Gear Boxes

hi all,
i have got a 1600 TP for my 66 beetle..

my question is, is it worthwhile upgrading my gear box from the original 1300 swing axle to a 1500 swing axle?

I do a reasonable amount of highway driving and am wondering if there is enough difference in the gear boxes to be bothered changing..

ALSO: what do i have to do to get the 1600 TP to mate up with the 1300 swing axle gear box.. i know there is a lug you are supposed to grind off.. what else should i do if i keep the 1300??:vader

cheers,
nick

The 1300 swing axle gearbox has a 4th gear of 0.89 and a final drive of 4.375.

This gives about 3400rpm at 60mph.

The 1500 swing axle gearbox has a 4th gear of 0.89 and a final drive of 4.125.

This gives about 3200rpm at 60mph.

So your 1600 engine will defnitely have "longer legs" with the 1500 gearbox (or the same 4.125 final drive put in the 1300 box - it's a straight swap).

With the 1300 box, you acceleration would be great but the top speed would be lower and the fuel consumption higher.

I misses an answer to the last question - if you want to keep the 1300 (6 volt) box, you will need to grind out the bell housing (probably the bottom two engine mount fittings inthe bell housing) to fit the larger 130 tooth 12v flywheel (I'm assuming your car will be converted to 12v).

The best way to do this is to fit the engine (with 130 tooth flywheel) up to the gearbox and turn it by hand so the flywheel teeth make a mark on the edge of the bell housing - then remove the engine and grind slightly more than those marks - and to the depth of the flywheel (as it projects away from the engine mountiing surface).

Make sure you use the right clutch plate - the 1300 and 1500 boxes require a clutch plate wiht the ring in the middle. the later style clutch plate has no metal ring in the middle of the fingers and it uses the "flat ear" type release bearing, so if you want to use THAT type of clutch plate, you must change the whole clutch operating arm in the bell housing to suit the flat-ear type thrust bearing (release bearing).

If you keep the car as 6v, then no grinding of the bell housing is needed, and you put the 6v (109 tooth) flywheel on to the engine. It should bolt straight up, so long as the engine it came off had the same O ring type of oil seal - not the paper and metal gasket type (original 6v type).

The pinion bearing in the bell housing must match the 6 or 12v starter (different diameter shafts).

If you keep the 6v flywheel, you will have a 180mm clutch instead of the 200mm clutch.

This is OK so long as you don't do a lot of hard launches - the 180mm clutch will handle the 1600 power (the 1500/1600 semi-auto uses the 180mm clutch plate), but it won't last quite as long as the 200mm clutch.

Be very very very very careful when grinding out bellhousings, as they are also a magnesium alloy casting. The dust from this alloy is extremely flammable - to the point that hitting one of the steel mouting bolts, which produces sparks can and will ignite any of this dust that is laying around. Magnesium burns at several thousand degrees. This is VERY HOT and will give you thrid degree burns in seconds which will require skin grafts. Its not a pretty sight.

So, take your time. Be very patient. Remove the mounting bolts, or at least go VERY CAREFULLY around them. Ideally, have a fan blowing the magnesium dust away from your worksite / body. If not, do a little bit, then sweep the grindings away. DO NOT sit crosslegged under the gearbox when doing this job. DO wear at least full cotton overalls and good gloves at the least when doing this.

Just be careful.

Doug.

Ummmm.... a voice of experience there Doug? 🙁

Are 1200 and 1300 6v gear boxes the same. Do they have the same ratios?

How can you tell from the outside what gear box (6v one) you have. 1200, 1300 or 1500??

I have a ??? 6 volt tunnel case gear box in my 57 and it seems really low geared. Would love to know for sure what it was.

Our father (doug and mine ) spent 3 weeks in the burns unit in royal perth, skin grafts and all as a result of mishap when clearancing my gearbox for 12V flywheel.

If you are going to do this ... do it with the gearbox OUT of the car and make sure there is NO ( That is NONE AT ALL ) steel bolts etc left in the gearbox.

My father was lucky to only spend 3 weeks in hosp as they said 6 to 8 when he first went in.

Grey 57 wrote:Are 1200 and 1300 6v gear boxes the same. Do they have the same ratios?

How can you tell from the outside what gear box (6v one) you have. 1200, 1300 or 1500??

I have a ??? 6 volt tunnel case gear box in my 57 and it seems really low geared. Would love to know for sure what it was.

I'm not absolutely sure about the earliest boxes, but the 1200 (40hp) and 1300 boxes are the same ratios, with 0.89 4th and 4.375 final drive (the 1500 semi-auto uses these ratios too.)

about 3400rpm at 60mph (100kmh)

The 1500/early1600 gearbox has 0.89 4th and 4.125 final drive.

about 3200rpm at 60mph.

The 4.375 and 4.125 final drives are a straight swap.

The later (73+) gearboxes have 0.93 4th and 3.875 final drive)

It's not a straight swap to put these in an early box.

about 3050rpm at 60mph.

Look on the right side above the VW logo and case part number - there should be a double letter faintly cast into the case.

1200 - AA
1300 - AB
1500 - AC

(I don't have my list with me and I can't remember the rest.)

There are different series numbers for KGs and type3s (some tiwh the same ratios though).