Go Back   The Ford Barn > General Discussion > Model A (1928-31)

Sponsored Links (Register now to hide all advertisements)

Reply
 
Thread Tools Display Modes
Old 02-06-2014, 02:57 AM   #21
Dusty
Senior Member
 
Dusty's Avatar
 
Join Date: May 2010
Location: Lincolnton, Georgia
Posts: 723
Default Re: Best overdrive

Quote:
Originally Posted by CarlG View Post
I guess we can put "Best Overdrive" on the list with:

What kind of oil
Which Radiator
Alternator vs generator
12 volt vs 6 volt
Anitfreeze or water
etc vs etc
Well you forgot green fenders
Dusty is offline   Reply With Quote
Old 02-06-2014, 06:52 AM   #22
QGolden
Senior Member
 
QGolden's Avatar
 
Join Date: Sep 2011
Location: Alton, NH
Posts: 1,231
Default Re: Best overdrive

Quote:
Originally Posted by w0ivb View Post
] What is the best way to obtain near hiway speed; overdrive or overdrive transmission for a model A ?
Quote:
Originally Posted by tbirdtbird View Post
On page 102 of Schild's "Restorer's Model A Shop Manual" it shows a chart with multiple torque, HP, compression, and speed curves, from a 1930 factory catalogue. 60 MPH corresponds to 2800 RPM. At 2800 RPM you have fallen way off peak HP and torque,

Plus there were few roads where you could actually accomplish 60 mph back then,

IMO anything over this and you are shortening the life of your babbitt, especially the center main, which gets the most wear anyway.

And Terry has a great suggestion about riding with others who have the various forms of OD to see what they are about.
I have Jim's book and it has some good info in it. I read his charts with interest. Only published chart I have found. I completely agree, as soon as you know what the torque and HP curve is of a motor, there is no point in exceeding that RPM, it accomplishes nothing but engine wear. Today's "average" road speed is different than the "average" speed of the 30's. Higher, and a lot longer distance at a given RPM, much less need to slow down for other cars, horses, etc.

It is personal choice, your comfort level, it's your car, keeping them original is a great goal. But there is a lot to be said for overdrive, synchromesh transmission shifting, the ability to coast without engine brake if wanted. Etc.
__________________
It's not what people think they know that will hurt them, it is what they think they know that aint so! -Mark Twain.

It is the very things that we think we know, that keep us from learning what we should know.- Unknown
QGolden is offline   Reply With Quote
Sponsored Links (Register now to hide all advertisements)
Old 02-06-2014, 08:51 AM   #23
modelAtony
Senior Member
 
modelAtony's Avatar
 
Join Date: May 2010
Location: lafayette,la
Posts: 459
Default Re: Best overdrive

Quote:
Originally Posted by w0ivb View Post
] What is the best way to obtain near hiway speed; overdrive or overdrive transmission for a model A ?
I like the Mitchell best. Really bolt on unit and after you have driven a short time you will realize it makes your car operate like it is fully syncro trans. F 150 unit like Gary Bernard and MR ken parker install are great but 1st gear is lower than orig. trans . You can replace the car bell housing and use the AA bellhousing and not cut the small gap in brake unit. I am originally from Dallas,TX area and in 2003 talked to Gary about his unit because I didn't want the extra shifter that the Mitchell had. Told Gary I was going to have car in GREAT RACE and that stopped everything cold. Gary had been trying to get the 4 speed ok'd for 3 years in the race and owner of race Tom MC rea [sp] always said no. This is the reason I went with Mitchell , I was also running 3.27 gear since 2001. Mr Mitchell thought it would be to high of gear but I knew my car and it's great wouldn't change anything. You can also get different gearing use just ask for it. Check out my avatar info for car performance. have fun modelAtony Lafayette,la
modelAtony is offline   Reply With Quote
Old 02-06-2014, 08:59 AM   #24
larrys40
Senior Member
 
Join Date: May 2010
Location: St Charles , Missouri
Posts: 1,990
Default Re: Best overdrive

I concur with Tom Endy that the Mitchell is the preferred way to go, 26%. You essentially have 6 forward speeds if needed for various driving conditions..... and it is a well built unit that will give years of service. It gets the engine RPM's down to a comfortable level for highway cruising. My '30 Tudor has an older Ryan ( Mitchell was just coming out then) and at 23% plus I kept my 3:54 it does well on the highways with a HC head. I have driven Pikes Peak with it and many mountain passes in Colorado.... and the additional gearing makes it nice.

