Originally posted by geish
I'm new to this hobby. I have a Piper Cub that is about 85% done. My plan is to mount the engine upside down. I have a K&B .45 engine that is about 7 yrs. old and I just got done breaking it in since it was never used. Basically, it's new. I went to the hobby shop to get the engine tuned because because I couldn't do it myself. I found out the glow plut was crapped up and I had the low speed disc setting too rich. My hobby shop guy told me to get a special glow plug (one with a bar near the coil) if I was going to mount it upside down.
Q1: Will I have problems mounting this engine upside down. My reason for this is because the head doesn't stick out of the cowl when it's upside down. The WHOLE engine is in the cowl.
It will be fine. The only issue is it may drip because the carb is lower than the tank. Mount the tank as low as possible.
Q2: Will I have heating problems because the engine head is not sticking out of the cowl. My plan is to cut out some holes in the front of the cowl to let some air in to cool the engine as well as to vent the carb. Also, I plan to cut out a hole at the bottom part of the cowl to have an outlet for the hot air. Basically, air goes in through the front holes, and out the bottom hole.
Sounds fine as long as there is enough airflow. Run the engine without the cowl for the first few flights. Then add the cowl. If it loses power, then heat may be the problem.
Running it without the cowl at first will helps as it will be easier to adjust the carb.
Q3: I just broke the engine in today according to the manual. It said to let it run on a rich setting for about one hour. I did that. It took about 5 refills to my 10 oz. fuel tank. This is different from what the hobby shop guy told me.
My hobby shop guy told me to run it rich to where I can touch the head, then run it lean till it heats up and you can't touch it anymore, then run it rich again till it cools. Keep doing this for 5-6 refills.
I tried the way the hobby shop guy told me, but I didn't know it was too hot to touch. Heck, even at the richest setting it was too hot to touch for more than 2 seconds. I got frustrated and just broke it in the way the manual says because it was more objective.
I have never seen an engine that could run that cool.
It is also good to stop, let it cool then run again. The heat cycles are part of the break in.