Re: Re :[Amel Yacht Owners] Re: Perkins M 4 .154 engine repairs, rescheduling trip

Mark Erdos

I think Joel was right on with his diagnosis:



More than likely your problem is the crankshaft bearings and the connecting rod bearings clearances are too large. As the engine warms the expansion of components causes the clearances to increase even more and hence the oil pressure to go down.





With best regards,





Sailing Vessel - Cream Puff - SM2K - #275

Currently cruising - Martinique


From: amelyachtowners@... [mailto:amelyachtowners@...]
Sent: Sunday, December 31, 2017 12:53 PM
To: amelyachtowners@...
Subject: Re: Re :[Amel Yacht Owners] Re: Perkins M 4 .154 engine repairs, rescheduling trip






I am afraid I have no good ideas that match your symptoms!  Since you have both the gauge and alarm reporting low pressure, I have to assume it is real and not a problem with the measurement.


Sometimes low oil level can cause low pressure at high rpm as the pump sucks so much oil out of the crankcase it sucks air, but you checked that.


A stuck open pressure relief valve that resets itself when the engine shuts down could be an an issue, but that seems unlikely.


Maybe someone else has an idea or two...  in any event do let us know what the solution turns out to be!


Bill Kinney

SM160, Harmonie

Key West, FL


---In amelyachtowners@..., wrote :

Here is


Yes - oil pressure gauge and l'os pressure alarme on

When oil pressure below  1 bar, alarme nées

Oil pressure drops quickly at 2000 rpm

Oil pressure remains stable when low or normal

Oil pressure remains low when reducing speed from 2000 


No loss of oil single de started.  

Ran 1hour maneuvring in port at 1300 rpm at 2 bars, went To idle after 1 hour at 700 rpm with 1.1 bar oil pressure.

Did  not  risk acceleration. 


Thks for assiste


Christian alby - Desirade VIII - Maramu 116 - now in Mindelo Carbo Verde





Le dim., déc. 31, 2017 à 14:58, greatketch@... [amelyachtowners]

a écrit :


Losing oil pressure at high RPM and having it come back at low RPM is a bit of a puzzle to me.  There are ways it can happen, but they are a bit exotic


Do you have an oil pressure gauge AND an low oil pressure alarm?  

If so, is the gauge showing low pressure AND you get an alarm?  

Does the oil pressure drop quickly at 2000RPM or does it drift down slowly?  

Is it stable, or does it bounce around?

Does it come back quickly when you reduce the RPM, or does it stay low?




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