Smellsofbikes...Some other MG owners that have done the conversion did modify the oil pan. It all depends how far back you push the engine. The smaller tubular crossmember that holds the steering rack does need to be cut regardless in order to provide clearance for the crankshaft pulley. Some have spared the main crossmember and have gone with a modified oil pan. The guy that will be doing my chassis work will look at how to make it work with the least amount of cutting. Will report back on all that at a later time.

Thaifrog...... Your the same guy with the Austin Healey on the MG Experience website? Great site here to get the information I need for my conversion. Gave up on finding a dogleg 5 speed 60 series gearbox. Only offered in 1979 from what I have read on this forum. Not many salvage Datsun cars in the North Texas area but did locate an H pattern 5 speed 60 series gearbox from a 1981 sedan. Happy with my find and ready to get this project moving along. Holiday season will likely slow things down. Thanks for the oil filter tip.

Thanks for the info Tom. If I didnt have end play on my crankshaft I could probably get away with doing a complete rebuild in my shop based on all the information I have so far. These Datsun engines are impressive to say the least. I will disassemble the GX head and check how the valves seat in the ports as well as check the guides. The block has 200,000 miles and will be interesting to see if the machine shop recommends boring. It looks in real good condition and the crankshaft turns freely. What I dont want is a blue smoke coming out the exhaust. That is my problem now with the British motor. 95 HP may be a bit much for the British differential. If that is what I end up with I'll have to be careful with hard accelerations. The original stock motor is a whopping 65HP.

So I attached images of 3 pressure plates and 3 clutches and noted the markings. As you can see the 1981 pressure plate housing has more metal. Any reason why? The 1982 and 1972 PP are similar but different. Are these parts salvageable or should I just replace both PP and clutch along with the throwout bearing? Can I salvage the A12 flywheel, have it lightened and then get a new clutch and PP to match it as you suggest staying with the A12 flywheel?

Left -1982 B310 sedan- no marks on clutch, Luk pressure plate
Middle -1981 B310 sedan-Nissan clutch (180CBL), Ampco pressure plate
Right - 1972 sedan - Valeo clutch (made in Korea), no marks on pressure plate

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Well these A series engines continue to amaze me. According to my application, the Flywheel link says that lightening is for racing applications. Would I benefit from doing this for street use? It does say that the flywheels are interchangeable. For my purpose, would you recommend putting the A12 flywheel on the A15 engine? It is 2.2 lbs lighter. I do recall the clutch and pressure plate are different diameters. So I would use the A15 clutch and pressure plate on the A12 flywheel?

So the datsun conversion may turn out to be a little lighter than the stock british engine/transmission?? Not sure why other MG owners installed heavier coil springs in the front. I can see the reason for better braking capability with the larger engine displacement and more HP. Will have to look into this a little more. Any thoughts on lightening the flywheel?

Well checked some MG websites and the car is around 1600lb, the 1275cc engine is around 260lb and the transmission around 45lbs. Cant say for certain on the engine weight. It is all iron however, including the cylinder head. I would expect the A15 is heavier than the British 1275 motor. Also will be using a 60 series 5 speed transmission. It seems comparable to the MG transmission. Other MG owners that did the datsun engine conversion used heavier front coil springs and some did install larger front disk brake calipers. Also someone suggested to lighten the flywheel since the datsun B310 car is heavier than the Midget. I was going to ask this question at a later time to ddgonzal but maybe you can offer some suggestions on doing this. Does the flywheel have to be balanced with the crankshaft if it is lightened? Would a machine shop simply shave off some metal on one side of the flywheel? I haven't done this before. Thanks for any information.

Thanks for all the information. I will pass this on to the machine shop to check the springs. He will also be repairing the end play on the crankshaft as well as checking the bearings. The H7240 head is still in the car at a salvage yard and the only way to make any port measurements is if I buy the engine, which I will pass up on. Talking with other MG owners, the only real desirable heads for the A series engine appears to be the H89 or GX. Will post follow up questions as they come up.

Much thanks ddgonzal! The following is a continuation of the previous questions....

