Morris Minor Owners Club

Hi, can anyone tell me if a 11 stud 12G940 head will go onto a standard 1098 block? I know there are an extra 2 holes to consider but will the existing 9 holes be sufficient to hold the head down without blowing the head gasket? I am looking at this head on ebay - http://cgi.ebay.co.uk/ws/eBayISAPI.dll? ... _855wt_958

Many thanks,
Will.

You'll always pay a bit more because it has the 11 holes! Folks assume it's for a Cooper S (oooohh - aaaahh). But yes it will fit. I assume you know how to avoid the collision of exhaust valves and block ? And have noted it has no by-pass hose...... I'm interested to know how it will get from Folkestone to Otley for £8.99! Usually carriage is at least £15 for a head.

Thanks Roy. Just wanted to check. So can I assume that I don't have to worry about the extra 2 holes i.e. the 9 holes will hold it down OK?

No bypass outlet? Does this mean I have to use a different water pump or should I drill a bypass hole? I know what you mean about the £8.99 - his mistake though!

Thanks again,
Will.

You will need to find a pump with no bypass - or block off the one on the pump. It's GOOD to have no bypass - don't worry about that - you just need to be aware of it in advance. Yes - the 9 studs will hold it down just fine - you need a 1275 gasket of course - and please confirm you know what to do about the valves ??? I don't want you coming on with a tale of woe........

Thanks Roy, as I understand it there may be a chance that the valves will clear the cylinder block. If not, I will have to have the valve seats recessed into the head approximately 40 thou to allow the appropriate clearance -this is my understanding of "pocketing". If we are looking at pocketing the block as I have heard mentioned then I am not so sure that I would want to go that far, it all depends on how much we are talking about. the engine is out of the car so that is not a problem
Thanks, will.

Exactly! So - measure carefully and decide. You need 320 thou. Sinking the exhaust valves is the easiest way to go - and will be fine if using a standard cam and NOT using fancy high lift rockers (which are useless anyway!). Here's a pocketed block - just so you can see what NOT to do![frame][/frame]

Thanks Roy,

It is god to see such sound advice coming from a fellow Scot I bought the head for better or worse I will take it to the local machine shop and see what the situation is. I went for this one as it has the rocker gear with it, I do not intend racing the engine and would like to stick with standard rocker gear if possible (please advise).

I was thinking of adding an MG Metro camshaft or Kent 266 (your advice would be welcome) I already have an MG metro inlet manifold and a Hif38 carb. I think once I have replaced the oil pump, big end and main bearings and honed/re bored the cylinders I should have a reasonably fit and peppy engine. I just want it to last and to be able to withstand a little exuberance now and again, it will never be thrashed or over revved.

Am I on the right track or would you go down another route?
Many thanks,Will.

MG Metro cam - YES! Note - it will need a matching oil pump, but you would be fitting a new one anyway. The Kent cam has too much lift - you would need too much sinking/pocketing. Add Duplex gears - don't get fancy high strength valve springs. Add a crankshaft damper (from a Mini engine) to help keep the crank in one piece. These pressed steel rockers are the best kind (ok - forged are even better, but very expensive and not necessary for this state of tuning) - however - you can clearly see from the pictures that they are NOT properly aligned over the exhaust valves - this is VERY BAD! The 'sintered' rockers that usually come with these heads are strong enough (but only just) - and they get away with the alignment problem by being very wide - so they straddle the exhaust valve - this is better, but not great! Best is to re-align the pressed steel rockers with spacer washers (and some filing) so they DO align properly over the exhaust and inlet valves. I hope you didn't pay £67 for this head!! ??????????

