Primary Gear - Bush Replacement

With the cost of new primary gears spiralling ever upwards, and the availability of good, serviceable used ones, fitting new bushes to existing gears is becoming a more common solution. For some reasons for bush failures and rectification to stop it re-occurring, see article Primary gear - Bush problems. Since there is no useful information given in any of the workshop or DIY manuals on this subject, following is my approach to dealing with the issue. The first thing to get to grips with is which bush is which. This has added an element of confusion to many conversations I have had with folks on this subject, so - the FRONT bush is the one nearest the engine block, the REAR bush is the top-hat one nearest the flywheel. This is because the front of the engine is actually the radiator end - quoted in 'in-line' engine-speak. The REAR bush is the same on all primary gears - be they for small or large bore engines. The FRONT bush is different for each though; the small-bore one is smaller

Idler Gear - Setting End Float

A fairly crucial part of how the idler gear operates is its tolerances and running clearances. part numbers: 22A1545, 22A1546, 22A1547, 22A1548, 22A1549, DAM4822, DAM4823, DAM4824, DAM4825, GUG705563GM, AAU8424, ADU6033, CCN110, 2A3643, 22A152, 53K547, Terminology: DTI - Dial Test Indicator End float is a continual problem as folk either ignore it through ignorance or lack of accessible information on how to do it, or belief special tools are needed. Also, later factory assembled engine units (from about 1992 onwards) were built up using whatever shims and thrust washers were available, since Rover were not making regular orders for all shim/washer sizes due to the forthcoming end of production. Consequently, many units left Rover with incorrect (usually too big) clearances. The idler gear was no exception. Too tight a clearance and the idler gear will either seize solid when it gets hot, or destroy the thrust washer thrust faces in the comparably soft aluminium gearbox and t

Primary Gear – Bush Problems

Although not of immediate interest to many road-runners/street-burners, mainly accorded to the racing scene, it seems to be a perplexing problem to a very large number of folk around the world, and has burned up plenty of telephone time.

part numbers: 13H2934, LUF10005, CE12, 22G109, DAM8889, DAM8887

With the cost of new primary gears spiralling ever upwards, and the availability of good, serviceable used ones, fitting new bushes to existing gears is becoming a more common solution. For some reasons for bush failures and rectification to stop it re-occurring, see article 'Primary gear - Bush problems'. Since there is no useful information given in any of the workshop or DIY manuals on this subject, following is my approach to dealing with the issue.

The first thing to get to grips with is which bush ...

Exhausts - RC40, Millennium and others tested

The recent rolling road re-test of the 1275 engine build I did saw an opportunity to do some exhaust systems testing.

I had noticed a few years back that the RC40 was being manufactured by a different process than the originals - giving rise to a change in the shape of the bends applied to the system. I had wondered if they would be causing a restriction at all - but hadn't had the opportunity to test it. The lack of expected power from the aforementioned engine lead me to investigate all possible angles from the tyre contact patch to the carb mouth. I found nothing that explained the 14 or so bhp I was 'missing'. After some application of the old grey cells I mentally narrowed cause down to one of two things - either the piston oil control rings were still causing excessive drag (75% of all internal friction of an engine is generated by the piston rings) or perhaps these new bends in the venerable RC40 were indeed causing a power loss.

2003-08, Oil gallery plugs

Here's something unusual that cropped up a little while ago that I've never commented on before - main oil gallery plugs/bungs.

I'd been conversing via e-mail with a guy that was experiencing weird oil flow/supply problems with his performance street engine. Initially he'd been blaming it on the supposedly superior oil pump he'd bought. He sent it to me; I inspected it and found it to be in perfect health with no signs of causing the issues in hand. Firstly there was a claimed total oil drain down from the pump causing lack of initial supply on start-up for a few seconds, and then repeated crank bearing failures when used in anger (i.e. at high rpm for protracted periods). Unless there is something drastically wrong with the oil pump and fitment - cracked pump body, non-flat mounting surface, mounting bolts too long, split gasket, etc. - it will not drain down simply because the inlet and outlet ports are above the centerline, near the top of the pump as it is mounted to the block.

Lubrication - Temperature critical

The correct running temperature of the oil is perhaps even more important than the water/coolant temperatures - so let us consider how to control them.

Mainly because it seems to be the most misunderstood of the whole process, and oil cooler fitment almost a reflex when over-heating occurs where a tuned engine of any type is concerned. And in many cases on standard production road cars for that matter.

Almost since the appearance of the immortal Cooper S, fitting an oil cooler has been the essential thing to do to any tuned Mini without any comprehension why. The original fitment was necessary because oil and bearing technology wasn't too advanced. Asking an oil of yester-year to cope with lubricating an engine at racing speeds, and a gearbox pushed their performance to the edge of their all too narrow capability, so extreme control over their working environment was essential for reliability. Hence oil cooler fitment.

