Author Topic: 1969 CL350 Kibblewhite Black Diamond valves  (Read 746 times)

Offline neildavies67

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1969 CL350 Kibblewhite Black Diamond valves
« on: May 08, 2018, 07:30:45 AM »
Hi, has anyone had any experience of replacing their standard oem valves with Kibblewhite "black diamond" valves? The inlet is 1mm oversize (35mm) and I am unsure whether I would need the valve seat cut to accommodate the 1mm over or whether you could "lap" them in? Any thoughts or tales of woe hard earned through experience greatly appreciated! Cheers!
1969 CL350 (in pieces - for now)

Offline Trigger

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Re: 1969 CL350 Kibblewhite Black Diamond valves
« Reply #1 on: May 08, 2018, 07:51:37 PM »
I don't have too much experience on the 350 head but, I know that Kibblewhite valves are stainless steel and S/S is soft. Not really suitable on a air cooled engine  ;)

Offline neildavies67

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Re: 1969 CL350 Kibblewhite Black Diamond valves
« Reply #2 on: May 08, 2018, 09:18:04 PM »
Thanks for the info Trigger, it just led me down the rabbit hole into the land of valves and metallurgy! My brain is well fried now. Apparently, Kibblewhite black diamond valves are made from EV8 stainless which, if I read correctly, is an alloy commonly used in performance engines for exhaust valves and is also known as 21-4N (EV8). The full article can be found here: http://www.enginebuildermag.com/2005/12/valve-selection-hot-valve-materials-for-hot-engines/
I'm not 100% but I think this means that they should be ok for intake valves? (although the article mentions different characteristics preferable in intake and exhaust valves). The guy that sells these valves races classics in the TT so I assume that they must be ok but admittedly, he may just replace them at the start of each season! I didn't ask him but I will now. Does anyone know what material/alloy factory fitted valves are made from? Cheers.
1969 CL350 (in pieces - for now)

Offline Trigger

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Re: 1969 CL350 Kibblewhite Black Diamond valves
« Reply #3 on: May 08, 2018, 09:59:48 PM »
Most non racing valves are SUH3 in old cars, not sure about a CL.
The problem with a lot of motorsport engine builders is, a lot of engines are rebuilt after every race these days. They must keep the engine at top reliability and performance  ;)

This should make things a bit more simple >>>http://www.kalyanicarpenter.com/products/valve-steel/
« Last Edit: May 08, 2018, 10:11:06 PM by Trigger »

Offline Trigger

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Re: 1969 CL350 Kibblewhite Black Diamond valves
« Reply #4 on: May 09, 2018, 07:01:55 AM »
Did a little research in to these valves and the DSS repro valves I think are  21-4N at not a bad price.

Offline neildavies67

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Re: 1969 CL350 Kibblewhite Black Diamond valves
« Reply #5 on: May 09, 2018, 09:30:26 AM »
Yeah, I called them the other day. Not in stock at the moment and no idea when they will be! Maybe I should have got me a unicorn, spares would have been easier to find  :o CMSNL have Honda valves for a combined cost of about £160! Ouch!
1969 CL350 (in pieces - for now)

Offline neildavies67

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Re: 1969 CL350 Kibblewhite Black Diamond valves
« Reply #6 on: May 14, 2018, 06:46:38 AM »
So, a forum member has generously sold me a set of nos CYB350/250 valves for a very reasonable price! Big thanks to that member! On to the next problem...
1969 CL350 (in pieces - for now)

 

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