ABC valve guides

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2 years 5 months ago #1205 by Dabney
Replied by Dabney on topic ABC valve guides
Peter,
As always they look excellent - hope my lathe work is 1/2 as good,
best wishes
Ian

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2 years 3 months ago #1213 by Guy ABC
Replied by Guy ABC on topic ABC valve guides
Love the valve guides in the pic.

I made mine out of cast iron. No expansion issues as they do run pretty hot, especially here in the tropis. My Dad said you could see the exhaust end of the head glowing on a dark night in summer. New SS valves is the go with commensuratly small stems helps lighten the load on the 'knitting needle' push rods. (Thats what mine are, great Grandmas knitters)

Also the little 'hats' under the springs should stop any desire for the guides to move. I liberaly rubbed colloidal graphite into the guides after machining. No oil to collect dirt and rubbish, just dry graphite. Seems ok so far.

Regards

Guy

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2 years 3 months ago #1215 by Peter Gillespie
Replied by Peter Gillespie on topic ABC valve guides
Hi Guy
The little Hats are insulators, trying to stop all that heat getting to the valve springs.
For interest which valves did you use?
Regards
Peter

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2 years 3 months ago #1216 by Dabney
Replied by Dabney on topic ABC valve guides
I am also keen to find out if another owner has found an equivalent valve to replace worn ones. We had a major failure when a valve pin was lost at high rpm on the 500 Bradshaw twin engine, with a similar valve retention design. The valve went into the cylinder, destroyed itself, the piston, the conrod and big end. Picture of valve attached. We subsequently converted that machine to use tapered collars.
best wishes
Ian
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2 years 2 months ago #1279 by Tony
Replied by Tony on topic ABC valve guides
Hi
I have just started to look at my ABC ( recent purchase ) and have found a mess in the barrels etc , one thing the engineers shop mentioned when I showed them the heads that the valve guides were worn , so before I go down the route of having some made .Peter are those guides for sale ? Tony .email
tcrumpy2@gmail.com thanks new to this so hope I haven't stepped out of line ?

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2 years 2 months ago #1281 by Dabney
Replied by Dabney on topic ABC valve guides
Tony,
If you are having some guides made I would recommend using cast iron, not bronze. I have had valves nip up on track runs using bronze guides. Also I am pretty generous with the clearance between stem and guide. If new, I use 4 thou on inlet, 6 thou on exhaust. I would not replace unless wear greater than 6 thou inlet and 10 thou exhaust. best wishes
Ian

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