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About jetpack

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    Club Racer
  • Birthday 12/05/1962

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  1. jetpack

    wrist pin stuck in piston

    See if you can gently start a tap in the hollow of the wrist pin for pulling. The tap and wrist pin will be hard material so do not use a lot of force or things will chip. If you can get the wrist pin to turn, your half way there. Keep it wet with penetrating oil also while doing this.
  2. jetpack

    Fuel Line Barbs for Water Supply Lines

    Du-Bro makes those for their tank kits. They sell them seperately.
  3. jetpack

    Bearing Retainer Direction

    This should make it all easy to remember...lol. Thank you, Ray!
  4. jetpack

    Bearing Retainer Direction

    When installing open main bearings with phenolic or plastic retainers, which way should the balls face? Should they be installed with the balls facing the counterweight or should the balls be facing the intake passage when on the crankshaft?
  5. jetpack

    head button shape

    I think you will find that alky heads are pretty much flat across their chamber with a small bubble. Very little squish band angle if any. This is what I have learned studying Webra engines which are built for low (10%) to no nitro.
  6. jetpack

    HOBART 2011

    Here's a postcard for those that couldn't make it. I grew up in Hobart and know my way around the lake and came home with this shot of the event. Never would have dreamed a model powerboat race downtown would ever take place. It is great to see and it is a first class event all the way around.
  7. HendricX did good with the screws he sent me. I was able to drill out what I needed all in the mill. Our tailstock is too heavy for light drilling on the lathe, otherwise I would have drilled and tapped a block in the lathe to hold the screw on center to drill instead of trying to pick up center on the mill, and also deal with squareness issues but I did it. Peck drilling is much easier in the mill though, that was one good thing about using the quill on it. The .12 is going on an unstarted Dumas Windy kit I've picked up.
  8. jetpack

    New Engine

    Loc-tite has their own remover. Methylene chloride, the major active ingredient in Chisel #79040, is available for retail purchase at automotive supply, painting, and home center stores. It's a nasty solvent chemical, so be careful using it. About new engines...along with all other comments, if the loose carburizing hasn't been cleaned from the factory hardening of the crankshaft...remove it. Loose carbon from hardening process can break loose into the bearings or other. Check with a Q-tip. If you wipe any unmachined surface of the crank and you see signs of contamination, it's scrubby time. If the crank is fully machined or ground there shouldn't be any worry.
  9. Does anyone have a half-inch length of this around before I have to go buy from mcmaster-carr and dent my wallet and be left with 99 screws or three feet left of threaded rod that will never be used? Ace has the size but not in brass. I believe the brass screws I have been able to find are electrical screws commonly used in the U.K.? Another close call on finding a threaded section cheap was a thumbscrew supplier, but the ad said "May not be fully threaded"..so I might have to contact them to find out. It would be only $5.00 instead of $20 at least for rod. I cannot find a 3mm brass screw online to save my life and I really rather not try it with steel or stainless and hoping someone else has been down this road before or has lots of odd stock around they can help with. I simply cannot justify buying a 5lb. bag from INDIA but thats all that seems available on google. And I know what your going to ask and no they aren't made anymore so replacement parts are out...
  10. jetpack

    OPS Twin

    Here's a rare one... It would be nice to see what the original carbs were and the exhaust looked like.
  11. jetpack

    Header Gasket Materials

    For those that cut their own header gaskets, what is your favorite material, thickness, source and methods for cutting...
  12. I though some might enjoy checking this out. Sorry I cannot post the slide pictures.
  13. jetpack


    Aero-Gloss is still sold. It is "Hot Fuel Proof" and means it can stand up to exhaust residue - trace amounts of fuel but I've used it on airplanes and does okay up to 15%. Look for butyrate, not nitrate dope if your looking for fuel proofness. There is a hot fuel proofer clear that ISNT dope that you can spray over decals and dope to further fuel proof it. Not a very good alternative these days. A good, cellulose-based varnish has been recommended by Dumas in the past in their finishing instructions. Not a bad way to go if using lower nitro.
  14. jetpack

    Straightening Prop Bores

    That was the part I was missing, if my idea on putty would work but how to deal with it. I do not want to be left with epoxy putty stuck hard as a rock to the prop to have to try and clean, or fight getting it off and bending it. I think I'll finish up the prop where I need to in order to be able to mount it up square where I can. I liked the idea of casting the prop inside a close fitting ring of tubing and doing it on the lathe. I have a full machine shop at my disposal and time to do it is why I monkey around with this kind of stuff which people mentioned is vintage, hard to find kind of stuff sometimes, so I don't mind trying to fix than replace. Just a part of the hobby for me.