Hit and miss question....

[pkastagehand]

I realized I should have posted here in the first place rather than hijacking an old thread...

The recent ice cream maker thread where Bob Shutt shows his Lil Brother prompted me to look for more stuff on these engines. I built one of these from original Breisch castings and drawings back in the early 80s. Never really gotten it running. Maybe ten seconds or so one time before and O-ring got warm and started dragging too much. It wasn't Viton I'm sure.

I'm thinking I might have several problems but maybe they are really only one problem. It doesn't have a lot of compression; I didn't get a true enough bore maybe to get a nice fit with piston. I'm trying Viton O-rings next.

But I also wonder about fuel; bad build on the mixer or if weak compression is just not pulling fuel properly.

I'm also not convinced my ignition is doing the best job it could. I tried to use the points setup as designed my Mr. Breisch and feel like it does not work every time. I base that on the fact that I'm using a "Tim 6" designed by Mr. Howell and the LED doesn't light every time the points do their thing. I couldn't see any points in your video so wondered what you're doing for ignition/points, etc. Hall Effect sensor or buzz box so there is always spark?

I will keep working on the compression thing to see if I can up that. Tried a bit of lapping and maybe more of that will improve the bore and then I could make a new piston as needed. I tried cast iron ring once but couldn't get it on the piston without breaking.

Any suggestions accepted.

Thanks,

Paul

 

[rickhann]

Hi Paul. I was having the same problems with my Lil Brother as you. Most of the problems have been hashed over ad infinitum on several boards, so I will not preach to the choir. My engine has an O-ring on the piston. It is a fairly loose fit, but when the flywheel is spun over there is a a good "bounce back". If you get the bounce back, I think your compression would be O.K. My Ignition is a simple 6V system using a auto coil, condenser, rechargeable gel battery and a homemade spark plug. I placed a small spark gap ahead of the plug, so I can see if it if firing. For fuel, I use coleman lantern fuel with a bit of Marvel oil added. My carburetor is a simple "vapor carburetor" consisting of a piece of threaded pipe with a couple holes drilled in it to let air in. Adjustment is a threaded sleeve that covers the holes as needed. I could never get my engine to run consistently for any period of time and it was extremely sensitive to the fuel level in the tank. One afternoon, I was fiddling with it and watching the valve events. As far as I could tell, the timing was near perfect as the plug was firing a few degrees BTDC. I then started looking at the intake cycle and it struck me that the exhaust valve was not closing soon enough for the fuel to be sucked into the combustion chamber. You should be able to hear the intake valve vibrate when it is sucking in fuel. I adjusted the exhaust valve so that it closed sooner. That seems to have solved most of the problems I was having. My engine is not nearly so sensitive to fuel levels in the tank. Plug fouling is not much a problem now. Good luck. Rick

 

[pkastagehand]

Just started to look at this again after leaving it set for some time. I will revisit valve timing and rocker setting for exhaust closing.

I do get some bounce when it comes up against compression, depending on how hard I spin, etc.

I am cleaning out any old residue that might have collected in the mixer, fuel lines, check valve, etc.

But I am thinking I might want to do something different with points. I get good spark when I use a bare lead to open and close the circuit but not a reliable spark when using my home-made points.

Paul