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Possible injection system problem

Fuel flow

I presume you have a monitor. Does it fluctuate one way or another from normal during these episodes?
 
The fuel flow monitor is currently out of the system. I was trying to remove possible contributing components. When it was in the system i would get some small fluctuation during normal ops but Airflow Performance said that variation was normal.

The EGT spikes when I reduce power so the fuel flow is changing anyway so I woukd not be able to tell change is due to throttle reduction and what is due to the root cause.

The EGT spike when reducing throttle normally means an induction leak, and we've fixed some of those. I will pull the intake tube for #3 today again and check it. I've had 2 cracked intake tubes and several bad o-rings.

I'll put the fuel flow transducer back in today since that apparently is not the problem.
 
Walt,

I have a HF 8mm wide inspection camera with a mirror that you can use. I used it during my last condition inspection and could see the valves using it.

Let me know and I can run it over during lunch today -- TJ
 
TJ - Walt may already at Hicks and I am getting ready to leave Keller for Hicks. I could come by 52F if that's where you are located and pick it up.

512-850-8339 cell if that works for you. I appreciate the offer.


In a post in another thread Mel says to beware of using SCAT tubing in the intake. I have a very old FAB setup with what I think is SCAT tubing.

What should I be using?

The original thread and posting is here http://www.vansairforce.com/community/showpost.php?p=55990&postcount=3
 
Just read the whole thing...

Wow, you have certainly had a time with this. I had an issue early on in Phase I. Could hardly keep the engine running on final or on the ground thereafter :eek:. Both cylinders on one side had were acting up (don't remember which side or whether they had gone hot or cold EGT). After talking with Precision, I pulled the top off the spider and found some small black specs of ?? in the spider. I cleaned it all up including flushing the injector lines. Problem solved. Did you ever check out the spider?? This could be an issue especially since the servo inlet filter wasn't always doing it's job...
 
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Thanks for the idea, Terry. Spider and servo were both rebuilt and tested last month by AFP. They didn't find any particular problem but they had an unknow but large number of hours on them and so I had them rebuild the system.

We also flow checked nozzles and lines last month and all checked ok. I might swap #3 and #1 nozzles and see if the problem moves, but I doubt that is the problem. All the nozzles were new as of a year ago.
 
So where do I go from here? Fuel injections and mags were rebuilt, engine driven fuel pump new, old hoses replaced, fuel filter checked and fuel tank vents are ok. Compression checked fine after the last occurance and the exhaust valve wobble test was passed.

I think i'll go back to drinking. I was better at that than owning/maintaining an airplane. It was a lot cheaper too.


Where do you go?
Don't be discouraged. Don't go back to drinking :) Re-read the PM I sent you as you put it back together. Even if you happened to fix the earlier problem, it is very likely to have things go wrong after having so many things apart.

This very thing happened to me recently with an automobile. A dealer installed a new short block under warranty. The mechanic was "our best". About a month later, I had steam pouring out from fender wells and grill. A small coolant hose never had the clamp moved the inch or so back up onto the noozle, so the clamp couldn't do it's job, the hose worked loose and came off. Bummer, yes. Unexpected, not at all. Changing a short block involved touching every single engine support system and accesory.

Instrumentation- it is important diagnostic tools are available so this can be figured out. Great that you have an engine monitor, you've already narrowed it to #3. Fuel pressure is steady? Pressure in range? Fuel flow?(that needs to go back on), so you can see if fuel is different when rough than not rough.

Lastly, try contacting Mike Busch. He started a business that occupies a very needed niche. Owners of certified Cirrus aircraft were finding themselves facing $5K annuals. Much of the proposed maintenance is not in the owners best interest. Mike helps owners sort out what is in the owners best interest. AFAIK, Mike won't take an RV on as a managed airplane, but if you are persuasive, maybe he would do a one time deal to work with you and a mechanic so this could be sorted out. He's a pro and by reading and listening to much of his work, I know he loves a good challenge. http://www.savvymx.com/
 
Thanks Stan. I may contact Mike but Walt A. is helping me sort it out right now.

