ENV gearbox

[Big col]

Can anyone advise if there is a manual available for a 1934 AC-ENV four speed gear box. I intent inspecting and servicing both the gear box and back axle at some point during the restoration of my car. I see that there is some info for the axle on the Two litre web site which looks helpful but I can't find anything related to the diff or the box.

[Robin A Woolmer]

I am not aware of any handbook relating to the ENV crash Gearbox, a Barry Foster an MG mmm owner has extensive knowledge & I will try to find out if he can recommend a source!
   These gearboxes were sought after by MG mmm owners & many AC gearboxes found their way into mmm cars!
   I am having one re-built with a better first gear ratio at present which Barry Foster supplied.
   
   Robin

[Big col]

Thank you Robin

[Robin A Woolmer]

Col
   If you Google MG mmm web site you may find the following Technical article number 25 from 1976 mmm year book which has some advice information.
   Also Service Information 14 Jan 1932 MG Magna.
   I will contact Barry to see what additional information he can suggest.
   
   Robin

[BE774]

http://crossley-regis.org/env_type_75_preselector_gearbox
   
   and
   
   http://crossley-regis.org/env_type_75_gearbox_manual

[Robin A Woolmer]

For some reason I assumed you needed information for the ENV crash Gearbox, perhaps you would be good enough to clarify if it is a Crash or Pre-Selector type!
   The information I have sent is for Crash Gearboxes which were fitted to PVT cars up to mid 1936, later in 1936 AC purchased Moss manual gearboxes & some cars had Pre-Selector types.
   The ENV Crash Gearbox is more efficient than Pre-Selector & a Mike Alison of MG Fame calculated that they would take up to I believe 250 lbs feet torque!
   The weakness of the AC boxes which have the favoured cross tube support is that the casing clamps do suffer from cracking, also as they used steel tubes they tend to corrode in the cross tube housing bores, they are rare & very sort after

[Big col]

Graham,
   thanks for coming up with that but it is the crash box that I have.
   
   Robin,  your right it is the crash box that I am looking for information upon..and thank you for those leads. I will endeavour to search and copy them.
   The weakness you mention of the casing clamps is a fault on the near side of the box. Luckily it looks upon initial viewing that I will have the means to repair it.
   I understood that AC started to fit the moss box to cars after mine but I didn't realise that the ENV is considered to be such an efficient box and therefore very sort after.
   If you can suggest additional information  through any other means I would be grateful.

[Robin A Woolmer]

Col
   Both sides of the box cross tube clamps were cracked, also I had a job removing the cross tube, had to cut it out, have had the clamps reinstated & laser welded, & re-machined, will be using a stainless tube when I fit it to my 16/80 Special & bonded mounts in the chassis!
   Have sent request to Barry Foster for any information he can supply, he did an article on the Morris MG crash box which is similar & somebody else did a cross section drawing, but we will see !

[Robin A Woolmer]

Col
   The best information source appears to be in Malcolm Green Book on MG Road Cars Volume One Chapter ten, this covers the MG 1929-1936 OHC cars & gives a comprehensive explanation on the overhaul of these cars , it covers the four cylinder cars & Volume two covers the six cylinder cars.
   Unfortunately these books are now expensive to purchase but you might be able to borrow one, Chapter ten basically describes the overhaul & faults on the MG box but they are similar in design to the ENV to which he refers, the same basic faults & repairs appear to be similar!
   I do not believe much more can be found unless you want to go the Vintage museum library, there is a first gear ratio modification for the ENV gearbox which Barry manufactures which gives a better first gear higher ratio!
   
   Robin

[Big col]

Robin,
   Many thanks for your diligence.  I am a member of the VSCC and so will be able to use there library. It will give me an excuse to visit the Old Post Office, which is something I have been considering for a while. I will try and arrange it when I am next working around the area.
   It may be of interest that I was visited today by the coach builder to discuss the body work and having it reframed. I hope to have some work started pre Christmas. It will slow down what I can do through the winter but at least it is moving on.