I know they're out there and I've tried searching for all of this but I wanted to start a thread that discusses VERIFIABLE weak links in the MC drivetrain.

*The tranny supposedly can't handle more than 150hp ~
-where can this be improved? Clutch, axles, etc or are we blowing out gears and input/output shafts?

*The crank and rods are mentioned somewhat ~
- Does anybody have any broken ones and have you done any analysis on them? What power level/RPM did this occur?

*Pistons, easy enough to get a cheap set so I'm not too concerned here.

Is there anything else?

This is not a thread to discuss the merits of trading up for an MCS or the fact that it doesn't matter because you won't get 150hp from an MC...it's intended for my education and the education of others as to what the weak links REALLY are and exactly HOW weak?

Thanks...

 

Midlands tranny (MC) couldn't handle the extra horses which is why the higher horsepower MCS got a Getrag from the start. What about the 5-speed Getrag box?? Better spec?

 

right...from the factory, they couldn't justify the 50k miles warranty on the Midland Gear 5-spd, but what about real world experience? Anyone pushing any decent power numbers from a standard MC and having problems?

 

there is a turbo'd cooper running around in miami....maybe you could figure out a way to contact him? Maxi tuner has had a turbo on their mini ONE(same engine and tranny as cooper....just ECU-controlled to produce lower HP) for a while now too...they want to put it into production....they are german so talking to them might be a bit harder, but just as helpful.

I know someone who threw a 6 speed gertrag in his cooper to handle his turbo . I havent talked to him in a while, but he has the tranny in and hasnt had any problems...just been working on tweaking the turbo. So switching out the entire tranny is an option....a very good one if you could find a salvage MCS that has a good tranny in it.

 

I don't think you want to start on the 6-speed MCS tranny swap. Its a pain in the ****. Different mounts and all kinds of little things that need to be swapped. Doesn't sounds too fun to try.

In the end, you'll end up spending as much or more money trying to get more power out of an MC as you would getting the MCS or things of that nature. If that's what you want to do I'd say you're going to need a new tranny and some kind of turbo or super charger.

You could try a new exhaust along with intake and an ECU re-mapping. That may get some extra ponies but I can't say how many.

 

I appreciate the the possible contacts for the turbo MC's, RallyMINI!

SoCalSam, I appreciate the advice but just to stay on track, I'm most concerned about real-world evidence as to how durable the stock stuff is. There's already enough threads about trading up to an "S" or swapping in different MCS parts. My real intent here is to find out if anyone "knows" the limits. Don't want to be the first, ya' know?

 

I soooo wish I could be of more help to you Turbo.....but things around these parts are scarse when it comes to turbo's for the MC. We have tried so many times to start a serious thread here and it just gets toppled over by "Why not just get an S?" and all of that BS........

I'm running about 115 hp to the wheels (just your standard intake, ECU, exhaust) which would put me at about 130 some odd engine hp. Not exactly to the max, but above what the normal 115 engine hp MINI proclaims for the MC (which would make the whp about 90 something?). I seriously would have been in line for the M7 turbo kit which they were going to put out for the MC but was scrapped for the sheer amount of parts that needed to be upgraded on the engine and tranny.

I agree that they SHOULDN'T have even tried back in 02.....it just wasnt worth it! I've gone thru 2 trannies already and I've only hit 55K! The first time I ran over a tree stump (cracked the tranny block-replaced), the second time (at 55K) the clutch went out (replaced with Spec 2 clutch and 8.5 lb flywheel). I have more faith now that the crappy clutch and flywheel are gone out of the mix, and can probably push the engine a little bit more. I still haven't done all of the things I want to do to the car as far as port/polished cylinder head, bigger valves, bigger TB, port/polished intake manifold, higher lift camshaft, etc. This should put me in the range of 170+ engine hp......and should give me that big #($%-eatin' grin I used to have........and should eat a bigger heavier MCS off the line and on the track. I also plan on gutting out the interior etc. for it to be a track car in the future. But if after I do all of the other head work still feel like the car can take a turbo, by all means, it's ON! And maybe put the car up to about 200 engine hp/torque (this is the maximum the Spec 2 clutch can hold, and might at that time move up to a Spec 3) with the turbo as well as the other mods........

