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Re: '74 R90S crankshaft in R60/5 engine case ?
Posted: Sat Aug 21, 2010 2:24 am
by KenHawk
Lasse wrote:900cc. Would the R60 cam work good on a 900 kit?
From all reports an R60 cam is not a very good choice for use with the larger engines. Use a 308 as specified by the factory.
crank grinding
Posted: Sat Aug 21, 2010 10:29 am
by vanzen
I will say that re-ground crank failure will often be the result
of failure to properly heat-treat the re-ground journals.
(heat-treating does not penetrate the surface very deep, regrinding removes that treated material)
Proper radiusing of the corners of the journals is also an often overlooked feature of a re-ground shaft.
Best to find a good used crank in any event – and they are pretty damn sturdy items !
Re: '74 R90S crankshaft in R60/5 engine case ?
Posted: Sat Aug 21, 2010 7:36 pm
by gspd
+1
But somebody on the planet must be reginding 247 cranks properly.
BMW has been listing oversize bearings forever and they could have no other use.
Re: '74 R90S crankshaft in R60/5 engine case ?
Posted: Sat Aug 21, 2010 8:01 pm
by ME 109
Is regrinding worth the risk when a good s/h crank can be found for perhaps the same $ as a re-grind?
I would go for peace of mind, and not wonder if the crank was going to break every time I hit red line.
Not that red line is any particular 'breaking point'
Re: '74 R90S crankshaft in R60/5 engine case ?
Posted: Sat Aug 21, 2010 9:01 pm
by gspd
I don't have that problem,
my new VDO tach has no redline.
I've always ignored it anyway, but t's less scary this way.
