Stainless threads

Discussion in 'Motorized Bicycle General Discussion' started by Boomer, Jun 20, 2008.

  1. Boomer

    Boomer New Member

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    Has anyone tried replacing and engine bolts, studs etc. with Stainless? My one experience doing this was replacing a steel valve cover with an aluminum one using stainless allen bolts. I experience oil leaks but never spent the time figuring it out and just put the steel cover back on. I know I could have used blue loctite (red is too deadly for me) and maybe that would have solved the problem, but then there was the contraction and expansion factor of aluminum. I also know there are some metals you can't put together as they will react with one another and erode or loosen to some degree. I was wondering if anyone has had any experience using stainless fasteners on any of these die cast engine parts?
     
  2. stude13

    stude13 New Member

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    i think stainless fasteners are used in food, medical and marine fitments. they are considerably more expensive and probably not needed in the type of metal we are working with in this hobby.
     
  3. Boomer

    Boomer New Member

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    Sorry but it doesn't answer my question. Im aware of the uses of Stainless Steel, know it cost more and know theres not a dire need in this application. Im more concerned with the looks of a finished product.
     
  4. Dan

    Dan Staff
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    I always thought that mixing any metals would lead to the less noble metal corroding. Most of what I found says with out water, should be OK. I replace studs with good bolts, but haven't used stainless.

    Electrochemistry - Wikipedia, the free encyclopedia
     
    #4 Dan, Jun 21, 2008
    Last edited: Jun 21, 2008
  5. grouchyolfart

    grouchyolfart New Member

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    When I worked at Pearl Harbor Shipyard, we always used stainless fasteners when dealing with aluminum. Dissimilar metals are always a problem on our ships so a lot goes into trying to keep these metals separate when possible and to use "neutral" fasteners.

    That being said, these bike motors are all made of cast aluminum. If you plan on doing regular maintenance and overhauls, I'd say change any fastener that comes in contact with the casings to stainless. This won't "stop"corrosion, but will slow it down immensely. Btw, even stainless fasteners will eventually rust when in contact with aluminum. Just not as catastrophic nor as quick as regular steel fasteners.

    Nothing scientific. Just what I learned working with the stuffs. ;)
     
  6. Walter F.

    Walter F. New Member

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    I like your username and your location, but mostly I like the info. I'm getting a new motor and after listening to the guys here I plan take the motor apart, port and polish, lap cylinder head & jug, re-gasket & replace all studs/nuts. I also thought about stainless steel used in conjunction with Heli-coil in threads. Like you say it's an aluminum casting and needs to be treated like real hard plastic. My question had more to do with heat transfer between the two metals, would the stainless get hotter/colder than the aluminum?

    Too much heat is the biggest enemy to any engine, and from what I gather it really affects 2-stroke engines a lot. Don't forget those 4 long studs hold the whole shootin'match together & and any expansion/contraction here and performance is in the crapper(c)Walter F.
     
  7. grouchyolfart

    grouchyolfart New Member

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    Not sure if the stainless would get hotter than the surrouding aluminum, but it will retain the heat a little longer. Check that. Senior moments suck. :oops: It could be the aluminum retains heat longer. Anyway.....the retention of heat by 4 studs is probably going to be insignificant anyway, as I doubt it'd be much different from a stock engine.

    Given that these engines run at low compression, I don't see any problems switching to stainless. With regular maintenance, problems with the studs, etc. should be non-existent. :) Now...to find all the stainless studs, etc. in metric sizes and in the right lengths. ;)
     

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