gearing up to go faster questions

[1935coupe]

I just installed the freshly rebuilt engine in the 35, top speed is about 50, engine racing. I would like to install a better ring and pinion like 3.25 or so but how to correct the speedometer? are there different speedo gears available somewhere? or would buying a 2 speed setup be better? I would like to be able to drive on long trips


A little about me and the car
I am New here but I have owned my 1935 coupe for about 14 years, got it from my grandfather, it was given to him from his aunt who drove it from 1936 to 1973. Her brother bought the car new and one day they were out driving he had died along side of the car.....
When I got her everything was covered in an inch of mud oil cake so much you could not see any grease fittings. everything looks stock unchanged as parts broke they stayed broke. original engine trans rear nothing changed. I have been slowly cleaning off the dirt and fixing what I see.
never really drove it much on the road till now

[hotcoupe]

first off ,Welcome. there are a lot of knowledgeable guys here that are willing to help. i`ll tell you what i did when i was faced with the same situation - `37 1/2 ton, 239 c. i., isky Max-i cam, single Holley 94, 3:78 r&p, 7:00 x 16 tires and Columbia two speed axle. at 70 M.P.H. the motor spins @ 2186 R.P.M. the Columbia provides a 28% overdrive and it is a period accessory, which was important to me.
tom

[JM 35 Sedan]

Welcome to Fordbarn. Looks like you have a nice 35 5w coupe. Maybe you could put up more pictures so we can get a good look at the entire car. Approximately where are you located in Maryland? Are you possibly a member of the Early Ford V-8 Club of America? We have a regional group (RG36) of the EFV-8 Club that meets on the third Tuesday of every month in Sunshine, MD.
I am thinking your 35 probably has 4.11:1 ring & pinion rear gears. You could change to 3.78 or 3.54 gears which would allow you to cruise at higher speed with lower engine RPM's. You could also consider getting a Columbia 2 speed ($,$$$) or a Mitchell 2 speed at less $$$'s. Good luck and happy V-8ing!!

[deuce_roadster]

I would vote for 3.54 or 3.78 if you have a Columbia, 3.25 would be too high. You most likely have 4.11s right now. Remember if you make your car go faster, you should do something to upgrade the brakes so that you can stop. You can change the speedo gear that bolts to the torque tube to make your speedo correct.

[tamnalan]

The Mitchell overdrives look promising too - easier to find than the Columbia setup and a reversible bolt-on mod that lets you keep your closed drive shaft setup. A bit spendy at about $1800 I think. I want to be able to cruise at 60 - 65 mph.

I think I'll go the Mitchell route on my '39 pickup unless I stumble across a Columbia. I first thought about an S-10 trans but shuddered at all the modifications for that.

[38 coupe]

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How fast do you want to drive? 55, 60, 65, 70, 70+?

How good are your brake? Worn out mechanical brakes won't stop you safely from 50. Good rebuilt (or never worn out) mechanical brakes stop fine, but take regular maintenance to stay in adjustment. Hydraulic brakes are more forgiving but are incorrect for your car.

What engine did you just install? A rebuilt stock 85 horsepower 35 motor? A fire breathing blown 8BA? Something in between? Power has a lot to do with how much gear you can run and still pull hills.

Where do you normally drive? In town, country roads, highway? Flat land, hills, mountains?

If you want to drive 60 a 3.78 gear ratio works well, and drives very nicely around town too.

If you want to drive 65, a 3.54 ratio works ok, and drive around town ok too. Hill climbing is affected, but not horribly.

If you want to go 70, a 3.25 ratio work ok, but is miserable in town at low speed. On long hills you will probably drop into second gear unless you have a really powerful engine.

If you want to go 70, or 70+, and be able to drive around town you need an overdrive. Depending on engine power you will probably be happy with either a 4.11 ratio and overdrive, or a 3.78 ratio and overdrive. The Mitchell overdrive is a nice unit, but may not fit without cutting your floor boards. The Columbia, when properly set up, will bolt in but is really expensive and complex compared to any other overdrive option.

Let us know about your engine and how you want to drive the car and then we can give you better advice.

edit: And welcome!

[1935coupe]

I am not in any club now, may look into it soon. live close to bwi
I was leaning to the 2 speed but a Columbia is so hard to find, looking at Mitchel but don't like the look as much. thought changing the gear would look better I have not found the speedo gear. I pulled the rear yesterday itching to get started but not sure which way to go.

