Home |
Search |
Today's Posts |
#1
![]()
posted to rec.boats
|
|||
|
|||
![]()
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 |
#2
![]()
posted to rec.boats
|
|||
|
|||
![]() "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 |
#3
![]()
posted to rec.boats
|
|||
|
|||
![]()
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 |
#4
![]()
posted to rec.boats
|
|||
|
|||
![]()
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. |
#5
![]()
posted to rec.boats
|
|||
|
|||
![]()
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 |
#6
![]()
posted to rec.boats
|
|||
|
|||
![]()
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 |
#7
![]()
posted to rec.boats
|
|||
|
|||
![]()
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 |
#8
![]()
posted to rec.boats
|
|||
|
|||
![]()
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. |
#9
![]()
posted to rec.boats
|
|||
|
|||
![]() "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 |
#10
![]()
posted to rec.boats
|
|||
|
|||
![]()
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 |
Reply |
|
Thread Tools | Search this Thread |
Display Modes | |
|
|
![]() |
||||
Thread | