Morris Minor Owners Club

hello gang, I am looking for a little more from my 948 engine. I have just got a 12G202 head. I am aware you have to skim it 0.060 to get good compression. I am now looking for a different camshaft.

anyone offer advice on whats best with the head change?

Controversially... Swap it for a 1098? Could work out cheaper and is more capable in modern traffic.

did think of that, but the 948 is a better engine, smoother and revs better. my one is very good 'down below' so want to keep it.

The 948cc engine is a good engine for tuning - I have tuned several over the years and they were always reliable and very smooth running.
Below is a picture of the tuned 948cc engine that was at one time in my Minor and had the following spec:-
948cc block bored to 998cc.
Centre main strapped.
998cc flat topped pistons and 998cc rods.
Camshaft - 2A948 (997cc Cooper).
All camshaft bearings fitted with white metal bearings. Important if using a camshaft other than standard.
12G295 head polished and ported and stronger springs.
Cooper S distributer (no vacuum advance).
Cooper S oil pump and oil relief valve spring.
Lightened flywheel.
Stronger clutch.
Duplex timing chain.
Lightened cam followers.
LCB manifold.
Twin 1.5 SU HD carbs on Oselli inlet manifold.
All above balanced.
Performance ignition coil.
Cooper S water pump.
The 12G202 head whilst a bit better than the 948cc Minor one is not the best. The best small bore heads are the 12G206/12G295 heads but now rather expensive that is if you can find one or the other.[frame][/frame]

With that 202 head - just fit the matching camshaft (AEA 300) from the 1098 engine - as long as you don't use stronger valve springs it will be fine without the additional cam bearings. Then add a larger carb when you can afford it. It will give '1098' power - but at ~ 10% higher revs than the 1098 of course.

bmcecosse wrote:With that 202 head - just fit the matching camshaft (AEA 300) from the 1098 engine - as long as you don't use stronger valve springs it will be fine without the additional cam bearings. Then add a larger carb when you can afford it. It will give '1098' power - but at ~ 10% higher revs than the 1098 of course.

ok, sound advice. I like this. I will use the springs I have and look for a 1098 camshaft.

thanks

philthehill wrote:The 948cc engine is a good engine for tuning - I have tuned several over the years and they were always reliable and very smooth running.
Below is a picture of the tuned 948cc engine that was at one time in my Minor and had the following spec:-
948cc block bored to 998cc.
Centre main strapped.
998cc flat topped pistons and 998cc rods.
Camshaft - 2A948 (997cc Cooper).
All camshaft bearings fitted with white metal bearings. Important if using a camshaft other than standard.
12G295 head polished and ported and stronger springs.
Cooper S distributer (no vacuum advance).
Cooper S oil pump and oil relief valve spring.
Lightened flywheel.
Stronger clutch.
Duplex timing chain.
Lightened cam followers.
LCB manifold.
Twin 1.5 SU HD carbs on Oselli inlet manifold.
All above balanced.
Performance ignition coil.
Cooper S water pump.
The 12G202 head whilst a bit better than the 948cc Minor one is not the best. The best small bore heads are the 12G206/12G295 heads but now rather expensive that is if you can find one or the other.[frame][/frame]

great. good advie. thanks

ampwhu wrote:

bmcecosse wrote:With that 202 head - just fit the matching camshaft (AEA 300) from the 1098 engine - as long as you don't use stronger valve springs it will be fine without the additional cam bearings. Then add a larger carb when you can afford it. It will give '1098' power - but at ~ 10% higher revs than the 1098 of course.

ok, sound advice. I like this. I will use the springs I have and look for a 1098 camshaft.

thanks

Just use a 1275cc Marina camshaft, same cam timing as the 1098cc engine and much more plentiful and usually will have incurred less wear.
Much wider lobes as well which is more beneficial to reducing cam and follower wear.
The only down side is that you will have to change the oil pump from pin drive to either slot or spider; but there again I would recommend that the oil pump is changed as a matter of course as part of the engine build.
As bmc says do not use any stronger valve springs otherwise you may get the camshaft picking up in the block because the middle and rear bearings are part of the block and do not have white metal bearings fitted. Only the front cam bearing in a 948cc engine has the white metal bearing.
Phil

Oh yes - the standard 1275 cam would be fine - AS LONG AS IT's NOT SPYDER DRIVE !! And many were.... There is no spyder drive oil pump for the small bore block.....

The spider drive pump (or any other large block pump) can be fitted to a small block 'A' series using spacer (Pt No: 12G1127) between block and pump.
You will also have to provide the spider (Pt No: CHM108) which has been discontinued but is sometimes available on 'e' bay.
http://www.ebay.co.uk/itm/SPIDER-DRIVE- ... SwLVZVlWWA

And will it still clear the cover with that spacer in place ? Not a problem on a Mini,,,but on the in-line engine ? Easier to just use a non-spyder cam. Unfortunately I binned a couple a few weeks ago as part of my clear out......

With a little bit of fettling it will fit together.
For example:-
Pictured below is the 1275cc Cooper S pin drive oil pump fitted to the 948/998cc engine above.
If you look closely you will see that I had to relieve the area around the two mounting bolt holes and countersink the third.
The boss in the centre had to be reduced and the oil pump cover slightly domed to give the necessary clearance.
It is possible mix and match the drive shafts but only use shafts and impellors that are keyed together.
When fitting this pump to the 948/998cc engine I was able to change the slotted drive shaft with the short one from the normal 948cc engine. As the pump had seen little use I was able to swop back to the long slotted drive shaft for use in the 1275cc engine.
There is a very good section (No: 17) in Clive Trickey's book Tuning The Classic Mini' (ISBN No: 0 947981 63 6) detailing the interchangeability of 'A' Series oil pumps and the modifications/fettling required including the use of pumps using the spider type drive.
[frame][/frame]

just a couple of questions regarding this.

I have stripped the head I have bought (12g202) and purchased new valves and guides for unleaded use. question is, when I give it to the engine shop to have the head skimmed 0.060", do I need to have new valve seats fitted as well? or would whats already there be ok and just need re-cutting?

also, valve stem oil seals, do I use the small rubber rings or can I use the 'top hat' ones I've seen for sale?

cheers gents

As regards the valve seats - If not already done I would have unleaded valve seats fitted.

The top hat seals should only be used with the later valve guides which have the locating groove for the top hat seal.
The valve guides with the location groove should be shortened to the same length as the original guide as fitted.
Whilst some do use the top hat seals with the non grooved valve guides it is not something I would recommend.
Top hat seals should only be used on the inlet valve guides though they were factory fitted to all valve guides.
The reason that they may be left off the exhaust valve guides is to allow some oil to the exhaust valve guides so facilitating the lubrication of the exhaust valve stem.
Phil