Primary Gear - Setting end float

A fairly crucial part of how the primary gear operates is its tolerances and running clearances. End float is a continual problem as folk either ignore it through ignorance or lack of accessible information on how to do it, or belief special tools are needed.

Terminology: DTI - Dial Test Indicator Also, later factory assembled engine units (from about 1992 onwards) were built up using whatever thrust washers were available, since Rover were not making regular orders for all shim/washer sizes due to the forthcoming end of production. Consequently, many units left Rover with incorrect (usually too big) clearances. The primary gear was no exception. Too much end float and clutch disengagement is adversely affected, the gear floating up and down the crankshaft in unison with the clutch plate. The result is a graunching gear change since the plate isn't clearing the flywheel and pressure plate surfaces fully. Too little end float and the gear is likely to be pinched tight as it

My own Twin point by Keith Dodd 1st June 2006

Having now covered 17000 miles in my twinpoint from new it developed bad oil leaks making it a true mini. The rocker cover seals perished along with a diff output shaft seal. The leaks now rectified, Duckhams oil was used to refill the engine.

My own Twin point by Keith Dodd 1st June 2006 making it a true Having now covered 17000 miles in my twinpoint from new it developed bad oil leaks mini.

My own Twin point by Keith Dodd 1st June 2006

Having now covered 17000 miles in my twinpoint from new it developed bad oil leaks making it a true mini. The rocker cover seals perished along with a diff output shaft seal. The leaks now rectified, Duckhams oil was used to refill the engine.

My own Twin point by Keith Dodd 1st June 2006 making it a true Having now covered 17000 miles in my twinpoint from new it developed bad oil leaks mini.

02.09.07 - Donington Park Report by Keith Calver

Once again I found myself swamped with work causing the now familiar last minute rush to check the race car over before departing to Donnington. This race weekend was going to be a very different affair than what has become the norm. Karin was having to work the weekend, my 'opposition' in my class and in another Clubby - Steve (Young) - has resigned himself to doing the last race of the year at Oulton park due to work pressures, and stats man and hospitality provider Keith (Manning – now Otto v

Mini Production dates

We have tried to get together as complete list as possible to show all the models made from 1985 onwards, hopefully this will help identify those cars that have been modified over the years. If you have any information that you know is correct or anything that you think is not right please let us know.

05.06.10, Brands Hatch race report by Keith Calver

I am not sure why, but I don't really enjoy Brands Hatch. It is a quite technically difficult circuit to set fast lap times on. It is most definitely one of those circuits that 'be slow to go fast' applies to.

You can not hustle or hurry it. I am speaking from the point of view of having to use treaded tyres that don't give a tremendous amount of grip. And probably a circuit where 'loose is fast' applies... but I am still building confidence.

Cylinder head 2022

Historical Article - Nov 1991 - Twini Mini

The front brakes are standard Cooper 'S' 71/2" variety with the standard drums on the rear, with the assistance of a servo the rear regulator valve has been left out of the system and the brakes work very well. As the weight of the second engine amounts to the equivalent of two 11 1/2 stone passengers. Rear cooling is taken care of using a 1300 radiator mounted in the standard position. The heater take offs are connected to a 19 row oil cooler.

Historical Article - Nov 1991 - Twini Mini

The front brakes are standard Cooper 'S' 71/2" variety with the standard drums on the rear, with the assistance of a servo the rear regulator valve has been left out of the system and the brakes work very well. As the weight of the second engine amounts to the equivalent of two 11 1/2 stone passengers. Rear cooling is taken care of using a 1300 radiator mounted in the standard position. The heater take offs are connected to a 19 row oil cooler.

Historical Article - Nov 1992 - Little Red Booster - fastest road legal mini

In the November 1991 issue of Mini Tech News, we found ourselves with a half page to fill, and for no particular reason really, decided to throw a picture of our man Phil Oram’s recently departed Riley Elf racer...

Historical Article - Nov 1992 - Little Red Booster 2

A strange choice, you might think, for inclusion in Mini Tech News but, surprisingly the GTM has more Mini parts on it than the Elf! (because the Elf is nearly all space frame).

Historical Article - Nov 1992 - Little Red Booster 2

A strange choice, you might think, for inclusion in Mini Tech News but, surprisingly the GTM has more Mini parts on it than the Elf! (because the Elf is nearly all space frame).

Historical Article-February 1995-Calver's Clinic

Calver's Clinic COOKING OIL This engine oil thing seems to have caught people's attention - which is good as there is nothing like awareness of what is good for your engine. Having done the 'Life Blood' article in Minitech News 6, and what oils to avoid in Mini Tech News 7.

Historical Article-February 1995-Calver's Clinic

Calver's Clinic COOKING OIL This engine oil thing seems to have caught people's attention - which is good as there is nothing like awareness of what is good for your engine. Having done the 'Life Blood' article in Minitech News 6, and what oils to avoid in Mini Tech News 7.