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  1. W

    How tight??

    On a Bridgeport, many users remove the "locating pin" because it is unnecessary and a PIA when inserting an R8 collet. Mine has been out for many years and I have never had a collet spin in the taper because I always tighten the drawbar properly. WOB
  2. W

    2 cycle rotary valve engine

    It is easy to limit RPM. Just throttle the engine with an undersized carb. It will also aid starting. WOB
  3. W

    2 cycle rotary valve engine

    IMHO, your valve timing is conservative and won't develop max power. This site Model Engine Tests has a multitude of engine tests. Some of the tests contain specs of the valve/port timing. WOB
  4. W

    Nickel plating my old zoomy pipes for the Little Demon

    This is incorrect. Gunsmiths use Cerrosafe for chamber casting. It is not the same material as Cerrobend. Cerrosafe is not suitable for bending as it does not expand sufficiently on cooling to grip the ID of the tube. Cerrobend does expand and makes bending easy on annealed brass and...
  5. W

    Model Aircraft Engine Refurb

    This article might help; AdriansModelAeroEngines.com :: Restoration of model engines WOB
  6. W

    piston rings and pistons for 4-stroke engine

    Pistons and other model engine supplies : OTTO GAS ENGINE WORKS List of some suppliers: Scale Model Engine Suppliers List WOB
  7. W

    Suppliers in US

    Small screws and such can be found here: Micro Fasteners WOB
  8. W

    Valve problem

    Pumice is finely ground volcanic glass and is too soft for use on steel. It is used in some toothpastes. All the valve grinding compounds I have ever seen were silicon carbide powder in grease. WOB
  9. W

    Fitting Oilite Bearings

    A simple way to effectively reoil a bearing is to drop it in a canning jar and cover it with 30W oil. Put a hose barb in the lid and connect it to your vacuum pump ( manual or electric). Pump until bubbles stop. WOB
  10. W

    Would Appreciate some advice on "Electric Furnaces"

    I have had a Neycraft Fiber Furnace (Neycraft Fiber Furnace - American Jewelry Supply) for many years. It has performed well for my purposes( heat treating). The ceramic fiber muffle is durable and light weight and I have never had a failure. The manual control takes some time to get a...
  11. W

    To ring or not to ring

    This is the correct process to fit a cast iron piston to a steel cylinder: AdriansModelAeroEngines.com :: Piston/cylinder finishing It requires building an internal lap for the cylinder and an external lap for the piston, but nothing beyond a hobby machinist's capabilities. You cannot use...
  12. W

    4 stroke spring selection

    The book "Aircraft Engine Design" by Joseph Liston (1942) has an entire chapter on valve gear. In it, there is a rigorous calculation procedure for determining valve spring specs. All components of the valve train are weighed and the radius of gyration of the rocker arm is measured. That...
  13. W

    Radial engine plans/kits

    If you can find a copy of Harry Higley's book "All About Engines" , it contains a good explanation of the differences between gasoline and glow-fuel engines. It is basically a model airplane engine book , but the info is applicable to any kind of model engine. WOB
  14. W

    Hodgson Radial - won't run

    Two things. When I built my Hodgson 9 Hall effect distributor(S/S CDI, 1/4-32 Rimfire plugs) I used nylon screws to hold the rotor contact(full width) to the rotor body. Seemed to me to be some insurance against unwanted arcing, but maybe wishful thinking. For a carb, I used the carb from an...
  15. W

    Hodgson Radial - won't run

    Check your distributor and plug wires. You might be getting crossfiring inside the cap. The wires should not run bunched in parallel for any distance. The distributor is barely big enough to work properly when all is correct. Expect malfunction if something is not right. WOB
  16. W

    wrist pin design

    To me it means same size hole in piston and rod(about .001" bigger than pin) WOB
  17. W

    wrist pin design

    delete post
  18. W

    wrist pin design

    The Hodgson radial uses full floating drill rod wrist pins running in 2024 pistons and 6061 rods. The pin is drilled thru with Mil Spec. 20470 dome headed soft aluminum rivets inserted in the ends to provide end cushions. No complaints but I will never run it enough to test the scheme. WOB
  19. W

    Thumper--a 1 3/8" bore i.c. engine

    Fatal error. Do not lap the cylinder with the piston. The piston surface is now contaminated with lapping compound and it cannot be removed without removing metal. The piston dia. should be about 2 thou. less than the cylinder dia. except for the piston head above the top ring which should...
  20. W

    Is Polyurethane resistant to Methanol

    See https://www.rcgroups.com/forums/showthread.php?2865026-Polyurethane-for-nitro-fuel-proofing-paint-jobs for diverse opinion. WOB
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