O-200-A stuck exhaust valve.

[Dan Thomas]

Doesn't the silicon carbide end up charging the soft (bronze?) guide with abrasive particles? A reamer has the advantage that it doesn't leave any non-metallic stuff behind.

Bronze isn't particularly soft. Engine manufacturers can't use soft metals for valve guides. Bronze is used because it resists wear better than steel or cast iron and can take the heat away from the valve better. In 1999 Lycoming finally got tired of valve guide wear (bronze) and went to a high-chromium-content bronze, which lasts well past TBO. I don't know if Continental has adopted the same stuff.

The silicon carbide hones are commonly used to finish dressing resized engine cylinders of cast iron or steel. The carbide doesn't embed in the metal. Like any grinding stone, the grit is held together by a fired clay, and the firing time and temperature determine how hard the clay gets and how securely the grit is held. The hones are made of soft-fired stuff so that the grit easily breaks away once it gets a little dull, and new, sharp grit is exposed. The balls of abrasive are mounted on flexible plastic stems that put very little pressure on the cylinder or guide, certainly far too little to embed anything. In any case, even rigid hones, using large pressures, don't embed grit in the metal.

Aluminum is so soft that it WILL pick up grit. That's why we never use emery cloth on it, since emery uses iron oxide in its makeup, and the iron causes corrosion.

Dan (thousands of hours in the 1980s and early '90s on various machine shop tools, including the big Sunnen CK-10 hone and many other grinding and cutting machines)

 

[Stewartb]

Most guys I know would stake the valve to get it to move and then add some mystery oil in the crankcase as a solvent. It works as often as not for minor stuck valves.

 

[Tom-D]

Valve guides are reamed/honed _once_, then?
And with honing fluid?

Many times it makes no sense to hone or ream an already oversized guide. Replacing the guide with out replacing the seat, valve and springs is penny smart pound foolish.

What it requires to replace the guide, mill out the old guide by removing all the metal except a few thousands of the guide that touches the head. drive out the rest of the guide. then clean up the hole in the head that the guide fits into. Buy an over sized guide and turn it on a lathe to fit the oversized hole. (plus .003") Heat the head, shrink the guide in Dry Ice and alcohol in a thermos, to 480 degrees below zero. then transfer the cold guide to the head and drive it in.
Then the new seat can be installed much the same way.

 

[Witmo]

I've yet to see a type club that didn't have its self appointed expert.

Much like this board.

 

[somorris]

Hi Greenhead.

I have an O-200 and have had valves stick multiple times. The first time, the A&P pulled the cylinder, drove the valve out, honed/reamed the guide, and put it all back together. Cost me something like $800. The next two times, my (new) mechanic tied string to the valve stem, dropped it into the cylinder and fished it out the spark plug hole, cleaned it up, reamed the guide and put it back together. Cost something like $200.

I use 100% Avgas, so lead content is a problem. I use TCP in the gas in an attempt to keep the lead scrubbed out. I lean aggressively, fly it an hour or more every week, cruise at 2550 rpm, and keep the oil changed. A long-time Cessna mechanic said you should use no more than 80 wt. oil, and a lot recommend Phillips 20W-50. I tried Aeroshell 5W-50 but went back to straight weight. The theory is that the thinner oil does a better job lubricating the top end. Some say MMO can be used for this purpose .

Good luck. A new cylinder is not necessarily needed. I have been flying behind the O-200 we have now for nine years.

 

[Tom-D]

Hi Greenhead.

I have an O-200 and have had valves stick multiple times. The first time, the A&P pulled the cylinder, drove the valve out, honed/reamed the guide, and put it all back together. Cost me something like $800. The next two times, my (new) mechanic tied string to the valve stem, dropped it into the cylinder and fished it out the spark plug hole, cleaned it up, reamed the guide and put it back together. Cost something like $200.

I use 100% Avgas, so lead content is a problem. I use TCP in the gas in an attempt to keep the lead scrubbed out. I lean aggressively, fly it an hour or more every week, cruise at 2550 rpm, and keep the oil changed. A long-time Cessna mechanic said you should use no more than 80 wt. oil, and a lot recommend Phillips 20W-50. I tried Aeroshell 5W-50 but went back to straight weight. The theory is that the thinner oil does a better job lubricating the top end. Some say MMO can be used for this purpose .

