Morris Minor Owners Club

urm..not how ive said this twice, but hey life is wierd sometimes...

Right well, MED charge a fair bit for porting, so maybe you would be better going to a cheaper place, but the results won't be as good. But you get what you pay for.

I would not recommend porting yourself as it's tricky and a bit of an art form. Basic profiling and following Vizard's advice on certain things is fine, but be REALLY careful you don't grind through into areas you shouldn't be in!! Practice on a scrap head first?

Compression should be covered in Vizard's book, if not then the machining place should be able to work it out for you if they have access to the block & pisons (or they will ask you for the measurements).

The standard crank will be fine, but just don't over-rev it. Stick to about 5500 as the rev limit.

I thought that the 12G295 head was the head to go for on a 1098. If so does it really need porting and bigger valves.

My reason for asking is that I have 1 sat in back of my garage just waiting to be skimmed and have U/L seats fitted.

Ialso have a 12G295 head, but with no valves and a very stubborn thermostat which the previous owner had tried to remove with a hacksaw Its not unleaded either, how much to have u/l seats fitted?? Also is it possible to fit larger valves just by lapping them in or is it more complicated than that? Good idea to try on a scrap head first, as I think ill give it a go modifying myself. I'll consider the rev limiter too.
Thanks for all your help,
Tim

I thought that the 12G295 head was the head to go for on a 1098.

Yes it is as a straight swap will produce a marked inprovement.

If so does it really need porting and bigger valves.

Nope, but you don't NEED to fit it either do you?? Porting and bigger valves will increase the gasflow potential and the head is usually the one thing on the A-series that really benifits from an improvement.

You can put an excellent carb, inlet, etc on but if the head is restricting the amount of intake charge you won't feel the benifit from the other items. If you make the head flow better, the more charge and the more power.

My reason for asking is that I have 1 sat in back of my garage just waiting to be skimmed and have U/L seats fitted.

The 12G295 head is a very good head, but nowhere near as good as a custom ported one with large valves done by a racing specialist.

I ran a 12G940 (1275 GT head) on my 1293 engine for a while which was excellent, but nothing in comparisson to the bog standard metro head that I had ported, gasflowed and large valves fitted. The difference was incredible.

how much to have u/l seats fitted??

I would not bother, just use the Castrol Valvemaster plus additive. If you really want them fitted then ring up a local machine shop for a quote.

Also is it possible to fit larger valves just by lapping them in or is it more complicated than that?

You would be there 'till the end of time if you tried lapping them in! You need the seats machined properly to fit the valves.

how much to have u/l seats fitted??

About £120 including Valves locally to me.

£120!? I only paid £50 for the head on ebay. But as it needs other work aswell (thermostat still very stubborn ) and no valves, springs, etc might look for another one. Apparently my aunt has a complete mini cooper engine in her garage, and I'm hoping it will yeild a better 12G295 head. From what people have been saying on this topic I feel it is best to get a really good head, and then over time improve the breathing, fit 1.5 rockers etc. I dont fancy running on additive though, would prefer to have unleaded, although I doubt there were any production unleaded 12g295 heads. Thanks for your help,
Tim

I am presently flowing a standard 12G202 head for my 1098. Following the advice in Vizards book I have opened out the siamesed port with a 1" grinder and worked around the valve stem as this is THE major restriction on these and many other heads. As for the combustion chamber, I have cleaned up the surfaces and removed some of the beak. I won't skim the head unless I find the CR to be so far down that I need to in which case I wil have the head converted to unleaded of find a good 12G295 whichever is cheaper.
I'm using a Dremel type drill with tiny 2mm grinding heads. It's slow, laborious and dusty and its easy to create grinding 'ribs' instead of eveny removing all the right material.
I'm reluctant to spend any money on this head because I have a 1300 engine in bits waiting to be overhauled.

I dont fancy running on additive though, would prefer to have unleaded

Running on just pure unleaded will cause a loss in power, higher running temp and make pinking more likely. If you use Castrol Valvemaster Plus then it will be much better for the engine and you can either have hardened seats or not.

I have had a look at valvemaster plus pricing, and I didnt realize you had to put so little of it in the tank. Also the idea of losing power has put me off going for unleaded seats
I'm currently beginning to take the engine out, to fit all all my mods, and I'm wondering if an engine crane is really neccassary, as how heavy can it be once Ive taken off the head, dynamo, carb, exhaust, etc etc. and ive got the radiator out aswell so there plenty of room. does anyone know how heavy the block will be with crank and pistons still installed?
Thanks again ,
Tim

It's more awkward to remove on your own rather than heavy. With the head etc off it can be lifted up off the floor but manouvering out of the engine bay is a different matter.

