Frequent Spark Plug Failure in Waukesh L5790 Gas Engine

[skhan2010]

Hi All,

I am doing the RCA of Frequent Spark Failure for the subject gas engine. We are using Champion RHM77N Spark Plug, within course of 2-3 months frequent failure occured and it some cases we change the spark plug and after running the engine for one day explosion was also happened.

Appreciate your experience advise to look for the different element of "5 WHY".

Regards

SK

 

[crerus75]

What are the symptoms or characteristics of the failure? Is mechanical damage (IE cracked insulator) visible? I ask this because you mention the word "explosion" in your thread. Are there any deposits on the plug? If so, do they appear to be metallic? What fuel is being used (propane, landfill gas, etc.)?

 

[Tmoose]

This link shows it as an interesting spark plug. 18 mm thread, armored shell, no ground "strap" electrode.

http://www.sparkplugs.co.uk/pages/database/plug-detail-ccp.asp?partno=RHM77N

 

[catserveng]

Depending on the application, fuel and operational load factors, 2-3 months may be normal service life for the plugs.

In analyzing spark plugs failures and service life issues there are a lot of things to look at.

Some of the questions have already been asked above, some others include,

How often does it start and stop?
What is current run time on engine?
Is it operating as a rich burn, lean burn or a just run it and go? Air/fuel ratio has a pretty big impact on plug life.
Is the engine oil consumption normal?
What is condition of the rest of the ignition system? Transformers, extension leads, primary wiring and the ignition module or magneto?
Can you better describe "explosion"? Was it an exhaust backfire, or in the inlet?
Are the plugs being properly gapped and installed?
How are you determing a plug has failed? Lower than expected cylinder temps? Indication for ignition system (if it's electronic ignition)? Poor performance or inability to maintain emissions?
Are you required to maintain emissions compliance? Is any form of after treatment installed?
What does your engine dealer or service company say about the problems?

Mike L.

 

[Lou Scannon]

Spark plug design & application is a truly esoteric subject. If you are not consulting with the spark plug manufacturer and the engine performance experts at the OEM, you need to be.

"Schiefgehen will, was schiefgehen kann" - das Murphygesetz