Upshur's opposed twin engine

Gordon · Oct 26, 2024

I usually check for leaks by screwing an adaptor with spark plug threads on one end and air fitting on the other end. I then put pressure in the cylinder with the air compressor and put soap around the potential leak areas. That obviously does nothing for things like valve timing.

Brian Rupnow · Oct 26, 2024

I just spent Friday and Saturday making an adaptor plate to put a 3 jaw chuck on my friends metal lathe. Nice to do some full size work for a change.

Brian Rupnow · Oct 28, 2024

I've been very busy with other things, but did manage to make a new intake manifold which accepts a Traxxas carburetor. Tomorrow I will install that on my engine and take another stab at setting the valve timing.

karolh · Nov 1, 2024

Brian Rupnow said:
Here is a bit of an odd question. I am using a 1/4"-32 sparkplug in this engine. The end which the wire attaches to is 0.160" diameter x +/-0.075" long. Does anyone know of a sparkplug boot that fits over this size of sparkplug or is it a flat/split wire terminator that snaps over the reduced area in the center of the sparkplug terminal?

ON our RC model plane engines that size plug is quite common, and we use the RCEXL ignition systems to fire them. A replacement spark plug boot can be had from any reputable RC hobby shop such as Valley View or just Google a search for 1/4" -32 spark plug replacement boot and you should be good to go..

Brian Rupnow · Nov 4, 2024

I haven't posted much for the last week or two, as I have been feeling under the weather. However, the new intake manifold with Traxxas carburetor has been installed on the engine. There is one very notable difference---When I crank the engine over and hold my finger over the carburetor air intake, I can see the fuel rushing up thru the transparent gas line to the carburetor. This is something that didn't happen with the home made carburetor in place. I haven't messed around with the valve timing yet, but I think this is very promising.---Brian

Allan Ostling · Sunday at 1:58 PM

I hope the new carburetor points to a solution.

Brian Rupnow · 2024-11-13T12:57:58-0500

I haven't worked on the engine for a couple of weeks. I go into the hospital tomorrow for my second total knee replacement. Hope it goes as well as the first knee went 5 1/2 months ago.----Brian