It is completely feasable to change out the tranny for the MC and put in a Getrag MC tranny (the MCS tranny would give you more problems than what it's worth with the different gear ratios setup for the higher horsepower S) that should hold up to the power. I've asked around and to do the job (while the clutch was out) and they quoted me about 3K for parts and about 10 hours of labor......at 80.00 .hr so your looking at around 4,000 bucks before its all said and done.........GOOD LUCK with your project TURBO!

 

Here are some comparisons between the MC and MCS engine itself, quoted from BMW'S internal training manual, "Introduction to the MINI":

R50 MINI COOPER Engine Number W10B16 Weight 129.22kg (referred to as the W10 engine)
R53 MINI COOPER S Engine Number W11B16 Weight 138.05kg (referred to the W11 engine hereafter)

Engine Construction
The engine block and bearing ladder are constructed from cast iron with an aluminum alloy cylinder head. The oil pan is manufactured from aluminum alloy to reduce weight. Despite the iron block and ladder bearing, the engine is very light (129.22kg). Main features of the engine include:
16 valves, single overhead chain driven camshaft
Hydraulic lifters
Automatic adjusting accessory drive belt
Supercharger on MINI COOPER S

Engine Block
The engine block is manufactured in two halves from sand cast nodular iron. The top portion (main cylinder block) includes the cylinder bores and has provisions for five main bearing top shells. The lower portion (support ladder) incorporates the lower main bearing shells and support for the rear main oil seal. The engine block and ladder are machined as a matched pair and are not serviced as individual components. Three locating dowels are used to ensure perfect alignment between the support ladder and the engine block.

A number is stamped on the engine block and the same number is stamped on the bearing ladder. This ensures that the matched pair of components remain together during engine assembly. The other number stamped on the block is the engine plant serial number.

Crankshaft Assembly
The MINI COOPER crankshaft is machined from nodular cast iron. The MINI COOPER S crankshaft is machined from forged steel. Both crankshafts provide a mounting point for the crankshaft sensor reluctor ring that is retained by three bolts. The drive for the oil pump is provided by machined flats towards the front of the crankshaft. The auxiliary drive belt pulley is a press fit on the crankshaft and retained by a bolt.

Crankshaft Bearings
All MINI COOPER engines use five main bearings. Lubrication is supplied through holes in the upper shell directly from the main oil gallery. The upper shell is grooved to transport oil to the lower plain shells located in the bearing ladder.
A thrust washer built into the center upper main bearing shell controls crankshaft end float. The connecting rod and main bearing shells are made of an aluminum base that is rolled onto a carbon steel backing.

Connecting Rods
MINI COOPER connecting rods are manufactured from 'non-coplanar' powder metal. They are manufactured in one piece and then fractured across the big end journal. The MINI COOPER S connecting Rods are manufactured from forged steel to provide additional strength and are fractured. The big end bearings are of a conventional plain shell design with oil supplied from a hole in the crankshaft. [ask me if you wish an explanation about the Fracture Process].

Pistons
The pistons are aluminum construction with a grafal coating applied to the skirt to reduce noise, friction, and scuffing. The MINI COOPER pistons have flat tops. The MINI COOPER S has a concave piston top with a volume of 1.66cc to reduce the compression ratio.
Grafal coating consists of a fine colloidal graphite which is bonded with resin. It is between 10 and 20 micrometers thick and is applied by means of a printing process, followed by curing. Improved adhesion properties are achieved by a thin metallic phosphate layer or other proven methods which are applied prior to coating.

Oil Pan
The oil pan is constructed of die cast aluminum. It is secured to the support ladder by 13 bolts. The oil pan provides a mounting position for the air conditioning compressor on the right side of the engine (viewed from the crankshaft pulley) and for the engine tie rod bracket on the left side of the engine.
The seal between the oil pan and the bearing ladder has a washer fitted to each bolt location to prevent over tightening and distortion of the seal. A lip on the oil pan seal ensures correct location to the bearing ladder.

