13 replies to this topic

[Fastorq]

I’ve got a 60 bhp 1275cc genuine RSP engine complete that I want to strip and re build
The head has 33.?mm inlets and 29.?mm exhausts

Firstly am I correct in thinking that these engines were MG Metro so they already have a decent camshaft as standard?

Secondly, shall I change to a 1.5:1 ratio rocker assy.

Lastly, rather than buy a new head should I just have the inlets opened out and replaced with 35.? mm ones and do some head porting and smoothing.

Is that likely to get me 80bhp

Regds
DavidR

Edited by Fastorq, 21 February 2019 - 07:34 PM.

[Cooperman]

I'm not convinced that the cam is an MG Metro version.

The MG Metro head has 35.6 mm inlet valves as standard.

 

With an MG Metro cam accurately timed in, 35.6 mm inlet valves, a matched inlet manifold, a well gas-flowed head and a CR of around 10:1 you should get around 80+ bhp at the flywheel. The ignition advance curve may need to be improved to match the above.

[Fastorq]

I'm not convinced that the cam is an MG Metro version.
The MG Metro head has 35.6 mm inlet valves as standard.

With an MG Metro cam accurately timed in, 35.6 mm inlet valves, a matched inlet manifold, a well gas-flowed head and a CR of around 10:1 you should get around 80+ bhp at the flywheel. The ignition advance curve may need to be improved to match the above.

Without need for ratio rockers ?

The head from what I’ve read was a smaller inlet valve version on later Metro MGs
I’ve not been able to find any confirmation that anything else apart from the head was changed.
The small inlet heads were lead free
The older big 35.?. heads were’nt.
Probably easiest just to pull the cam out and check it.

Cheers
DavidR

Edited by Fastorq, 21 February 2019 - 10:18 PM.

[Mrpeanut]

I’ve got a 60 bhp 1275cc genuine RSP engine complete that I want to strip and re build
The head has 33.?mm inlets and 29.?mm exhausts

Firstly am I correct in thinking that these engines were MG Metro so they already have a decent camshaft as standard?

Secondly, shall I change to a 1.5:1 ratio rocker assy.

Lastly, rather than buy a new head should I just have the inlets opened out and replaced with 35.? mm ones and do some head porting and smoothing.

Is that likely to get me 80bhp

Regds
DavidR

I've heard rumours that some rsp engines have mg metro cams. I bought one and it had the mainstream cam. If it hasn't got one, I'd fit a minispares evo 1 cam - that's what I did. It's very mg metro ish (but has a bit more go about it) and more built in lift so you won't need the rockers.

[whistler]

I have a cam from an RSP in my 1293 and it is an MG Metro cam.

Edited by whistler, 22 February 2019 - 11:19 AM.

[limby2000]

Did,nt the late mg metro,s have smaller valves because the were unleaded.

[Fastorq]

Did,nt the late mg metro,s have smaller valves because the were unleaded.

Yes, that’s what I had heard also.

[Fastorq]

I have a cam from an RSP in my 1293 and it is an MG Metro cam.

How can I recognize that.
Will there be a part number on it somewhere and what would the number be?

[Mrpeanut]

Did,nt the late mg metro,s have smaller valves because the were unleaded.

Yep, small valve unleaded head.

[wile e coyote]

yep - smaller valves once unleaded heads introduced... cam, from memory MG metro ones have a recessed ring in them between lobes 1 & 2....

 

Personally I wouldn't fit 1.5 ratio rockers - too much stress on the valvegear and reports of consequential accelerated wear , the OE rockers are (again from memory) at a variable ratio of about 1.2.. -  the original S rockers  were 1.25..... so if in the market I'd shop for a nice set of 1.3 roller rockers....

 

If 80hp is your goal then fine  that's easily achievable  IMHO a decent cam & head coupled with a 1.75" SU, LCB and decent exhaust system will after a rolling road tune, do that for you without breaking the bank but as I bore everyone senseless stressing an MG metro lump in standard trim on a 3.44 diff  and fine fettle  gives plenty of go for a road car - the crucial part to enjoying your car is set up and alignment - makes all the difference a well set up and tuned car can be a joy - even in std  form.....

[whistler]

 

I have a cam from an RSP in my 1293 and it is an MG Metro cam.

How can I recognize that.
Will there be a part number on it somewhere and what would the number be?

 

See image.

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[Fastorq]

Thanks that’ll let me identify it.
Is the Metro MG cam similar to the original Mk1 CooperS ??
DavidR

Edited by Fastorq, 22 February 2019 - 08:01 PM.

[wile e coyote]

Actually better. but in simplest terms pretty similar... original S cam came on the power 1200- 6000 MG Metro 1500 - 6500, same lift but differing duration, both perfectly civilised and easy to live with - the only other one I've lengthy experience of was a 276...... just that bit more ragged with a slightly lumpy idle which got annoying for minimal discernable  advantage - so swapped back when gearbox let go....

IMHO the MG metro cam was the best of the factory offerings....although the SW5 much used by others (I've no experience of one) seems to impress..

[Cooperman]

I was once told by a guy who was in quite a senior position at Longbridge that because Rover were so bad at paying their suppliers on time, sometimes a supplier put Rover 'on the stop'. 

When that supplier was a cam manufacturer, Rover Production just fitted whatever cams they had 'on their shelves', so a Mini could have any one of a number of different A-Series cam profiles (MG Metro, Saloon, Commercial. etc.). As a former supplier I can confirm that Rover always too around 6 months to pay their bills. In the end I decided to no longer do business with them as they always wanted the cheapest price and then didn't want to pay.