Tom..yes replacing the synchros as pictured. There are 5. Not sure what I am getting into here. Will have to go real slow and take lots of pictures along the way. First time ever opening up a gearbox like this. Engine is in the machine shop and will take several more weeks so have time to get the gearbox done. Sent the cam off to Isky. Datsun guys here recommended them. Called their tech (Rob) and he seemed very knowledgeable about the A series engines. It will be a very similar grind (260/.425) as to what you got from Delta. He referred to it as a mild street cam.

DD...got this kit from a supplier here in the states that rebuilds them himself. Paid $199 with the synchros. Looks to be quality bearings (made in Japan). You familiar with the brand? I think he sent me an extra main input shaft bearing. There are two of those and two smaller ones, total of 4 and two needle bearings. I can only see two roller bearings with the gear assembly all together. Once I get this opened up, I will post back with questions/comments.

Thanks Andy. Set a block of wood on the end of the main input shaft and after several blows with the rubber hammer it backed out of the transmission case. There was no way this was going to come out by holding the gear assembly and hitting the backside of housing as the service manual calls for. That main bearing is really set in there good. The shop that sold me the kit also repairs these transmissions and he does the same thing. All the gears look in great shape. Kudos to Nissan once again. The main bearing is the only one that seems to require replacement but will change all of them out since I have the entire kit. I attached a close up of the bearings and seal for your reference. The seal appears to be made in Taiwan and the bearings in Japan.

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Attempting to go through my transmission to replace bearings. Received the bearing kit and also have a copy of the original PDF service manual. Trying to separate the transmission case from the adapter plate (step 12 from service manual). I can get them separated by about 1/2 inch and then it gets hung up. Dont want to put to much blunt force on the transmission case with the rubber hammer. Also as I was pushing/pulling the gear assembly gently to try and separate them, one of the fork rods slid towards the transmission case and now the gears will not turn. Hope I havent damaged anything. All the gear components look in good shape from what I can see with the rear extension assembly off. Any help on this would be greatly appreciated.

I agree with you. Will see what the machine shop says. Are the grooves in the Cam bearing ok? And is the yellowish color on the pistons normal? When I disassembled the motor, I noticed a couple of the coolant passageways in the H89 head were clogged with a white substance and the water pump was seized. This motor likely overheated and dont know the extent of any damage, if any. After removing the valve springs, I had to tap out several of the intake valves from the valve guides. All the others came out good and felt snug. Will replace all valve stem seals.

Ok DD....you got me thinking about aftermarket bearings. I checked the tolerances for the main and rod bearings and they are all within specifications .038mm to .051mm which are the two closest measurements on the plastigage scale (Haynes manual has a maximum of .060mm for the rod clearance and tech wiki shows a maximum of 0.50mm ???). They all look in real good shape unless you see something out of the ordinary. No significant scratches that I can see. I dont mind spending money on a rebuild but if these bearings truly do last 500K miles and they are OEM Nissan parts, I may just put them back in the motor. I will have the machine shop polish them along with the crankshaft. The cam bearing closest to the timing chain has a couple grooves. Is this normal and some sort of oil passageway? this same bearing has a slight scratch which I hope can be polished out. Also all of the pistons has a slight yellowish color as pictured. Any concerns here? Everything goes to the machine shop tomorrow. Will have them mic the crankshaft and cylinder bores and get everything cleaned up including the GX and H89 head. And turn the flywheel. Will report back later.

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58custom (Tom)...thanks for the explanation on the imported motors. And I did take your advice (pop off the valve covers) and got lucky with this H89 head. I have enough parts now to build two engines.

Tom...I have been thinking about building a race motor with the spare A12 I have. But will save that for another day. Have my hands full at the moment with the A15 conversion on the MG. Bearings look ok for the A15 but may go ahead with replacing all of them. There are kits on ebay that are fairly reasonable which includes rings and bearings. Is there another supplier that sells good rebuild kits? Rockauto seems to be popular. Want to make sure I get quality parts.

DD....oval ports for the H89 head pictured on the bottom in the photo. Measures approximately 35mmx29.25mm(+-), compared to the GX 39mmx30mm. I read Tech Wiki and it says 36mmx30mm for the GX head?? I dont think this one was modified. Used calipers on the manifold side to measure the oval ports. Should I be measuring on the inside of the port?

H89 head is closed chamber and is highly sought after by MG enthusiast for the nissan conversion. I got real lucky finding both in the North Texas area.

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Thanks Tom. I can still use regular unleaded fuel with that ratio?

Ok guys. I got a more accurate syringe at a feed store and its in ml which is equivalent to cc. Measured it several times. GX head is 28 ml/cc and the piston dish is 13 ml/cc. Can someone run the numbers for me? I really prefer not to use premium gas if I dont have to. But DD makes an interesting point that if I have higher compression it will get better fuel economy which makes it a wash.

You guys may notice I am a novice at all this but slowly picking up alot along the way and will be better prepared for my next build. I have worked on a variety of automobiles for many years but not with the technical components (cam lift/duration, compression etc) of an internal combustion engine. You all must be engineers.......

Well no idea how it ran. I pulled it from this salvage 1981 210 wagon. I had no intentions of getting another A15 motor while I was looking for a 5 speed 60 series transmission but what caught my interest was the oil filler cap. Is this a JDM motor? I popped the valve cover off and it had the rare H89 head (single spring). So took it home. A problem I see with this motor is that the water pump was seized with alot of crud. And when I went to take the head off, one of the bolts (#1) was very difficult to remove. Finally worked it loose. The bolt also had some crud on it. Likely overheated and maybe caused damage? The head surface is flat and dont see any signs of a cracked or damaged head. The motor turns freely and the crank has less end play than my other A15 motor so I plan to go through it and give it a refresh. Still can see the original cross hatches. I will be taking it to a machine shop to get it cleaned with a good detergent (no harsh chemicals) and they will spec out the bore for me. If its good, I will have them hone it out. Its a toss up to go with either the GX head or H89 head but will likely stay with the GX head for this build.

If this is a JDM motor any idea how it ended up in North Texas??

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Ok understand DD. The bearing clearance specs is what I compare to the plastigauge results. So how about the side to side play on the piston rods? It's not much but noticeable. Is that normal?