Oh dear I assume that was too much I have not paid for it yet but I will have to honour my bid. I took an average of the completed listings on ebay and combined this with the low delivery cost.I am compiling my tuning bits and pieces while I have the time and the money as very shortly I will have neither
More important to me is having the right advice and the correct components to make my efforts worthwhile, I hope you are not going to tell me you have got one and you only want twenty quid

Cheers,Will

I was down that road and was nearly finished but my mate who did the valve sinking thought he was doing me a favour by modifying the combustion chamber actually ruined the head. He has since replaced the head with another 11 stud Cooper S head so I'm back in business.
On the new head the average distance from the valves to the bottom of the head is 7.3mm so according to my calculation, critical. Some valve sinking required. The combustion chamber looks OK and will not be touched.[frame][/frame]
Re-aligning the rockers is actually a pleasant job. The pressed steel rockers are slightly heavier (86g to 80g) than the sintered ones but they are 0.5mm wider on the shaft so all four pedestals need modification.
I used a homebuilt lathe rather than filing but not everybody has access to such equipment. By turning down a 1/2" copper pipe to be a snug fit it was easy to machine the faces of the pedestals.[frame][/frame][frame][/frame]
Finished pedestal[frame][/frame]
The rockers now line up nicely.

Regards

Must admit I didn't go that far with mine! Using the washers from the rocker shaft ends of my spare assembly, I padded out where relevant, so although not dead central, the rockers were what I considered close enough. What does the Scots Sage think??

What you paid for the head isn't so bad, just some people expect the world for a fiver As you say, the postage will offset it anyway! Make sure your engineering people understand just what you are trying to acheive. Any doubts and I am sure one of us could EMailyou a clear description to help anyone doing the job!

Hi guys, thanks for the replies

I am afraid I have no access to machining equipment but I do understand what you have done and why. I was thinking more of using spacers/washers to compress the rocker shaft springs and so align the rockers over the valves that way.

I just want the machine shop to do a pressure test, measure the depth/thickness of the head and recess the valve seats accordingly. I may go for unleaded inserts and have the deck planed for good measure (funds permitting).
I will check back with the forum to double check tolerances and critical dimensions once I am in a position to proceed.

Filing was mentioned at one point can you explain what would need to be filed as I feel able to tackle that.
Cheers,Will.

No need for unleaded seats - don't bother. Just measure from the top surface of the valves - to the surface of the head. You need 320 thou to be clear - assuming standard cam and NO fancy high lift rockers. And yes - washers realign the rockers nicely, although you may want to file a little off the sides of some - depends how fussy you are! And -emmm -yes - that's a LOT more than I would pay for a 940. I did warn you it would be expensive - because of it's 11 holes!! I do have some heads - but I have just re-valued my stock up to £67 each!

Ah well, we live and learn Anyway, the guy I bought the head from has offered to check if the rocker assembly has been put together incorrectly, failing that he has offered to fit a set of used sintered rockers free of charge. Should I take him up on his offer or persevere with re - aligning the existing rockers

I have also been looking into the science behind high lift cams and specialised roller rocker systems and various ratios and to be honest I don't think the improvements gained warrant the expense required. It would be different if I had a 1275 and could afford to go racing but I don't and I can't so yes I will be sticking with standard rockers but will be fitting an MG Metro cam ( I have just missed two on ebay 20 odd quid and 30 odd quid.

Just electronic ignition and a free flow exhaust and we are in business

Thanks again,Will.

In my case I had to machine the pedestals on one side (~1mm) and add spacers on the other side. Perhaps this explains it a bit better.[frame][/frame]
Regards

Pressed steel rockers are stronger than the nasty sintered rockers. MG Metro cams are few and far between these days, and these two were very cheap.

kittyfell wrote:Pressed steel rockers are stronger than the nasty sintered rockers. MG Metro cams are few and far between these days, and these two were very cheap.

Pressed steel-that's exactly what I'll be fitting. I got a set on ebay recently but just cleaned one up for that photo above.
Regards

Hello again that photograph of the rocker shaft and indications of where to file/space is very helpful Declan but am I right in thinking they are sintered rockers?
From the sounds of everybody's comments I think I should stick with the pressed steel rockers and persevere with re aligning.

One question though - if I file a pedestal or rocker flat is it not going to make the valve gear more noisy and subject to wear as there will be more metal to metal contact

Thanks,Will

A badly worn rocker will have gone through the hardened surface and into softer metal and will wear badly no matter what you do

Yes they are the sintered rockers. I took the photo before I got pressed steel ones. You can see the pressed steel and sintered along side each other further up.

Regards