How can I get more power from a 1275?

[KirstMin]

Hi all, I'm new to this forum and would like some advice.... I have a 1966 convertible and have recently had disk/servo conversion, handling and suspecsion upgrades and a 1275 marina engine put in. However, I was wondering what the most effective way of improoving the power output of the 1275 is (which in its current guise is a little disappointing)? I'm not talking blow away power, maybe another 20bhp or so. Is there anywhere that could do the work for me and what would I be asking for...

thanks again

Kirsten

[bmcecosse]

First move is to fit a modified cylinder head - from any of the many many Mini tuners - but Morspeed gets a good name for value-for-money. Then chase up an MG Metro alloy inlet manifold, and a decent exhaust manifold (Mini Spares do a Minor one - check their website) and of course a bigger bore exhaust system. You can use this with your existing carb - or get the bigger 1.75" Su as fitted to the MG metro (£10 / 15 on ebay). next - get an Mg Metro camshaft - usually about £10 on ebay. Fit this lot (unfortunately engine out to do the cam UNLESS you know for sure you have a peg drive oil pump in which case changing is easy in the car) and you will have the same power as the MG Metro (more if you buy a GOOD head) so at least 72 bhp up to 80 and still very very tractable. The MG cam is highly recomended - very nice low down with lots of torque, but does begin to run out of steam at about 6000 rpm.

[Cam]

Then chase up an MG Metro alloy inlet manifold, and a decent exhaust manifold (Mini Spares do a Minor one - check their website) and of course a bigger bore exhaust system. You can use this with your existing carb - or get the bigger 1.75" Su as fitted to the MG metro (£10 / 15 on ebay).

I'd do this first, as it's just simple bolt-on stuff and cheaper than buying a modified cylinder head. It should give you a 15-20% boost in power. Then, if you want more, go for the head/cam.

[KirstMin]

Hi both, many thanks for replying to my post so soon! From what you are saying it looks like decent gains can be made by dealing with the exhaust, carb and manifold to begin with. I'm no mechanical expert so would appreciate your comments on the following info I have sources from 2 websites - mini spares and the MM parts centre. I thought that getting this down in the thread might possibly help others in the future. Basically, I have sourced parts from these places but would appreciate advice on which and what is best (I could source the carb from ebay as bmcecosse mentioned but thought it helpful for others to include on the list). What do you think I should go for? for instance: would I need to purchace the SINGLE S/STEEL MANIFOLD DOWNPIPE if I were getting the MULTI-BRANCH MANIFOLD?

On the mini spares site, it looks like 2 things have the same description - is one the manifold and the other the exhaust? So I would need both? and would that and a metro carb do the trick? or would it be advisable to find a MG Metro alloy inlet manifold too? Its all a bit confusing!

Thanks both

Kirsten


From Birmingham MM parts centre:

http://www.morrisminor.co.uk/improvlist.asp?Section=4#J

SINGLE S/STEEL MANIFOLD DOWNPIPE EXH1002 A

Longlife guaranteed single stainless steel downpipe for use with 1 1/2" exhaust system from Marina manifold. £22.12

S/STEEL FRONT SILENCER SECTION EXH1002 B

Longlife guaranteed stainless steel 1 1/2" bore front silencer section for use with either EXH1002 A or B. £60.00

S/STEEL REAR RESONANCE SECTION EXH1002 C

Longlife guaranteed stainless steel 1 1/2" bore rear resonance section for use with EXH1002 B £39.24

STAINLESS STEEL MULTI-BRANCH MANIFOLD EXH1002 D

Longlife guaranteed stainless steel 1 1/2" bore multi-branch manifold, 3 into 1. £76.70

1 1/2" METRO CARB

When used in conjunction with a large bore exhaust can help to increase engine power by around 10-15% £40.00



From Mini Spares

http://www.minispares.com/


MANIFOLD MORRIS 1000 LARGE BORE FREEFLOW
[ok, im getting there - i think this is for the 1098?]

http://www.minispares.com/Product.aspx?pid=37360

Free Flow exhaust Noticeable performance gains can be had by simply bolting on a free flow exhaust system. Your Morris will sound sporty, yet not obnoxious, and throaty, yet mellow. In other words, it will sound great, and the neighbours won't mind! A

£100.93


MANIFOLD MORRIS MINOR LARGE BORE LCB

http://www.minispares.com/Product.aspx?pid=34718

Free Flow exhaust Noticeable performance gains can be had by simply bolting on a free flow exhaust system. Your Morris will sound sporty, yet not obnoxious, and throaty, yet mellow. In other words, it will sound great, and the neighbors won't mind! A

£115.59

[KirstMin]

Oh, and by the way - just to make things more complicated, here is a third source of uprated MM exhausts/manifolds - any thoughts/preferences?

http://www.maniflowonline.co.uk/index.p ... ion=morris

MORRIS MINOR 1275 LCB

Classic Road and Competition Hi-Flow Components

Exhaust Manifold
£123.37

Twin Box Exhaust System
£116.32

[Cam]

For the exhaust system and manifold, go for the Maniflow system, they are much better. Forget the minispares place as the engine in a Mini is the wrong way around and the manifold won't fit a Minor (or the exhaust for that matter). I know it says Morris Minor, but check before you buy! Although I would go for the Maniflow one personally.

You can keep your original carb, just change the needle and get hold of an appropriate alloy water-heated inlet manifold (but don't connect the water heated part). Oh and get a decent air filter for it too. K&N are just about the best, but they are noisy (which I like ).

[KirstMin]

Ahhhh... thanks to your help I think I am getting somewhere!

I think I will go for:

1. Maniflow exhaust and manifold system (will this fit on marina or Ital 1275 - dont currently know which I have?)

2. METRO CARB

3. an appropriate alloy water-heated inlet manifold

When the jos done I'll let you know the results!

Kirsten

[Cam]

Yep, the heads have the same fitting, so it does not matter which engine you have.

Keep us updated as to the results! Good luck.

[KirstMin]

I'm sorry Cam - i do have one more question.... should I be looking for an HIF 38 metro carb or HIF 44? What's best?

thanks

Kirsten

[Cam]

Well, either will do, but so will your standard carb. Just because it's standard equipment, does not mean that it won't be a good performer! I would stick with the standard one as it will save you money and not increase your power at all by 'upgrading' to a bigger unit.

BUT if you want to get one, then I guess the HIF44 is the one to go for as it's bigger and so won't restrict flow if you want to use more power modifications later on, you won't have to change it!

[KirstMin]

great, thanks for the info. Finally there I think ;)

[rayofleamington]

Which carb do you have?? It would be best to check that before deciding to stick with it or not...

[bmcecosse]

To get a decent power increase you will need to get a better head with raised compression ratio, and change the cam. But the MG Metro inlet manifold really is tops - especially if you gas-flow it a bit. Often very cheap on ebay - last two I bought were less than £5 each. beware though - not all alloy inlet manifolds are good - read the Vizard book to find out why. Also HiF 44 carb (1.75") will be the one to have once you do the head/cam - but until then any late model 1.5 " Su will do - both fit the MG inlet. The minispares exhaust manifold IS for the Minor - i'm saving up for one now ! Certainly Maniflow get a good name - but they are not inexpensive.