A few months back i aquired a D722 engine that had a broken crank. I was told it hadn't done much work (which it hadn't, the bores still had cross hatching marks). I was speaking to a buddy last week and he said he had one that had a knock, used oil and smoked that i could have. I promptly picked it up and on the weekend pulled them both down to try and make one out of 2. For a secondhand crank they wanted $800 for!
It seems the one with the broken crank was run out of oil, all the centre main bearings had been spun BADLY and i can only assume the slop allowed the crank to flex and snap.
Long story short, i swapped cranks and big end bearings and it now works a treat! it will even start on compression alone. This on an in-direct injection engine is pretty good. Total cost of $0, i even managed to use the old head gasket sprayed with Hylomar (if thats how you spell it).
I found out what caused the smoke and knock in the engine with the good crank, the nozzle tip in the injector on number 3 was stuck inwards making the fuel drip and not spray. It has eroded a crater into the top of the piston, i had only heard that leaky injectors will melt the top of pistons. I can now confirm this! ensure your injectors are in good shape or you WILL do damage to your pistons.
I will post pictures when time allows, if anyone wants to see it that is.
It seems the one with the broken crank was run out of oil, all the centre main bearings had been spun BADLY and i can only assume the slop allowed the crank to flex and snap.
Long story short, i swapped cranks and big end bearings and it now works a treat! it will even start on compression alone. This on an in-direct injection engine is pretty good. Total cost of $0, i even managed to use the old head gasket sprayed with Hylomar (if thats how you spell it).
I found out what caused the smoke and knock in the engine with the good crank, the nozzle tip in the injector on number 3 was stuck inwards making the fuel drip and not spray. It has eroded a crater into the top of the piston, i had only heard that leaky injectors will melt the top of pistons. I can now confirm this! ensure your injectors are in good shape or you WILL do damage to your pistons.
I will post pictures when time allows, if anyone wants to see it that is.