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Building Tips and technical articles. => 1/2 A building. => Topic started by: Andrew Tinsley on June 06, 2011, 01:15:44 PM

Title: Wasp 0.61 hold down screws
Post by: Andrew Tinsley on June 06, 2011, 01:15:44 PM

Hello Everyone,
  Have taken the plunge and purchased an AP Wasp. I have taken Larry's advice and stripped it down and cleaned it out thoroughly. The cylinder hold down screws are a bit 'iffy to say the least. Although I can find my thread gauge, I can't find my magnifying glass, can someone tell me what metric thread is used, so that I can get some decent replacements?

  Thanks in advance,

Andrew.

Title: Re: Wasp 0.61 hold down screws
Post by: John Crocker on June 06, 2011, 01:38:39 PM

not sure, but can tell you, those are not the ones to worry about.  Its the 2 holding the carb in place that you will lose.  I took to using some jb weld to hold mine in place and tossed the screws away

Title: Re: Wasp 0.61 hold down screws
Post by: Andrew Tinsley on June 06, 2011, 02:33:14 PM

Thanks John,
 I am not worried about the carb, that will head to the spares bin........Oh hang on you mean the carb fastening screws? Yes I will need them or a replacement. I intend to make a new carb (when my lathe is running) and use a Texas Timers 120 tpi nva assembly.
  The cylinder hold down screws on this Wasp are showing screwdriver damage and I did use the correct screwdriver!
  If I can't see those threads properly, I suppose I don't have any hope with the carb retaining screws!

Thanks,

Andrew.

Title: Re: Wasp 0.61 hold down screws
Post by: kenneth cook on June 06, 2011, 03:21:51 PM

         Andrew, I replaced the screws on my Stels engine due to the slotted screw heads would blow off. Those screws were 2mmx4. Dubro actually makes those screws available in the r/c car section of most hobby stores and they come 6 to a package. I paid $1.99 for them. The stock # was 2111. They come in a Dubro racing package which is black white and orange unlike the red and yellow packages Dubro supplies. These screws have worked in my Norvel's as well as early AME engines. I see no reason why they would be any different for the AP. Ken

Title: Re: Wasp 0.61 hold down screws
Post by: Andrew Tinsley on June 07, 2011, 02:39:32 AM

Thanks Ken,
  I will order some from my usual supplier.

Regards,

Andrew.

Title: Re: Wasp 0.61 hold down screws
Post by: Bill Adair on June 07, 2011, 11:54:57 AM

Andrew,

I used a longer screw all the way through the venturi, with a nut and washer on the other end. Much easier to make a venturi without threaded holes.

All the later Norvel .049/.061 engines used the same through screw arrangement, and there doesn't appear to be any performance penalty with any of these engines.

Better yet, order a venturi and spray bar from Jan Holuszko here on the forum, and use the stock needle, o-ring, and ratchet spring from the AP carb.

Bill