Engine losing oil pressure
 

Help!!!

Hi all

anyone had this problem?

I have a twin engine searay
with 454's


I just hand the heads , valve's, new rocker arms, and valve springs
done in the one engine

I ran the boat at the dock for a good 8 house with no issues. I even
changed the oil several times just to be sure


I took the boat out last night and after running under load for about
15 minutes the engine in question started to lose oil pressure.

At once I shut the motor down.

I got back to the dock expecting to see oil sprayed all over my engine
compartment, but I found nothing, no leaks drips or any sigh of oil
leakage

Checked the dip stick and it was fill and very clean.

well I got back to my slip and took a look at the oil filer , it
seemed to have some stuff in it as I assumed that it would, so I
changed it, and re started the motor.

As the filter filled the oil pressure gauge jumped up, but not as high
as it should.


Anyone got any thoughts ?

on why all of a sudden I got no oil pressure?

Thanks
M

Engine losing oil pressure
 

"Big gus" wrote in message
...
Help!!!

Hi all

anyone had this problem?

I have a twin engine searay
with 454's


I just hand the heads , valve's, new rocker arms, and valve springs
done in the one engine

I ran the boat at the dock for a good 8 house with no issues. I even
changed the oil several times just to be sure


I took the boat out last night and after running under load for about
15 minutes the engine in question started to lose oil pressure.

At once I shut the motor down.

I got back to the dock expecting to see oil sprayed all over my engine
compartment, but I found nothing, no leaks drips or any sigh of oil
leakage

Checked the dip stick and it was fill and very clean.

well I got back to my slip and took a look at the oil filer , it
seemed to have some stuff in it as I assumed that it would, so I
changed it, and re started the motor.

As the filter filled the oil pressure gauge jumped up, but not as high
as it should.


Anyone got any thoughts ?

on why all of a sudden I got no oil pressure?

Thanks
M


"No" or "low" oil pressure? Was the engine still warm after you changed
the oil filter?

It's perfectly normal for oil pressure to drop from a high reading to a
lower one once the engine warms up. You didn't mention doing rings, etc.,
so I assume they are original. General rule of thumb for an engine with
some hours under its belt is a minimum of 10 psi per 1000 rpm engine speed.
I can't think of a reason why a valve job would influence oil pressure,
unless the valve guides were screwed up and you were burning oil big time
although it seems like it would take longer than 15 minutes of running to
burn up most of the oil. But then again, I am not a mechanic.

Eisboch

Engine losing oil pressure
 

I just hand the heads , valve's, new rocker arms, and valve springs
done in the one engine

I took the boat out last night and after running under load for about
15 minutes the engine in question started to lose oil pressure.


Assuming that the headgaskets were changed and that you are not running
a drysump or scavanger oil system, there might be the possibility that
the oil drain backs from the cylinder heads are restricted.

This would cause engine oil to remain in the rocker area and not drain
back to the pan, causing the pan oil level to drop and, after a while,
resulting in the oil pump pickup drawing air and lowering your oil
pressure. Since you were probably on plane and moving around, lowering
the level a only a couple of quarts could result in this situation.

Since you did not say any lower end engine work was performed, one can
assume that the oil pump and bearings have not been touched so that is
not the issue. Also, it is not a ring issue since you said the oil
level is full when you returned to the dock.

You should be able to check the drain backs by removing the rocker
covers and visually inspecting the passages. They will be in the lower
corners of the cylinder head (I can not remember if the 454 has only
one in the rear or one in the front and rear).

Another possibility, although not really probable, is that the head
gasket or cylinder head has a slight opening to the crankcase from an
oil pressure passage and the oil pressure is leaking there - but I
doubt it.

well I got back to my slip and took a look at the oil filer , it
seemed to have some stuff in it as I assumed that it would, so I
changed it, and re started the motor.

As the filter filled the oil pressure gauge jumped up, but not as high
as it should.

Unless you have a non-bypass oil filter (I have not seen one in years
and years) then even if the oil filter was completely plugged, you
would still not loose oil pressure. This is probably not your problem

What kind of oil pressure were you seeing?

Thanks and good luck!

GPG

Engine losing oil pressure
 

On Thu, 24 Aug 2006 10:54:43 -0400, "Eisboch"
wrote:

I took the boat out last night and after running under load for about
15 minutes the engine in question started to lose oil pressure.

At once I shut the motor down.

I'd start by changing the oil and filter one more time and ensuring
that you use straight HD 30 weight oil. Those are hard working
engines and multi viscosity oils like 10W-30 can be a problem.

Engine losing oil pressure
 

I'd start by changing the oil and filter one more time and ensuring
that you use straight HD 30 weight oil. Those are hard working
engines and multi viscosity oils like 10W-30 can be a problem.

I would tend to disagree about multi viscosity oils being an issue -
unless you use a very wide range oil (10W30 is nominally very stable)
or the oil is an exremely off brand or very used.

However, in this situation, I would also recommend a straight weight,
high quality oil, unless you are using this vessel in a wide range of
ambient temperatures (winter use, etc).

This is not probably not related to your problem, however, with one
caveat. If the oil was whipped up into a foam, then again you would be
introducing air into your oil system, causing the oil pressure to drop.


Again assuming that you are not running a dry sump system and that the
lower end has not been touched, overfilling the oil pan can cause the
oil level to get into the crankshaft, causing the oil to be sheared and
whipped into a foam. The lack of a required windage system can also
cause this issue.

Most wet sump engines that are used for marine and high performance use
have a windage tray in the crankcase that prevents oil from being
whipped (when the oil level is at the correct setting). Since you did
not state that any lower end work was performed, we will assume that
any windage system should still be in place.

