SOHC.co.uk Forums > CB350/400
400 four main bearings - will need replacement STD bearings.
Nurse Julie:
Indeed that is green one Ted.
McCabe-Thiele (Ted):
--- Quote from: Oddjob on March 21, 2021, 03:31:37 PM ---Whatever you do Ted don't mix the shells or forget where they came from.
As Julie says that definitely a green, so that journal requires a green pair of shells. You could use the back of the shell markings and see if the one you've identified is the same as the rest. They tended to use the same marks for the same colour for the same production run, so if any other shells match that marking it's reasonable to assume that's a green shell as well. The conrod shells use the same method so check the side of those for colours as well.
--- End quote ---
Good point so far they are all still in the right position but I will record them when I take the crank out - looking at the meaningless codes on the 5 shells they are D6H-A,D6I-A,D6T-A,D6I-A & D6H-A that means they mix the colours on an individual crank bearing. The Green one is D6I-A there are two with this colour journal 2 & 4.
Bryanj:
They NEVER mix colours on one pin but different colours on different pins is common.
Non of the numbers on the shells mean anything apart from production code, last thing done in production is measure thickness to 0.001mm and colour code them
McCabe-Thiele (Ted):
--- Quote from: Bryanj on March 21, 2021, 04:34:35 PM ---They NEVER mix colours on one pin but different colours on different pins is common.
Non of the numbers on the shells mean anything apart from production code, last thing done in production is measure thickness to 0.001mm and colour code them
--- End quote ---
I'm learning here I have never encountered a car with such complications as different coded journals on the same crank - wonder why STD didn't mean just that with oversize being +0.1 or whatever.
K2-K6:
"I'm learning here I have never encountered a car with such complications as different coded journals on the same crank - wonder why STD didn't mean just that with oversize being +0.1 or whatever."
It is, in essence, a view of the lengths they went to in production tolerancing. Ordinarily in most process as it advances the tolerances are accumilative (unless by happy accident one error cancels another) with the accepted machine accuracy and repeatability available producing the components being recognized, the range of 5 different shell dimensions is planned to compensate for that process capability. It effectively pulls all of that production line tolerance back to as close to zero that they could get it.
In terms of "old money" a BMC A series built with en40b crank fully balanced, ground, nitrided, micro polished to perfection, with rods balanced end to end and rod to rod, etc etc, effectively the best hand finished blue printing only gets close to what these engines came off the production line as absolute standard. With near 100bhp/litre and usually ten thousand rpm ceiling to go with it, that really shows just how good this design and production was, that's in mid to late sixties and early seventies, there's nothing that came close to them.
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