As with any car... you have to know your car, gearing/load/when to shift... do not lug... etc

As Tom says the cost of the overdrive adds value to the car as a tour car if a sale is desired. I have installed Mitchells and all have gone well. They are a bolt up install except for the floorboard cut.

Larry Shepard
larrys40 is offline   Reply With Quote
Old 02-06-2014, 10:42 AM   #25
Jim Huseby
Senior Member
 
Jim Huseby's Avatar
 
Join Date: May 2010
Posts: 361
Default Re: Best overdrive

With a Mitchell, you don't have to have an extra shift lever coming through the floor, as there is a sturdy cable operated option. If you're gonna run this set up in a speedster or a severely lowered car you will have to turn the cable lever on the O'D unit upside down and mount the cable from the rear to get clearance to the floor.
Jim Huseby is offline   Reply With Quote
Old 02-06-2014, 11:11 AM   #26
Tiny
Senior Member
 
Tiny's Avatar
 
Join Date: May 2010
Location: Redding Cal
Posts: 1,388
Default Re: Best overdrive

Sponsored Links (Register now to hide all advertisements)
Quote:
Originally Posted by Dusty View Post
Well you forgot green fenders
And unsightly Whitewalls
__________________
Blackwall Panthers
Nor Cal chapter
Tiny is offline   Reply With Quote
Old 02-06-2014, 02:48 PM   #27
Dick M
Senior Member
 
Dick M's Avatar
 
Join Date: May 2010
Location: Ukiah, CA
Posts: 474
Send a message via Yahoo to Dick M
Default Re: Best overdrive

I know many happy Model Aers who have the Mitchell OD. They are very well made and are good units. However, I have the Laycock (Volvo) OD in my coupe. I love it for two reasons. First, the price is less expensive the Micthell. And second, the ease of shifting the unit in and out of overdrive. It can be shifted without engaging the clutch and it is operated with a toggle switch located under the gearshift knob. It also does not take up any valuable floor space. JMO
Dick M is offline   Reply With Quote
Old 02-06-2014, 03:15 PM   #28
apbright
Senior Member
 
apbright's Avatar
 
Join Date: Dec 2012
Location: San Francisco, CA
Posts: 169
Default Re: Best overdrive

I installed a Mitchell on my own as a Rookie (with only a little help from the local shop to get the pinion gear onto the Mitchell shaft). It was undoubtedly the best modification I made to the car. I drive about 300 mi / week, about half of them having to be on the Interstate. Before I had the Mitchell, I rarely could stay above 55, and was revving the engine so hard it was painful and embarrassing to listen to.

Also, when climbing hills here in Northern California, the 2 1/2 gear is essential - there is just too much gear ratio space between 2nd and 3rd when climbing these hills.
apbright is offline   Reply With Quote
Old 02-06-2014, 05:50 PM   #29
Duffy1
Senior Member
 
Join Date: May 2012
Location: Mo. City , Texas
Posts: 725
Default Re: Best overdrive

Lots of folks run f-150 and love um . Me for one .
Duffy1 is offline   Reply With Quote
Old 02-06-2014, 06:02 PM   #30
Jordan
Senior Member
 
Jordan's Avatar
 
Join Date: May 2010
Location: Ft. Worth
Posts: 1,006
Default Re: Best overdrive

I have the 4-speed from Gary Bernard. I absolutely love it. It's fully syncro so no worries about grinding gears. I had a worn out transmission anyways, so when going for an overdrive it was a no brainer to just get the 4 speed. I do however miss the whine of the Model A transmission. If the transmission is good in my next car, I'll get a mitchell so I can have the best of both worlds.
__________________
Cowtown A's
Jordan is offline   Reply With Quote
Old 02-06-2014, 08:41 PM   #31
modelAsteve
Senior Member
 
modelAsteve's Avatar
 
Join Date: Nov 2010
Location: Penn Valley (Nor-Cal) Ca
Posts: 128
Default Re: Best overdrive