Thanks -
GPG

Engine losing oil pressure
 

Hi and thanks for the speedy response

its was just the heads and a valve job. the head gaskets were
replaced.

the engine was warm when I changed the oil filter.

the oil pressure started to drop after I put the engine under a load.
3500 RPM's and the oil pressure dropped to zero and the red warning
light on the dash board went off





On Thu, 24 Aug 2006 10:54:43 -0400, "Eisboch"
wrote:


"Big gus" wrote in message
.. .
Help!!!

Hi all

anyone had this problem?

I have a twin engine searay
with 454's


I just hand the heads , valve's, new rocker arms, and valve springs
done in the one engine

I ran the boat at the dock for a good 8 house with no issues. I even
changed the oil several times just to be sure


I took the boat out last night and after running under load for about
15 minutes the engine in question started to lose oil pressure.

At once I shut the motor down.

I got back to the dock expecting to see oil sprayed all over my engine
compartment, but I found nothing, no leaks drips or any sigh of oil
leakage

Checked the dip stick and it was fill and very clean.

well I got back to my slip and took a look at the oil filer , it
seemed to have some stuff in it as I assumed that it would, so I
changed it, and re started the motor.

As the filter filled the oil pressure gauge jumped up, but not as high
as it should.


Anyone got any thoughts ?

on why all of a sudden I got no oil pressure?

Thanks
M


"No" or "low" oil pressure? Was the engine still warm after you changed
the oil filter?

It's perfectly normal for oil pressure to drop from a high reading to a
lower one once the engine warms up. You didn't mention doing rings, etc.,
so I assume they are original. General rule of thumb for an engine with
some hours under its belt is a minimum of 10 psi per 1000 rpm engine speed.
I can't think of a reason why a valve job would influence oil pressure,
unless the valve guides were screwed up and you were burning oil big time
although it seems like it would take longer than 15 minutes of running to
burn up most of the oil. But then again, I am not a mechanic.

Eisboch

Engine losing oil pressure
 

well the oil pressure that I was seeing was once the engine was under
a load
3500 RPM

the gauge started to drop
all the way to zero and the red warning light went off

The engine still continued to run and there was no strange tapping
sounds or anything


On 24 Aug 2006 08:38:36 -0700, "gpg" wrote:

I just hand the heads , valve's, new rocker arms, and valve springs
done in the one engine

I took the boat out last night and after running under load for about
15 minutes the engine in question started to lose oil pressure.


Assuming that the headgaskets were changed and that you are not running
a drysump or scavanger oil system, there might be the possibility that
the oil drain backs from the cylinder heads are restricted.

This would cause engine oil to remain in the rocker area and not drain
back to the pan, causing the pan oil level to drop and, after a while,
resulting in the oil pump pickup drawing air and lowering your oil
pressure. Since you were probably on plane and moving around, lowering
the level a only a couple of quarts could result in this situation.

Since you did not say any lower end engine work was performed, one can
assume that the oil pump and bearings have not been touched so that is
not the issue. Also, it is not a ring issue since you said the oil
level is full when you returned to the dock.

You should be able to check the drain backs by removing the rocker
covers and visually inspecting the passages. They will be in the lower
corners of the cylinder head (I can not remember if the 454 has only
one in the rear or one in the front and rear).

Another possibility, although not really probable, is that the head
gasket or cylinder head has a slight opening to the crankcase from an
oil pressure passage and the oil pressure is leaking there - but I
doubt it.

well I got back to my slip and took a look at the oil filer , it
seemed to have some stuff in it as I assumed that it would, so I
changed it, and re started the motor.

As the filter filled the oil pressure gauge jumped up, but not as high
as it should.

Unless you have a non-bypass oil filter (I have not seen one in years
and years) then even if the oil filter was completely plugged, you
would still not loose oil pressure. This is probably not your problem

What kind of oil pressure were you seeing?

Thanks and good luck!

GPG

Engine losing oil pressure
 

thanks for the reply

I will try that and I am current using Penzoil 40 strait 40 weight




On Thu, 24 Aug 2006 11:41:26 -0400, Wayne.B
wrote:

On Thu, 24 Aug 2006 10:54:43 -0400, "Eisboch"
wrote:

I took the boat out last night and after running under load for about
15 minutes the engine in question started to lose oil pressure.

At once I shut the motor down.

I'd start by changing the oil and filter one more time and ensuring
that you use straight HD 30 weight oil. Those are hard working
engines and multi viscosity oils like 10W-30 can be a problem.

Engine losing oil pressure
 

"Big gus" wrote in message
...
Hi and thanks for the speedy response

its was just the heads and a valve job. the head gaskets were
replaced.

the engine was warm when I changed the oil filter.

the oil pressure started to drop after I put the engine under a load.
3500 RPM's and the oil pressure dropped to zero and the red warning
light on the dash board went off


Hate it when that happens. Forget everything I suggested. You have a
problem.

Eisboch

Engine losing oil pressure
 

If it has oil pressure now and didn't then it sounds like the pump was
sucking air for some reason. That could be that the oil is not
getting back to the pan fast enough. Or the pickup fell off the oil
pump. Another possible explanation is that the relief valve on the
pump got stuck open for some reason.

Eisboch wrote:
"Big gus" wrote in message
...
Hi and thanks for the speedy response

its was just the heads and a valve job. the head gaskets were
replaced.

the engine was warm when I changed the oil filter.

the oil pressure started to drop after I put the engine under a load.
3500 RPM's and the oil pressure dropped to zero and the red warning
light on the dash board went off


Hate it when that happens. Forget everything I suggested. You have a
problem.

Eisboch