17 replies to this topic

[oliver122]

as the title reads really , been looking on wiki it says the austin has 63bhp and the mg has 72bhp with similar lb - ft and was wondering what makes the 10bhp difference

[Ryang556]

As far as I've heard it's something to do with the head? I may be wrong though

Edited by Ryang556, 21 March 2012 - 07:19 PM.

[oltonlad]

the difference is that the MG engine has a higher compression ratio, different cam and big valve head.

[Mini-Mad-Craig]

Are you gonna buy an MG Metro engine and put it in an austin Metro, i wouldnt blame you, they are far superior than the Mini!...

[racingbob]

the mg metro engine is a great engine

i have one in my car, plus i have full maniflow exhaust

kn in original housing, engine balanced, and inlet ports been touched up

believe it or not it goes like hell

[mab01uk]

"Whilst most of the engines do not really give a whole lot of difference in performance, the one outstanding version is the MG Metro engine. Where the majority of the variously similar power plants put out around 63-65bhp, the MG metro achieves a more spirited 70-74bhp. This is due to a higher compression ratio (10 -1), larger inlet valve (35.7mm instead of 33.3mm), and - mainly - a more sporty camshaft with half-decent induction and exhaust systems. The inlet manifold being a reasonably good flowing, water heated aluminium example. Rover finally got the hint having witnessed the prolific after-market fitment or such an item to Minis in epic proportions for years. The exhaust manifold is a cast iron 'LCB' style with a pair of exhaust downpipes instead of the more common single item and works very efficiently. A bonus of this over the more common after-market steel-tubed LCBs is that it is much quieter by dint of absorbing more exhaust 'noise'. Coupled to a pair of Maniflow tubular steel downpipes it is very nearly as efficient as a full tubular steel manifold. The cylinder head is more along the lines of the old Cooper S spec and in fact flows slightly more air than it's predecessor, the camshaft being the sportiest fitted to any production A-series engine. It uses the inlet profile and timing of the original 997 Cooper cam and the exhaust specification of the old Leyland Special Tuning '731' fast road cam."
http://www.minimania...?DisplayID=1601

[oliver122]

cheers for the info guys , no im getting my hands on a austin metro engine with 28k genuine on the clock , so really getting a better head with bigger valves + ported and slightly skimmed to raise the compression ratio will help get the power up ?

[Pigeonto]

Certainly get the compression ratio up to MG spec,10.5:1 but dont go ordering a big valve head until you have removed this one because it may well already have the 35.6mm inlet.the same as the MG did.It depends whether the engine was leaded or unleaded fuel.I believe that the head for leaded use on a std 1275 Metro was in fact an MG Metro head and that the power difference you asked about on the MG came from the better cam and inlet manifold,compression ratio.My MG head flows enough to give 90 hp in standard form,obviously with a better cam and things but that doesnt change the fact that its a standard head, it all has to flow through there!

[Pickwah]

Sorry to restart a completely dead thread..

 

I've recently purchased a Metro 1275 from a kit car but am unable to identify it.

 

The engine number reads 12HC01AA but am still unsure whether it be an Austin or a MG.

 

I have had the head off and measured the valves and they match up with the 37.5 inlet.

 

Would I need to take the cam out to confirm it is the MG engine.

 

Cheers

[jaydee]

Yes the MG camshaft has the groove between lobes 1 and 2..but

Crank is a cam6232 on the MG

Ordinary Austin metro crank is the less desirable 12g505

[ACDodd]

Ok all a+ metros use the same crank 6232 with the exception of the turbo, which has the 6581 crank. The 1505 unit is from the a-series based 1275 engine without the rolledfillet radiused journals. If you are intent on building a modern version of the mg spec engine, limit the compression ratio to 9.75:1 with the MG metro cam. It will run smoother and give more power. The fuel we use now simply won't perform with that cam at 10.5:1.

I also do not choose to run the mg cam now as technology/design has moved on in the 35 years or so this cam was designed. It is now possible to have a smoother idle, better emissions more torque and higher bhp with a wider power and all from using a more modern profile. The mg metro cam while good for its time is now simply dated thinking.

Ac

Edited by ACDodd, 22 January 2016 - 06:13 PM.

[jaydee]

I've found on an few A+ the crank was not the 6232, so is that due to a mismatch from previous rebuilds or a leftover used in factory builds?

[Spider]

I've found on an few A+ the crank was not the 6232, so is that due to a mismatch from previous rebuilds or a leftover used in factory builds?

 

I think they all had the same forging number on the web, but a different part number, I think the turbo cranks had a different heat treatment.

[ACDodd]

Its a replacement crank. Different forging numbers

Ac

Edited by ACDodd, 24 January 2016 - 10:30 AM.

[Coxie]

I've found on an few A+ the crank was not the 6232, so is that due to a mismatch from previous rebuilds or a leftover used in factory builds?

I've just got an ellegro 1980-82 a+ that is still on its standard bore and Pistons and that has a 1505 crank.