[40cpe]

Welcome to the 'barn. That looks like a really nice body. The mechanicals can be repaired easier (for me, anyway) than body defects.

[38 coupe]

One other thing to consider: a car is only original once. After you change it you can restore the car, but it isn't truly original anymore.

[1935coupe]

The engine is the same one that came with the car, 85hp. I had Bill Colman do a stock rebuild. It runs great! I do think I have 4.11 in there now. brakes are stock I plan on going through them this winter after I'm done with the rear and suspension, springs need cleaned and lubed shocks need work. I would like to be able to drive 65 or so but around here there is a lot of traffic and a lot of stop and go.

[JM 35 Sedan]

Bill Coleman is a well know flathead engine builder in the Baltimore area and has built several of my friends engines.
I still have mechanical brakes on my mostly original '35 fordor sedan and they stop my car as well as any of the '39 to '48 Fords I have driven that came with hydraulic brakes. You do need to maintain them well and also think about installing floaters for best performance.
I replaced 4.11 gears with 3.78's on my fordor last year and this allows me to easily cruise at 60 - 65 mph.for as long as I want to go at that speed. I am planning to install 3.54 gears this winter in my '35 5w coupe.

[flatheadfan]

1935 coupe-

Over the years I have been testing the relationships between rear axle ratios-tire size-engine revolutions. I am sure others have been doing the same and may have different results from what I found. With that in mind, this is what I have generally found with typical '35s and '36s. Transmission types were also included but only complicate things rather than clarify conclusions. At any rate......

Status: 3.54 rear axle, 6.00 x16 tires, speedo gear "18," stock transmission

Idle (warm) 720 rpms
25 mph 930
35 mph 1440
40 mph 1680
50 mph 2040

As for Columbia vs Mitchell. I favor the Mitchell. "IF" you can find a decent Columbia you still could be faced with a professional rebuild at a cost of some serious money. And, if the work is done to a "bullet-proof" standard, you still have a piece of mechanical hardware that is in the neighborhood of six decades old or more! On the other hand, the Mitchell is new, known and has the reputation of reliable help when needed.

One more thing. If you decide to go with some oversize tires to give your '35 the "look" or you go with a 3:25 rear axle, you should change the speedo gear to a "17" to keep your speedometer somewhat reasonable to your actual speed This is a Model "A" gear (will fit a '35) and can be hard to find.

Hope this helps.

Tom

[John R]

38 coupe makes some excellent points.
Most likely your rear axle ratio is 4.11. With this ratio, you can comfortably cruise at 55, maybe 60. The engine is a bit "busy" at these speeds but it will not be harmed. Supposedly, there was a 4.33 ratio available in 35, but its very unlikely you have this one.

[FlatheadTed]

Yes only original once ,A simple fix is You could get some spare wheels and go for a larger diameter rear tyres for out of town , Ted

[chap52]

Welcome to the Forum. Nice car. Lot's of great contributors here and tons of information. 38coupe said it all.
Run a search on rear ends there were a couple mentioned that might interchange and get you the ratios you are seeking.
Enjoy the adventure and remember "it's your car". (But if you decide to paint it florescent pink you may get some negative responses.)

[rockfla]

Flatheadfan gave you the speedo gear sizes for the R & P size, we did 3:54's in our 32 from 4:11's and its great, as luck would have it right after we changed we had the car out in Cal. for a summer for several shows and a couple of tours and had some very mountainous roads to travel and we wished we had the 4;11's for that but now back on flatter land the 3:54 is the ticket!!!!

[Art Maurice]

looking under the rear end where the drive shaft meets the center housing there should be two numbers. cast IN THE HOUSING DIVIDE THE NUMBERS TO GET YOUR RATIO.

[oldsman41]

welcome. the Mitchell od is good choice but rather expensive. you can find a early Volvo od. that can be put in the torque tube and they work very well. I have ran them in model a and other low horsepower engines, that way you can keep your original rear and have best of both worlds. you find them any where from 300 to 700 bucks electric od so no handles to fool with. if you find one make sure you have reverse lockout in it so you don't scatter it all over if you forget when you put it in reverse.