Additional actions since last posting:
1) checked compression on all cylinders cold - 1, 2, 4 were >75 BUT 3 was 45!
2) looked in cyl 3 and saw a small amount of oil pooled. Cyl 1, 2, 4 did not show that. Makes me suspect rings
3) started engine and it ran rough but I think I over-primed it. Once it cleared out it ran smooth and everything looked normal.
4) shut it down and did a warm-cylinder compression check. ALL CYLINDERS now tested >75 including #3
5) Yesterday we did a cold compression check on #3 and it was 72 - a little low. We also removed the valve springs and checked the valve guides in cylinder #3 and they were fine. The valves operated smoothly. Also checked dry lifter valve clearance - also ok.

Two possible paths:
1) Fly locally to try and get the condition to repeat itself and record all the data. I love my SkyView but unfortunately it does not have a data recording feature right now.

2) I think the problem is one or more bad rings in #3 and may pull the cylinder next weekend and take it to a shop for a thorough check.
 
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#3 cylinder compression

#3 w/ cold compression at 45psi is grounds for further inspection if it does repeat a second test at near 45psi (cold) after operated to operating temp.

There are cases of low compression readings that are misleading, when cold, due to good and serviceable rings being in alignment. This is rare, but proven to happen. Point is there should be a second, cold compression test performed to clarify this issue. Also, a small grain of carbon deposits can cause the same if on the valve seat. To check, remove the valve cover and with a rubber mallet strike squarely on top of the valves which will crush any deposited preventing a good seal of the valves.

You may have heard and/or done these tests. If so, just disregard.
 
2) I think the problem is one or more bad rings in #3 and may pull the cylinder next weekend and take it to a shop for a thorough check.

It is great Walt is helping you. Hope you guys figure it out. Have you detected where the air is escaping? Very helpful if you can hear hissing say from the dipstick tube, exhaust system...intake system. Also, it isn't unusual to see oil on the "wrong" side after the engine has sat for a while. How do the plugs look? If it looks like oil fouling, then sure pull a cylinder. but pause for a moment if the valve stems are in spec and the plugs look good. Ask yourself and the person suggesting you pull the cylinder, how does low compression cause rough running? I can't get the memory out of my head of the test stand engines that get hours and hours of abuse, end up having really low leakdown test numbers, and still put out rated power.

I like the boroscope idea much more. Mike Busch did an excellent presentation you can watch on cylinders and boroscoping over http://www.eaavideo.org/video.aspx?v=1204537102001
Webinar- All About Cylinders
October 6, 2011 - Mike Busch presents a webinar about cylinders: including construction, failure modes (head cracks and separations, exhaust valve failure, barrel wear), maint.-induced failures , factors affecting longevity, repair, replacement, top overhauls, etc

He makes a convincing argument that leakdown tests might have been the best we had years ago, but they don't tell us very much. These days with the wide availabilty of boroscopes, that is the go to tool.
 
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TJ leant me a boroscope which I used a bit. The link to the EAA video was broken but I know how to track that video down.

The plugs looked good. Maybe a smudge of oil on the lower plug but really nothing to suggest fowling. Top plug looked great.

One other thing that Walt found was we pulled the intake tube on #3 and there was very slight evidence of poor sealing in one small area. I bought a new gasket and installed it with a thin coat of #2 Permatex on both sides. The slight leak may have been a contributing factor but I doubt it is a significant factor but what the heck, we might as well keep eliminating possibilities.

The air was escaping out the crankcase vent which implies rings.
 
My buddy Mike (A&P) and I went to the hanger this morning to pull #3 cylinder. I was out of ideas and just decided to pull it and make sure every thing was right.

When I disconnected the oil drain line Mike blew throguh it and it felt to him like it was plugged. He blew more and all of a sudden it blew freely. We checked the other three lines and all blew freely.

We decided not to pull the cylinder until we get some understanding of what effects we would see in the engine from a plugged or mostly plugged oil drail line.

We have seen a oily bottom plug and some residual oil in the troublesome cylinder. Could that somehow be caused by oil backing up in the valve cover?
 
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We have seen a oily bottom plug and some residual oil in the troublesome cylinder. Could that somehow be caused by oil backing up in the valve cover?

Sure, this would both keep the valve guide submerged, and if the inflow vs blockage is high enough it would add pressure to the submerged guide.

