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MG parts spares and accessories are available for MG T Series (TA, MG TB, MG TC, MG TD, MG TF), Magnette, MGA, Twin cam, MGB, MGBGT, MGC, MGC GT, MG Midget, Sprite and other MG models from British car spares company LBCarCo.

MG MGA - Cylinder Head Search

Well, it's on again, off again with the procurement of an MGB head. I am on my way back to the states the end of July/first of August and I had a head lined up that I was going to run to the machine shop and have it worked over and then lug it back to Japan with me. Well, I was told the head was no longer available so I resigned to just stick with the stock head-which is in fine mechanical shape.

Rats! After this past weekend of cruising, I feel that the head may be a good addition after all. Tired of getting smoked by the Bug Eye Sprite!

Now comes the task of actually finding one.

The head must appear stock for the year of manufacture, so an early one is a must. If I take a car in for inspection and it has air injection ports-even if blocked off-the car will fail and I will have to find another one anyway. Of course, as Barney has pointed out, a Euro head sans ports may work as well.

Perhaps anyone out there have a spare '18' head they wish to part with? I plan to ship it to KY and have it worked on so I can just pick it up when I pass through town.
Tom Baker

Tom

The guy in Scotland who advertises on ebay can do them very reasonably. You need a 12H-1326 casting head to avoid cutting eyebrows in the block. It's a big valve head too. No air injectors. see here http://www.flowspeed.com/cylinder-ident.htm

Otherwise, I have an Oselli 1500/1600 Stage2 head sitting on my shelf which you can buy off me. Doesn't go with my 1622 high comp engine and a SC. It's done about 200 miles since Oselli redid it (lead free too).

dominic clancy

This is the guy
http://www.britishclassiccarspares.com/
dominic clancy

Hi Dominic,

Thanks for the information. I am interested in the Oseli head you mention. Please contact me by e-mail with the details. It is a big plus if it is ready to go! I may be able to put it to use. How does it compare to an '18' head as far as specifications/performance?

Tom
Tommy Baker

Problem with the 12H-1326 head is the larger volume combustion chamber. To use this head on the MGA 1500/1600 engine you need to shave the head to reduce the chamber volume to get the correct compression ratio. Having reduced the depth of the chamber you may then need the eyebrows in the block.
Barney Gaylord

I am ready to add eyebrows if necessary. Let's hope it has already been shaved as that may be a bit cost prohibitive.
Tom Baker

dominic, Thanks for the info on www.flowspeed. You have helped me identify a 12H1326 head - the 42cc per cylinder is very useful.
Barry.
BM Gannon

Dominic,

Any details on the Oseli head? I am still interested. Hopefully it will be a good match.

Thank you,

Tom
Tommy

Hi Tommy

I sent you emails a few days ago. Was wondering why I hadn't heard back. Maybe you should check that they didn't land in your spam box.....

Mail me a phone number and i'll call you
Dominic
dominic clancy

Hi Dominic,

No e-mails. Must be lost in space!

You may try:

mgb1972@yahoo.com

ashgreenmga@yahoo.com

What is your e-mail? Will be happy to send my phone number by mail then we can speak if that is OK.

Thanks for continuing to work with me.

Tom
Tommy Baker

Tom
Have sent the first mails to ashgreen email, just resent to the mgb one. Phone is +41796877079, skype id is dominic-ch
dominic clancy

email is firstname@lastname.ch
dominic clancy

Hi Dominic,

Just sent an e-mail to you for as a test. I checked my yahoo mail and spamblocker was on. Perhaps it sees the ch domain and just deletes it. I changed the settings to allow it to come in. Amazingly, I do not have skype. I use a 7 year old computer at home and I am lucky to have e-mail. Maybe a new computer is in order or if I can use skype without a camera then that would work as well (I will look into it).

I think Japan is 7 hours ahead of Switzerland, so about 2:30 pm your time. I have to catch a 5:30 am train so I am off to bed but I will be free most times otherwise.

Thanks for keeping in touch and let's try this again!!!

Tom
Tommy Baker

Hi again,

Dominic was gracious enough to give me the details on the Oseli head he has. Seems as though it is an A head rather that a B one. This could be a great head for those of you wanting to keep the stock head, but want a bit more power.

So, I am back to searching for an early B head. I saw one on ebay, but the auction had already ended. Maybe I'll keep an eye out for future ones. In the meantime, if there is someone out there with a reasonably priced 18 head they would like to part with please let me know. I will be back in the US later this month and it would be a good time to take it in for machining.

Thanks to all,

Tom
Tom Baker

On a standard 1500 or 1600 engine, an early B head will not bring more power, as the compression ratio will be lowered by having larger chambers in the head. Having the larger valves in the 1800 head will help breathing, but that will bring you more or less back to where you are now in power terms. It's only advantageous to do fit a B head if you are going to fit a supercharger and you want to reduce the compression ratio to increase the boost without getting into predetonation issues.

The best route for more power is a fast road cam, a lightened flywheel, amd a stage 2 A head. Of course adding a SC to the mixture will eat the others for breakfast.

Unfortunately, when I blew the 1500 block two years ago, the new head I had just ordered for it didn't match the 1622 high compression engine that I replaced it, but a 1800 head produced just the right level of compression that special copper gaskets could not.

The Oselli head is supposed to be good for 8-10HP extra. Quite a boost over the standard setup.
dominic clancy

Dominic, I thought the thing to do was to skim the MGB head so you get back the compression ratio you wish to have.
J H Cole

I have run an early MGB 18 head on my MGA 1500/1600 engines for 20 years, and it works great. Without modification the B head does give lower compression ratio, but the larger valves and better porting more than make up for it. The 1500 with unmodified B head will run about even up with a stock 1600.

The better fix is to shave the B head about 0.047" from original thickness of 3.187" to 3.140", thereby lowering the compression chamber volume from 43cc to 38cc to restore original compression ratio. This not only makes the 1500/1600 run stronger, but also brings the 1600 very close to the spec's of the 1600-MK-II 1622 engine with original larger valves. Beware to check valve head clearance after shaving the head or installing a higher lift cam, as it may require adding clearance eyebrows in the block (easy to do).

You can reduce flywheel mass a little. A late production MGA MK-II or early MGB flywheel is about 20 pounds vs 28 pounds for the earlier MGA. This gives better throttle response and a bit better acceleration in the lower gears, and is easy driving. The lighter you go the trickier it is to drive on the street. A 14 pound alloy flywheel is not recommended for street use.

You can slip in a fast street camshaft to gain 10-12 HP with any of these engines, with a slight loss of torque below 1500 rpm (and a bit more fuel consumption to make the extra power). The more radical you go with the cam the more awkward it is to drive on the street. As you step up the camshaft profile you can use higher compression ratio due to more valve timing overlap reducing pressure at lower engine speeds. Change to the fast street cam with no change from stock compression ratio allows my engine to run on the cheapest grade of pump fuel without pinking.

The big valve head (not radically ported) and fast street cam do quite well with stock intake and exhaust. Before you get more radical with parts and tuning, keep in mind that such modifications are synergistic, meaning the total may be more than the sum of the parts if done right. Doing one substantial modification alone, like radical porting of the head, may not do much by itself, and could even reduce performance if not done in proper harmony with other mods.
Barney Gaylord

This thread was discussed between 02/07/2007 and 11/07/2007

MG MGA index

This thread is from the archive. The Live MG MGA BBS is active now.