mg metro cam into 1098 auto

[limby2000]

Hi guy,s i,m still undecided as I have various option,s my mini 30 auto when rebuilt will have a 1098 crank and piston,s 40" oversize, it will have a 12g295 which I've just got back from having u/l exhaust valves and seats fitted, it has been skimmed 80 thou from standard deck height. I have a good condition mg metro cam I planned to fit in my build. However after speaking to a local mini man have been advised it would not be suitable because of the torque curve. Has anyone fitted this cam to a small bore auto?. I also have a sw5 cam and the standard mini 1000 cam at my desposal. I have already asked this question on the mini forum but without reply.

[wimfournier]

You must bear in mind, Limby (is this really your name?) that a car with an automatic gearbox is different. Such a car has a torque converter.
This is ment to convert the power that is put in by the crank to the box. From stand still the engine is turning over about 700 rpm whilst the car is not moving yet. You take your foot from the brake and the car gets moving. You apply the throtlle so that the engine gets turning over about 2000 rpm. The difference in rpm is 'converted' by the hydraulic converter.
So, when you drive a car with a clutch, the difference in rpm is consumed by friction. That's different.
Mini's with manual boxes have a final drive that is much wider than in a automatic Mini. So the engine in an automatic Mini has a heavier task to pull the car forward.
The nature of the automatic box in a Mini is, that at low speeds already the box is shifting up to the next gear. 
That means that de rpm of the engine is still quite low when the box is changing gear. Each time.

So, to speed up the car, it is importent to have lots off bottom power.
That means, a cam with a 'low profile', that means -not- opening early the inlet halve, -not- closing late the inlet valve, -not- opening early the outlet valve and -not- closing late the outlet valve.
This is the opposit of what all the guys are seaking that drive manuaal cars.

What you have done until now is all in the favour of bottom power.
Don't spoil that with a cam that only gives furious power above 3000 rpm. An automatic car is driven mainly at ease. You will be happy by much bottom power. At the traffic lights you will be the first by several lengths.

Anyone to comment on this view? Be welcome.

[limby2000]

Hi Wimfournier,thanks for your reply. I am building the engine for low end grunt and am too aware of torque curve needed.I am getting drawn back towards the standard auto cam, although it is a 998 and not 1098, weither that will make a difference. This cam will make or brake this car, I've gotta get it right.

[limby2000]

Forgot to mention,I did contact swifttune and they said the sw5 is suitable for an auto. Has anyone fitted one to a 1098 auto?

[sartine]

Aug 8, 2015 21:07:56 GMT limby2000 said:

Forgot to mention,I did contact swifttune and they said the sw5 is suitable for an auto. Has anyone fitted one to a 1098 auto?

Probably this is true for a 1275 auto, which supplies with cc's the lower end that is lacking in a 998 or 1098.
For a 998 and a 1098 i would stay with the std cam, and work on a correct cam timing (a little anticipated as recommended by David Vizard), a good working ignition distributor or best an electronic conversion with programmable advance curves like the 123 or the CSI, and an increase on compression to a value of about 10.5 +/- which was the way followed by BMC back in the early '80s when they revised the A into the A plus, searching for an increase in efficiency and brilliance.
A stage 1 lit also will help a little in gaining something as is a way to optimize inlet ad exhaust in search for major efficiency.

this is about what i've done to my 998 automatic Innocenti Minimatic and from my point of view is the maximum that should be done to the auto engine. My personal opinion infact is that an auto mini is something special and today rare which is to be choosen for the easy of drive and comfort mixed with the unique sensations that only when driving an hystoric car are felt - and if a more racy attitude is desidered it is best to switch towards a manual version of the mini.

A big increase in power and torque means a decrease in reliability and a lot of work ( and money) simply not worth.

[simonw]

I'm rebuilding my auto to mimick a small bore project by an Australian engineer here call Graham Russell. The finished product will be about 1220 CC. The cam that I will use is his grind called a 266SS. This profile has proven to produce low end torque very well. Post your camshaft to him and he will grind it for about $150 Australian

[simonw]

My opinion is that the auto will not have the off the mark performance of a manual given the torque
converter, however any engine modifications will help with the rest of the gears when it's up and running and it can be just as fun I believe manually shifting the box. modifications, in my opinion, to your engine will not be wasted, go for it!

