Piston ring compressor & Oil pressure 0-200A
Mike Dwyer <mdwyer@...>
I've had my Cont 0-200A engine apart due to the no oil pressure problem I reported a few weeks ago.
After nearly 1000 hours it is clean inside. I found one spot of surface rust on the crank near the front bearing. I use Shell 100W and change at 30 hours so this seems to be working. The bearings look worn but nothing real bad about them.
I was reading the overhaul manual and it recommends to lap in the oil pressure regulator. Great idea. Did that yesterday with some automotive valve laping compound and the seat looks way better. Forget doing this when the accessory case is on the engine. There is no decent way to clean out the laping compound. I filled the cavity above the oil pressure regulator with mineral spirits and it doesn't leak, I learned this trick from Don George in Orlando who is a great engine guy if anyone needs work done. I had a exhaust valve leak in one cyl and called Zephyr Hills Aircraft Engine, they didn't even bother to return my call. Don George said, "hey bring it over and maybe I can do it while you wait" which he did. I was most impressed and learned a lot about cylinders. http://www.dongeorgeaircraft.com/
I measured the crank and found I have a standard crank. That's good as I could have it turned down 10 thousandths but it looked great so I didn't do anything to it. After putting in the new $200 bearings and torquing down the rod bolts I find the rods have less slop than they did. Hard to explain but the rods shouldn't have much angular play in relation to the crank. They slide forward and backward ok, but with the old bearings you could change the angle from the rod to the crank. I think I have an idea how this came about. I've pulled the cylinders off several times over the life of the engine and the piston pin is generally pretty hard to get out. Usually I ended up taping the pin with a wood dowel and light hammer taps. I think this helped to crush the soft bearing surfaces due to the side force on the rod bearings. I think I'll make a piston pin remover for next time.
At Sun N Fun I searched for a piston ring compressor. No one had one. Couldn't believe it. Figured I'd just borrow one from a friend but I really wanted my own. Yesterday my friend was test flying a pilotless drone airplane for Velocity (guess they want a real person to fly off the 40 hours) and long story ... he was not around for me to beg from. I thought about using a curved piece of thin aluminum with a 4" hose clamp. It worked great, better than the professional one I had borrowed before. So for $1 I got myself a nice ring compressor.
Don George says you gota take the valve bodies out and drain them in order to check the valve clearances. He also says that 30-110 tho is the limit and if you go over 110 then the exhaust valve tends to burn like mine did. I drained my lifter bodies so we'll see how this works.
The engine is going back together but I'm leaving off the vacume pump drive on the lower front of the engine. I threw it up in the air and it came down hard which tells me that it is heavy and not used so by by. I read that the gears fling oil out the breather also and a Erocoup builder group recommends removing it. Hey, that's a factory plane, how can they do that!
I still plan to make the breather tube extender mod to reduce blown out oil. Also have some 431 Stainless tube and 437 filler rod to make me some nice 4 into 4 exhaust pipes. My factory supplied steel 4:1 exhaust is looking pretty ragged and I hate having to take the whole thing off each time I work on a cylinder...
Still got a couple of weeks of work before flying... But the weather here in FL kinds of stinks right now anyway. Sun N Fun weekend was beautiful except for the generally 15K direct crosswind on the landing runway. One note about Sun N Fun. They are now charging $30 a head or $25 if EAA. 10 years ago it was $15 and your wife got in for free. They now have 1/2 the number of Experimentals and Antiques fling in. I think it sucks that they charge people that drive in the same price as the people that show their planes. Each year they raise the price on the commercial vendors but have less traffic. I 'd like to know where the money goes cause they aren't spending it on cleaning the porta potties!
Mike Q200 N3QP - Status - in pieces