1. Is there a link on this forum for measuring CC?
2. Replace crankshaft main bearings? Do the piston rods have bearings and replace them as well?
3. OK
4. OK
5. Measured 11mm. So go ahead with swapping out the A12 gears and chain? Should I replace the tensioner?
6. OK
7. http://datsun1200.com/modules/mediawi ... ?title=Valve_springs...is this the link for checking the springs?
8. OK. I would expect to replace valve guides but will use the method described on the link. I did use a straight edge and couldnt see any gaps. It looked real flat. Will get a more accurate straight edge and use the feeler gauge test. Does the rocker assembly require anything?
9. OK
10. OK

Do I take the engine block to a machine shop and have them dip it into a solvent tank to clean the inside? Will that harm the cam bearings?


Also........I have been rummaging salvage yards in the North Texas area and came across a cylinder head from a 1974 B210 car (80 HP engine). I know about the H72 head but this one has 4 digits H7240. Does this mean anything? My intentions are to accumulate hard to get Datsun parts that are worthy in the event I want to take on another project. There aren't many Datsun cars left.

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Thanks DDgonzal! I have 10 more questions (for now....... :

1. If cylinder bore is ok, can I reuse pistons and simply hone and replace rings? No need to replace pistons with this size dish that is matched up with GX head?
2. Turn crankshaft and replace bearings. I have some end play, which will need to be repaired?
3. Replace camshaft and lifters as you noted. Install new cam bearings. Can I reuse the pushrods from the A15 cylinder head?
4. Do I replace freeze plugs?
5. http://datsun1200.com/modules/mediawi ... shaft_replacement....This link indicates more than 15mm extension of the tensioner replace the timing chain. If so, can I reuse the gears or replace both gears as well?
6. Replace oil pump?
7. Expect to replace all GX head valve springs?
8. Will plan to get the cylinder head rebuilt. Any advice here? History of A12 engine is unknown.
9. Will the GX exhaust manifold work that I show in the pictures? Is this the stock GX exhaust? I couldnt believe what someone was asking for this in the classified section.
10. Carbs will need to be rebuilt. Any additional information on these based on what you see in the pictures?

Any response would be greatly appreciated. I am sure I will have many more questions later on. I did have an opportunity to talk with Peter Zekert and he advised not to bother with dipping the block in any harsh chemicals when it goes to a machine shop and not to replace any freeze plugs. The A series blocks have longevity and dont require much if your wanting only a mild rebuild. Let me know what you think about that.

BTW, history on the 72 coupe is that the previous owner bought the car for the body only and put a 240sx motor in it and was parting with the A12 engine and transmission. Unfortunately its the 4 speed. I have read where the 5 speed GX transmission is very rare.

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Hello Datsun1200 members....1st post but very familiar with the site. I have come to the conclusion to transform my 72 MG Midget into a Japanese/British hybrid car. The A series engine is an excellent choice as suggested by many MG owners. I was directed to this site for expertise in rebuilding and identifying parts as I accumulate them. By reading numerous threads, I have definitely come to the right place and hope I get the help I need as I move along. My intentions are no more than 80-90 HP and a mild rebuild with twin carbs I picked up from an A12 motor. First order of business is fabricating motor mounts and other modifications to the chassis but want to get some engine information as the chassis work gets done so that it can go to a machine shop afterwards.

I have acquired an A15 engine from a 1982 B310 car (pic attached) which had about 200K miles and surprisingly the motor turned freely and the cylinders appear to be real good shape. Even the timing gears look to be in good condition. The H95 head will sit on the shelf and be replaced with a GX head (I think) from another purchase. Reading the 1200 tech data, it does appear to be the GX head. No numbers are stamped on top, only Japan Nissan. Also have the intake and exhaust manifold. This all came from a 1972 Coupe. My concern is that the engine does not have a dual point distributor. Is it a GX head?

My understanding is that the A series cylinder heads are interchangeable with the different blocks. I read on one of the threads that an oil passage hole has to be drilled if a GX head is used with the A15 block. Any information on this would be appreciated as well as camshaft modification and other rebuild advice. Can I use the lifters that were used with the H95 head? Enough said for now and will wait for replies and post more pictures later. Thanks.

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