Sönke
13 posts
Joined: 16/09/2004 18:58:58
Location: Quito Ecuador
gearbox
Ok I have a Authi Mini 1275 GT, Oct 1973, spanish and when i bought the car in dec 2003, I didnt know what I get for the money. I started with the engine, to make it work and found out that the gearbox is not propper one. I need now urgent advertise to change the gears. The first gear is going up to the speed of 20 kmh, the 2 gear is going only to 40 kmh, the 3 is going up to 62 and the 4th not more than 84 kmh. My question is now what gears i must put in the box to speed up more and not going on like and old turtle. I hate going slow. Please URGENT HELP. Pleeeeease Sony
Posted: Nov 15, 2004 09:58 PM
Simon@minispares.com
94 posts
Joined: 08/09/2004 21:32:29
Location: fdgfghgfjgj United Kingdom (Excluding channel Islands)
Gearbox
Hmmm, doesnt sound like so much of gearbox problem, but a general running problem? What RPM is the car doing before you have to change gear?
Posted: Nov 15, 2004 10:11 PM
almost running on 7000 rpm, mesured with the tachometer, and the speedometer is new and calibrated
Posted: Nov 15, 2004 10:23 PM
Glen
10 posts
Joined: 01/10/2004 10:52:09
Location: Nr. Winkleigh United Kingdom (Excluding channel Islands)
For a quick fix, if you havent lowered your car too much, you could try fitting 12 or 13 wheels, if yours has 10 on already. Or swapping for higher profile tyres. Wont do much to speed your car up, but itll help a bit. That must have a fairly awesome diff in there to drop your speed that low! 5.3:1???? Not got a calculator to hand. Cheers, Glen.
Posted: Nov 16, 2004 03:54 PM
Keith
173 posts
Joined: 13/09/2004 07:56:05
Location: United Kingdom (Excluding channel Islands)
Certainly sounds like a final drive ratio issue. Probably got a 4.1-1 in it... Go see the articles I did on this in the Gearbox section of the artciles. KC.
Posted: Nov 17, 2004 07:18 PM
Sorry - that should have been Calvers Corner under the articles section. KC.
Posted: Nov 17, 2004 07:21 PM
Soenke
tahnks everbody, i will see to get the other crown wheel / pinion to speed up a little bit more, do you think it ok to put in the gearbox the crown/pinion 59/20???
Posted: Nov 17, 2004 08:46 PM
Posted: Nov 17, 2004 08:50 PM
Posted: Nov 17, 2004 08:52 PM
John
163 posts
Joined: 09/09/2004 09:32:06
Location: DK-2000 Frederiksberg Denmark
Im not sure which final drive youre looking for, but a 2.95FD (59/20) will definately give you more speed at the sacrifice of brutal accelleration. Depending upon what youre using the car for, you might find that this is nice on the highway, but you may find it laboring too much for the race track. The TECH TIPS tab will take you to the Technical Downloads pages, where you will find a Classic Mechanical Parts Catalogue. http://www.minispares.com/Auth/Downloads2.aspx?con=cmpc&if=../Html/ClassicMechanicalPartsCatalogue/mini_akm2_index.htm
Posted: Nov 17, 2004 10:34 PM
Still think something is a bit amiss. To only be able to do 84km/h (53ish mph) in top at 7000rpm is seriously undergeared! Or something doesnt add up. Have you used GPS or speed camera etc to confirm your speedo is right? Tacho is definitely 7000rpm? Maybe it is, but would have to be lower than 4.1:1..... ? Glen.
Posted: Nov 18, 2004 09:49 AM
GDR1
2 posts
Joined: 18/09/2004 17:44:40
Location: Morpeth United Kingdom (Excluding channel Islands)
gearbox trouble
I just got a 1275 engine (year 1990 from a metro) and im having a bit of trouble with the gearbox. The engine is out on a bench,with the diff assembly removed so I have a bit of a view inside the box. The thing is im having trouble getting gears as the selector rod is running on the topbellcrank lever and I can pull the selector rearward to engage a gear but cannot push it forward to do the same.It looks like the lever will not go forward enough to move the selector arm up of down to get any other gear. at the moment im tryimg to get the clutch/flywheel assembly off to get a better view (but its being a sod), possibly to swap boxes from another engine. Any ideas???
Posted: Nov 19, 2004 10:20 PM
Posted: Nov 19, 2004 10:22 PM
a2lt16v
Joined: 23/11/2004 08:55:45
Location: andover United Kingdom (Excluding channel Islands)
gearbox 998 > 1275
WILL a 998 gearbox fit onto a 1275 if yes any one know whats the best type of 998 garbox to use they had different final drive values didnt they?
Posted: Nov 23, 2004 09:03 AM
68Moke
33 posts
Joined: 10/09/2004 21:06:12
Location: Lakeville United States
998 gearbox fit onto a 1275
Rod change or remote box? Rod change or remote, should be no problem. If you are not using the flywheel housing that originally came with the gear box (assuming that it was matched up to the gear box correctly), you will have to make sure the measurements for the intermediate gear thrust washers are correct. Most I have seen came with a 3:44 but you will have to count the teeth to verify what it is. The final drive depends on what you are using it for. Road car , autocross, track days, etc.
Posted: Nov 23, 2004 04:28 PM
Posted: Nov 24, 2004 12:50 PM
Just had a very quick play on Excel, forgive me if my figures are slightly amiss, I realise tyre crawl etc will taint the answers. But as a quick knock up. Assuming you have 145/70/10 tyres. A 1.087 straight cut drop gear. A 5.9 diff (and Im not sure they are that easy to come by????????). Your road speed in 4th, with 7000rpm at the crank, should be about 94km/h! That is assuming you have have a straight cut, lowest ratio drop and ground out diff and box casing to take a silly low ratio diff. And you have 145 tyres (which would be shredded in all 4 gears with that kind of ratio). Can you see, 84km/h is not likely without an external factor, like clutch slip or worn driveshaft splines, broken diff. ???????? If your road speed is that low from gearing, and assuming you have about 65hp or so at the crank, your car should be able to lay rubber in the first three gears! Is this right? Best of luck, Glen.
Posted: Nov 25, 2004 11:42 AM
Posted: Nov 26, 2004 05:33 PM
nick the greek
4 posts
Joined: 01/12/2004 23:07:01
Location: poole United Kingdom (Excluding channel Islands)
sccr gearbox
hi, im building a high boost mini turbo. ive been offered a straight cut close ratio box built with a minispares gearkit, question is, will it be strong enough?
Posted: Dec 01, 2004 11:20 PM
SC gears are viewed by most to be the strongest vs. a helical cut.
Posted: Dec 02, 2004 01:39 AM