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1100 engine and gearbox refresh.
https://www.ausmini.com/forums/viewtopic.php?f=5&t=84616		 Page 1 of 4
Author:  Flash [ Sun Feb 16, 2014 6:43 pm ]
Post subject:  1100 engine and gearbox refresh.
This has been done a bazillion times before but I have a camera I enjoy using and I'm hoping to do this step by step. So, with a 1128 gearbox, an 1100 block, and a 202 head on the way, I've decided to kick this one off. Don't be checking back every five minutes though, I'm not exactly a fast worker.

The plan is to warm the head, throw in a mild cam, use the twin 1-1/4" SU's in the shed, and find an exhaust to give me that barking cooper sound. But those are the easy bits.

First off, the gearbox: I have access to a great workshop and I shall throw the complete box straight into the parts washer before disassembly. The box is an unknown quantity and knowing my luck, will need a load of new parts before reassembly. I'm not exactly mechanically inept but I've never done one of these before so I'll be asking questions along the way. In fact, can anyone here tell me anything I should be looking out for before and during tear-down? I don't want to be saying, "Gee, was that ball spring-loaded? Where could that have gone..." :(

I'm determined to make this old car drivable.
Author:  pturnedge [ Sun Feb 16, 2014 7:35 pm ]
Post subject:  Re: 1100 engine and gearbox refresh.
Hi Flash, I found this link quite interesting about gearbox rebuilds. I haven't got there myself yet, but will be eventually. Worth a look in my humble opinion.

http://www.minimania.com/Classic_Mini_G ... ania_Video
Author:  boomini [ Sun Feb 16, 2014 9:23 pm ]
Post subject:  Re: 1100 engine and gearbox refresh.
Organisation is the main thing flash. Keep your parts organised in plastic parts boxes. If its going to be a while before you rebuild it take photos. Get a workshop manual and read and understand before you start. Things like detent balls and springs can disappear without you even seeing them..

There is plenty of knowledge here as you know.
Author:  Flash [ Sun Feb 16, 2014 9:43 pm ]
Post subject:  Re: 1100 engine and gearbox refresh.
pturnedge wrote:
Hi Flash, I found this link quite interesting about gearbox rebuilds. I haven't got there myself yet, but will be eventually. Worth a look in my humble opinion.

http://www.minimania.com/Classic_Mini_G ... ania_Video


That's a great place to view them. I saw these on Youtube but you can never find them when you go back to review.

boomini wrote:
Organisation is the main thing flash. Keep your parts organised in plastic parts boxes. If its going to be a while before you rebuild it take photos. Get a workshop manual and read and understand before you start. Things like detent balls and springs can disappear without you even seeing them..

There is plenty of knowledge here as you know.


I've done motorcycle gearboxes before and I usually stack all the parts in order on a piece of broomstick (something like a kitchen roll holder), or a wooden rod with slabs of cardboard in between each part, so they don't get mixed up. My biggest issue here is being able to tell what's serviceable and what needs to be tossed. I will be swapping out all bearings etc though.

You are right though, there is loads of good info here. :D
Author:  miniRock [ Mon Feb 17, 2014 12:02 am ]
Post subject:  Re: 1100 engine and gearbox refresh.
Ill be following this closly as tomorrow ill be removing the gearbox off my 1100 and rebuilding it. Please keep us posted and any little tricks you find
Author:  Flash [ Mon Feb 17, 2014 12:29 am ]
Post subject:  Re: 1100 engine and gearbox refresh.
This link is good for the early gearbox.

I was wondering if it was possible to use the A+ gears and in this one he shows us how. He's also not scared to use punches when installing bearings where I would usually use a tube but he's probably done a few more of these than me.

miniRock wrote:
Ill be following this closly as tomorrow ill be removing the gearbox off my 1100 and rebuilding it. Please keep us posted and any little tricks you find


You'll probably be finished way faster than me. I don't get much time to do this after work as I don't want to get home too late.
Author:  Minimadmarty [ Mon Feb 17, 2014 9:00 am ]
Post subject:  Re: 1100 engine and gearbox refresh.
Flash wrote:
He's also not scared to use punches when installing bearings where I would usually use a tube but he's probably done a few more of these than me.


I'm with you Flash using a punch is just showing off!! I've always used the old bearing against the new bearing and then a tube.

I'll be watching this thread closely as I am now very close to sourcing a 1275 and shall be going through the same process as you (probably even slower tho!)
Author:  timmy201 [ Mon Feb 17, 2014 2:11 pm ]
Post subject:  Re: 1100 engine and gearbox refresh.
I'm looking at doing something similar in the next year or so, it'll be good to see how you go with it
Author:  Flash [ Mon Feb 17, 2014 8:52 pm ]
Post subject:  Re: 1100 engine and gearbox refresh.
Okay, I had a look at the two blocks I have. The one on the gearbox is as it left the factory but with rust in the No.4 bore. It's so bad, it won't turn over. The other looks good but is already 60 thou over.

Again, this is all low cost and until about an hour ago, I was going to throw them both in the scrap bin (too hard basket) at work but then I got to thinking, "How deep can rust go in a block?" 20 thou, 40 thou? Whatever engine I use will probably receive an overbore anyway so is it worth looking at the rusty one?
Author:  drmini in aust [ Tue Feb 18, 2014 1:47 pm ]
Post subject:  Re: 1100 engine and gearbox refresh.
I'd bore the rusty one to +.080" or +.100"... 8)
Use flat top pistons if you can get them.
Author:  Flash [ Tue Feb 18, 2014 3:31 pm ]
Post subject:  Re: 1100 engine and gearbox refresh.
Too much power is never enough with you lot, huh? :D

It helps if you don't measure bores in the dark. The good spare block is in fact .030" over. Unless something like a 1275 comes along before I finish the gearbox, this will be the block I use. Would flat-top pistons really be necessary? This will be my daily hack.
Author:  drmini in aust [ Tue Feb 18, 2014 8:36 pm ]
Post subject:  Re: 1100 engine and gearbox refresh.
Flash wrote:
Too much power is never enough with you lot, huh? :D

It helps if you don't measure bores in the dark. The good spare block is in fact .030" over. Unless something like a 1275 comes along before I finish the gearbox, this will be the block I use. Would flat-top pistons really be necessary? This will be my daily hack.


Well if you run flat tops you can use a 12G295 Cooper/Sprite head, or open the chambers up on a 202 so it breathes better.
But if staying near stock with a 998 or 1098 head, dished ones are fine.

[Dished pistons + a 295 head = ~7.5:1 C/R, is stupidly low, because of the BIG head chambers. Flat top pistons help avoid this].
Author:  Flash [ Tue Feb 18, 2014 8:51 pm ]
Post subject:  Re: 1100 engine and gearbox refresh.
drmini in aust wrote:
[Dished pistons + a 295 head = ~7.5:1 C/R, is stupidly low, because of the BIG head chambers. Flat top pistons help avoid this].


I see your point.
Author:  miniRock [ Tue Feb 18, 2014 8:55 pm ]
Post subject:  Re: 1100 engine and gearbox refresh.
Although a low CR opens the door to a supercharger if im correct
Author:  boomini [ Tue Feb 18, 2014 9:03 pm ]
Post subject:  Re: 1100 engine and gearbox refresh.
Yes supercharge that 1100 I say
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