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| Large Engines Discuss Engines Used on Giant Scale Aircraft. Gas/Glow, as long as they're big! |
Topic Review (Newest First)
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| 02-26-2012 07:51 PM | |
| Flypaper |
Re: Is this normal? I wanted to know what motor it was in order to ask on the net if that was a characteristic of that particular engine but I guess I won't need to now. Let us know what the problem was. |
| 02-26-2012 07:44 PM | |
| bartman |
Re: Is this normal? Glad to hear that Alex. |
| 02-26-2012 07:11 PM | |
| AlexL |
Re: Is this normal? This post is now closed, my friend the previous owner of the engine, a true gentleman, offered to set it up and test run it for me. Really appreciate all the constructive ideas. Alex |
| 02-26-2012 06:01 PM | |
| oldtomcat |
Re: Is this normal? Alex: shrugg>..??? oldtomcat |
| 02-26-2012 05:37 PM | |
| RAMJET |
Re: Is this normal? it looks like it may have been ported.does it look like the port has been opened up(you will be able to tell if the chrome is sharp on the bottom edge of the port).that is a large opening ,even the engines I have seen designed this way had a very small clean cut opening.no base gasket will close that gap though it may make it small enough to reduce the amount of exhaust entering the motor on start up ,I am sure if the port does not look messed with it was made that way.and should be ok,this type of motor is also very sensitive to back pressure.try to start it with no exhaust this will stop the inert gas(exhaust) from entering the engine.this motor may have to be started with a starter like the other fella said ,exhaust is a inert gas and will prevent combustion in large amounts. I think I would get the gasket material out also ,make a gasket and close that gap a bit. |
| 02-26-2012 04:26 PM | |
| AlexL |
Re: Is this normal? Some pics, the feelers have been stacked, closed to being 2mm in thickness. You can easily see the gap between the bottom of the piston and the exhaust port in pic #2. I also poke the feeler gauge onto the otherside of the cylinder wall but I think the piston is of a uniform height, and not one side longer than the other. Alex |
| 02-26-2012 03:12 PM | |
| Flypaper |
Re: Is this normal? Also, what make is the motor or do you have a pic.?? That may help too. For what it's worth Cox used to make a motor where the piston came above the ex port. They called it sub base induction if I remember right. Remember, the longer I live the shorter my memory gets. 
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| 02-26-2012 03:07 PM | |
| bartman |
Re: Is this normal? Alex. I wonder if the missing base gasket would lift the cylinder enough to cover the piston? Or it could be broken or backwards. Time to pull off that cylinder I think. |
| 02-26-2012 03:02 PM | |
| Flypaper |
Re: Is this normal? Was thinking the same thing as you Tomcat. I've seen it happen before. I don't know how high it is but you may be able to see the other side of the piston with a flashlight, or stick a popsicle stick in and see if the other side is lower. Another point, the sparkplug is one of the best instruments to tell you what's going on with the engine. As I said, if the plug is wet, it's likely flooded. And if it's dry after choking, needs more fuel. I worked on these things for 35 yrs in my own shop and the first thing I do is check the plug as it tells me the condition of an unknown engine. |
| 02-26-2012 02:57 PM | |
| AlexL |
Re: Is this normal? I have been all over the internet, to see whether there is any one out there has a similar make, to see whether they can check whether it is the design of this particular model, or just a fluk. But so far, no one has responded. I tend to agree with you, Tomcat, that there is no way that the bottom skirt passes the exhaust port reaching TDC, leaving such a wide opening, and totally depleted the build-up of the pressure for the explosion stroke - i.e. downward. I may be wong but that is the reason why I started this thread at the first place. I had the chance of working with this engine the past few days and come to love it, the CNC crankcase, the reed-stiffener, etc. If only I can get it started. Alex |
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