Cheap, and easy to test fly it with the line now free-----I would go for it.
 
My buddy Mike (A&P) and I went to the hanber this morning to pull #3 cylinder. I was out of ideas and just decided to pull it and make sure every thing was right.

When I disconnected the oild drain line Mike blew throguh it and it felt to him like it was plugged. He blew more and all of a sudden it blew freely. We checked the other three lines and all blew freely.

We decided not to pull the cylinder until we get some understanding of what effects we would see in the engine from a plugged or mostly plugged oil drail line.

We have seen a oily bottom plug and some residual oil in the troublesome cylinder. Could that somehow be caused by oil backing up in the valve cover?

Did something actually come out of it? If it was full of oil it would be difficult to blow thru until the oil cleared. Can't say as I've ever heard of a plugged oil line before but it certainly is possible (may a piece of old gasket material or silicone?).

It could definatly account for oil running into the cylinders thru the guides and the engine getting rough if it starts to pump a bunch of oil into the cyl. When I removed the valve covers last week to check the valve side play I did not notice any excessive oil build up. Did you ever notice a cloud of blue smoke coming out the tailpipe (like some of my old cars used to do)?
 
I never noticed any blue smoke and no one mentioned seeing any, and oil consumption was normal, about 1 qt per 10 hours.

One of the other tubes had some residual oil but it blew out easily. This one definitely took more to blow it out according to Mike.

Here's the other revelation that came to me last night in my sleep. Yesterday Ron, who owns the hanger I rent, stopped by and listened to my tale of woe and we started thinking about spark plugs. We checked the Champion literature to make sure I was using the right plugs. I currently use REM-38E plugs installed about 2 years ago during a condition inspection. Before that time the engine had REM-37BY plugs, both of which are listed for an O-360-A1F6D engine.

Ron suggested going to a hotter plug in case that cylinder was getting oil on the plug and causing fouling. After he left I went to the Sacramento Sky Ranch on-line troubleshooting guide to read up on spark plugs and found that higher compression engines need cooler not hotter plugs! My engine has higher compression pistons installed when the cylinders were replaced 3 years ago.

Perhaps my problem is I should go back to the REM-37BY plugs! Could it be that simple? I don't know but I might go back to the old plugs and see if the problem comes up again.

I need to check the engine log book to see when I put the hotter plugs in and then check my pilots log book to see if that was just before the first occurrence of the problem, which was on a flight to Iowa. If the occurrence was after the plug change then we may have found a contributing factor.

When I got back from that flight to Iowa I inspected the ignition harness and found two spots where the insulation was worn away. I replaced the harness and thought I had fixed the problem. It never occurrence to me to put the old plugs back in, i.e. reverse what I did immediately before the problem started.
 
An update

I did some serious digging on the internet looking for information on what the effects from a clogged drain tube would be. Some information was at Sacramento Sky Ranch, but I came across a great series of articles about lack of oil flow to the odd-numbered cylinders on Lycomings by Bill Marvel and Bill Scott. Here is a link to the first of the series, and links at the bottom of each page will take you to the next installment.

http://egaa.home.mindspring.com/engine1.htm

These articles are very informative even if you do not have an engine problem. They really explain a lot about lifters that I found very interesting.

One thing they say in the articles is the flow up the pushrods into the valve covers is used to carry away heat from the valve stems. If insufficent oil is being pumped up there then heat will not be carried away fast enough. I would surmise that if insufficient oil is draining out heat might not be removed fast enough either.

The articles talk about problems with engines in Mooney TLS aircraft typically flown long periods at cruise power at high (but still normal) CHT temps. Apparently there was an abnormally high rate of valve distress in these aircraft. We would think that long, constant power cruise would be a good environment but apparently as originally configured there was some time related and oil flow related problem on the right side. The same engine and aircraft model used for short hops or low power ops had few occurances.

Heat was causing either valve sticking (due to coking of the oil?) or excessive valve guide wear.

Lycoming's fix was to provide another flowpath of oil to the cylinder heads to cool the valve stems along with larger diameter drain tubes to drain the larger volume of oil.

