oil in a diesel engine

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obenton

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Aug 7, 2016
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how long should it take to get oil up to the rocker arms after a cold start - in 3208ta engine.
 
Rocker shaft is pressure fed through passages in head and rocker supports. Rocker arms distribute oil to pushrods and valve tips by dribble. Takes a little while for oil to get everywhere up there.

Why are you asking? Engine having a problem?
 
oil i

diesel surveyor said the starboard engine was slow to get oil to the rocker arms- said it took 15minutes for him to see oil with the cover off and should have been a minute or two.
 
15 minutes? Odd...our 3208TAs have only a few moments of valve clatter, then quiet.

When was the last time the oil was changed?
 
The pathways for oil to get to the valve gear needs to be clean. I've taken appart valve systems in the old days that were plugged up. Modern engines are very much cleaner than the old but running at a very low load, basically cold invites the buildup of deposits that minimize oil flow and eventially can plug up an engine.

It's possible this engine is partially plugged up and when cold oil is slow to move through the passages and get to where it's needed.
 
Be careful about premature wear obenton. Honda and Mazda V6 engines sold in Australia some years back had inadequate oil feed to the quad cam engines, ruining the valve gear and costing a heap for owners and for warranty.
How did it sound compared to the other one, after the oil arrived and it warmed up?
 
A modern diesel lube oil is very high in detergents , so a couple of changes HOT ,after a long hard run might be cheap insurance.
 
Take the rocker shaft off and make sure oil passages are clear.

Oil pressure sender and alarm switch are on the head, so if gauge is reading good pressure, you know the oil has at least made it up into the head.
 
engine oil

the engine ran well. made the rated prop rpm and speed. He said it was not critical but may be a cam bearing problem and oil should reach this area sooner and needs to be investigated. No alarms sounded. His routine is to check all temps with the gun and gauges at 200-400- 600rpm ect for 20 minutes each ; then wot for 5 minutes. It is a 3 to 3 and a half hour sea trial. I admit it is mostly over my head.
 
diesel surveyor said the starboard engine was slow to get oil to the rocker arms- said it took 15minutes for him to see oil with the cover off and should have been a minute or two.


15 minutes :eek: run forest run something is drastically wrong and damage may have already taken place
 
15 minutes :eek: run forest run something is drastically wrong and damage may have already taken place

I would even say 15 SECONDS is too long based on my engineering experience designing and testing automotive camshafts for both gas and diesel engines.
 
If oil pressure read normal on start, then cam is fully lubed and oil pressure is present in head where rocker shaft mounts and where oil pressure is measured.

If oil pressure reads normal and it is just slow to start bleeding out of rocker shaft, the problem is local to rocker shaft and its port in the head, cam is not affected.
 
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