Cylinder Head
Introduction
The cross flow design cylinder head includes a single overhead camshaft, two rocker shafts, and four valves per cylinder. The valves are arranged in two inline banks, the intake side facing towards the radiator, the exhaust facing towards the firewall.

Cylinder Head Gasket
The head gasket is constructed from three layers of sheet metal and is termed as a "multi-layered steel gasket". Four small rivits on the outer edge of the gasket hold the three layers together. The head gasket contains an oil restrictor that controls the oil flow to the cylinder head. The standard thickness of the gasket is .065mm with a thicker (.095mm) available.

Valve Train
Camshaft
The camshaft is machined from nodular iron. Nodular iron combines many advantages including good castability, excellent machinability, wear resistance, and weight savings.
The camshaft consists of 5 bearing journals and three valve lift lobes per cylinder. The camshafts are identical for both derivatives. The intake side uses one rocker per valve, while on the exhaust side a single rocker operates both valves.
A machined recess in the cylinder head next to the Number 5 camshaft journal controls the camshaft end float. The camshaft retaining pedestals support both rocker shafts.

Rocker Arms and Rocker Shafts
The rocker shafts are hollow to allow an oil supply to the hydraulic lifters that are retained in the end of the rocker arm. The valves are opened by roller rocker/hydraulic lifter assemblies, which pivot on the rocker arm shafts.

Valves
Powder metal valve guides and seats are installed on both engine derivatives, the valves, springs, and retainers are of conventional design.

Intake Valves
The intake valves are made from carbon steel. The carbon content allows the valve to be hardened and tempered to increase strength and also to be locally hardened to improve wear resistance. The MINI COOPER S uses an upgraded material.

Intake Valve Seat Inserts
Powder metal technology is used for valve seat inserts as the sintered part requires little or no machining and any number of material compositions can be developed to satisfy particular engine demands.

Exhaust Valves
The exhaust valve specification is an austenitic steel, a particular type of steel with characteristics that are ideal for exhaust valve manufacture. The MINI COOPER S has upgraded exhaust valves.

Exhaust Valve Seat Inserts
Many characteristics for the intake valve seat inserts carry over to the exhaust valve seat inserts. In addition, the exhaust valve seat uses what is known as "Grade J" steel, this contains molybendum and tungsten. This provides high heat hardness giving increased resistance to indentation and wear. [ask if you would like me to provide an explanation of Powder Technology].

Timing Chain
There is a fixed chain guide on the intake side of the engine. The exhaust side has a semi-floating guide that is spring-loaded and contains a self-ratcheting tensioner to retain the adjusted position. Engine oil pressure fine-tunes the free play using a hydraulic tensioner.
The timing chain incorporates three copper color links that are used to assist timing chain installation. Both the crankshaft and camshaft gears incorporate timing marks, which are used in conjunction with the copper coated chain links.

Timing Chain Tensioner and Drive Gears
A key way locates the crankshaft gear (23 teeth). The camshaft timing gear (46 teeth) is located by a key way and is retained by a central bolt. The camshaft gear is driven by a roller timing chain.

Lubrication System
The lubrication system is the full flow filtration pressure feed type. The oil fill process at the factory allows for a tolerance of 4mm above and 4mm below the maximum mark on the oil level dipstick. The oil level will depend on the oil temperature and length of time from the last engine switch off.

Oil Circuit
Oil is drawn up through the oil strainer to the oil pump, which is located at the front of the engine: the oil pump delivers oil under pressure throught the full flow oil filter to the main oil gallery.
The main oil gallery runs the full length of the engine block and delivers oil to the main bearings. Diagonal drillings in the crankshaft webs deliver oil to the connecting rod bearings. The cylinder bores and connecting rod small end are spash lubricated from directed slots in the connecting rod thrust collar.
The main oil gallery also supplies oil to the cylinder head assembly via a vertical hole on the exhaust side of the cylinder block between bores two and three. The cylinder head gasket incorporates an oil restrictor to ensure that oil volume to the crankshaft is maintained and oil volume to the cylinder head is reduced.
Upper engine lubrication is provided by one main feed to the number three camshaft bearing cap. Oil is then routed through the rocker shafts to the remaining camshaft bearing caps and rocker arms/hydraulic lifters. Oil returning to the sump pan from the pressurized components supplies lubrication to the valve stems.

