-60K miles was the average span before a "ring & valve job" might be needed. Today's cars go 100K+before you need to change plugs, much less need to replace rings, bearings or a valve grind.

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There is another factor in the Model A equation and that is whether the engine is original or restored.

Some years ago I read an article in the AACA magazine about the Model A engine. It seems Ford took a lot of trouble over the question of balance. The weights of rods and pistons were carefully calculated and all engines were balanced to a fine tolerance.

This had to do with Ford selling a 4 cylinder with rigid engine mounts, against the 6 cylinder Chev and "Floating Power" Plymouth 4 and also with the rising hiway speeds of the day. A Model A was considerably faster than a ModelT.

According to this article problems could arise when rebuilding the engine. The new pistons on the market often weighed considerably more than the originals, up to twice as much.

Of course this ruined the balance of the engine. I have ridden in Model As that had been rebuilt in this way and they suffered terrible vibration at 30 MPH or higher. This was not true when they were new, indeed it is doubtful they could have sold any unless they were as capable as their main rivals if not more capable in speed.

So it seems the Model A was capable of speeds up to 60 and was happy cruising at up to 50 if circumsances permitted. No doubt the same would be true today if the engine was rebuilt using light weight pistons, and the engine carefully balanced.

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I also read somewhere that the Model A engine was built with loose tolerances in the bearing to crank or rods. Henry Ford realized that the cars would be driven on dirt roads and without oil filters and the loose tolerances allowed the fine particles to do less damage to the bearing surfaces if they tolerances were tight. I have also read as did Rusty that the engines were balanced to prevent vibration.

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Lets get a few Model A facts and current machining practice out on the table to get the correct picture.

The Model A crank was built to tight tolerances. I have a copy of the print. The crank was balanced to a 1.4oz dynamically. I have a copy of the rod print and Ford specified that each end was to be a certain weight +-1gram. I do not have the piston weights or prints, but I am told they were within a few grams. The 60 lb flywheel was to be located to less than .001" from the center line of the crank. The flywheel was also balanced. The thickness of the babbitt was kept to a minimum and only .002" of steel shim was used on the rods or the crank. You expect to get in the 50,000+ mile range before you might need new babbitt because you have taken out all the shims.

Today there is a lot of opinion running around. Most of it not fact or based in reality.

The original A off the line was capable of running 50+ mph for extended periods of time. It will not beat the bearings out of the block.

The reason why there are so many problems today is because no one is restoring the parts to original accuracy. As you can see from the many posts, few even know what the correct accuracy was from the factory.

Today the cranks are ground such that the rear and center mains are now off center. This causes the crank to bend when clamp in the block. You end up with a 60lb flywheel off center and wobbling. The rods from the better places are held to 5 grams total weight. I have seen modern pistons off by over 50 grams in a set. If you take the A crank to a grinder and tell them you want it done to the original specs they tell you that you want a racing grind. They double the price.

Take your time to learn the facts. A restoration is about restoring the car to original, you have know what was original first.

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