[Ianrhall]

Been wondering about changing gearing too. Are 3.78 or similar gears readily available, how much?
Ian

[Bassman/NZ]

Originally Posted by FlatheadTed

Yes only original once ,A simple fix is You could get some spare wheels and go for a larger diameter rear tyres for out of town , Ted

Ted's idea is great. Keep your 600s on the back for around town, put another two wheels with 7.50s on the back for long trips. The 7.50s will effectively change your 4.11 gears to 3.78s or 3.54s because of the increased circumference. You may even like them enough to leave them on all the time if your engine is good. The "turtle" at the front end of the torque tube contains a gear which can be changed to a different tooth number to alter the speedo. Options are available from suppliers like Macs, Snyders (Model A is same), and various others. Ted also supplies the floaters to upgrade your brakes, a simple and effective fix.

[PeterC]

I'm with Duece Roadster re thinking about brakes so that you can stop ... but even go further (well tuned mechanicals are excellent brakes as are later hydraulic) - but these early Fords are not designed to stop fast no matter what brakes you have ... skinny tires and high speed just mean locking up the brakes and at 70mph so you will need a long runway to stop.

I learned this lesson with my 296cu Flathead powered 39 Coupe with a Columbia and remember it every time I drive an early Ford - you can not compete with modern high speed traffic and modern cars that stop on a dime with drivers that have no clue or respect for what we are driving.

[1935coupe]

Thanks for all the great info! found the numbers, thanks art, 9 37 so it looks like 4.11
looking to join the Ford V-8 Club

thank for all the compliments on the car. I was told the aunt that drove the car all those years would never drive in the rain because the roof leaks. lived in Baltimore city and kept the car in the garage. when she would take it out she drove very slow. did not get a drivers license until the mid 50's. yes the car is almost rust free the wood under the car you can still see saw marks on it but every fender is dented banged out and dented again. I love the look and do not plan on changing it.

[motordr]

I have 3.54 gears in my 32 Vicky and find them a great all around gear. This winter I'm installing a Columbia Two-speed with 4.11 gears, just to cut the revs down when cruising the highway.

[scooder]

Originally Posted by Ianrhall

Been wondering about changing gearing too. Are 3.78 or similar gears readily available, how much?
Ian

Ian, is this on your pickup? If so 3.78:1 is standard (mostly) you can't fit the other Ford V8 ring and pinion sets, the pinion is for 42-47 pickup only. To use other sets, your looking at having to use a closed drive to open drive adaptor, the stock pickup bits are similar but not the same. This would work out spendy.
I would go for (and have on my 42) overdrive of some type. Mine is a 49-early 51 Merc box (transmission)
Martin.

[Ianrhall]

Yes an overdrive box would be nice, not too many of those around either tho
Ian

[scooder]

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Important add on to my bit and to clarify.
If my 42 had a 3.78 up it, I wouldn't need an overdrive, in my opinion that is a fairly near to perfect ratio for these vehicles.
If mine had 4.11 I'd maybe look lazily into some kind of overdrive, but probably only go for it if I fell over one very cheap.
Mine has 4.27 Merc axle and overdrive, cus that's what I had.
I base my opinion on these ratio choices from experience, my old T had flathead, 39 trans, 8.20x15 tyres and 4.11 rear. It would snoockle up the motorway at north of 70mph with ease. Oftentimes significantly north of 70! Would have no problem doing it again.
If the op's 35 tops out at 50mph with 4.11 rear, it's broke. I good fetal, 70 with ease, she'll do 80 if you wanted to. Be buzzing, but it should do it.
I have a test procedure writ here someplace that's for testing for weak valve springs. With 4.11 and 600/16 tyres it should do 50mph in SECOND with no valve float. If it won't, the valve springs are weak.
See what I mean about 70mph with ease?
Martin.

[Lawrie]

even with the 4.11 rear it should do much more than 50,look at the factory specs,it was meant to be able to go 83 mph.
When I had the 4.11 in my stock 33 it would run all day at 55-60 mph.
but after fitting a 3.78 from a 46 it sure seems happier.
lawrie

[Kurt in NJ]

I also agree with Scooder and Lawrie, if it truly will only do 50 something is wrong

Before my 36 was taken apart I knew it would do 60 ---the engine had no problem with it---the steering,brakes trans and door latches didn't like it though --all were very worn out----the 39 with the 4:44 rear and 60hp had no problems with 65-70---and flat out could almost make 80, and I drove it up the parkway for hundreds of miles at a time at 70, on hills I found that downshifting to 2nd at 40 gave the best gas mileage ----I know the 60 is a much different engine, but the 85 should be able to out perform it.