Having said that I removed an engine from a scrapyard car as a complete unit with ancillaries by just removing the front panel and jacking the engine up and mauling it out, but I would not recommend that for an engine you want to keep!!

Perhaps a scaffold pole across the engine bay, some rope and a strong(ish) friend would do the job.

Thanks for that advice cam, but I may now be able to borrow an engine crane from a friend, which will probably be safer for me and the engine!

I am just wondering how much power I will lose out on by using the leyland 649 profile cam, I want to use it because I got it very cheap, but how good is it compared to a kent 276 or similar? Also I got some standard rockers from an MG metro turbo for just 10p on ebay , will these be better to use instead of the standard pressed steel ones I have at the moment? I think I heard somewhere that they have a slighlty higher rocker ratio...
Thanks,
Tim

Hi Tim,

If you have a C-AEA-648 (Leyland 649 profile cam) then you have the following:
Leyland 649 = Lift = 8.00 Duration = 300 Timing = 50/70 75/45 Powerband = 3000-7500

You do know that the 649 is a full race cam? Anything over about 286 duration in a small cc engine (the smaller the cc the cammier things get) will be virtually undrivable in traffic!

a 649 won't like ticking over and you won't get any useable power until you are well over 3000 RPM! It is an excellent cam (bit old now) but excellent none the less. It is better than the 276 in terms of 'peak power' but it's very poor on torque when it's 'off peak RPM'. Which is why it's so good for racing on a track and so poor on the street.

In comparrison then Kent 276 and 286:
Kent 276 = Lift = 7.43/7.99 Duration = 270/280 Timing = 29/61 66/34 Powerband = 1500-7000
Kent 286 = Lift = 7.99/8.22 Duration = 280/290 Timing = 34/66 71/39 Powerband = 2000-7500

I PERSONALLY would not consider a 649 for street use as for 'street-driving' you will get far more 'useable power' out of a less peaky cam like the 276 or similar.

Cam choice is quite important and there are lots to consider. One important point is your rev range. there is no point in having a cam whose power REALLY comes in at about 6000-7500 RPM (like the 649) if your engine rev limit is 5500!! You might as well get a less peaky cam with a lower flatter powerband so you can use most of it!! Personally I think the 276 in a 1380 (the higer ccs make it a bit less peaky) pulls really well up to just over 7000 RPM. So in a 1098 it would probably go a bit higher (bottom end allowing! ).

You might ACTUALLY find (daft as it might seem) that the standard 1098 cam will be better than the 649 in terms of practicaility and extracting more useable power, especially with a good free-flowing head/inlet/exhust system.

As for the rockers: The MG Metro turbo ones are just like any other A+ rocker and as you say are better than the pre-A+ pressed steel ones. They are about 1.25:1 ratio and will be fine for whichever cam you choose. If you want MORE power out of your motor then go for a higher ratio rocker (1.5) as they will give you a bit more lift which is always handy. Incidently, the 649 really likes higher ratio rockers as it's a bit down on lift compared to some others.

Thanks cam,
looks like the 649 will be no good for what I want to use the car for, as I thought it was a road/rally cam not full race!! The one I acutally have is a C-AEG-530, the 649 profile but for start drive oil pumps. If anyone is interested send me a PM as its in good condition.
I think I'll go for a kent 276, and get a strap for the main centre bearing as you suggested earlier.

Ive been offered by a friend a better 12G295 head than the one I have at the moment. It is not ported, but has been skimmed, is in much better overall conditon than my standard one and has 29mm exhaust valves and 33mm inlets, and has double valve springs fitted. How much should I pay for this? also I am aware that with the valves being so big they will hit the block, so how much will pocketing the block cost? I thought that just fitting bigger valves without modifying the head will not make much difference, as it increases valve shrouding according to vizard. I might just stick with putting the standard one on because I've got insurance to think about too
Tim

How much should I pay for this?

Well as they are quite a desirable head that is quite a hard question to answer and a lot will depend on the seller and the heads condition.

so how much will pocketing the block cost?

That will depend on your local machine shop prices and they vary quite a bit were I am London prices are dear compared to areas like Wales, you really need to ring a local shop to get a price.

Just joined this thread - reading about 12G295 cylinder heads.

