Mo' Welly - Playing with the engine

How can you get more welly?

Well, lets start with what we have.
From the Morris factory, the Cowley, Oxford and Isis offer engine outputs thus:

Morris Cowley Oxford Isis

Engine 1200 B-series 1500 B-series 2.6L C-series

Power (low comp) 43bhp 50bhp 86bhp

Torque(low comp) 58ft/lb 78ft/lb 124ft/lb

Power (hi comp) n/a 55bhp 90bhp

Torque(hi comp) n/a 83ft/lb c.130ft/lb

Morris	Cowley	Oxford	Isis
Engine	1200 B-series	1500 B-series	2.6L C-series
Power (low comp)	43bhp	50bhp	86bhp
Torque(low comp)	58ft/lb	78ft/lb	124ft/lb
Power (hi comp)	n/a	55bhp	90bhp
Torque(hi comp)	n/a	83ft/lb	c.130ft/lb

(low compression=7.2:1, high compression=8.3:1) Although adequate, more power and torque can be gained easily.


Oxford/ Cowley		The Oxford and (even more so) the Cowley were/are never thought of as high performers... the perfect Q car!

Isis		Almost no average mortals know about the Morris Isis and they think it's just an Oxford, so even in standard form they can get up people's noses. Imagine the fun if it went faster!

Get a bigger engine from a later car or

Mess around with the original engine

General points:

On any motor, before you go wild with engine swaps etc.; check that the car is tuned up properly (HT leads, plugs, points, timing, carb(s) etc.) - you may be pleasantly surprised.
With the Oxford and Cowley, one thing to note is that their standard diff ratios are rather low, so seemingly modest gains to torque or power will make quite a noticeable difference to acceleration.
The cylinder head on all models can always benefit from some attention, so if you've got the head off; have a look at the combustion chamber in the head.
'ave a look at this...:

Standard chamber	Reshaped chamber

It was a BMC quirk to have this large shroud between the valves (often called the Westlake prominitory, after it's inventor) and it's purpose (I think) was to produce swirl in the mixture and prevent it from touching the hot exhaust valve too soon. However, they were a little over enthusiastic and the prominitory can be trimmed somewhat to encourage better gas flow and minimise any tendency for the head to crack along this bit. In fact on the later 1800 BMC B-series used in the MGB, 1800 and Morris Marina BMC/BL did just this. You may want to give the head a shave to bring the compression ratio back up (see below).

If you're playing around with the compression ratio, my experience here in New Zealand is that the 7.2:1 ratio will run easily on 91 octane petrol. Some cars with the 8.3:1 ratio run easily on 91, but then some will only run nicely on 96, so bear that in mind if you're playing around with the head - lowering the compression ratio a fraction might be desirable. I'll try to come up with something more scientific soon :-)

All Cowley, Oxford and Isis models should have only one muffler in the exhaust system - any more and you'll reduce power and the lovely Morris exhaust note.

Cast iron manifolds are fairly inefficient (but quite 'cost-effective' ie. cheap!). However, later cast iron manifolds for single carbs (1622 onwards) seem to be more efficient than earlier ones as fitted to the Cowley and Oxford. Early ones look pretty though (aluminium inlet, cast-iron exhaust). What about free-flows? Well, read on...

Playing around with bigger motors from later models

Cowley and Oxford: BMC B-series

The BMC B-series was a long lived motor (1954-1980 in petrol form), and was available in the following sizes:

Size Vehicle
1200cc Used in Morris Cowley and the Austin Cambridge A40 only.

1489cc Many vehicles but higher performance applications in MG Magnette, MGA, and Riley 1.5 and 4/68. See messing around with original engine.

1588cc Only used in the MGA 1600, and will be rather hard to get hold of!
1622cc Austin A60, Morris series VI and Wolseley 16/60. High performance versions in MG Magnette markIV, Riley 4/72 and MGA markII.

1798cc MGB, Morris Marina (and front wheel drive 1800 range, but we can't use them so easily).

Size	Vehicle
1200cc	Used in Morris Cowley and the Austin Cambridge A40 only.
1489cc	Many vehicles but higher performance applications in MG Magnette, MGA, and Riley 1.5 and 4/68. See messing around with original engine.
1588cc	Only used in the MGA 1600, and will be rather hard to get hold of!
1622cc	Austin A60, Morris series VI and Wolseley 16/60. High performance versions in MG Magnette markIV, Riley 4/72 and MGA markII.
1798cc	MGB, Morris Marina (and front wheel drive 1800 range, but we can't use them so easily).

One of the easiest and most cost effictive ways of obtaining more welly (and possibly economy) is to swap your Cowley/Oxford's 1200 or 1489 engine for a bigger one, after all; these engines have to work pretty hard to shift a heavy car!

