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Sensei's B6 rebuild and swap
My friend Brad (FF member Sensei) picked up a nice 93 GL a while back. The paint is faded but the body and interior are in great shape. The major mechanical problem? Tons of blow-by! If you pull the oil filler cap and dipstick and then crank the car you get a nice plume of white smoke shooting out of both holes. We had a vid of it somewhere that was pretty hilarious 
Since the motor needed rebuilding he opted for a little more power so we sourced a B6 from a 323 for his rebuild since it's almost a direct drop in. I didn't take any before pics of the motor during tear down but let me just say that the previous owner didn't seem worried about oil changes. Most of the rings were stuck and you could tell they either skipped or pushed an oil change or two. Luckily Mazda floods the engine with tons of oil pressure so the bearing surfaces were in decent shape.
This thread picks up after the engine was disassembled and hot tanked. We haven't removed the old B3 engine yet but I've started the rebuild process on the B6 so it will be sitting on the stand waiting to get installed when we take the old one out.
Here's a before pic of the engine bay with the old B3 still in the car.
Here's a couple of pics of the bare B6 block after I honed the cylinders, a thorough washing (to remove oil and rock dust from honing), and all gasket and bearing surfaces cleaned.
The crankshaft after a good cleaning and all the journals polished.
One of the pistons after a good cleaning. I really wish I had taken before pics of these. It took 3 good scrubbings with SuperClean to get them looking this good. I had to clean the oil ring holes with a drill bit because they were all completely plugged and all 3 ring lands were hideous. Also note the small scores on the piston skirt.
This is the same piston after going over it with a fine Scotchbrite pad to help polish out small scores, pits, and left over carbon deposits.
The next step will be to inspect/rebuild the oil pump, install new rings on the pistons, and start installing the internals back into the block.
Since the motor needed rebuilding he opted for a little more power so we sourced a B6 from a 323 for his rebuild since it's almost a direct drop in. I didn't take any before pics of the motor during tear down but let me just say that the previous owner didn't seem worried about oil changes. Most of the rings were stuck and you could tell they either skipped or pushed an oil change or two. Luckily Mazda floods the engine with tons of oil pressure so the bearing surfaces were in decent shape.
This thread picks up after the engine was disassembled and hot tanked. We haven't removed the old B3 engine yet but I've started the rebuild process on the B6 so it will be sitting on the stand waiting to get installed when we take the old one out.
Here's a before pic of the engine bay with the old B3 still in the car.
Here's a couple of pics of the bare B6 block after I honed the cylinders, a thorough washing (to remove oil and rock dust from honing), and all gasket and bearing surfaces cleaned.
The crankshaft after a good cleaning and all the journals polished.
One of the pistons after a good cleaning. I really wish I had taken before pics of these. It took 3 good scrubbings with SuperClean to get them looking this good. I had to clean the oil ring holes with a drill bit because they were all completely plugged and all 3 ring lands were hideous. Also note the small scores on the piston skirt.
This is the same piston after going over it with a fine Scotchbrite pad to help polish out small scores, pits, and left over carbon deposits.
The next step will be to inspect/rebuild the oil pump, install new rings on the pistons, and start installing the internals back into the block.
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