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  1. Jasonb

    Maerial Suppliers

    I use M-machine quite a lot, they will cut the larger sections to whatever length you need, catalogue download towards bottom of page. Only downside is not shopping basket type site so I usually e-mail a list of what I want and they e-mail an invoice back and I phone through the card details...
  2. Jasonb

    T head engine by Brian

    My engines tend to run a 5 to 10deg BTDC, your 20deg sounds a bit early to me particularly for these slow running types. that way you are more likely to get all the explosive force pushing the piston down, too early and that force is pushing down on the piston while it's still coming up and on...
  3. Jasonb

    Compound steam engine.

    Dean as torque is lbs.ft the crank throw possibly comes into what torque is being applied to the crankshaft HP 100lbs force x 0.5" crank throw 4.16 lbs.ft LP 33.3lbs force x 1.5" crank throw = 4.16 lbs.ft
  4. Jasonb

    Bore stroke ratio

    As well as a decent size flywheel you can play about with the cam profiles and also ignition timing, he timing can make a lot of difference. But all will depend on whether you are just making the engine to tick over slowly for display or want it to be doing work at low speed.
  5. Jasonb

    Compound steam engine.

    Depends what you call "proper" the in-line configuration is quite common and introducing gears or belts would completely spoil the original layout and look. No doubt one could thrash the life out of the old engine to get the revs up but I'm with Steamchick and would treat the old girl with...
  6. Jasonb

    30cc Inline Twin 4-stroke Engine based on Westbury's Wallaby

    I'm not a fan of seating cutters I prefer to turn a chamfer with the topslide set over to 45deg at the same setting that the valve guide is reamed at so all stays concentric. This can require some complex setups when there is no separate insert and the seat is machined directly into the head...
  7. Jasonb

    Compound steam engine.

    Thats right a 180 crank compound or double high will be smoother running than the same engine with a 90deg crank but could get stuck at TDC/BDC. Not such a problem on something like the genset shown as once started it will be running the same way but in something like a boat or vehicle which...
  8. Jasonb

    Compound steam engine.

    Self starting would be one of the main reasons for a 90 degree crank on a compound and plenty are made that way, Take the Stuart compound for example, not much good if you stop to stick it in reverse and it gets stuck at TDC or BDC. And just about every compound traction engine I can think of...
  9. Jasonb

    Compound steam engine.

    The problem with making the passages too small is that they will not hold enough steam to fill the LP cylinder once the HP exhaust is closed. The tube linking the two cylinder sis often termed the receiver and is sized to contain enough of the lower pressure steam to be able to fill the LP...
  10. Jasonb

    Compound steam engine.

    Actually crankshaft shape would depend on the layout. If it were your typical vertical then a double throw crank to suit bearings at each end and one in the middle would be the most complex. On the other hand if you did it as a horizontal cross compound type layout then you could have the...
  11. Jasonb

    Compound steam engine.

    He is talking of having a 1" dia Low Pressure Cylinder as opposed to a 1.75" dia low pressure cylinder. As both are the Low pressure cylinder they will get the same pressure all be it lower than the High Pressure cylinder. Diameter altered but still all to do with the Low pressure cylinder
  12. Jasonb

    Compound steam engine.

    He is talking of having a 1" Low Pressure Cylinder as opposed to a 1" low pressure cylinder. As both are the Low pressure cylinder they will get the same pressure all be it lower than the High Pressure cylinder. What the Torque and Power figures would be will be different but without a prony...
  13. Jasonb

    Compound steam engine.

    As we generally measure pressure in pounds per square inch you will have a lot less square inches of piston area for the part expanded steam to act on with a 1" LP piston compared to a 1.75" LP piston. So will not get as much force pushing against the smaller LP piston. Area of 1" piston is...
  14. Jasonb

    Looking for glowengine plans

    If your only reason for that size is to do it without rings then you can build larger engines without rings, Have a look at my build of Alex Whittaker's "Firefly", it's larger at 7.5cc but doe snot need rings just a lapped cylinder liner and piston, glow ignition and several have been used to...
  15. Jasonb

    T head engine by Brian

    Gordon, your method if fine for cams with flat flanks but the other method is needed for radiused flanks or use something like CamCalc if the cam has to be held horizontally ( long multiple cam shaft) as you can only reach down so far with it held vertically. The method was described in Model...
  16. Jasonb

    T head engine by Brian

    Sproket, this is the type of setup As the blank is moved around the base diameter if formed by a series of 4 deg facets ( or however much you turn the table)
  17. Jasonb

    30cc Inline Twin 4-stroke Engine based on Westbury's Wallaby

    The 6061 won't hold up too well, there is a risk of it stretching around the holes and as I said earlier it is not that good a bearing material. Although Dural is no longer made 2024 or 2014 both in T6 temper are a much better option and often specified on model engine drawings.They won't...
  18. Jasonb

    30cc Inline Twin 4-stroke Engine based on Westbury's Wallaby

    2014 which is the old HE15 spec is about as close as you can get to Dural. It's heavier than 6061 so could muck up the counter balance weight calcs but not as heavy as GM
  19. Jasonb

    30cc Inline Twin 4-stroke Engine based on Westbury's Wallaby

    I missed that and was going by the colour of the part as the original used Gunmetal (bronze) castings. I thought the same was going to be used which makes it easy to soft solder the bearing cap on and machine as one. If it is going to be aluminium then I tend to screw the two parts together...
  20. Jasonb

    30cc Inline Twin 4-stroke Engine based on Westbury's Wallaby

    Yes keep it coming. Having done a few similar conrods it's interesting to see how others go about it. Judging by the colour of the 3D image you are going to be using bronze which can make a difference to the machining methods over an aluminium one which is mostly what I have made mine from.
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