The series of articles is mentioned in VAF forums and lead me to lots of discussion about Marvel Mystery Oil (MMO) and Camlube and other additives to prevent valve problems. I used to lease a 172 to a flight school and that plane (O-320) flew 100 tough hours each month without any problems. The mechanic that took care of that plane and most of the rental fleet used MMO in the oil at every oil change.

There was also lots of discussion about MMO in the fuel especially when using auto gas, which I don't use, and how it can help stuck rings, which I suspect is part or all of my plane's problems.

So, I pulled the bottom plugs on all cylinders and the top plug on 3, the main offender. On all cylinders I squirted some MMO up against the top of the cylinder then pulled the prop through about a dozen times. On #3 I put the plug back in the bottom, brought the piston up to TDC and filled the combustion chamber with MMO. I then worked the prop back and forth about 20 degrees to try and get some oil on the cylinder walls and to the rings.

I then dropped the bottom plug, and drained out the remaining MMO, then finished replacing a worn alternator bracket, cleaned, gapped and installed REM37BY plugs in #3 cylinder, put the cowling back on and went flying. The plane seemed to generate full power, flew well, and never skipped a beat for a 30 minute flight.

By that time it was getting dark and I needed to get home. I will be back out to the hanger tonight to pull the cowling and check the alternator bracket installation and fly some more if time permits. I have a business trip to Kansas later this week and if things feel right I may take the RV. About 2 hours by air and if the MMO solves the problem perhaps I will know it.

The part that strikes me about the article is the apparent time factor in the Mooney problems. It was during prolonged cruise that the problem presented itself, and that is when my problem has always occurred - after 1-1/2 to 3 hours of cruise flight.

I guess only time will tell but I intend to continue to use the MMO in the oil and did add some to both full tanks before flying this last time. If rings are the problem and MMO helps unstick rings then I am all for it.
 
45 minute flight successful

I flew 45 minutes last night and temps, power and all seemed fine. I need to go to Kansas (1+45 flight time) tomorrow afternoon and intend on taking the plane. There are a lot of airports along the way and if it starts having problems I'll stop, get a rental car and drive the rest of the way.

It will take a while for me to relax about all of this but that cannot happen if I don't stretch the flight time out.
 
REM37BY spark plugs

All the oldtimers at my airport swear by the REM37BY spark plugs and won't run anything else. I ran them in my Cherokee too, they always stayed cleaner and never fouled. I intend to buy a set for my new-to-me RV-6 after my bank account recovers somewhat from the initial purchase of this plane. I'm a true believer in those plugs.
 
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5 hours flying time no problems yet

Flew from Fort Worth to Enid, OK with no problem, then an hour locally for some photo shoots, then refueled and flew back to Fort Worth. No recurrence of the problem.

That's about 5.0 hours since

1) treating all cylinders with Marvel Mystery Oil (MMO)
2) adding MMO to oil
3) adding MMO to fuel
4) putting REM37BY plugs IN Cyl 3

No conclusions yet but everything seems to be working fine.
 
Another 1.0

Flew it hard for an hour today without issue and until the next incident hereby declare it fixed. I say that as much for my sanity as anything else. At some point I just have to start flying it regularly and relax and enjoy it. That point is now.

Weather pending I'll fly my wife from Ft Worth to Midland next weekend to see her Dad and then I'll do some sight seeing over west Texas I have been wanting to do, then fly back with her on Sunday. I will keep an eye on available landing spots, but we all should be doing that all the time anyway. But I will do my best to relax, enjoy, and trust.
 
I "hope" that the plugged oil tube was the true source of the problem, otherwise, MM oil is just putting a temporary band aid on the problem (stuck rings or valves). Assuming that the plugs had previously been swapped around to other cylinders, the only thing the 37BY plugs will do is resist fouling better then the 38E.
 
In my mind there are three different things to separate.

Sticking rings and/or valves may be cured by MMO. Since the mechanism that causes rings and valves to stick is unknown by me, I have no way of eliminating the root cause so the MMO is less a bandaid and more a over-the-counter drug that provides alergy relief. It does not cure the root cause of the alergy but does manage the symptoms.

The spark plug issue is probably not the root cause of my issues. The plugs have never shown fouling probably because i lean during taxi and cruise.

