Determining Burnt Valves
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Posted by: matin ® 10/07/2006, 03:54:49 Author Profile eMail author Edit

Wartsila SW 18 V 38 series engines are installed at our facility for power generation each rated at 11.3MW.The exhaust valves usually are damaged/burnt out during the operation of the engine. We usually record the peak pressures using a digital meter by LEMAG PREMET L that shows something like everything from individual KW produced to deviations and exhaust temperature everything Is it possible to predict on the basis of peak pressure which units valves are burnt or will be in the near future and on what parameter this prediction can be done.

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Re: Determining Burnt Valves
Re: Determining Burnt Valves -- matin	Post Reply	Top of thread	Forum

Posted by: matin ® 10/17/2006, 05:25:56 Author Profile eMail author Edit

Well the engines have covered 60,000 hours and have been completely overhauled but still the problem of valve burning continues. Yes the engines intake valve also gets burnt out in the same fashion as exhaust valves. Can you explain in detail how can excessive air can damage the engine.

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Re: Determining Burnt Valves
Re: Determining Burnt Valves -- matin	Post Reply	Top of thread	Forum

Posted by: Kelly Bramble ® 10/07/2006, 08:05:31 Author Profile eMail author Edit

Normally, burned exhaust valves are an indication of lean burn combustion. If fuel regulation and delivery is identical on all engines, then you should be able to predict valve failure after a few failures. Exhaust temperature is probably more indicatative of life expectancy for a exhaust valve. Assuming you are measuring in the right place. If you have exhaust oxygen readings, you may be able to correlate A/F, to valve failure.

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Re: Re: Determining Burnt Valves
Re: Re: Determining Burnt Valves -- Kelly Bramble	Post Reply	Top of thread	Forum

Posted by: randykimball ® 10/07/2006, 10:12:51 Author Profile eMail author Edit

I agree completely with Kelly, pressure has NOTHING to do with valve burning. If you have taken measures to save fuel by leaning out the mixture, you have done so at the expense of maintenance. The huge success in modern engine power, longevity, ecomony, and reliability, for the most part, have come from the ability to monitor and control combustion chamber temperatures. Also the ability to monitor incoming air volume and oxgen content of the exhaust. We control the temperature by controling the amount of fuel to intake air volume. Too rich a mixture will waste fuel, too lean a mixture will waste engine life. You have commented in the past about exhaust temperatures being high. Have you messed around with the fuel blend or injector sizes in an effort to save fuel costs at the expense of engine life? Your engines were designed to run on a fuel, are you running the fuel specified by the engineers that designed the engine? ... without fooling around with the mixture? Modern diesels now have electronicly controled injector systems that allow control of the fuel/air mixture. As a result torque and life have multiplied. Perhaps money spent to update to a newer control system would save labor, fuel, and engine life enough to greatly offset the costs. However, if you are running diesels 24/7 for power.... they ARE going to wear out, eventually. How many hours do these engines have on them when they show valve failure? Does this engine have intake valves? If so do they not fail? The worst suggestion of your lifetime may be the catalyst to the grandest idea of the century, never let suggestions go unsaid nor fail to listen to them.

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