A bad fan (damaged blades?}, or having a slow speed pulley so the generator charges at low speeds can make the fan spin fast and make a lot of noise at highway speeds ---you said it was only driven slow for most of it's life, it could have been changed to keep the battery charged driving slow around town

[dean333]

My 36 Fordoor has P215-70/R16's, haven't verified ratio yet. It will DO 60, but the engine is really revving. I realized how much I wish I had overdrive when I drive my 57 Studebaker Commander 259V8, what a dream when it shifts into overdrive at 35.

[scooder]

Originally Posted by dean333

My 36 Fordoor has P215-70/R16's, haven't verified ratio yet. It will DO 60, but the engine is really revving. I realized how much I wish I had overdrive when I drive my 57 Studebaker Commander 259V8, what a dream when it shifts into overdrive at 35.

Just run some numbers, if yours had 4.11 rear, at 60mph it would be pulling a hair under 3000rpm.
Is that really revving? Obviously it's down to opinions, in my book that's not really revving.
With 4.55 it'd be about 3300rpm, still very reasonable in my book.
It depends what your used to I spose, my Cortina is at 4000rpm at 70mph, he'll do it all day if you want. Not the same engine I know but still a 48 year old engine designed 50+ years ago. I'll agree that 4000rpm is bit busy even for me.
Martin.

[Ianrhall]

What does a stock flathead rev to 4k?
My 53 lopes along at around 70 on the clock fairly easily
Ian

[GEOFFNZ]

I agree with a previous post and from past experience that in mixed terrain the 3.78 ratio averages out very well with good cruising and hill climbing depending on tyre size, weight and motor size.All factors that have to be considered.Cheers

[Ianrhall]

Ok, where could I get those gears?
Ian

[1935coupe]

I could go faster and had her up to 60 no problem but not having a tack the engine sounds like it is over revving. Just dumped a lot into it so did not want to have it come apart. I can not drive it now but thinking may be the direct drive fan may make it sound like the RPM's are higher.
With all the input here decided to go with a 2 speed from Mitchell. I can put it in and if I want to return it back I will have the old parts to do so. I called yesterday and am on the list, it should be here in February.

[supereal]

I put a Ryan overdrive in my '47 years ago. I chose a 33% reduction. With my 3:78 rear, it is a bit tall. I shift into it at about 40 mph, and can run 70 easily. Below 40, it lugs a bit. In hindsight, 30% probably would be a better choice. OD is the best choice for overall driving. The advice regarding having good brakes is well put. Drum brakes fade quickly at higher speeds. High speeds also demand top condition front ends, too.

[AnthonyG]

Welcome to the FB, great source of knowledge and interesting chats. While I'm not sure how old / new your tires are? If you need to change them anyway or a cheap way to increase speed to rpm factor and that gives it a nice look is to go from your 600 rear tires to 750's. it will increase your speed at the same rev approx. 20%. I'e. if 50 mph at 3000 rpm becomes 60mph. Or the 3000 will be reduced to 2400 at 50mph. I do agree with most indicating your top speed with 4:11 s/b over 50. Should do 70 to 80 with the fresh rebuild. Perception can fool you, depending on your muffler even 2700 rpm can sound like it's revving pretty high when in actuality it's not a bad cruising rpm at all. This sounds simple but check to see you are getting full throttle when you rev it up. Your pedal to carb linkage may be messed up so you not getting full throttle when floored.

[Bruce in southern OH]

Welcome, lots of information on the barn, enjoy your car!!!!

[38 coupe]

1935coupe please post pictures of your Mitchell installation. Several of us are interested in floor to overdrive clearance.

[Kerk]

I called Mitchel on 12-11-14 and the cost is $ 2400 + $ 150 shipping with a 10 to 12 weeks delivery time after a deposit of $ 350 . Am thinging of for my 35 P.U. and do not expect any clearance issues. Just currect info. good luck.

[Ianrhall]

$2500!! Bit more than I had in mind!
Ian

[scooder]

Ian, to answer your question how high does a stock flathead rev. Much more than 4000, 5000 easy, much more and the stock valve springs can't keep up. Built in limiter if you like.
Look up the Elgin race 1933 or 34. These were stock mechanically, were down shifted at north of 80mph into second gear on down hill parts. The engine braking helped them.
I try to tell folk that flatheads arnt made of chocolate, and they definitely arnt fragile.
Martin.

