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MG Midget and Sprite Technical - MG Metro TURBO head

Further to last post, it now transpires I have an MG Metro turbo head to bolt on to my beloved.

I believe this is no great issue save having to remove more metal in order to port to recommendations, but some points....

Coolant bypass - under thermostat - it does not have one. Can I thus simply block off the associated pump take off with a suitable bolt?

The heater take off port - for the brass tap - is blanked off at a point some 10mm from the face. Fixing holes are OK. Can I simply drill it out?

Exhaust ports on the head - how does one mate these up accurately with the exhaust manifold itself so no irregular gas flow occurs? Same goes for inlets I guess....

Cheers

Mark







Mark O

Fit a new correct pump, 14 quid won't break the budget surely?
http://www.ebay.co.uk/itm/FAI-WATER-PUMP-AUSTIN-ALLEGRO-METRO-ROVER-MINI-COOPER-WP3710-/221555852419
Heater outlet - yes you can drill it through.
David Smith

David

Appreciated, but if a bolt and thread tape does the same job for free? - unless correct pump is significantly different in rating and operation to existing.....

Cheers

Mark

Mark O


Mark - so that's how wives get treated over the border!

Mine won't let me look at her face let alone get within 10mm.

Shame on you.

Gavin Rowlesx

Yep I blanked mine off with a bolt. I replaced it with the correct pump when the original finally died. Lasted about 4 years...
Bob Beaumont

The MG Metro Turbo head has the same inlet valve size as a standard Metro head but I think on the Turbo head they used sodium filled? valves. The MG Metro (none Turbo) head has a bigger inlet valve, the same size as on the Cooper S head, though the exhaust valve is slightly smaller than the Cooper S head due to cracks between ports.

The place where the heater valve sits is blocked off on this head but is easily drilled out. I did that when I put a 1275 engine in a Frog.

The ports are usually matched using a good quality exhaust manifold gasket as a template. If the inlets don't have locating rings or you choose to do without them you need to find a way of locating the manifolds to the head or all your efforts at opening out the ports may be negated by miss-aligned manifolds.

I think a new water pump would be wise as you may find it has a higher through-put than a standard Midget with bypass.

Rob
Rob aka MG Moneypit

The 1969 cooper S (the perfered design) exhaust 1.15inches ( same as stock for regular heads) the intake 1.401 inches

The cooper head before pre 1969 that was notoris for cracking had a intake of (1.488 ???) ...im not sure about the exhaust, but I want to say it didnt have hardened seats ithere

Stock intake is 1.3

One both of my heads the machine shop repostioned the intake guild over a fraction when I went to the 1.401 size

Something else to consider, rimflow intakes . But the standard stainless valves are okay, my thinking if your going to drop $500 on this head, whats another $300 for rimflows. heads aint cheap, thats where all the performance is at, so dont build them cheap is my thought and you wont be rebuilding one in the near future

Prop
Prop and the Blackhole Midget

Mark up to you, I'm just saying what constitutes a proper job. To me, not having a bodge and a failure point is worth every penny of 14 quid.
Have you heard of "spoiling the ship for a ha'porth of tar"?
David Smith

As a point of interest not all engines have inlet valves bigger than exhausts. IIRC one of the Lancia Thema turbo engines, 2l FIAT twin cam based, had larger exhausts than inlets as the turbo can provide assistance to get the combustion mix in and more of it as turboed so having a larger exhaust helps get the combustion results out of the cylinder. IIRC they were tuned for torque production to provide easy motoring.
David Billington

This thread was discussed on 25/09/2014

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