the best Valve Guide Materials and Why

Vincent Brake

Well Known and Active Forum User
VOC Member
Now i have been using in the past 8%alu bronze, with tufrided (nitrided) valves (V3) whom are pretty hard like 700HV (Nimonic) for 2 thou. At both sides Hardness is there, but the guides are prone to rapid wear, as when no lubricant its not good to use. I started with about 0,001" play on the inlet and 2 for exhaust.
Now i have been looking up Mr Google, and hes come up with just Phospor bronze: 0.2-0.4Ph 8Sn, Colsibro: 2Ni, 0.6Si or as a best Ampco 45: 10Alu, 2.5Fe, 5Ni and 1Mn. Than it goes further to materials with a lot of Zn and Mn in it, where it is said that Mn in conjuction with ALu increases hardness. Zn: i guess used as with modern engins, seals, no side thrust (DO Cam), one needs still some lubricant, at witch Sn, Zn and e.g. Pb are very good.
some mention the use precipitation hardening, i presume if able one should do it, but will it hold at an exhaust guide?

i forget about cast iron as the heat expansion in alu does not match so well, and its not Vincent's

Now:
I Hope there are experts out there whom know more, and i just like to be in the know, especially the why, maybe books? or any advise very welcome
 

davidd

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VOC Member
Vincent,

I am no expert, but I had guides made of NiResist many years ago and continued using them for decades. I do not remember the alloy I had them made from. The wear was very low and the expansion rate was near aluminum. I think it was a popular valve guide material for aircraft engines. It may be a good material to look at. I was running the same clearances as you are.

David
 

Gene Nehring

Well Known and Active Forum User
VOC Member
Vincent,

I am no expert, but I had guides made of NiResist many years ago and continued using them for decades. I do not remember the alloy I had them made from. The wear was very low and the expansion rate was near aluminum. I think it was a popular valve guide material for aircraft engines. It may be a good material to look at. I was running the same clearances as you are.

David
Inlet and exhaust? Or just inlet?
 
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