[1935coupe]

I was looking into Mitchell and found $2750 through Mac, though I would call direct and ask a few questions before ordering and wow I am glad I did. She gave me a lot of information, I did not know there were 3 shift options stick on the floor, no not enough room, under the dash, ok but when she told me about the on the shifter option that was it. nothing but a switch on the shifter handle. then the price 2400 a lot better then 2750

[Tony, NY]

Originally Posted by Ianrhall

Ok, where could I get those gears?
Ian

http://www.joblotauto.com/specials.a...currRecord=37#
Joblot Automotive for your needs. They show 3:54 gears.

[Ianrhall]

Looks good, not exactly sure which parts on that link I would need for a 40,s truck.
Been told it "probably" has either 4.11 or 3.78 as standard
Ian

[Tony, NY]

Sorry, forgot you're truck is 42-47. Those gears are not for that. Joblot did have a set of gears for 42-47 pickup when I called a couple years ago. Don't know what ratio they were. Maybe, give them a call.

[JSeery]

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Originally Posted by Ianrhall

Looks good, not exactly sure which parts on that link I would need for a 40,s truck.
Been told it "probably" has either 4.11 or 3.78 as standard
Ian

It is fairly easy to check, I would start there.

[dean333]

Ok, I have P215-70 R16's with a 4:11 rear. What tire size to I need on the back to effectively mimic a 3:78 ratio?

[JM 35 Sedan]

Originally Posted by dean333

Ok, I have P215-70 R16's with a 4:11 rear. What tire size to I need on the back to effectively mimic a 3:78 ratio?

This might help....

http://www.flatheadv8.org/formula1.htm

or maybe this....

http://www.btc-bci.com/~billben/rpmtire.htm

[dean333]

Thanks John, didn't help me though.

[Ken Arms]

I looked hard at Mitchel for my 34, after some measuring it looks like the floor pan would need to be altered for clearance, I decided to go 354.

[JM 35 Sedan]

Originally Posted by dean333

Thanks John, didn't help me though.

I had 750 x 16 Diamondback radials on the back of my '35 fordor sedan when it had 4.11:1 rear gears. I believe I (or someone) calculated this to be close to 3.78. I have since installed 3.78 gears and gone back to 600 x 16 Coker radials and the car seems to run about the same as the previous setup.

[dean333]

Sounds good JM but your missing a number, that's what's confusing me. For RADIALS P750-??/R16's?

[JSeery]

Johns formula should help:

MPH = RPM * Tire Diameter / Gear Ratio * 336

then

Tire Diameter should = (MPH X Gear Ratio X 336) / RPM


If you want to drive say 65 MPH and you have a 4:11 and cruise at say 2200 to 2400 RPM it will give you the required tire diameter.


TD = 89762.4 / 2200 or 40.8

TD = 89762.4 / 2400 or 37.4

So a tire diameter or 37 to 41 should get you between 2200 and 2400 RPM at 65 MPH. Someone with the larger tires will have to check and see if this came out correct.

Note: just checked mine and this sounds to big, my rear tires measure about 29. So that would be:

TD = 89762.4 / 3100 or 28.96

So, with 29 inch tires it would run about 3100 RPM, not that bad for a 4:11 gear.

[scooder]

Originally Posted by dean333

Ok, I have P215-70 R16's with a 4:11 rear. What tire size to I need on the back to effectively mimic a 3:78 ratio?

Just had a play on a tyre gear ratio program. Looks like you need to go to 235-80-R16.
These are a tadge big but close.
This is the info I got.
Your 215-70-R16 are 27.8" tall. At 70 mph in direct drive with 3.78 would be revving at approx 3198 rpm.
At the same rpm with 4.11 rear and 30.8" tyre (235-80-R16) the speed would be about 71mph.
This was using an online program.
Hope this helps.
Martin.

[scooder]

Typing at the same time.
Did you say 37-41" tyre !!!!! I think some numbers are muddled.
Martin.

[Brendan]

John, how was stopping your car with the 750s ?

[JM 35 Sedan]

Originally Posted by Brendan

John, how was stopping your car with the 750s ?

Brendan, did not seem to be any difference in stopping between the 750Rx16 versus the 600Rx16 to me. The floaters work great once I got them totally tuned in.

[Brendan]

Kool I was wondering how it would stop.