Exhaust manifold

[Chris Edgar]

My Wife's Convertible has, as far as I can tell, a Metro cast iron LCB manifold.
Combined inlet/exhaust. Two outlets.

I am looking at a separate inlet manifold, advertised on Ebay. (a photo of it was on a recent thread)

Is it feasible to cut off the inlet part of the existing manifold to allow fitting of the separate, new inlet manifold?

From the twin outlet exhaust m/fold there are 2 downpipes which do not go through the usual aperture in the chassis, but run closely down the side of the engine, before joining & going into the silencer.
Any work involving the exhaust is complicated by the fact that, due to the size & shape of the torque converter, the engine is mounted approx 2" lower than usual.

Did all that make sense?
I hope so.

[chrisryder]

you can remove the inlet section, takes some time with an angle grinder but it works. the tip is to make sure you don't break into the exhaust chambers. you wont be able to salvage both parts, so deliberately break into the inlet ports.

the question is, why do you want a separate inlet manifold? ok it reduces the hot-spot where they would join, but the metro manifold is one of the best flowing inlets around.

i trust you have the exhaust for your two port manifold, they're a bugger to get hold of if you havent.

[Chris Edgar]

Many thanks for that advice..
I think that, from what you say regarding the "best flowing inlets", I will leave it alone. I'd probably make a mess of it & end up with nothing!
The twin downpipe that is fitted clearly has been custom made....because of the lowered engine, a standard set up would not fit...
of course downpipes do last a very long time. It is made from mild steel & goes into an SS silencer & pipe.
Unfortunately a previous owner has managed to put a big dent into one of the downpipes.
To have a replacement in SS, I will need to have another custom made.
No rush though. I can take my time looking around.

regards

Chris

[chrisryder]

vague recollection from the Vizard bible is that the Metro manifold is the best flowing of all the manifolds fitted as standard. an aftermarket one can flow better but it's horses for courses. According to Mini Spares, the Mini Spares heated inlet is the best flowing aftermarket inlet manifold on sale, but they could be biased! Titan Motorsport ones are quite good too by all accounts.

[Chris Edgar]

I've got a copy of the Vizard Bible on order from Amazon.
I'll see what he has to say.

[Matt]

It won't be a metro one...

The metros with the twin outlet used a seperate cast alloy inlet - which is a good flower

http://cgi.ebay.co.uk/MG-Metro-exhaust- ... 1e5f9e81ab

http://cgi.ebay.co.uk/MINI-METRO-HIF-44 ... 230c0858a8

Itals used the combined inlet/exhasut manifold - they are the same shape but just have a hotspot!

http://cgi.ebay.co.uk/mini-carburettor- ... 4aa6aa065c

Just examples, not nessesarily good prices

[chrisryder]

http://cgi.ebay.co.uk/mini-carburettor- ... 4aa6aa065c

is that not found on some metros? i'm no expert so i could be mistaken. i guess it's just the metro alloy separate inlet that is the good flower then?

[Chris Edgar]

Aha!
Matt, you seem to have found the separate exhaust manifold.
Which means that I could get the advertised (or similar) inlet manifold & not have to butcher the combined one to fit it...

I am not so interested in performance as improving efficiency & therefore economy.

Thanks
Chris

[bmcecosse]

The cast-in inlet manifold - Metro or otherwise - IS to be avoided at ALL cost! The ALLOY MG Metro inlet is the one to have - and yes - just cut away the old cast inlet section as others have advised making sure you don't get into the exhaust part!