Close ratio gears

Hotrodfil

Hotrodfil

Senior Member
Popped over to Belcher Engineering here in the UK on the way home to ask about a set of close ratio gears for my Fordor.

They manufacture two types of close ratio gears for the Model A gearbox with gears made from EN36 steel, case hardened and run on needle bearings. Straight cut, no synchro just like stock only far better ratios.

Ratios:-
20 Tooth to 27 Tooth
1st 2.2 to 1
2nd 1.3 to 1
3rd 1 to 1

18 Tooth to 29 Tooth
1st 2.59 to 1
2nd 1.55 to 1
3rd 1 to 1

I run the 2nd set behind a B engine in my Tourer and they shift lovely. They currently have six sets of blanks on the shelf so if there's enough interest they'll run a batch off.

They also have a couple of F head kits for sale if anyone is interested.

belcher-manifold.jpg


prototype-F-head.jpg
 
Thats some engine you have there Phill !! I bet that car really moves
I know Gary and old Brian Belcher they do very Good work.
They also design and make parts not just import them from somewhere else .

I see from your Avatar your a Rock & Roller Do you go to the Rhytm Riot or the Rockabilly Rave ? Maybe I'll see your car there one day !!

John Cochran
 
Not my engine I'm afraid - although I do have a head to fit sometime to a diamond B block that needs... everything.

Buy myself a present? Yup. One new hub seal...
 
Ballpark figure is around £200 more than new stock gears.
Standard ratios are... awful.
From the Macs spec page.
High-1:1
2nd-6.89:1
Low-8.75:1
 
Interesting steering box mod. I did a similar thing with the box on my roadster when I put the flat head V8 in. The only different is that the block is mounted on the out side of the frame instead of the top.
 
Hotrodfil said:
Didn't think the Macs specs seemed right...!
Click to expand...

I first noted these specs (6.9:1 and 8.75:1) in "Model A Specifications" on pages 30 thru 33 of the May-June 1988 issue of "The Restorer" (MAFCA), subsequently included in Volume V (pages 10-13) of "How To Restore Your Model A" so they seem to have a life of their own. However, I believe the 1.85:1 and 3.12:1 are more accurate.

Final drive gear ratios for transmissions such as are found in the Model A, are calculated as the ratio of the output gear (diameter or number of teeth) to the input gear, or where there are multiple gear engagements (such as in first and second gear) the product of such ratios and are expressed as the ratio of the number of input shaft revolutions required to give 1 revolution of the output shaft.

Thus, for first gear, where the 16-tooth input shaft drives the 31-tooth gear on the cluster gear, and where the 18-tooth cluster gear then drives the 29-tooth low/reverse sliding gear, the number of input shaft revolutions to give 1 output shaft revolution is given by 31/16 x 29/18 = 3.12 (rounded down). Consequently, first gear is said to be 3.12:1.

Similarly, second gear, where the 16-tooth input shaft drives the 31-tooth gear on the cluster gear, and where the 24-tooth cluster gear then drives the 23-tooth second/high sliding gear, the ratio is given by 31/16 x 23/24 = 1.86 (rounded up), giving the 1.86:1 (sometimes seen as 1.85:1) second gear ratio.

For third gear, the forward portion of the second/high sliding gear internal teeth engage with the after portion of the input shaft external teeth and neither the low/reverse nor the second/high sliding gears otherwise engage with the cluster gear (which keeps spinning due to its permanent engagement with the input shaft). The after portion of the second/high sliding gear remains splined to the output shaft and consequently the output shaft is driven with no gear reduction and the final 1:1 “ratio” is achieved.

Reverse is the product of three ratios, inasmuch as the 16-tooth input shaft drives the 31-tooth gear on the cluster gear, the 15-tooth gear on the cluster gear drives the 18-tooth reverse idler gear, and the 18-tooth reverse idler gear drives the 29-tooth low/reverse sliding gear, giving a 3.75:1 reverse gear ratio.

Probably more than is needed for this discussion…

Model A Transmission.jpg
 
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That is great info, thanks.. I was considering a Mitchell but was concerned of cost of especially quality.. I'm not crazy about the stock ratios and the English and Chinese[ Mitchell] options seem interesting..
 
Thanks for the info. 200 pounds over new standard gears is a lot just to get a better first and second. I put a mitchell overdrive in Barry's coupe, and while the cost is quite high, it was a nice addition to the car. I looked into a Laycock overdrive, but it requires 12 volts, and my cars are 6. Still undecided what to do. I have a set of 3.27:1 rear end gears I could put in the coupe. According to my crummy math skills, the mitchell makes a 3.78:1 rear gear about 3.00:1 in overdrive. Barry's coupe ran fine in most circumstances when just left in overdrive, but it was nice to have the stock low gear for parades.
 
The syncro gears from Mitchell Manufacturing are a better ratio. Has anybody had any experience with their syncro gears?

Charlie Stephens
 
The last I spoke with the folks at Mitchell, there were 3 ratio options which I thought was nice.. I was wondering about quality since its chinese.. Mitchell said they have had no issues ,, but,, I've heard some have had problems..
 
FWIW...I'll post some of the ratios that can be attained using Model B trans case or V8 '32-48 cases.
The 28 and 29 tooth ones (teeth counted at front of cluster) are both very common V8 Ford ratios, the 25 and 26 tooth ones are from 1940's V12 Lincolns and are fairly pricey.

All ratios courtesy of my 50 or 60 year old Iskenderian "Dream Wheel", a little circular slide rule that can compute speed versus tire and gear possibilities.


29 tooth 3.11 1.770 1.00
28 tooth 2.82 1.607 1.00
26 tooth 2.327 1.576 1.00
25 tooth 2.12 1.435 1.00

The Lincoln gearsets were meant to be used with very low R&P and overdrive of about .70 ratio.
 
I have a Mitchell trans plus O/D in my slant screen we inported & like it very much, One can shift more quickly with the shorter throw, plus the taller ratios make it more like a B trans , coupled with the O/D its a nice driver, Expensive set up but the vehicle came that way, Love my O/Drive, Derek spring is here, swap meets & Speedway . 45 years sunday wedding aniversary,
 
I have 2 Columbia O/D,s that I modified to fit my "A",s and I love them.One has been in use since 1960 & the other I modified a few years ago.Both have 4.11 gears & 2.94 in O/D. 1st & 2nd in O/D are great ratios too.
 
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