[tony105]

This is a very interesting topic and I have found all the comments to be insightful.

As an automatic Mini owner and enthusiast, I have always been fascinated by the engineering of the ap auto' box. Over the years I have had many manual Mini's also - often fitted with performance upgrades. I admit to being a mechanical novice so am always keen to learn more about the potential and limitations of any modifications to the automatic Mini.

In my own Mini - which is a 1996 spi automatic 1275cc, I have fitted an upgraded Maniflow Manifold, K & N filter and RC40. That's as far as I have taken the modifications and have noticed a significant improvement. My aim was not to really attempt to turn the Mini into a street racer, but to improve the performance slightly. The result I have noticed was how much more comfortably the Mini could sit on the motorway at 70 mph. The most significant improvement was the degree to which the car could respond at overtaking on the motorway - giving an improved mid range and instant rev increase to pass a vehicle for example. The improvements are also noticeable from a standing start as the car just seemed more responsive and to be breathing better (if that makes sense?)

I have toyed with the idea of possibly fitting a stage one cylinder head and/or fitting high lift rockers - however I take the point made earlier in respect of how this may not be an advantage in terms of torque and low end power. That said I wonder what specific areas of performance upgrades are possible and advisable to be fitted to the automatic Mini?

I'm aware that for the automatic gearbox, the degree of pressure the system is under could affect the transmission - however I am not sure if all performance modifications will adversely affect this?

My final point is, the transmission has naturally been subject to development and improvement over the years. I wonder if this means that certain models eg later Mini's (1275cc) have capacity for increased power and upgrades?

It would be great to develop this thread further.

[wimfournier]

There is one thing you have to account with. Our automatic is served by a torque converter. This apparatus has the duty to convert the torque that the engine gives in a way that it is strengthened as long as the rpm of the engine is higher than the rpm of the primary axle of the box.
But, most Mini's are several years old and the probleem of our cars is, that the engine oil is used in the box also. As a result of which there is always 'caol' and other contamination in the oil. Because the torque converter has about a liter oil inside, there is contamination too. Well, the circumferance of the converter is quite huge. There are centrifugal forces inside the converter. The contamination is pressed along to the wall and sticks there. And that is the place where the plates in the converter meet each other.
As a result the principle function of the converter is abused. In cases so much so, that you have to wait a second after putting the lever in drive an applying the throtle. If not, the car is going away with screaming tires. Well, this is the effect of the contamination in the converter.
Special firms can open them up, clean them and put them together again for quite little money.

So you may conclude that a 'stage one' means decarbonizing of the converter too.
When the converter is working well, that means that the bottom power is multiplied by the converter. So -perhaps- you are better of with top end power from your engine. When the converter is working well, there will be no one at the traffic lights that could beet you!

[simonw]

I'm not sure where this idea that the AP can't handle more power is coming from.
We have a fella here in Australia very successfully running an auto in his hill climb race car .
Also another owner here runs it in his 1412 stroker no problem that I've heard of..

Interest comment on the converter sludge and its effects , very insightful.
We've had a few owners here try to modify the converters and create hi stall... But to no avail, I don't know the details as to why they are so difficult to mod.

[limby2000]

Got my engine back from the machine shop, 40 thou rebore, refaced block. Have decided to use the mg cam although i might regret it. Will have a 1275 gearbox from a 93 sprite which will be fully rebuilt, I already have all the plates and seals. Does anyone know if a metro gear selector will fit a mini floor pan and the one that came from the sprite was damaged .

[limby2000]

[mra-minis]

I have built a turbo engined Mini (1293) with about 120bhp I did need to upgrade the friction material and this is the expensive part, clutch plates were specially made for me, the bands I re-lined in house using a carbon/kevlar material with a massive friction coefficient, however with all the mods made this makes the auto transmission very expensive but amaxingly quick off the line and through the "gears" oil cooler required as are several other mods...