The plugged drain tube may have played a role but I do not understand the mechanism between the effect (rough engine, high EGT on the cylinder, loss of power) and the possible cause (clogged drain.). I really have nothing to go on other than one statement that Lycoming said that oil backing up in the valve cover can cause loss of power.

I agree with you, Walt. I hope the drain tube was the real root cause. I will check all four tubes during every condition inspection. If the drain was the problem the MMO bandaid will only cause minute harm to my pocketbook which is a small price to pay for peace of mind.
 
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My take on it.

The plugged drain tube may have played a role but I do not understand the mechanism between the effect (rough engine, high EGT on the cylinder, loss of power) and the possible cause (clogged drain.).

The clogged drain would have allowed pressure to build inside the valve cover, and forced oil past the valve guide.

This could have cause spark plug fouling, which results in incomplete combustion. Remember that the second plug is not only a redundant source of ignition, but due to the low compression, and large bore, it is needed to get the total fuel/air load to burn completely. That is why you get a drop in RPM when doing a mag check-----it takes both plugs to get all the fuel/air mix going.

Incomplete combustion results in loss of power, rough running, and high EGT due to the fuel still burning as it goes out the exhaust, instead of being consumed in the combustion chamber like it should be.
 
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Mike - that may be true, but getting past the guide still only gets the oil to the top of the valves. On the exhaust side the hot exhaust gases rushing out will carry away or burn away the oil on that valve.

On the intake the air is flowing into the cylinder so your idea seems to be logical especially since the piston is sucking the air in so there would be a greater pressure differential working to bring the oil in. Wouldn't it be more pronounced at low power levels when the throttle plate is partially closed so the manifold pressure is low rather than close to atmospheric?

If that were the cause the bottom plug on #3 should have been oily but was dry. Now perhaps once I landed and taxi'd in the oil burned out of the plug but it seems unlikely.

I'm not saying you are wrong, I'm just saying "inconclusive."
 
Just returned home after a 6 hour 2 day cross country. No issues noted. Still planning on a weekend trip to see my father in law but maybe the problem is behind us.
 
Updates

Just returned home after a 6 hour 2 day cross country. No issues noted. Still planning on a weekend trip to see my father in law but maybe the problem is behind us.

Thank you for the updates. We all learn from others issues.

Glad to see your success.
 
Wow, that is some tale! If nothing else, you seem to have rectified a lot of small snags which may have caused you other problems in the future. I really hope you have found the root cause.

I'm not flying yet, but think I will bookmark this thread for ideas if I ever get engine problems!
 
It's a Marvel...

If the drain was the problem the MMO bandaid will only cause minute harm to my pocketbook which is a small price to pay for peace of mind.

John,
I grew up with an IA Dad who operated our 57' C-182 on MoGas for 33 years. He used Marvel Mystery oil in both the fuel and the oil, 5 hours prior to change. Why? MMO is a high detergent fluid. It breaks down carbon deposits and disperses them into the oil, removed during change. He also used it fervently in fuel in small Continentals, notorious for sticking valves. Additionally, we always ran REM 37BY plugs in every engine we operated.

I have been flying RV's for 20+ years and operated my RV4 and current RVX on MoGas/MMO with REM 37BY plugs (Mag) and Autolite 386 plugs on my Electronic Ignition. I have had clean plugs and engines for over 2500 hours.

That's good enough for me...

V/R
Smokey
 
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I have been flying RV's for 20+ years and operated my RV4 and current RVX on MoGas/MMO with REM 37BY plugs (Mag) and Autolite 386 plugs on my Electronic Ignition. I have had clean plugs and engines for over 2500 hours.

That's good enough for me...

V/R
Smokey

If Smokey says it here and I think Pierre is a big proponent of MMO (hope I did not just put words in his mouth) then I'm on board.

I flew just over 3 hours this weekend and that brings time since starting the MMO to just over 17 flying hours without a hitch. The proof is in the pudding as they say and right now the pudding is better than it has been in a long time.

I really appreciate everyone's ideas, comments, wisdom and stories of problems encountered and overcome, but most of all the encouragement. It was pretty embarrassing to admit that I could not definitively identify the cause of the problem and started throwing $s at the problem but I don't think anyone chided me for it.

Looking back, the encouragement was at least as important as the help analyzing the problem.
 
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