Exhaust

[alanlad]

Hi
Looking to put a 1.5 su carb with the correct manifold on my 1969 minor,can I fit this to the same exhaust pipe that is there now (presently the standard exhaust)?
Or is it better to save my pocket money and buy a larger exhaust pipe?

thanks Alan

[rayofleamington]

There's lots of options - the world is your oyster card...

You can get a manifold to suit the bigger carb and small exhaust but personally I wouldn't waste time on it. changing the head to a 12g940 (bigger valves, better flow, slightly higher compression) would give more benefit.

Alternatively if you're dead set on the 1.5" carb, you'd be better off getting a Marina-esque larger bore cast manifold and an off the shelf larger bore single pipe exhaust. These should be available off the shelf from some of the minor parts suppliers for saloons, vans etc...

Next option on the list is a separate inlet manifold (lots around from scrapper boy-racer dead minis e.g. on ebay)
The run the exhaust out via an Minor LCB & larger rest of pipe - there are a number of manufacturers so take advice on which system people prefer.

[bmcecosse]

69 Minor should have a 1098 engine. Yes - the larger carb will be well worth having - but make sure it is on a good alloy (if possible) inlet manifold.. The important thing is to make sure the inlet is NOT part of the exhaust manifold to avoid the dreaded 'hot spot'. Yes - do get a 940 head - but make sure the exhaust valves have sufficient clearance from the block (320 thou ). I simply cut (and threw away) the old inlet off a standard manifold - and used the exhaust section with a standard exhaust system. I have since fitted a 3 branch manifold (ex Mini Cooper) with a larger bore exhaust and single straight through silencer. I don't believe it goes significantly better than it did with the standard exhaust. An LCB is not a good idea for such a low level of modification - these only come into their own when you start to upgrade the camshaft (731 upwards) which you won't be doing with a 1098 engine !! Do try to get hold of a crankshaft damper and don't rev it above 6000.

[alanlad]

Hi
Thanks for your replies which have confirmed I need to spend money buying a new exhaust and do more research on the fitting.
The main reason for the change is to get up hills, the red line on the rev counter is set at 3000 which I never exceed.
So I'm only looking for a bit extra on hills and will not go near 6000 revs.
Thank you
Alan

[MarkyB]

What pressure do you have in your tyres and is the vacuum advance working?

[callyspoy]

I must be honest, i would be more than happy to take a 1098 in standard form above 3000RPM. I certainly wouldn't want to exceed 4500RPM too often, but if only using that much of each gear, it will feel very slow.

A good bit of sound deadening and popping grommets in all the little holes in the dash will do wonders also.

[alanlad]

Hi
I'm not used to driving cars like the minor and treat it gently,used to have a Carlos Sainz twin turbo 4 wheel drive this was built to drive. This i enjoyed but the Minor is not in my view built to do this but will take it out tomorrow and put my foot down.
Thank you
Alan

[bmcecosse]

3000 rpm is not really doing you any favours - better lift the limit and let it run. If only doing 3000 rpm - you don't need a larger carb, because you don't need to pass any more air in to the engine. The standard carb will give you all the air you need at 3000 rpm.

[alanlad]

hi
Was going to go up a few hills tomorrow but it's going to rain so will have a at the weekend.
Will see how it goes when I put my foot down.
Alan