Piston Cooling - MINI COOPER S Only
The MINI COOPER S incorporates oil "squirt" jets to assist in the cooling of the piston crown. The four jets are located in the cylinder block next to the main oil gallery. Oil spray is controlled by a ball and spring. These allow oil flow only when the oil pressure exeeds 2 bar. The position of each jet is critical to the effectiveness of the cooling.

Oil Pump
The oil pump and pressure relief valve are located on the front cover (internally) and are secured by 10 bolts. They are both manufactured from aluminum. The oil pump consists of two gears. The internal gear is driven directly from two flats on the crankshaft nose and is in permanent mesh with the outer gear.
The eccentric rotation of the gears creates a low pressure at the inlet suction crescent end of the pump and draws in oil. As the gearwheel rotates, oil will be compressed between the gears and discharged at the outlet port end of the crescent at a high pressure.

Oil Pressure Regulator
The oil pressure relief valve is installed in the oil pump housing. The valve consists of a spring, retaining cap, circlip, and hollow plunger with radial holes.
If a blockage or restriction occurs and the oil pressure is sufficient to overcome the spring tension, the plunger will be forced back, exposing the radial holes, and the oil will return to the low pressure side of the pump.

Flywheel
The MINI COOPER flywheel is constructed from steel and is retained on the crankshaft by eight flanged head bolts. Two dots are used for correct alignment, one on the crankshaft and the other on the flywheel.
On MINI COOPER S a dual mass flywheel is used to insulate the gearbox from torsional and transient vibrations produced by the engine or drive line. The flywheel consists of a primary and a secondary wheel. The drive between the two is transferred by a torsional damper made up of four coil springs located in the inside diameter of the primary flywheel. Under high torque loading conditions the secondary flywheel can rotate in either direction up to 70 degrees in relation to the primary flywheel.

Cooling System
Engine cooling on the MINI comes in two forms, although the basic layout remains the same. Both systems use a 50/50 coolant solution with standard kevlar reinforced EPDM (Ethylene Propylene Diene Monomer) cooling hoses.

Cooling System Operation
When the engine is cold the thermostat is closed, preventing coolant from circulating through the radiator. Coolant is able to circulate through the heater core, expansion tank, and on the MINI COOPER S, the oil cooler. The MINI COOPER S has a pressurized expansion tank, and allows coolant to enter the top via the heater core pipe, and exit the bottom of the tank to join the heater core return pipe. As the coolant temparature increases the thermostat gradually opens. This allows a bleed of coolant from the bottom hose into the cylinder block via the coolant pump, and allos hot coolant to flow to the radiator via the top hose. The flow of hot and cold coolant is balanced to maintain the optimum engine temperature. When the thermostat opens fully, the full flow of coolant passes through the radiator.

Coolant Pump
The coolant pump is manufactured from die cast aluminum and is driven by the auxiliary belt on the MINI COOPER. It is installed on the intake side of the engine block (towards the front of the car).
The MINI COOPER S coolant pump is driven by the supercharger via a reduction gearbox. The coolant pump is fitted directly onto the supercharger housing and is connected by a two legged dog drive.

Thermostat
The thermostat is located in the cylinder head and is retained by a plastic housing (aluminum on COOPER S). The thermostat begins to open at 89-92'C and is fully open at 103'C The MINI COOPER thermostat housing also includes the cooling system pressure cap (MINI COOPER S system pressure cap is installed on the expansion tank).

Expansion Tank
The plastic expansion tank for both models is located between the primary and secondary bulkheads. The MINI COOPER expansion tank is a non-pressurized type, it is only used to collect excess coolant due to heat expansion, and this coolant will be drawn back into the system as the coolant cools.
Both models use a pressure cap to pressurize the cooling system to 1.1bar at which point the cap vent will lift to relieve pressure. The MINI COOPER S is fitted with a conventional pressure cap on the expansion tank.

