Valve guide bushing material

Trying to repair a damaged air cooled motorcycle cylinder head. With
largest oversized (O.D.) valve guides, still unable to get a tight fit.
What would be a suitable material to make a sleeve out of? I have some 6061
aluminum, but not sure it will stand up to the high temperatures, especially
since the affected valve guide is on the exhaust side. The valve guide
material is a silicon bronze and the head is aluminum.
Reply to
Larry & Cindy
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Absolutely not 6061. At any sustained temp over 600 degrees, 6061 turns to mush, galls badly.
Larry & C> Trying to repair a damaged air cooled motorcycle cylinder head. With
Reply to
RoyJ
Silicon or aluminum bronze would be my choice. Both are available in small quantities from the normal hobbyist's metal suppliers such as
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Randy
Reply to
R. O'Brian
Turn a sleeve out of SI Bronze like the guides are made from. Or TIG the holes and rebore them to the correct size.
Reply to
Steve W.
SAB available everywhere. Remember, buy a guide reamer and ream after pressing. Steve
Reply to
Steve Lusardi
If I understood this question right, all the previous replyers missed the boat. I think that what he wants to do is bore the hole that the guide fits into out to a specific size and press in a sleeve with the proper bore size that will allow the stock guide to be pressed in. I think steel would be OK for this. Engineman
Reply to
engineman1
Haven't used it myself yet, but a material named Colsibro gets mentioned a lot for making valve guides.
Larry & C> Trying to repair a damaged air cooled motorcycle cylinder head. With
Reply to
Jordan
I, personally, wouldn't recommend steel as a candidate. I've done this a bunch of times, and more than once repaired the location because someone tried that avenue, only to have the difference in expansion rates, as well as the amount of interference fit required cause the head to crack or the steel insert to move.
I've tried different methods, and it's always come down to welding in a plug and remachining the guide hole, then installing a new standard size guide.
Here's one example -
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Hope that helps a little.
Best,
Weyland
Reply to
Weyland
Why is the valve guide bore oversized? Because someone tried to clean it out with abrasive paper perhaps? Knurl the o/d of the guide, polish it back down to a 2 thou fit and put it in with locktite. Alternatively make a new guide. It'll be much more work to make a sleeve. -- Dave Baker
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Reply to
Dave Baker
Strong agree. Simply turn a new guide out of Si Bronze, install, and ream bore to size. The sleeve will eventually be a CF.
Jim
Reply to
jim rozen
Can you electroplate copper on the guide, then (optionally, true it up and) press it in? I did that once with a badly worn brass shaft: plated heavily & then turned it true.
Reply to
David R Brooks

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