new rings?

M

mAlton

New member
While taxiing this evening, I ran past a guy who later told me I had a considerable amount of blow-by. The plane wasn't run much for a few years before I got it, it has one cylinder with low compression and I was hoping after some use, it would improve a little. If I need rings, are there any for an O-435 that can be had? If so, does anyone know of the price for them? Thanks.

Michael
 
He said I had oil blowing out the vent tube under the engine. Knowing I have one cylinder with low compression, I am thinking maybe rings. I haven't opened anything up yet to investigate. With parts being so hard to find, I was wondering if it would be hard to even find new rings if I needed.

Michael
 
Do you have undue oil consumption? How low is the compression? I am all about fixing things that are not correct but I am even more about making sure they are not correct before fixing them. There is a tremendous amount of money and time spent on unnecessary repairs and I caution against jumping at symptoms that may not mean anything. To qualify my statements I am an A&P, IA and have been working on and restoring old airplanes and engines for quite a bit now, though not as long as Dan C. What are your thoughts Dan?

Cheers.

RT
 
I hope it can turn out to be unnecessary to worry about. With these engines being so rare, I am just worried about causing more harm than good by not doing anything. I, by no means, am anywhere near being a mechanic. Your opinion is valuable to me. I got this plane last November and have been going through it since then as time and money has allowed. When it came in, it seems like every hose and fitting on it was loose. Oil was coming out of everything. After tightening everything up, I don't seem to have any leaks now. As far as consumption, it has only flown a few hours and high-speed taxied for maybe three more hours total. I have added one quart so far. As some earlier posts had suggested, I added Marvel's Mystery Oil when I changed the oil right after it came in. The one cylinder that is lowest was at 45/80 when it came in. The plane wasn't run but about an hour each year for three years before I got it. The mechanic working with me suggested that I wait a bit and see it the compression comes up some after it gets used more frequently. I will say that after only an hour of time, that compression did come up to 55/80. I haven't checked any of them since that time. I just changed out the brakes and wheels to Cleveland's and was thinking it was about ready to start flying it more when the guy saw it going by and saw what he said was a lot of blow-by coming out. I should also add that at the same time, I stopped and was listening to a whistling that I was thinking might have been the brakes squeaking, but when I stopped it kept on squeaking. After he talked to me, I am thinking it was the air blowing through the tube underneath. Sorry to ramble on, but I wanted to get as much info out as I knew. I appreciate any help in determining if there is a problem or not.


Michael
 
A short reply......
The 14-19 came with an O-435A engine, which had quite a few differences from the military engine that was the "A's" origin. I suggest you obtain the manuals for both engines and determine what you have. Many shade tree "mechanics" felt free to use parts from the military engine 'cause they were dirt cheap until a few years ago. Some are Ok and some could cause your problem.
Another problem is that 98% of A/Ps don't know what they are looking at under your cowl.......
The military engine was an oil burner when new in 1944. If you have these parts in your engine, you will burn 1 quart an hour, guaranteed.
You can continue the discussion on the forum or give me a call after 6PM PDT.
Dan
 
I know that from the amount of oil leaks in a Franklin that they are externally lubricated! :) I have heard the same about the O-435.
The previous advice that you were given is good advice! Don't rush to fix something that may not need fixing. Get the manuals and part lists, learn your engine (and airplane). Find a mechanic who knows the plane/engine.
A quart in 3 hrs is not the end of the world. We are not flying behind O-320's or O-360's (well most of us aren't) so expect to put oil in it. I would suggest that you download a copy of Continentals SB on compression testing. It gives a lot of good insight in to what to look for. And it is not yet printed exclusively in Mandarin or Cantonese.
See:

http://www.tcmlink.com/pdf2/SB03-3.pdf

Good luck, and keep asking questions. It makes the rest of us have to think!

Larry
 
A question relating to the squeaking you are hearing. Do you have a vacuum venturi on the airplane to drive the gyro instruments? If so those quite often whistle/squeak in the slipstream of the prop when on the ground.

Next question relating to the engine blow-by. Is there excessive oil on the airplane underside aft of the breather tube?

As all have already said, that oil cosumption is not anything to be concerned about with a 0-435.

Cheers.

RT
 
Yes, I do have a venturi. Maybe I just haven't heard the noise before now. When the plane came to me, there were so many leaks that the underside was coated in oil (when it sat after first coming in there was oil dripping out of the tail!), but after stopping all of the leaks I could find, I cleaned the underside and now there really isn't anything there to speak of. I haven't flown many hours yet, but was surprised that it is pretty clean. Maybe I am overworrying about it, I was just wanting to err on the side of caution if anything. Thanks.

Michael
 
I can almost guarantee that the squeaking you are hearing is the venturi. You can test this by blocking the entire front end of the venturi with something such as a sock secured with a ziptie. Obviously no flying like that but if you do that and run the engine at idle my bet is that the squeak will be gone. After running it make sure you remove whatever you used to block the front of the venturi.

As far as the engine goes, if it were mine I would continue to run it for a few more hours hoping the compression comes up on that cylinder. You can determine the source of the poor compression by conducting a compression check, and while the cylinder is pressurized with the compression tester listen to three places; carb airbox, exhaust pipes as they exit the cowling and the oil filler port with the cap removed (make sure while listening to any of these places you do not place your head or body in the arc of the prop, very important). In theory if the cylinder is not cracked the only places it can leak are the intake valve, exhaust valve or rings. Once you determine where most of the air is escaping then there may be other things that can be done without cylinder removal.

Hope this helps.

Cheers.

RT
 
It's funny, I was just thinking today that I could cover the venturi and see if the noise quit. I will try it in the morning and see what happens. Thanks.

Michael
 
You were right, RT. I covered both venturi's and the whistling stopped. After uncovering them, it was back. I don't know why I never heard it before, but I am glad to know where it is coming from. I have not checked compression again, but will try to do so this week. Thanks.

Michael
 
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