Radiator
The radiator installed in the MINI COOPER (COOPER S) is a conventional cross flow type. It is constructed from aluminum tubes, wavy corrugated strips, and plastic end caps. Coolant flows from the top left to the bottom right (viewed from the front of the car).
There are two radiator arrangements for the MINI COOPER (manual or automatic) and only one for the COOPER S.

Oil Cooler (MINI COOPER S)
The MINI COOPER S is fitted with a plate type oil cooler mounted directly onto the oil filter housing. Engine oil from the filter housing and coolant from the hoses flows through the cooler tubes adjacent to each other. This process takes place continuously: there is no thermostat control. The inlet and outlet pipes are connected in parallel with the heater core pipes.

Auxiliary Drive Belt Tensioner
The MINI COOPER uses a torsional spring to apply load to the belt and a friction damper to reduce the pulsating vibrations from the engine.
The MINI COOPER S spring travel stop uses a compression spring to apply load to the belt and a hydraulic damper to control the engine pulsation. The auxiliary belt should be repaced at 100,000 miles on MINI COOPER and 60,000 miles on Cooper S.


Supercharger (MINI COOPER S only)
The MINI COOPER S is fitted with a "state of the art" supercharger that has been specifically engineered for small engines. It was designed as a compact unit with the ability to provide performance that is synonymous with the COOPER S name...


Intercooler (MINI COOPER S only)
MINI COOPER S uses an air to air intercooler. The major advantage of the air to air intercooler over the air to liquid intercooler is its capacity to reduce the temperature of the compressed air charge to around 40-50'C


EXHAUST SYSTEM (MINI COOPER S)
The MINI COOPER S has a center silencer but its size has been increased to 3 liters. The rear section of the exhaust consists of two silencers, one mounted on each side of the vehicle. The rear silencers are mounted by two sets of silicone based hangers. Two pipes leave the left hand silencer and exit the body in the center of the vehicle. The tail pipes are finished with polished stainless steel trim.


If you find any of this info useful, and would like me to privide info about clutch and transmission operation and differences, let me know.

 

Of course I did! Wow...thanks. Very definitive. The powdered metal rod thing...that's what the new LS1 GM engines had, too. I just wonder how many people have actually cracked one in a mini. Yummy, sodium filled valves (I assume) on the MCS...a nice upgrade!

McCullster, great mods! Mind sharing brands? 130hp at the crank would hopefully help overcome the sluggishness with the A/C on and people in the back seat. That's really all I NEED to accomplish. Not looking for a racer, just a more capable street-machine. So the Getrag 5-spd came in the '05 models? I've got an '03. Work at an independent BMW shop so labor won't kill me but used parts would still be nice!
d
For the future, I'm actually still leaning toward trying to fudge the new Chrysler 2.0 in there and keep it naturally aspirated. Wish I had a picture or some dimensions of a 1.6 Tritec sitting next to a 2.0 Chrysler.

Doing a turbo on my 1.9liter bimmer hatchback at the moment because I don't care if that one breaks!

 

So I know there are other threads for this, but I guess it's reasonable to assume that the following would not tax the stock 1.6 too much as a "stage 1" upgrade:

-Intake
-Cat back exhaust
-Coil upgrade/Plugs/Wires
-ECU tuning

...and they might actually get me about 15hp or so at the wheels without breaking parts?

 

Yep, that sounds about right Turbo........thats about it for Stage 1. Stage 2 would consist of maybe a reworked head, bigger throttle body and header for the exhaust.

I'm actually quite surprised at the numbers I put down to the dyno. I have a buddy with an 03 Cooper with just an intake and MTH put down 106hp to the wheels. I'm only putting down 115hp? WTF? But then again, I only have the exhaust and plug wires up on him.

PM me some time turbo or check my list of mods over at:

www.metroplexmini.org

Check out the Garage area and look for "McCullster"......I really do love modding the Cooper......!

