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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These are just different manufacturers. Same diameter. I notice they are all high-quality 6-spring discs (cheap discs use 4 rubber springs).

You can reuse the clutch disk if they aren't worn down too much (examine the depth to the rivets). Also make sure the springs are still tight. Valeo is good quality from my experience.

You can reuse the pressure plate, if not crazed or heat marked. The A15 pressure plate can be used, regardless of which flywheel you use. The Ampco is Nissan OEM, so it will have a specific rating. Aftermarket A12 plates may be stiff enough for A15 use.
* B310 A12A: 573-684 pounds
* B310 14/A15: 739-849 pounds

Texasmidget I am familiar with Sprigets and 1275 A-series motors. The run group I'm in at the vintage races has several Sprigets and I have a couple of friends who own them. The ring gear is rather small much like the 1200 which is roughly a 5 11/16 ring gear. The fastest 1275 cars are putting out around 110hp to the rear wheels. The rear end housings look stock but I know they have heavily modified internals. Some the cars are using $5000 Hewland gearboxes so I expect the diffs are similar high end stuff as well.

As for the clutches pictures I'd run which ever has the most meat left on it. If you can get the 1200 flywheel turned cheaply then go for it otherwise just bolt it on.

Tom

I put an A14 in a Spitfire. Some things to consider about getting the engine in the frame and under the hood: 1200 and a lot of A14/15 engines had front sump oil pans, and that sits right in the middle of the frame cross member that joins the front suspension towers on Spits and Midgets. Some B210's had mid-sump oil pans, and that'll get your engine 15cm lower by itself. (Get the matching oil pickup tube as well.) I ended up chopping the front out of the oilpan and welding in the back of a front-sump pan, so there is only enough clearance for the crank. That got me another 10cm. If you can move the engine so far back that the sump is behind that cross brace, you can drop it way down. I don't know how the frame rails are on the Midget, but I couldn't push an engine back as far as I wanted because the 60-series transmission wouldn't fit between the rails anymore.
The position of the oil pump, and specifically the filter, also was kind of terrible for a low/back placement. I ended up going with a remote oil filter, the filter itself on the backside of the front bumper, and that helped tremendously. The drag is that to mount/unmount the oil pump side of the remote, I have to remove the oil pump, to screw the adapter on, but in theory that should be a one-time thing.
It's way easier if you have a RHD midget. LHD means the exhaust wants to be just about where the steering linkages are (and you can't scoot off to the right because of the oil pump.)

And yeah the A14 is way lighter than the stock Brit engines, and the result is quite nice when you get it running.

By the way, expect some excitement the first time you let the clutch out: british master cylinders don't talk all that well to datsun slave cylinders, so you get full engagement in a couple cm of clutch pedal movement and it's pretty neck-snapping.

depending on how far forward or back you position the engine the oil filter can clash with the suspension mounting gussets.
I got around it by using a small filter from Toyota.

See picture attached of :
Large filter which came with the engine
Medium filter which is what i was given at the motor factors before realising i had a clearance issue
Small toyota filter i ended up using.

Also picture of the box from the small one for the part number

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Good find! I see that 90915-YZZE1 has a 3/4-16 UNF thread, same as Datsun. Length is 80 mm - shorter than the shortest Nissan A-series filter (100 mm). The original Datsun 1200 filter was 145 mm long.

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.

most jap cars have interchangeable thread and sealing o-ring diameters.
I used a ford Z9 monster with anti drain back valve on my old Camper Toyota 2L L4 pushrod antiquity with very good oil life extension.

I can't get a good shot of the chopped oil pan, but here are shots of the spitfire installation and a closeup of the oil pump remote filter adapter and the lack of clearance between it and the right shock tower. There's about 2mm of clearance between the filter and the shock tower, and on the other side 3mm of clearance between the exhaust and the steering shaft, and on the bottom, about 3mm of clearance between the pan and the steering rack.

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