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matix99def
07-12-2012, 7:50 PM
my buddy has had crazy problems with his crank. ended up having to ship it from manitoba to texas to get it hardchromed and re specced and when the speced the journals both have a taper to the same side. and he was told way back that was a common problem back in the 60-70s with triumph cranks and said they came factory like that. so he can leave it or grind it down and order new bearings. but has anyone heard of the problem before?

Torch
07-13-2012, 9:50 AM
I've never ran into that, but I learn new shit every day.
cut them .010 under and be done with it.
but what is this stuff about hard chrome?... the journals are just a polished bearing surface, we do it all the time on our lathe at the shop.

TRUMPNUT
07-13-2012, 6:31 PM
That one is new to me and I do lots of cranks .

Trinda
07-14-2012, 11:11 AM
but what is this stuff about hard chrome?... the journals are just a polished bearing surface, we do it all the time on our lathe at the shop.

also curious about that.

Torch
07-14-2012, 3:54 PM
it kinda sounds like he's getting ' Hard Fucked"
we do an engine rebuild a week and we send many cranks in for machine work and my crank shop has never said that to me before.

Trinda
07-15-2012, 5:55 PM
it kinda sounds like he's getting ' Hard Fucked"
we do an engine rebuild a week and we send many cranks in for machine work and my crank shop has never said that to me before.

maybe so, but i could see advantages of hard chrome plated rod bearing journals, too. unnecessary, but they'd be smoother for longer should anything catastrophic happen inside the case.

Torch
07-15-2012, 6:23 PM
according to my research, Hard chroming is ok to build up journals on lower RPM engines but the extra hardness can cause the crank to crack at the ends of the journals because of the crank flex,(like a Triumph crank does).
hard chrome is not really good for engines that spin up to 6k and higher, and is usually used on rare cranks that need building up to be saved, there are oversize bearings available for Triumphs up to .040 oversize, so why do it ?

I've had a lot of Triumph cranks machined down, welded back up, balanced and turned and polished the crank shop I've used for years now (Marine Crank shaft Co.), I trust what David tells me and does, he has never told me about tapered journals and hard chroming.

I really think that guy just needs a different machine shop.

matix99def
07-19-2012, 5:58 PM
well british cycle told him to go there. he didnt chrome the journals just the crank i think then noticed the journals were tapered or something along those lines. hes had so many problems i forget what they were