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MG ZR ZS ZT Technical - MG ZR gearbox?

Hi

hope someone can help. I am about to buy an MG ZR 120. I was wondering if anybody could tell me what type of gearbox they have - is it the Rover PG1 as used in the MGF?

Reason for asking is I have raced Lotus Elise' in the past, and have gear ratio's, lightweight flywheels, LSD and heavy duty clutch's sitting in my garage, and want to know if I can fit them.

I am intending to convert the engine to a 190 bhp VHPD pretty much straight away so will want to make these changes also.

cheers!

Owen
Owen Geddes

If it's a 1.8 i believe they used the PG1 box.
Gareth kidman

Gareth

thanks for that - thats great news, will save me a lot of money whilst upgrading.

regards

Owen
Owen Geddes

Yep 1.8's have PG1 and 1.4's have R65, which is not as strong as PG1.

What engine mods do you plan to do to the 1.8K?

I now this engine is more tunable than the VVC brother.
David Harasym

David

I will put a ported HPD head on with big valves and probably Piper 285 cams with solid lifers etc... Forged rods and pistons. Jenvey 42mm DTH throttle bodies with an Emerald M3D 32 bit ECU. That will get me to around 190-200bhp.

Whilst I am getting that lot together I will put on a 140bhp head, trophy throttle body, VVC inlet manifold and different air filter - that will give around 145 bhp with more torque than a VVC.

cheers!

owen
Owen Geddes

Monster, Owen! :o)

Are you keeping the Elise as well? You'll have quite an interesting stable of cars :o)
Rob Bell

No am selling the Elise at the moment. Have just bought a Van Diemen 96 single seater to race :->

Has a 2 litre Zetec in it - which is going to 250bhp soon - all in a car that weighs 500kg :->>>>

Owen
Owen Geddes

Nice :o) A friend purchased a Van Diemen for sprinting... 'Spose I'll have to keep plugging along in the ol' F! LOL

Great to see you here Owen. Spot on regarding the PG1 gearbox - the R65 was only for the lesser powered cars; lower torque limit.
Rob Bell

Anyone know where i could get a adaptor plate for a 1.8 K series to fit onto a 1.4 K? I'm doing a little project you see...
Many thanks.

Gareth
Gareth kidman

>>Anyone know where i could get a adaptor plate for a 1.8 K series to fit onto a 1.4 K?<<

Not sure what you are after Gareth? An adapter to fit two engines together???
Rob Bell

>>>I will put a ported HPD head on with big valves and probably Piper 285 cams with solid lifers etc... Forged rods and pistons. Jenvey 42mm DTH throttle bodies with an Emerald M3D 32 bit ECU. That will get me to around 190-200bhp.<<<

Not neccessarily true I am afraid in the saloon body. You could be 20 or even 30 shy of this when comparing identical spec engines seen in Elise and Caterham that do actually produce this sort of power.

The probability for the shortfall is almost certainly in the exhaust but this is an ongoing question mark which may be answered by the first weekend in June. The results showing these anomolies are sitting on Dave Walker's computer that is sitting on his dyno. A specific R200 based car is operating such an engine with an almost identical spec and is falling short leaving scratched heads after many runs and many changes.

Rog
Roger Parker

Rob, read again... (with out being sarcy)
'Adaptor plate for a 1.8 to fit onto a 1.4', i.e to make a PG1 box fit onto a 1.4 box would need the adaptor plate from a 1.8 ... Which means getting rid of that crappy Peugeot gearbox they fitted to 1.4 engine, they still break even without the torque!
Hope this clears it up a bit for you.

Gareth
Gareth kidman

Out of interest........How much will that lot be setting you back Owen?
David Harasym

Roger

I was assuming with that number that the exhaust config would make a significant reducion in power. An Elise in that config can easily make a fair bit over 200bhp. Will be interesting to see what it all comes out at. May also look at roller barrel throttle bodies and an additional set of injectors.

David

I already have most of it lying around my garage - so will probably only cost me another 1500 to get the rest of the bits.

regards

Owen
Penguin

>>Rob, read again... (with out being sarcy)
'Adaptor plate for a 1.8 to fit onto a 1.4', i.e to make a PG1 box fit onto a 1.4 box would need the adaptor plate from a 1.8 ... Which means getting rid of that crappy Peugeot gearbox they fitted to 1.4 engine, they still break even without the torque!
Hope this clears it up a bit for you.
<<

Hi Gareth,

yup, all cleared up!

Not sure where you'd get one of these. I'm not 100% sure that the block castings are the same between the big - bore 'damp' liner engines (the 1.6 and 1.8) and the smaller bore engines (the 1.1 and 1.4). It stands to reason that they should at least be similar... but who said reason applies?

Best bet for the cheapest option is a scrap yard and compare the two engine blocks. Is an adapter plat absolutely necessary - or can a PG1 actually bolt straight on?

On a different tack, it is interesting to note that the BMW MINI uses a modified, dual syncro PG1 gearbox.

More interesting is that the Cooper S uses a 6-speed gearbox.

It stands to reason that the two gearboxes, whilst not related, should occupy a similar space, and have drive shafts in a similar place.

So does this mean that a Cooper S 6-speed gearbox could be made to fit onto a K-series engine in the Z cars or the roadsters?

There's a challenge for someone to take up methinks! ;o)
Rob Bell

This thread was discussed between 14/04/2002 and 03/05/2002

MG ZR ZS ZT Technical index

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