Inlet / Suction valve cut

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Pengze
Mechanic
Posts: 60
Joined: Tue Sep 23, 2008 8:57 pm

Inlet / Suction valve cut

Postby Pengze » Wed Jul 11, 2012 3:51 am

Dear Sirs,
What are the causes for inlet / suction valves cut during operation for a medium speed diesel engine ?
Appreciate yr valuable feedback. Thks.

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Big Pete
Engineering Mentor
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Joined: Fri Apr 24, 2009 11:18 pm
Currently located: Solihull, England

Re: Inlet / Suction valve cut

Postby Big Pete » Wed Jul 11, 2012 10:24 am

Sorry Pengze. i do not understand your question. Please elucidate.
BP
It is always better to ask a stupid question than to do a stupid thing.

jimmys
Officer of the Watch
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Joined: Tue Nov 16, 2010 4:09 am
Currently located: Glasgow Scotland

Re: Inlet / Suction valve cut

Postby jimmys » Wed Jul 11, 2012 10:47 am

Usually caused by poor valve rotators, and worn guides. Medium speeds are famous for this. The exhaust valve is removable in a pocket sometimes and the intake valve is never looked at. Water can be a problem in the air from intercoolers and can cut valves.

regards
jimmy

Pengze
Mechanic
Posts: 60
Joined: Tue Sep 23, 2008 8:57 pm

Re: Inlet / Suction valve cut

Postby Pengze » Wed Jul 11, 2012 7:49 pm

If the valve stem seals are defective, will this contribute to the suction / inlet valve cut / damage ?

jimmys
Officer of the Watch
Posts: 127
Joined: Tue Nov 16, 2010 4:09 am
Currently located: Glasgow Scotland

Re: Inlet / Suction valve cut

Postby jimmys » Fri Jul 13, 2012 12:50 am

The stem seals control lubication to the valve stem and if they wear build ups of carbon due to over lubrication appear on the stem and the valve sticks and can seize in the guide. Sticky valves can off course contribute to cuts. Once the suction valve leaks and gas passes the stem seal there is no lubrication and a grey scum is seen in the valve area and contaminates the oil.

regards
jimmy


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