Having two K3500 CC/LB trucks in the family ('89 & '91), and having recently been "gifted" with three 6.2L diesel engines ("660" block ID), by my friend who's moving to the lower-48, I've been trying to educate myself on the subject of crankshafts. We plan on keeping these trucks until they rust out from under us.
What I'm hoping I can do:
1) - Build two 6.2L engines with NEW crankshafts. (Reliable bottom ends that won't leave us stranded with broken cranks, hundreds of miles from the nearest help.)
2) - Build for fuel economy - NOT power.
Problems:
1) - Cannot find NEW cranks for use in the "660" blocks. (Forged steel or nodular cast iron.) These blocks utilize the two-piece rear main seal. All NEW cranks that are marketed are for the "599" and newer blocks, which utilize the one-piece seal.
2) - Used two-piece seal cranks (nodular iron) available all have 100k+ of miles on them. And living where I do (Fairbanks, Alaska) these cranks have likely seen the equivalent of MANY more miles, due to all the wintertime idling.
I've read so many horror stories about broken cranks, and on one of the engines I was given, the crank is broken outside the engine where the harmonic balancer (damper) mounts. I'm aware the blocks are weak. I'm also aware of the need to use a GOOD balancer, and to try to keep the POP pressures close on each cylinder, to minimize any damage to the crank.
Possible Solution:
I've read somewhere that one of the forum members (MaxPF) purchased a new-old-stock, one-piece seal GM crank, and machined the read end of it to work in a 6.2L two-piece seal block. Therefore, I know it's possible to make a NEW crank work in these old "660" blocks.
I was thinking of buying a NEW one-piece seal forged crank, and having it machined to fit. If I had this work done, I'm not sure how well the lack of a large-diameter oil slinger ring would work out.
Questions:
Does this solution have drawbacks? Durability issues? Too expensive?
What say you?
-Nacla
What I'm hoping I can do:
1) - Build two 6.2L engines with NEW crankshafts. (Reliable bottom ends that won't leave us stranded with broken cranks, hundreds of miles from the nearest help.)
2) - Build for fuel economy - NOT power.
Problems:
1) - Cannot find NEW cranks for use in the "660" blocks. (Forged steel or nodular cast iron.) These blocks utilize the two-piece rear main seal. All NEW cranks that are marketed are for the "599" and newer blocks, which utilize the one-piece seal.
2) - Used two-piece seal cranks (nodular iron) available all have 100k+ of miles on them. And living where I do (Fairbanks, Alaska) these cranks have likely seen the equivalent of MANY more miles, due to all the wintertime idling.
I've read so many horror stories about broken cranks, and on one of the engines I was given, the crank is broken outside the engine where the harmonic balancer (damper) mounts. I'm aware the blocks are weak. I'm also aware of the need to use a GOOD balancer, and to try to keep the POP pressures close on each cylinder, to minimize any damage to the crank.
Possible Solution:
I've read somewhere that one of the forum members (MaxPF) purchased a new-old-stock, one-piece seal GM crank, and machined the read end of it to work in a 6.2L two-piece seal block. Therefore, I know it's possible to make a NEW crank work in these old "660" blocks.
I was thinking of buying a NEW one-piece seal forged crank, and having it machined to fit. If I had this work done, I'm not sure how well the lack of a large-diameter oil slinger ring would work out.
Questions:
Does this solution have drawbacks? Durability issues? Too expensive?
What say you?
-Nacla
