915 (911) Gearbox identification 72 or 83 or neither!

[Strictly]

Hi can anyone shed any light on this geabox? It looks like the stamped number/type is missing on the bottom perhaps having been scrubbed off by dragging on the ground, or im looking in the wrong place (but dont think so)

Im trying to work out if its from a '72 2.4E 911 or an '83 911 SC, or perhaps neither. Does the clutch cable "mount" give us a clue? The last one i saw like this was on a '76 911 2.7 I used to own? I bought two project together ('72 E and an '83 SC), which came with one '80 sc 3.0 engine, and one 915 gearbox (plus other bits)

I understand this has no real bearing, as this can apply to many models, but the codes on the nosecone, bellhousing, and middle bit are :

bellhousing = 915 301 101 0R
middle bit = 915 302 101 0R
nosecone = 915 301 301 0R
Code stamped on top = R
code number on bottom = nothing/scrubbed off

[Lightweight_911]

Looks like a magnesium casing & it has drive for a mechanical speedo so my guess is '72-'77.

Mike Bainbridge is the person tp pin-point exactly what version it is ...

[Strictly]

Looks like a magnesium casing & it has drive for a mechanical speedo so my guess is '72-'77.

Mike Bainbridge is the person tp pin-point exactly what version it is ...

Ah intresting, the 72 had a 2.7 engine fitted at some point in its life so that might just explain it. Either its the original 2.4E box, or its a later 2.7

I know, im hoping Mike will see this thread! lol. Mike, if i need to confirm its a 2.4, i'll open 'her up, but not sure i'll be any good at measuring ratios!

Out of interest where does the electronic speedo mount? Is it on the side by the diff, i think ive seen a sensor there on my old 78 sc, which means i probally hunt down an sc gearbox for the 83. Mike? lol

[Mike911scrs]

HI Strictly
the gearbox is a early Mag case box, with Mechanical speedo drive, there is no provision on the box for a electric speedo, the box looks like it is around the 1972-75, as after 75 the C.V. joints changed to the small 6 bolt type, will need a photo of the inside of the bell housing to see how late it is, there are small date castings on the cases with the week and year on them, on the end case where the casting No' is, down to the right of the No' may be a small round casting with 2 No's cast in it, the top is the week and the bottom is the year.

as for the ratios, the only way to check correctly would be to take the box apart, which will then involve a full strip of the pinion shaft and a clean/dry assembly, to make the box reliable.

it will be a 7:31 CWP

Poss' gear ratios for a 5 speed box

1st 11:35
2nd 18:33
3rd 23:29
4th 26:25
5th 29:22

the box may be a 4 speed (try to select the gears to see if all the gears are there for the 5 speed )

regards mike

[Strictly]

Hi Mike,

Thanks so much. I was really hoping you were going to see this thread =) =)

Ok good, so it sounds like its most likely for my 72E.

I have attached a photo of the bellhousing, if you can tell me where to scrub, i will have a look for the date castings you mentioned above. I have had a quick scrub, but nothing catches my eye for stamping.

I cant actually get it in out out of any gear, when i turn the input shaft both flanges move in the same direction, so in know its in gear. I'll fit it to the car and see if that give me more leverage.

Im going to give the car a full resto, and you will certainly be getting to know the inner workings of its gearbox, but that will be some time away. For the moment, i just wanted to try and work it if it was for my 72E, so i knew whether to keep the gearbox or not.

Bell housing photo :