Morris Minor Owners Club

thanks peetee I'm encouraged by that as it would a responsible sum to spend in terms of extra power gained

carb, inlet manifold etc shouldn't be too hard - but what about the head ? Ebay ??

At £200 I'd be very interested in tuning rather than replacing the engine with a 1098 unit

Would still be interested in knowing if any has or knows if fitting a 1098 helps with the breathing of a 950 cc ??

295 heads tend to be horribly overpriced. And sometimes have cracks - so caveat emptor..... The 202 head and cam from a 1098 engine will make a worthwhile difference without overstraining the engine. The head would need some skimming. And an MG Metro inlet manifold with HIF 38 carb - just cut the exhaust off the standard manifold (or indeed unbolt it if the early type and blank the hot-spot) and it should have ~ 50 bhp but at highish revs.

A 1098 head has larger valves that that of a 948 so there would be an improvement - but only a small one. The 295 head valves are larger still and experience tells me that it is very worthwhile. It's only worth putting a alloy inlet and 1.5 carb on the 295. In an ideal world you need a matching intake diameter for the carb, inlet and head so that turbulance is kept to a minimum and the full benefit of the larger componant (be it head, carb or inlet) is realised.
As with any upgrade you need to be sure the base engine is healthy and can take the extra strain. Also a rolling road tune can make the difference between top performance and no additional performance whatsoever!

Eeeh? The 998 Mini engine has the same head as the standard 948 engine (small valves) and yet MG Rover deemed it well worth fitting the HIF 38 carb........ The inlets on the 202 head are only marginally smaller than the inlets in the 295 (which are hard = expensive to get these days) and the ports on the 202 are already opened up same shape as the 295 - and the exhausts are just the same size. Yes - the 295 has better chamber shapes - doesn't take long with a grind stone to make a fair approximation if you really want to - but then even more skimming required and only marginal additional power gain. Obviously THE head to fit is the excellent 12G 940 head but I wasn't going to mention that at this stage.......

I'd vote to keep the 948 with the 4.2 diff (if that's what's there) unless you carry a LOT of load and/or live somewhere with a lot of hills.

The later diff (4.2:1) will limit the accelleration of a 948, and reduce it's ability on hills but will be a benefit on open roads and long distances. The 4.5:1 diff is not ideal if you want to keep up with traffic on a dual carriageway etc..

I've only had a few Minors with 948 engines and they were the most relaxing & pleasant ones to drive compared to the gnashing/vibrating 1098's.
Tuning the engine is the last thing I'd recommend unless/until you've driven a standard set up for a good few thousand miles. The original set up is/was good enough to make the car a legend in it's own lifetime. Tuning it for speed is nearly always at the expense of some of the driving pleasure of having a nice calm car.

....not that I've had any standard Minors in the last 5 years so I can say that I often forget take my own advice. ;-)

A 948 fitted with the 12G202 head (skimmed 60 thou) and 1098 camshaft - with a larger carb from a Mini will run very nicely, retaining the 'short stroke' smoothness of the engine without becoming in any way intractable.

bmcecosse wrote:A 948 fitted with the 12G202 head (skimmed 60 thou) and 1098 camshaft - with a larger carb from a Mini will run very nicely, retaining the 'short stroke' smoothness of the engine without becoming in any way intractable.

Seconded. We've got a 948 with a 1098 head and cam, and even with the standard manifold and standard carb it's a very pleasant vehicle to drive!