bearings....what to do about them?

[Wayne Galligan]

Clarence Lee......where are you?


  ----- Original Message ----- 
  From: Verne Koester 
  To: discussion at nsrca.org 
  Sent: Tuesday, August 05, 2003 4:01 PM
  Subject: Re: S.S.Bearing- What to Do about it??


  I'm currently using Powermaster Mean & Green with 18% synthetic oil and 15% nitro. Since I bought this fuel at Toledo, they've released a new fuel called 16/15 Power which is supposed to be geared toward the 2-strokes in this size range. As I understand it, it's basically the same as what I have except the oil has been reduced to 16%. I contacted them and tried diluting my fuel to about 16.5% oil by adding methanol (didn't have any nitro) but it didn't seem to matter much. I'm absolutely convinced that in my particular application, the bearing simply wasn't getting enough oil/fuel to it. It's not too hard to see when you put a brand new bearing in it, have it go "gritty" in two ten minute flights and then pull it right back out with a layer of burned oil on it that looks just like corrosion. The engine ran just fine through all of this, BTW and still has the original glow plugs (Mintor head) that I started the season with. I think there are more factors in the mix here that will give different results with different setups. I suspect the tuned pipe plays a large role in all of this and may be scavenging the case too efficiently. In any event, the EFI bearing with the seals left intact is working where nothing else I tried would. I have a spare, BTW, and checked the manufacturer and part number. For those interested since Tower is currently out of stock, the EFI bearing is an NTN 6904LU. I called my local bearing supplier who normally stocks that exact bearing and just happened to be out at the moment. They charge $40+ dollars as opposed to the $25 or so that Tower's getting. Maybe someone else can find it cheaper. However, I'd stick with the NTN because I think the grease they're packed with makes a difference.

  Verne


    ----- Original Message ----- 
    From: Wayne Galligan 
    To: discussion at nsrca.org 
    Sent: Tuesday, August 05, 2003 4:30 PM
    Subject: Re: S.S.Bearing- What to Do about it??


    Verne,

    So what is the oil content of the fuel your are using?  I use Cool Power 15/17 and the original set of bearings lasted about 125 flights.

    WG
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