I love my Volvo!
modelAsteve is offline   Reply With Quote
Old 02-06-2014, 10:04 PM   #32
bettlesr
Senior Member
 
bettlesr's Avatar
 
Join Date: Nov 2010
Location: Florham Park, NJ
Posts: 396
Default Re: Best overdrive

I made up a chart of engine RPM vs car speed before I changed my trans to a f150 trans. I used the small V8 gearing to 1st gear as low numerically (3.01:1) as possible. Trans code AK.This is based on using 16" radials on my car. With a .100 over engine and 7.5:1 head, there is no problems in using OD even at 35 mph. This is a full pressure inserted engine. And no, I don't try to climb steep hills in OD!
Attached Files
File Type: pdf Ford Gearing.pdf (15.0 KB, 40 views)
__________________
1965 Lotus Elan S2
1930 Model A Sport Coupe
bettlesr is offline   Reply With Quote
Old 02-06-2014, 11:13 PM   #33
Kurt in NJ
Senior Member
 
Kurt in NJ's Avatar
 
Join Date: May 2010
Location: on the Littlefield
Posts: 6,132
Default Re: Best overdrive

. However Ford did the original factory crank/flywheel balance no one seems to be able to duplicate it today. ---when many machine shops have the attitude that it is just an old car, it won't matter it's hard to get anything done to oe specs

Plus the universal joint is a single joint, not one on each end of the drive shaft as was done later. Thus there is a constant fast/slow component to the rotation of the driveshaft The angle of the engine nearly matches the angle of the driveshaft, not enough of an angle to be a factor.

Plus there were few roads where you could actually accomplish 60 mph back then, unless you were on a track, so to me the 60 mph was a lot of hot air to accomplish some nifty advertising. --from the may-june Model A News -in 1933 a model a with 62,000 miles averaged 62 mph traveling from LA to Phoenix, and on the return trip averaged 60, previous to this they did 500 miles on the salt flats at 66.66 mph average speed (It must have been a wild ride for the observer in the back seat)

If there are any Barners who have driven stock Model As out there at 60 mph for thousands of miles without engine damage let them come forward. To me, a stock A redlines at 2000, maybe 2200 rpm. I never run mine over 2000. (I have a full time tach). --- On the 3rd day of driving the freshly done babbitt I knew that the car would show 67 on the speedo, but I tried to keep it under 60 for the next 1000 miles, on the way home I tried to break it, rarely under 60, PA turnpike at 65(averaging 23 mpg), 2000 miles more ----I don't know how many more miles. I used to unhook the cable so my parents didn't know how far I drove


I want my babbitt to last a good long time. Choose your priorities, do your research, and make your choices accordingly. -- When my car was first restored with a professionally rebuilt engine I rarely got over 50,drove it easy-- that job only lasted 3000 miles before the babbitt crumbled ---so I figured that I couldn't do worse doing it myself, I have spent the last 25 years trying to break it, even though I know that I have a flywheel/crankshaft balance problem ---the only thing I have broke is the babbitt on 1 rod, one I shouldn't have used when I put the engine togewther, but it was closest to the other 3 in weight---and yes I was going above 65 when it came apart--but being babbit it did no damage to the crankshaft, and i drove it home after it happened.


And all this in responce to a first time post by someone that just wants to go "near highway speeds "---over 30 posts about overdrive.

I think I am getting closer to breaking my engine, the flywheel vibration is getting a little more pronounced, from the beginning the car would move in a circular motion going through 8-900 rpm, I know the crankshaft was ground .003 off center, it was the first time I poured babbitt and I have figured how can I know how good I did if i didn't try to break it, I have run the car in a circle for over 1 hour at idle in 3rd on a 95 degree day, lugged it through deep sand, left it at full advance for most driving, some of the oil changes were done with used oil, and I have come to the conclusion that there is not much you can do to save bad babbitt, and conversly that there isn't much you can do to hurt good babbitt.
I also feel that proper restoration to original specifications and tolerances will eliminate the need for most modifications in normal use

If I was to install an overdrive I will use a Columbia because it is the cheapest option for me
Kurt in NJ is offline   Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump

Sponsored Links (Register now to hide all advertisements)


All times are GMT -5. The time now is 10:09 PM.