I have just fitted a 12G206 head to a std 1098 block.

The 206 head is very rare, but exactly the same spec as the 295 (only difference is raised locating rings for inlet/ex manifold)

These heads are from either Cooper S/ MG1100/ or MG midget cars, (whose engines closely resemble the moggie) and differ by having larger inlet valves and open combustion chambers, there should be no need to pocket the block or the cylinders (unless hi lift rockers are used) I had my cylinder head skimmed down by 60 thou to reduce the combustion chamber to a decent size and have had no problems with the large valves and a standard 1098 block.

With a standard cam, water heated manifold from a metro turbo, HS4 carb, and midget mk1 exhaust box there is a tremendous improvement in power and acceleration; so much so that I have fitted a 3.9 diff to help keep the revs down. This combination wants to go off the clock!!

I found the cylinder head by emailing all the mg midget and frogeye sprite spares dealers. I paid £60 for the head, which required complete overhaul, including repairs to a rocker stud seat - damaged by hydraulicking. Fracture repair, Head skim, unleaded valve seats, new springs ( double sets) valves, guides, seals and gasket set cost £250. A total of £310.
Expensive compared to an unleaded exchange moggie head (approx £150), but well worth the result.

I was just wondering how the block would be 'pocketed' if it needed because the valves hit it. I have a portable grinder that I have used to modify my cylinder head, could I use this to cut small indentations in the block where the valves would hit it? I've read somewhere a good way of working out how close the valves are to hitting the block: Stick large lumps of plasticene on the heads of all the valves, and then put the head on without the gasket and turn the engine over slowly a few times with the starting handle. When the head is taken off, you will be able to see how close the valves come to the block. One concern I have with pocketing the block too much is that the piston rings might get fouled by the pockets cut in the block, which might damage them or make them wear very quickly Although I have never heard of this actually happening. I'm interested because I have bought from a friend a 12G295 head with 33mm inlet and 29mm exhaust valves, and I think they are likely to hit the block. Also wont pocketling mean I have to recut the head gasket to go round the pockets? Any help much appreciated.
Tim

I have a portable grinder that I have used to modify my cylinder head, could I use this to cut small indentations in the block where the valves would hit it?

I would not recommend it. I would get it done at a proper engineering place and don't do it with the pistons in place as the filings will get down the sides of the piston (even if you stuff a rag in there).

I've read somewhere a good way of working out how close the valves are to hitting the block: Stick large lumps of plasticene on the heads of all the valves, and then put the head on without the gasket and turn the engine over slowly a few times with the starting handle. When the head is taken off, you will be able to see how close the valves come to the block.

Yep, the method is used a lot with success.

One concern I have with pocketing the block too much is that the piston rings might get fouled by the pockets cut in the block, which might damage them or make them wear very quickly Although I have never heard of this actually happening.

The rings are quite a distance down from the piston top compared to the amount you would be removing to pocket the block so I would not worry about that.

Also wont pocketling mean I have to recut the head gasket to go round the pockets?

I think the normal method is to use a gasket suitable for the head and not the block. If it clears the valves in the head then it won't be a problem.

I think the normal method is to use a gasket suitable for the head and not the block. If it clears the valves in the head then it won't be a problem.

that right with a 12g940 as the waterways dont line up if you use the 1098 gasket. you should i think redrill on of the galleries to match the new head and plug the old one with a grub screw ( cannot remember if oil or water)

On a 12g295 it should use the same gasket as the standard minor 1098 head? and give no problems with hitting the block as it a small bore head on a small bore block

the 12g940 (1300 big bore block head)some times needs the block pocketing but this depends on how much it has been skimmed and the rocker ratio/cam used

I droped a 12g940 on my 1098 turbo with no clearence problems (on standard cam) Ray has the head now but it did not look as it had been skimmed.

I think vizzard quotes somewhere in the a series bible that the 1098 cam was so good it was used in early coopers?

I agree with Turbo minor - 12G295 is a small bore head and will go onto the small bore block. (as with cooper S, MG1100 and front wheel drive cars that these heads came off of). If your concern is of valve diameter ( 12G295 has substantially enlarged inlet valves) -I am using a head with exactly same spec as 12G295 on a 1098 standard block. No pocketing was required. If you are thinking of a hi lift cam, or hi lift rockers, then clearance may be an issue. Take your new head - remove an inlet valve and put it back in minus the springs. place the head on a flat surface and measure how much lift is available. This assumes the worst case, where you are using flat topped pistons.

Max