Good luck. A new cylinder is not necessarily needed. I have been flying behind the O-200 we have now for nine years.

$200.00 Plus $800.00= a new cylinder.

 

[weirdjim]

Heat the head, shrink the guide in Dry Ice and alcohol in a thermos, to 480 degrees below zero.

Dry Ice (solid carbon dioxide) and ethyl alcohol both change state at -40C so I don't think 480 below zero is going to happen.

Jim

 

[Clark1961]

Dry Ice (solid carbon dioxide) and ethyl alcohol both change state at -40C so I don't think 480 below zero is going to happen.

Jim

I'm wondering what temperature scale Tom is using...if it's supposed to be Farenheit then he's got some 'splainin' to do...

 

[Tom-D]

Dry Ice (solid carbon dioxide) and ethyl alcohol both change state at -40C so I don't think 480 below zero is going to happen.

Jim

OK brain fart on the temp. you can also use liquid N2, O2, etc.

 

[Henning]

We tried that but made no difference. Had my fingers crossed.

So, would the best move be to bite the bullet and purchase new cylinder? Then rebuild my original as a spare, assuming that it's a seat problem and nothing else. Trying to go smartest route for the money. Like most, flying on a tight budget with myself and 15yr old daughter using to get ppl. Safety first with her also.

Just trying to weigh out options before jumping.


I want to Die with Memories, Not Dreams!

Yes, the best solution on this will be to replace the cylinder now. You'll spend nearly as much fixing this one, and likely have a return issue. Switch to MoGas to prevent further issues.

 

[Greenhead]

Yes, the best solution on this will be to replace the cylinder now. You'll spend nearly as much fixing this one, and likely have a return issue. Switch to MoGas to prevent further issues.

Yes, decided to do just that after researching. Any specific type/brand I need to concentrate on? Stay close to original or get the aftermarket types? They all seem within a few hundred bucks of each other.

 

[Tom-D]

Yes, decided to do just that after researching. Any specific type/brand I need to concentrate on? Stay close to original or get the aftermarket types? They all seem within a few hundred bucks of each other.

Go with the ECI cylinders, they have an exhaust rotation device installed on the exhaust valve which pretty much eliminates the burned valve problems.

Then switch to Phillips 20W50, and change oil at 25 hours.
Mogas will not stop all problems with the cylinders. Its just a different set of problems.

 

[Greenhead]

See where ECI cylinders have had issues in the past. Concerns?

 

[Let'sgoflying!]

Go with the ECI cylinders, they have an exhaust rotation device installed on the exhaust valve which pretty much eliminates the burned valve problems.\

Zis true on big bores, Tom?

 

[Tom-D]

See where ECI cylinders have had issues in the past. Concerns?

There has never been an AD issued for the 0-200-300 cylinders there has never been any "ISSUES" with ECI cylinders for the 0-200/0-300/GO-300

Know what you speak, before you slander a product.

 

[Tom-D]

Zis true on big bores, Tom?

Don't know big bores, but all their operators have problems with all makes, this was the major driver for LOP operations with these engines.

I don't operate them.
I don't fix them.
I don't play with those who do.

 

[Greenhead]

There has never been an AD issued for the 0-200-300 cylinders there has never been any "ISSUES" with ECI cylinders for the 0-200/0-300/GO-300

Know what you speak, before you slander a product.

I didn't pull that thought out my Ass.
You have stock in them? I like anyone else "googled" what you suggested and immediately had multiple articles pop up. I'm no mechanic, just asking a simple question. Slander? Better sue Google but that Ahole comment of yours did more damage for ECI in my book.

 

[Tom-D]

I didn't pull that thought out my Ass.
You have stock in them? I like anyone else "googled" what you suggested and immediately had multiple articles pop up. I'm no mechanic, just asking a simple question. Slander? Better sue Google but that Ahole comment of yours did more damage for ECI in my book.

I did too, and found on bad issues for the ECI 0-200 cylinders

https://www.google.com/?gws_rd=ssl#q=0-200+ECI+cylinders

Be certain you google the right subject.