Menu Sign In Contact FAQ
Banner
Welcome to our forums

Sticking O-200 exhaust valves

I also started experiencing this “morning sickness”on my newly overhauled engine of my old C150.I was using Aeroshell W100 Ashless disp.,100LL,agressive leaning and mostly 65% power.Problem resolved by dumping 100LL and solely using unleaded autogas.

LGGG

I have to say I’ve heard that aeroshell and total are the same oil.

I wonder if silvaire has touched on something with the use of unleaded fuel. A friend of mine ran a C150 for about 1500 hours on UL91. And he had no lead fouling problems during that time. He did however have one cylinder replaced due low compressions.

That engine now has 3600 hours on it. With as far as I know no other maintenance.

Unfortunately we don’t have UL91 at our home base and the self filling with forecourt mogas isn’t allowed.

Thinking about the other 3 cylinders one would assume that they will be in a similar state. Shoukd they get similar attention or let’s just carry in?

UL91 is very good but not permissible on my engine whilst running on straight oil during the running in period.As soon as I,m on multigrade with the correct additive I ,ll revert to my former habit of running on a mix of 100LL/UL91 as available and leave one of my smaller tanks exclusively 100LL.

EGMD EGTO EGKR, United Kingdom

Stampe wrote:

UL91 is very good but not permissible on my engine whilst running on straight oil during the running in period.As soon as I,m on multigrade with the correct additive I ,ll revert to my former habit of running on a mix of 100LL/UL91 as available and leave one of my smaller tanks exclusively 100LL.

What engine? Lycoming allows the use of additive for unleaded AVGAS during the break-in period.

ESKC (Uppsala/Sundbro), Sweden

MedFlyer wrote:

I also started experiencing this “morning sickness”on my newly overhauled engine of my old C150.I was using Aeroshell W100 Ashless disp.,100LL,agressive leaning and mostly 65% power.Problem resolved by dumping 100LL and solely using unleaded autogas.

We have used unleaded autogas and that have created troubles with valve sitting, and leak problems on exhaust valve. After adding additive with lead (for old car engines) … problem is gone. This is based on Conti o-200 and Lycoming o-360 experience.

LQVI,LJMB

My experience of the O200 has been much better. Many locally get over 2000 hours with one top overhaul. 2900+ is common, and not flown high monthly hours. Mainly on Mogas.

Maoraigh
EGPE, United Kingdom

Actually that ties in with a jodel owner local to me. He run about 800 hours almost totally on mogas and he tells me it’s as clean as a whistle and he not even had to clean or changes spark plug in 800 hours. I get through between 2 and 4 every 150 hours.

So going forward I can

Use UL91 – not available to me
Use Mogas – Ethanol free isn’t available
Lean more aggressively – I lean pretty aggressively as it is.
Work the engine harder – not going to happen due increased fuel burn.

So it looks like the problem won’t go away.

Of course continental could design better cylinder heads but again that not going to happen either.

I wonder if the real issue is with lack of engine instrumentation i.e. correct leaning? I know leaning is generally not covered in the PPL, and this is for understandable if unfortunate reasons (lack of time in the syllabus being one). But I have not cleaned my plugs in hundreds of hours too. They are taken out at each service but there aren’t any deposits worth removing.

Administrator
Shoreham EGKA, United Kingdom

You do not benefit much from instrumentation in leaning a small carbureted engine like the O-200. Mixture distribution is uneven regardless of instrumentation. I’d bet not leaning is part of the issue, but it is a relatively simple thing with a simple engine.

Hello Batman.

If you have no choice but to run on AVGAS, then at least reduce your oil change intervals to 25h and only use straight mineral oil. We had some trouble with stuck exhaust valves on mid time cylinders and later again with new ones from Continental. After doing some research we now have been trouble-free with:
using car fuel (maybe you can find some ethanol free after all? TOTAL and SHELL, as far as I know, promise to keep their premium fuel free of alcohol),
aeroshell w100, oil change every 25 h,
oil filter adaptor for spin on oil filter.

If one cylinder has sticking valves, do yourself a favour and check all exhaust valves. Check out “rope trick” on youtube.

Those new valve guides have a harder material and seem to not make the situation better with new cylinders.

If you clean the valve guides be sure to do it correctly with the right tools.

Have I mentioned the importance of very regular oil changes?!!!

Good luck

20 Posts
Sign in to add your message

Back to Top