 

turbo740,

You might want to talk to Randy Webb of Webbmotorsports or Eric Savage from Helix13 about "weak links" when modding an MC. They both have experience with heavy mods to both manual and CVT MC models.

Also see-
https://www.northamericanmotoring.co...ad.php?t=20153
(A very highly modded CVT- and seems to be doing just fine)
Also these days you can try MTH for ECU mod rather than the PowerChip.

I believe Helix13 will be working on a turbo kit for the MC. They are keeping HP to a reasonable and safe level for reliability sake.

 

Tarzan,

What a great post lots of good info for the likes of us who are semi savy to engines and to those of us who are not Excellent write up and thanks for the Info. I'm going back to reread it again
Thanks from all of us.

 

Yah, this is a good stage one. You could easily run this on either of the MC trannies. I have these mods on a CVT car and it has run really well.

I wanna step it up to stage two now, but like you, im interested in finding the weak points

 

For a decent account of the MCS powertrain, see this article. (It was written back in 2002, so some features may have been updated).

http://www.mini2.com/pdf/mcs_powertrain_us.pdf


Lot's of good info, though!

 

Hey Rally, if you're talking about Maxy, Andy said Steve had to make some parts to get that tranny to fit... it ended up being a big pain. But, on the flip side, you're right, it seems like the only problems with his car now is getting the turbo to work.

 

ah, good call kilo :smile:

 

But dang man, it would be nice to have a 6 speed Getrag in our Coopers.

 

I disassembled a damaged cooper motor yesterday. It has two broken rods, a hole in the support ladder and a hole in the cylinder block. It appears that the first broken rod made the holes and the second rod failed afterwards. Everything else looks to be in great shape. I’ll know the details on the head later, but for now no damage is detectible. This cooper ran through a puddle and ingested water.

 

I agree! I am going to have hubby read that post to learn more about my Wanda and for future reference. Thanks so much, Tarzan...it's a keeper!


Clover

 

So, if I read Tarzan's post right (GREAT POST, BTW!), the main differences are the rotating parts: pistons, rods, and crank. Add upgraded valves, and you'd be about 95% there? (Except of course, the SC!) The only things missing would be the flywheel and harmonic balancer. And I assume the upgraded belt tensioner is necessary because of the supercharger.

Tarzan's post also mentions the oil cooler. If I were hopping up a Cooper, I think I'd definitely want that. Is this something that can just be attached to the motor? (Or an aftermarket unit.)

 

I know nothing about the ONE. Did I misunderstand the sentence above?

The only difference between the ONE and the Cooper (at least drivetrain-wise) is the programming?

If so, I would assume that's to get better gas mileage and run on regular, right?

What's the price difference between the ONE and the Coop? If it's more than a hundred bucks, I think there would be a HUGE market for ECU upgrades. Buy a ONE, upgrade the ECU, and you've just bought yourself a Cooper for xxx dollars less.

 

The oil cooling on the Cooper S is actually accomplished by running the oil lines adjacent to coolant lines in a block at the back of the supercharger. Heat transfer takes place because of the proximity of the two lines to one another.

An aftermarket oil cooler would be pretty simple to plumb, and would be recommended for either standard or S engines.

Another big difference is the piston cooling jets that squirt engine oil at the underside of the pistons to cool them.

Thanks for the positive responses to my lengthy post. I was fearful it would be deemed too lenghty...

 

Hi.. going to stage 3 here...

MTH tuner software(98octanes)
BMCCDA
ngk iridium
MCS Throttle body
decat
MCS 6spd gearbox(163bhp)

Runing about 130\140 bhp

Next steps
camshaft
headers
and ecu fine tune up(in a rolling road session)

I have a cooper S engine to take out some parts... and i am going to change the valves for more reliability..

I am going to 150+ bhp barrier and i think it's achievable... i would like to turbocharge it but there is no one to share info that has turbo charged the mini...

BTW i have a mini one!!
Ive done 235km h with the cooper s gearbox and 240(downhill =) ) with the 5 speed.. and i dont recommend to push above 130bhp with the midlands gearbox.. they are really a very weak link!