The 1200, 1489 and 1622 engines are straight swaps, eg. for the Cowley; dropping in a 1489 makes a huge difference in acceleration and hill-climbing (with the original low-ratio differential), and a 1622 will drop in to an Oxford (or a Cowley) with similar effectiveness.

The single carburettor 1622 gives 61bhp and 90ft/lbs or with twin carbs you could get from c.68bhp (Riley 4/72, MkIV Magnette) to 86bhp (MGA) depending on the camshaft, head etc.
Of course, there's nothing stopping someone from building up a standard A60 1622 engine to an MGA spec. and putting it in their Oxford...

The 1798 engine comes in 2 different versions: a 3 bearing crankshaft (in the early MGB) and the later 5 bearing crankshaft.
The 3 bearing crankshaft engine will fit as a straight swap I believe - if you can find one, or want one - they apparently have a tendency to break crankshafts.
The 5 bearing one will need some work to fit in, because the rear engine plate has a true oil seal (quite a novelty for a BMC car...); the engine mounts are quite different neccesitating a change of front engine plate too, and several other things. The Farina MG/Riley web-page (see my links page) has a section about doing this conversion to one of those cars, and it wouldn't be too far removed from doing the conversion to an Oxford/Cowley too (and there are cars that have had it done).
The single carburettor 1798 gives c.78-86 bhp and 99-101ft/lbs; twin carbs give around 96bhp.

Please note that the bhp figures given above are for 'factory standard' engines - eg. A60, Morris 1800 for single carb figures; MGA, Riley 4/72, MGB etc. for twin-carb figures. You could easily get more with some determination...and cash, of course...

Worth bearing in mind: if you're thinking about uprating any older car, don't forget about the brakes etc. - e.g. my early Morris Cowley has the smaller 8inch drums, and I'd be a bit daft to give that car too much more power unless I changed them!

Isis

The BMC C-series was used from 1954 until 1969. It is available in these sizes:

Size Vehicle
2639cc Single carb used on Austin Westminster, Morris Isis, Twin carbs for Wolseley 6/90, Riley 2.6, A105 and Austin-Healey. Twin carbs give 95-105bhp.
2912cc All applications twin carburetter (or triple!): Austin Westminster A99,A110; Wolseley 6/99, 6/110; Princess 3-litre; Austin-Healey 3000. Twin carbs give 103-150bhp.

Size	Vehicle
2639cc	Single carb used on Austin Westminster, Morris Isis, Twin carbs for Wolseley 6/90, Riley 2.6, A105 and Austin-Healey. Twin carbs give 95-105bhp.
2912cc	All applications twin carburetter (or triple!): Austin Westminster A99,A110; Wolseley 6/99, 6/110; Princess 3-litre; Austin-Healey 3000. Twin carbs give 103-150bhp.

Note: the 2912cc engine in the MGC and Austin 3-litre are not the old-style C series type - I have no idea if it can replace a C series, but I imagine that spares are harder to come by, as would be the engines themselves).

The 2912cc C series engine is a straight swap, and gives a Morris Isis quite a kick (and no doubt quite a thirst too), and for the brave of wallet; with Austin-Healey 12-port head, 150+bhp is easily possible!
The standard cylinder head didn't change from the 2.6 to the 2.9 engine, but through a contact, I have heard of a motor engineer in Australia who has hacked around with an ordinary C series cylinder head and produced results almost identical to a 12-port head. Very interesting...

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Meddling with the original motor

Cowley and Oxford

If you want to keep the same block for originality reasons or whatever, the 1489 and 1200 (and of course 1622 and 1798) engines can be tuned to whatever stage your heart (or wallet) may desire.

Giving the existing head a careful polish, reshaping the combustion chambers and twin carbs would yield a productive 60-68bhp (perhaps a little more), as on the MG Magnette.
A more efficient exhaust system would be beneficial, as the cast iron units are fairly inefficient.

A Riley 1.5, MGA or Magnette head has bigger valves allowing better gas flow and hence more power.
A head from a 1622 (bigger valves again on the Riley/Magnette/MGA 1600) will fit but I believe it needs a shave to restore the compression ratio.
A 1798 head would fit, but it can take some fudging around because it has very big valves.

Note that with a bigger head alone you'll loose some low end torque (luggability), which is a pleasant feature of these motors.

It is quite possible to get around 120bhp from a 1489; such figures were given to me for an Oxford (no really! click here to see an Oxrocket - it'll open in a new window) and Wolseley 1500 involved in classic racing in Australia. Will the Axeman please stand up? :-)

Also worth mentioning for the brave of wallet is the HRG-Derrington alloy crossflow head for B-series engines...figures show that these could give >108bhp from a 1622 motor.

Isis

Similar things can be done to the Isis, twin carbs initially giving 95-105bhp. Later heads appear to be exactly the same, except for the Austin-Healey 12-port head which is rather more efficient (and expensive).

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