Will an MGB manifold fit onto a 1275 engine??

[williamraff]

Hi folks, can anyone advise if an MGB 1.8 cc LCB exhaust manifold will fit onto a 1275 A series engine engine?
Thanks Will .

[bmcecosse]

Errrrrrrrrrr - NO!

[williamraff]

I know , it was just a long shot. I am having trouble finding a reasonably priced 1275 LCB. I have always wanted a 1275 minor and now I have got one I want to make the most of it
Will.

[Peetee]

I have a standard tune 1275 Ital engined Minor and had a large bore exhaust sytem and Marina manifold with single downpipe. When I change to a LCB manifold I noticed no difference in performance whatsoever. They really only become advantageous at high revs and the standard engine is not happy up there anyway. To cut a long story short, unless you plan to plonk on a better head and cam, don't bother with an LCB.

[williamraff]

That's good advice, I am not really looking for top end screaming power. I would prefer to keep the revs as low as possible and have more actual pulling power (torque). Trouble is I am not entirely sure how to acheive this? I have an 11 stud 12g940 head, a HIF 38 carb and a metro manifold I was planning to install but again, I have no real understanding as to what this will acheive.
I am told the engine has an ital half race cam fitted but I have no way of confirming this, even if such a thing exists.
All I can say is that this car is slow next my previous 1275 standard tune Marina - now that car was quick - all things considered .
Will.

[IslipMinor]

Will,

Have sent you a PM.

[bmcecosse]

" ital half race cam " - not words you often see in the same sentence...........

[IslipMinor]

Need to understand a bit more about what you have.

12G940 head is a good start - what size valves does it have? Has it been skimmed or flowed? The standard head thickness is 2.75", so is it anything less than that?

MG Metro inlet manifold is fine, but a 1275 that has been modified should have an HIF6/44, rather than the HIF4/38. The 44 was a standard fit on the MG Metro.

Cam -

ital half race cam " - not words you often see in the same sentence...........

yes extremely unusual!!

Really do need to know what has been fitted. Is the cam out of the engine? Can you see what has been stamped on the end? Either the timing chain pulley end or oil pump end?

Exhaust, definitely at least use a 1 1/2" bore (1 5/8" o/d) exhaust pipe, even up to 2" o/d, if you are planning some serious mods - that is what is on our MInor with 3 straight through silencers to keep the noise at an acceptable level for track days (~93db). An LCB is an easy fit and does allow the engine to breath, which is what makes torque and power!

[bmcecosse]

All 1275 (non Cooper S) engines have the 12G 940 head - well except for some export models. The fact you say 11 bolt 'suggests' it may have the bigger inlet valves - but not necessarily so - many Mini lads drill the extra holes - especially to sell better on ebay!! And yes - an HIF 38 may give best economy - but is not really big enough for decent power. LCB manifolds are really only required when using a lairy cam - so yes - would be good to know what the cam is - 'half race' doesn't mean much!

[williamraff]

Thanks all, I have a picture of the cam which I will post shortly. I will measure the head thicknes and valve size and report back.
Cheers,Will .

[rayofleamington]

Although it is not the best option - a standard 1275 will runy well with a 1098 minor manifold and carb!
The size of the exhaust should strangle the engine, however in practise you still get the lovely original Minor sound and the majority of the 1275 performance boost as well. I've run 2 Minors with this set up now (last one was this summer) and it really does go better than people think it should.

food for thought - and doing that doesn't stop you changing over to marina manifold and bigger single pipe later as you've not lost anything by having the half way house to start with.