13 replies to this topic

[rofert]

Anyone help please?

Just did a dry fit of A+ engine (MED1380) to an A gearbox and number one journal is hitting the casing. I know that this is a problem with early casings but:-

Question is how much do you need to grind away and number 4 is obviously the same, the case already has some marks by number 4 in it where a previous journal has rubbed. Does 2 & 3 give problems also.

If anyone has a picture of the grind would be appreciated to show exact location to work on as I want to get the engine in ASAP missing driving the mini so much especially with a nice new MED 1380 Type R..........

thanks Rofert

[rofert]

Bump

[Guess-Works.com]

It's unusual for the conrods to hit, unless it's an early 3 synchro box....

However, to get round your issue the only option is really a trial and error approach... I assume it's the leading edge which is contacting the gearbox at the front of the case.

This may not be much help but what I would do is gut the box, dry fit the block onto the box with no gaskets and see where it hits and start grinding away with either a die grinder or dremmel until you have clearance. Dry fitting without the gaskets means when they are added you'll have a few extra thou' of clearance.

[haz]

I had a similar problem a couple weeks back - it turned out id been sent the wrong con rod bolts - whilst they torqued up fine and looked to be right on the short engine, when i fitted the box there was a clearence issue. What con rods are you running?

Edited by haz, 20 August 2009 - 11:34 AM.

[rofert]

Thanks Guessworks, thought it was going to be a trial and error job, do journals 2 & 3 give clearance issues as well and do they only foul on the leading edge???

Haz not sure what rods they are as it was all supplied and put together as a short motor by MED, will have a look at the casting numbers tonight. How did you overcome your clearance issues?

Rofert

[rofert]

Thanks Guessworks, thought it was going to be a trial and error job, do journals 2 & 3 give clearance issues as well and do they only foul on the leading edge???

Haz not sure what rods they are as it was all supplied and put together as a short motor by MED, will have a look at the casting numbers tonight. How did you overcome your clearance issues?

Anyone else got experience if this?
Rofert

[rofert]

Done me gearbox grinding and it is a slow trial and error job, as one journal clears another catches but got there in the end.

Gear box and engine now mated together, onto my next question?

I need to get a new priamary gear straight cut for 1275 crank and to match the intermediate and 1st motion gears, am I correct in thinking that I will need to fit a A primary not A+ as the gearbox has A gears?

Also does anyone have a 23 tooth straight cut A primanry gear to sell.

Rofert

[Cooperman]

It's only the helical transfer gears which are a different form from A to A+. Straight-cut drops are, to my best knowledge, all the same, so long as they come fromn the same supplier. I do have doubts, although I've never tried, as to the wisdom of mixing, say, part of a Mini Spares set with parts of a Mini Sport set.
The only thing I will say, and from experience, is that straight cut drop gears for a road car are horrendously noisy and not really necessary.

[rofert]

They are for on a sprint car, and as you say it's best to fit a matched set from one supplier to ensure compatibility of teeth.

There are differnces in the Idler gear beteween A & A+

[Cooperman]

The idler gear stub-shafts are bigger on the A+. When I fitted the SC drops to my 1964 rally car I had to get the transfer gear casing precision machined to allow for this as my casing was/is a really early one. Now i wish I had stuck with the old helical gears as thet lasted 30 rallies without any trouble, then the transfer gear stripped. However, had I changed the helical gear each time I re-built the engine i don't think I would have had any problem. They are so noisy I have to wear ear plugs on the road.

[rofert]

I find intercom head seats good especially with a passenegr so you can talk.

Found a set of helical ones in the garage tonight which used to be in a 1295 (short stroke) engine that was fitted to my rally GTM Coupe, I changed them to straight cuts and never had any problems with them it just used to eat through it's bing end bearings.....I did rev it to about 8.5-9k though so that may have something to do with it.

I have early casing and want to retain it as it matches the age of the car, so will need to buy a set for an A series box which are available just got to get the pennies together.

Rofert.

[bmcecosse]

Hope you ground some good clearance into the gearbox - because the crank will 'whip' in use - and you don't want the big ends rattling off the casing!

[Cooperman]

About a year ago I built an A+ engine for a car with a 3-syncro box. I had completely forgotten about the early casing problem until I got it all assembled - then it all came back to me after 40 years. It's called 20/20 hindsight!
Anyway, I took the engine off the box, marked the sides of the box with 'engineer's blue' and used a rotary burr to remove metal. Once I got clearance at all points, I took about another 0.015" off the areas of minimal clearance and it all worked fine. I've not tried an A+ on a later Cooper 4-syncro non A+ box, but it should be OK. I'll find out soon as I have a Clubman GT engine to do with A+ rods going onto an A 4-sync box.

[rofert]

Ground them to give clearance then a bit more off, and also used some thick gaskets to give a bit more.

All seems OK hand turning just lots of fingers crossed for the first time at 7K

Rofert