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Thread: stainless oil cooler lines?

  1. #1
    Registered User mysteriousfish's Avatar
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    stainless oil cooler lines?

    I see many threads on switching to SS brake lines...I did on my RT and like the result.

    As I contemplate my plan of attack on my new monolever, was wondering whether many folks have used SS lines for the oil cooler? I saw that Flatracer has them made up for the RS, but no other models....other than cosmetic coolness factor and possible durability, I assume it would take a special hose to handle the temperatures involved in hot engine oil as opposed to brake fluid...thoughts?
    michael
    __________
    1991 R100 classic; 1980 R100RT

  2. #2
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    Quote Originally Posted by mysteriousfish View Post
    I see many threads on switching to SS brake lines...I did on my RT and like the result.

    As I contemplate my plan of attack on my new monolever, was wondering whether many folks have used SS lines for the oil cooler? I saw that Flatracer has them made up for the RS, but no other models....other than cosmetic coolness factor and possible durability, I assume it would take a special hose to handle the temperatures involved in hot engine oil as opposed to brake fluid...thoughts?
    Missive on “stainless steel” brake lines:
    “Stainless steel” as in “stainless steel brake lines” simply refers to the type of sheathing material that is braided around an internal flexible tube as reinforcement to resist burst pressures – internal pressures in braking system of 2,000psi might not be unusual under load. The internal flexible tube used in “stainless steel” brake lines may be the exact same material that is used in “non stainless steel” lines - if heat is a problem that needs to be managed it is a problem for all regardless of reinforcement materials. Steel is stiffer than some of the other materials used as reinforcement, so there is less “give” under pressure, which translates to a firmer feel. It can also mean that the line is less flexible along its length. The need for “stainless” steel is simply addressing the need to avoid the reinforcement corroding. That a stainless steel line can look “cool” is a cosmetic feature.

    To the question:
    Even cold starting in low ambient with fresh oil the maximum oil pressure in a regular internal combustion engine with plain bearings like an airhead is very unlikely to exceed 200 psi. In normal operations above idle oil pressure is likely to be around 40psi and max out around 80psi at start-up. Heat in oil lines is not a problem - look at the external lines used in any dry-sump engine (British bikes and 99% of race cars come to mind). Therefore, there is no obvious functional need for “stainless steel” flexible oil cooler lines on an airhead, but a set may well look cool!
    Last edited by R100RT_Mark; 09-28-2012 at 02:29 AM.
    Mark

    Current - 1974 TR5T : 1993 R100R : 1994 R100RT ~ Past - 11# 1970s BSA/Triumph Singles & Twins : 2# 1970s CZ 125s : 1# 1985 BMW R65 : 1# 1976 Moby X7

  3. #3
    Sir Darby Darryl Cainey's Avatar
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    When I built my 1974 Rickman Honda I seached out aircraft quality stainless oillines.

    Expensive, overkill, great visual effect!
    Ambassador BMW MOA Ontario Canada
    President Niagara BMW Riders #298
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    1977 R100RS, (Retired) 1993 R100GS (just getting started)

  4. #4
    Registered User toooldtocare's Avatar
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    My Motorsport had SS lines with anodized fittings. They were done when the cooler was added and worked perfectly. They also look good.

  5. #5
    Rally Rat
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    Stainless braided hoses for oil coolers (and other non-brake applications) do indeed have a rubber hose inside the braiding. They are a bit of overkill in this application, since the cooler will rupture before even the stock hoses. The thermostat on most of the bikes prevents excessive pressure at low temps. The GS type filter cover is drilled to reduce pressure in the cooler.

    However, there is no denying that stainless braided hoses look far cooler than plain ol' rubber ones. You can get them from Bob's BMW, but be warned that they are expensive.

  6. #6
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    I don't see any reason why you can't use the R14 PTFE hose like they do with brake lines. Expect to spend $3-5/foot for the line. Most people use reusable hose fittings.

    Cutting the line can be a little challenging, but not that difficult. I think there is a previous thread on how to do it. If you can't find it, we can explain how to do it.

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