So yes it is possible to make it capable of sustaining higher torque loads and yes the later boxes hold a lot of the "better" ingredients

[limby2000]

Nice one Martin, it must be the worlds first turbo,ed auto. Is it still around?.How did you get the kickdown to clear the turbo as its bang in the way. My build will be round about 60 bhp so not earth splitting.

[mra-minis]

No I don't think so, I am pretty sure there are 2 of a si,ilar build in Australia, governor was by cable, I toyed with the idea of a different turbo system to clear it, buy opted for standard, also the hardest part was getting the exhaust pipe past the diff....

Is that a picture of your new engine ? A 998 with an MG cam will be like driving a race engine, but your convertor etc will not cope, ie your stall speed will need to be about 3500rpm therefore you will NOT have the torque to get off the line, sorry but best you find out now rather than later.

[limby2000]

Yeah, I've mixed feeling on the mg cam, its actually a 1098 40thou rebore, with a 12g295 head on 80thou skim. Running sc 5 port injection. I am aware of the t/c stall issues and was going to run with the original 998 t/c on the 1275 auto sprite box. What do you think, shall I get a different cam?.

[mra-minis]

Well the 1098cc being that much longer stroke will give better lower torque, could be comparable to a 1275 ... could be an interesting buid

[limby2000]

Yeah hindsight is a wonderful thing, me being pig headed about keeping my car an auto in the face of everyone telling me to convert to manual,tbh if i,d known it was possible to convert a metro turbo engine to run on the autobox I probably would have gone down that road. I,d already spoke to someone at minispeed about supercharging an auto, and they just laughed at me. Eventually I bought into the sc injection system as I wanted reliability and smoothness .I always remember what it used to be like when cold or running lumpy.Thanks for your imput Martin, much appreciated,

[mra-minis]

Yeah I often hear this comment from ignorant fools who only know a bit about Minis but work for a Mini shop which clearly means they become experts over night...

[mra-minis]

I have found great success by installing an ECU to control the spark to improve the smoothness by 100X also the SU is a brilliant carb.

[limby2000]

The sc kit comes with the typhoon ecu, which will take a fair bit of setting up, i,m still hoping I can just link up the kickdown mech to the sc throttle body crank like on the original carb. I,m still to strip down and rebuild the 1275 box I have, I have no history of it, but compared to the 2x 998 boxes it looks new. I've got nos genuine forward and top +reverse clutch packs including the metal plates. I won't know what I don't have till I strip down. Is there any service tools i,m gonna need where I can't improvise?.you may well be hearing from me nearer the time Martin.

[mra-minis]

Good one, when you say metal plates, do you mean the "steel" reaction plates or metallic friction plates ?

One of my forward clutch pack holding tools would be worth it's weight as it makes sure you don't damage the clutch plates as you install the forward clutch pack assembly in to the case.

Also if you are rebuilding the clutch packs I make a sleeve to help fitment and protection of the seals.

[limby2000]

Both the thin steels,and the thick x3 plates. Yeah I will need to speak to you nearer the time .

[simonw]

Any updates limby2000?

[limby2000]

Hi Simon, engine and gearbox are all done ready to go in, doing the bodywork now. Went down the sw5 route in the end after talking to various people regarding the torque curve,stall speed ect. Have specialist components injection and engine management, 12g295 head with rimflo (slightly bigger) inlets, 80 thou skim and 3 angle seats. I only get to work on my baby every other weekend so progress is slow.

[limby2000]

[simonw]

Looks fantastic ! Will be great to drive and see how the combo works out

[simonw]

The sc injection looks intriguing! Would love to know more about it

[limby2000]

It runs fully mappable engine management via there typhoon ecu and trigger wheel, it also has a tps (throttle position sensor), ive also got their wideband lambda sensor to go with it. Its not cheap and i,m not rich but i wanted drivability and reliability. Once fully set up on a rolling road ,it should be set and forget. There plenty of video,s showing this system running on youtube. They say you,ll get similar power as weber 40 but with low down grunt. I opted for 1098 as i wanted to retain my original block, but i have a late 1275 gearbox (better clutch pack). Will keep all interested parties up to date on my progress.

[69hcode]

Where did you get the thermostat housing? Looks sharp.