Slant Six Forum :: Slant Six Cranks

Hmmmm.....the plot thickens more. Good article on the /6's - thanks for the tip and timely info, Josh. By the engine stamp # on the block, then, it appears quite likely it is the original motor for the '73 car. I see 2 possibilities explaining the dilemma: 1) Either the guy who sold me the car rebuilt the motor (or else had it rebuilt) incorrectly with a cast crank, or 2) The machine shop botched the job and tried to fit the block with a cast crank (and different bearings). The engine bore technician told me last week there was some problem with fitting the bearings (which had to be reordered), so I'm betting on #2 but I'll hear what the shop owner has to say tomorrow. In either case, though, I don't think I should accept the work. If there were issues/ problems/ questions encountered during the job, he either should have done a little homework and/ or let me know what was going on before he went ahead and did any "creative engineering." The fact that he was "incommunicado" lends me to think something went seriously wrong here. I'll keep you posted regarding the outcome.

Author:	Charrlie_S [ Mon Jul 03, 2006 2:51 am ]
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Quote: :?The machine shop botched the job and tried to fit the block with a cast crank (and different bearings). The engine bore technician told me last week there was some problem with fitting the bearings (which had to be reordered), . As stated before, It is not possible to fit a cast crank/bearings into a forged crank block. The connecting rods are different, also. It was more likely, a preliminary inspection, indicated the crank needed to be turned "X" thousand, and the proper beaing for that size were ordered. When the crank was ground at the crank shop, it was found to need a different size bearing, so new ones needed to be ordered. Or possibly the bearings that were ordered, were found to have a problem (wrong size in the box).

Author:	Joshie225 [ Mon Jul 03, 2006 7:13 am ]
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One more time since it doesn't seem to be sinking in. You cannot fit a cast crank into that block. The main bearings are wider on the forged crank block and will not allow the cast crank to drop in. Quote: Hmmmm.....the plot thickens more. Good article on the /6's - thanks for the tip and timely info, Josh. By the engine stamp # on the block, then, it appears quite likely it is the original motor for the '73 car. I see 2 possibilities explaining the dilemma: 1) Either the guy who sold me the car rebuilt the motor (or else had it rebuilt) incorrectly with a cast crank, or 2) The machine shop botched the job and tried to fit the block with a cast crank (and different bearings). The engine bore technician told me last week there was some problem with fitting the bearings (which had to be reordered), so I'm betting on #2 but I'll hear what the shop owner has to say tomorrow. In either case, though, I don't think I should accept the work. If there were issues/ problems/ questions encountered during the job, he either should have done a little homework and/ or let me know what was going on before he went ahead and did any "creative engineering." The fact that he was "incommunicado" lends me to think something went seriously wrong here. I'll keep you posted regarding the outcome.

Author:	blake lewis [ Mon Jul 03, 2006 7:35 am ]
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OK, I think I got the point. The rebuilder just told me the crank was forged, not cast. He's still got the cast bearings from the kit in the box. What is still puzzling me though, is why are there foundry spots on the bottom "flanges" of the crank - is this just a different casting process used with this crank that may be due to the "BH" designation of the motor (instead of the "BF" on my '72 block)?

Author:	sandy in BC [ Mon Jul 03, 2006 8:51 am ]
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I dont know a whole lot about cranks....but I wont let that stop me from mouthing off. forged cranks will have marks or little flanges from the forging process. A large chunk of metal is literally pounded into the shape of a crank then the journals are machined. This pounding is done in big freekin dies in a number of steps....some pound marks or squish flanges are normal. Dont read to much into the BF or BH marks on the block,,,,BH is a good block that requires a forged crank,,,,,I have one in my car. When they did the crank in my car they ordered new bearings....for a cast crank. The bearings had to be reordered which took some time. I think you are encountering the normal insurmountable difficulties one finds when dealing with an ancient motor in a modern machine shop. If the guys are good it will all work out. BH block= forged crank with attendant rods and bearings.

Author:	blake lewis [ Mon Jul 03, 2006 10:05 am ]
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I just squared everything with the shop guy. He was a little "honked" that I stopped payment on the check. I'm just very grateful he didn't deposit it and write more checks on it before he went on vacation! So, sandy in BC how did you waste such a sweet ride?

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Author:	sandy in BC [ Mon Jul 03, 2006 10:41 am ]
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Its a waste when it sits in the driveway for weeks at a time while I work. Some people think I destroyed the car with the mods Ive done.\\\ Its not as sweet as you think.. It is a class winner in the Pro-Beater category.

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