1st. condition inspection- need new cylinder

I am doing my 1st. condition inspection on my RV9A with a O320 D2A Lycoming and found cylinder #1 had compression check of 40/80. All other cylinders in mid 70's. The engine was installed new when plane was new 108.9 hours ago.
You can hear air rushing out of the exhaust valve and through the exhaust. We "staked" the valve and got the compression up to 65 but after short run it was back down to 40. I called Lycoming and they are sending a new cylinder under warranty even though engine was put into service 13 months ago. They didn't say whether they would pay for labor.

I had to replace the Skytec starter 2 months ago because of problem with the solenoid.

I had the new Slick mags with the service bulletin re the carbon brushes. We pulled and inspected these but brushes seem OK but will need inspecting again.

2 comments and questions:
1. I am disappointed to have so much trouble with a new engine, a new cylinder, a new starter and mags that have potential problems. I bought a new engine rather than a rebuilt one to avoid problems such as these.

2. When I flew the airplane just before the compression check, I could not tell that anything was wrong nor did I see anything unusual on my engine monitor. How do I check for another stuck valve in the future and what can I do to prevent it? BTW, I have not had trouble with fouled plugs and they looked OK when we pulled them so I don't think I have been running too rich and thus causing carbon build up.

Cleve

Pull the prop through

The answer to your question is to make sure the mags are off and then pull the prop through four times to feel the compression of each cylinder. I do this every so often to get a quick health check of the engine.
I bought an overhauled engine because I didn't want to build one and I ended up tearing it down and sending the case out for work 130 hours after installation because of a build error by the person who overhauled the engine.
I guess its all part of playing the game. I'm sure after you get these couple of items taken care of your time and money spent will be well worth the effort.

sad

Cleve - sorry to hear this happened. At least Lyc is making it right. Any idea what actually failed? Cracked exhaust valve? Rings? Other?

Leaning

I hate to ask but can you tell me how lean you run the engine?

You aren't alone...

Sorry to hear about your troubles.

Lycoming has a service bulletin out on sticking valves. There is a lot of focus on oil in that bulletin.

It could give some insight into the problem, or at least let you know their thinking on it.

It might make sense to consider looking at the other three cylinders' valves as well.

Hold it Cleve.....

...before you pull that cylinder and squirt some Marvel Mystery oil onto the valve through the spark plug hole. In the past, we've rigged up a can with a small diameter hose and sucked it into the 1340 Pratt radial engines when we had stuck valves. The stuff's amazing.....most Auto parts stores carry it.

Regards,

Cyl.

Cleve:

Sorry to hear about your problems.

If you--- or anyone else here has a problem with the Skytec starter solenoid, take it to your local automotive starter/alternator electrical shop. The motor and solenoid are common off the shelf, in stock parts.

Mine went out on me, thankfully after I had returned home from long trip. Took it to my local starter/alternator place where they replaced the solenoid within an hour. I saved a lot of money and time.

pierre smith said:

...before you pull that cylinder and squirt some Marvel Mystery oil onto the valve through the spark plug hole. In the past, we've rigged up a can with a small diameter hose and sucked it into the 1340 Pratt radial engines when we had stuck valves. The stuff's amazing.....most Auto parts stores carry it.

Regards,

Click to expand...

Pierre, that might work for a stuck ring, but when you can hear the air leaking through the exhaust system past the valve, then it probably won't do any good. Since staking the valve did do some good, I would suggest dropping the exhaust pipe and having a look at the valve stem for carbon build-up, and borescoping thru the plug holes to look at the valve and seat while the valve is open (off of the seat)
If it's carbon or crude on the stem, it's easy to clean off once you drop the valve into the cylinder and fish it down thru the lower plug hole. The valve guide can also be reamed or cleaned-up if necessary while the valve is out, all while the cylinder remains on the engine.

It's no big deal to pull a cylinder. It will take longer to get the baffling, exhaust stack, and other stuff off than to pull and replace the cylinder.

I had the rings line up on #3 and my compression was down in the low 60's and never came back up. Sure enough, when I pulled the cylinder the rings were all lined up. Indexed the rings and had it running again in three hours. And that was with the usual RV gang standing around talking and asking questions.

The bigger question is why? Cooling, LOP, bad timing, what?

R.P.Ping said:

The answer to your question is to make sure the mags are off and then pull the prop through four times to feel the compression of each cylinder. I do this every so often to get a quick health check of the engine.

Click to expand...

I do this before the first flight of each day.

Webb said:

I hate to ask but can you tell me how lean you run the engine?

Click to expand...

David-aviator said:

Lycoming says in the Flyer, do not lean until above 5000'. I ignore that instruction all the time.

Click to expand...

I also ignore that instruction and LEAN the way it says above except during break-in. Ran over 2,100 hours that way with GREAT service.

