M10 to M42 Getrag 240 mechanical speedo conversion
Posted: Mon Mar 25, 2013 3:15 am
Hello guys! long time without posting anything technical related.
I hope this post would help a lot of people and break some myths about the M42 swap on a car with mechanical speedo.
This is not the cheapest way, not the easy way, but in my opinion its the best and correct way to drive the speedo on any E21 or 2002 M42 Swap, and you have a Gearbox with mechanical speedo and the correct mountings for the car
Yes i know you can retrofit an electronic speedo, but after reading a lot about it, i think its a bit of "frankestein" on that mod, althoug iám an electronic technician and i dont like it.
You need 2 things to do this conversion, first of all ,of course an M42 Getrag 240, and the rare E21 M10 Getrag 240 from any 4 cilinder car.
Yes i know its hard to find but not imposible, i found 4 gearboxes like this here in Uruguay so for you i think its not going to be hard.
In this conversion you have 2 ways, the Easy way and the Hard way. wich way you are going to choose depends on the condition of the M10 Getrag 240 you get.
The internals are the same, the only 3 things different between the 2 gearboxes are:
1- The type of lubricant they use, the M10 uses gearbox oil, and the M42 uses ATF. (The difference is in the material and composition of the sinchros and gear clutches) . Remember if you follow the "easy way" you have to use Gearbox oil, and if you follow the "hard way" you have to use ATF.
2- The output shaft of the Gearbox its a bit longer, to hold the speedo gear ,and mechanism.
3- The rear and front bellhousing, are diferent but they share the same bolt pattern, and the internal casting is identical.
Easy and Hard way explain:
The Easy way : Put the front bellhousing of the M42 Getrag in the M10 Getrag 240
Just that, swap the front bellhousing and you have a ready to go, mechanical speedo gearbox to put on your M42 Conversion.
This is not hard, and you can do it, if you have minimal technical skills.
The Hard Way:, in my case i have a Worn out M10 Getrag so i have to swap the rear housing, the internals of the M42 gearbox, the output shaft of the gearbox and disassemble entirely the 2 gearboxes.
Importan Note: You only need to disassemble the entire gearbox if your M10 Gearbox, is in bad condition or worn out. If you have a good condition M10 Getrag 240, you Just swap the front Bellhousing, with out all the "titanic" disassembly.
Disasembly and etc:
So first of all, a bit of cleaning of the gearboxes, in this picture you can see the similarity between them, and this picture gives you a clue that internaly the gearboxes are exactly the same:
After disasembly, the gearboxes are identical, and almost all parts can be switched between them:
Main gearset comparison, as you can see they are identical!
And finally the Front M42 bellhousing and the rear M10 housing, they fit perfectly:
-
I hope this post would help a lot of people and break some myths about the M42 swap on a car with mechanical speedo.
This is not the cheapest way, not the easy way, but in my opinion its the best and correct way to drive the speedo on any E21 or 2002 M42 Swap, and you have a Gearbox with mechanical speedo and the correct mountings for the car
Yes i know you can retrofit an electronic speedo, but after reading a lot about it, i think its a bit of "frankestein" on that mod, althoug iám an electronic technician and i dont like it.
You need 2 things to do this conversion, first of all ,of course an M42 Getrag 240, and the rare E21 M10 Getrag 240 from any 4 cilinder car.
Yes i know its hard to find but not imposible, i found 4 gearboxes like this here in Uruguay so for you i think its not going to be hard.
In this conversion you have 2 ways, the Easy way and the Hard way. wich way you are going to choose depends on the condition of the M10 Getrag 240 you get.
The internals are the same, the only 3 things different between the 2 gearboxes are:
1- The type of lubricant they use, the M10 uses gearbox oil, and the M42 uses ATF. (The difference is in the material and composition of the sinchros and gear clutches) . Remember if you follow the "easy way" you have to use Gearbox oil, and if you follow the "hard way" you have to use ATF.
2- The output shaft of the Gearbox its a bit longer, to hold the speedo gear ,and mechanism.
3- The rear and front bellhousing, are diferent but they share the same bolt pattern, and the internal casting is identical.
Easy and Hard way explain:
The Easy way : Put the front bellhousing of the M42 Getrag in the M10 Getrag 240
Just that, swap the front bellhousing and you have a ready to go, mechanical speedo gearbox to put on your M42 Conversion.
This is not hard, and you can do it, if you have minimal technical skills.
The Hard Way:, in my case i have a Worn out M10 Getrag so i have to swap the rear housing, the internals of the M42 gearbox, the output shaft of the gearbox and disassemble entirely the 2 gearboxes.
Importan Note: You only need to disassemble the entire gearbox if your M10 Gearbox, is in bad condition or worn out. If you have a good condition M10 Getrag 240, you Just swap the front Bellhousing, with out all the "titanic" disassembly.
Disasembly and etc:
So first of all, a bit of cleaning of the gearboxes, in this picture you can see the similarity between them, and this picture gives you a clue that internaly the gearboxes are exactly the same:
After disasembly, the gearboxes are identical, and almost all parts can be switched between them:
Main gearset comparison, as you can see they are identical!
And finally the Front M42 bellhousing and the rear M10 housing, they fit perfectly:
-