I also had one cylinder that was 46 / 80 11-hours after cylinder rebuild. Found a LEAK around the exhaust seat and not through the valve. Borescope said the seat / valve was good. When I pulled the cylinder, I also found a HOLE in the intake port to the spring. Did a SOLVENT leak check of the head and found a leak around the seat. Cylinder was sent to the shop that inspected the cylinders to see if they were serviceable and they told me to SCRAP it. When the cylinders were new, they were ported, polished, and match flowed. IMHO, more material was removed than should have been. The replacement intake spring seat (washer that goes under the spring) had a larger inside diameter hole and a larger outside diameter than the one that came out. This allowed some movement and helped wear through a thin intake port wall.

The shop that inspected the cylinder to determine if the cylinder could be rebuilt after first run of 2,154 hours said that the cylinder was good to overhaul so I paid for ALL NEW Parts only to find that after 11-hours, the cylinders are no good. There went almost $3,200 out the window. Four new ECI cylinders cost me almost $4K with overnight air to get back in the air.

The shop that did the inspection does not want to refund any of the money spent for their BAD inspection or the new parts that I now cannot use. I will be off to SMALL CLAIM COURT in an attempt to recover something.

Before someone asks, I cannot tell the difference (seat of the pants feel or performance data) in performance between porting, polishing, and match flowing than I could from new Superior or new ECI cylinders out of the box.

I will NEVER again attempt to overhaul a cylinder that has been ported, polished, and match flowed.

You might want to...

captainron said:

Pierre, that might work for a stuck ring, but when you can hear the air leaking through the exhaust system past the valve, then it probably won't do any good. Since staking the valve did do some good, I would suggest dropping the exhaust pipe and having a look at the valve stem for carbon build-up, and borescoping thru the plug holes to look at the valve and seat while the valve is open (off of the seat)
If it's carbon or crude on the stem, it's easy to clean off once you drop the valve into the cylinder and fish it down thru the lower plug hole. The valve guide can also be reamed or cleaned-up if necessary while the valve is out, all while the cylinder remains on the engine.

Click to expand...

...perform the Lycoming SB388C service procedure on all of the other cylinders at this time.

http://www.lycoming.com/support/publications/service-bulletins/pdfs/SB388C.pdf

This is the "valve wobble check" that is a rough check for loose or tight valve stems in their guides.

Stuck exhaust valve

Thank you all for the info and encouragement!
I have been running 25-50 degrees rich of peak above 5000 ft. My #3 cylinder head temp is borderline high in the summer so I have been reluctant to lean below 5000'. My spark plugs do not foul so I don't think I have been running too rich. If anything the low speed jet is too lean! I can't get a rise in RPM on mixture shut down.

I have been running Aeroshell 100 and changing it at 40-50hrs. I did use pure mineral oil during first 25 hours. Should I use it again when I put the new cylinder in service or should I use detergent oil?

I have not done a bore scope yet but will do it and I hope that Lycoming will inspect the returned cylinder and let me know what they found. Is that customary?

Gil, I am not a mechanic but inspecting all the other valves and guides sounds like quite a job!!!! The bulletin you quoted seemed to be about defective valve guides. My engine was shipped in 2007. Was the problem with the guides corrected before then?

Again, thanks to all!

cleve_thompson said:

Thank you all for the info and encouragement!
I have been running 25-50 degrees rich of peak above 5000 ft. My #3 cylinder head temp is borderline high in the summer so I have been reluctant to lean below 5000'.
<snip>
The bulletin you quoted seemed to be about defective valve guides. My engine was shipped in 2007. Was the problem with the guides corrected before then?

Again, thanks to all!

Click to expand...

What temp CHT temp are you describing when you say borderline high?

You have the high chrome guides but that doesn't mean their can never be an issue.

My guides wore...

asav8tor said:

What temp CHT temp are you describing when you say borderline high?

You have the high chrome guides but that doesn't mean their can never be an issue.

Click to expand...

...loose to fail the wobble test in my Tiger in 500 hrs. They were the new high chrome ones.

The test is actually quite non-invasive and can be done easily if you have the fixture. The valves do not get removed for the test, they are depressed about 1/4 inch by the fixture as it is tightened, and then the "wobble" is measured with a dail indicator by pushing on the top of the valve.

I think Lycoming will rent you the tool if you can't find one locally.

Since the test also detects tight valves, it would check your other valves for "coked up" valve guides with a corresponding lack of play.

cleve_thompson said:

Thank you all for the info and encouragement!
I have been running 25-50 degrees rich of peak above 5000 ft. My #3 cylinder head temp is borderline high in the summer so I have been reluctant to lean below 5000'. snip

Click to expand...

Cleve, 25-50 ROP is right at the place where maximum cht occurs. I am not implying that #3's temperature is related to your present problem, but it is the potential gotcha associated with trying to lean without all the information such as peak egt by cylinder by fuel flow. The way it often goes is one leans (as we all were taught) until a little roughness occurs (one or more cylinders is/are lean enough where its power output drops), then enrichen a little. This could put one cylinder right at your 25 - 50 ROP, peak cht zone. The others may be quite different from this. In the training type aircraft, an overabundance of cooling exists, so from a cht point of view, the engine doesn't care where it is in the ROP/LOP range. Our RV's are different in this regard; one could say they are optimally cooled, meaning no excess at all.

There is quite a bit in these archives about this, as well as the great John Deakin articles to be found on avweb. Good reading all.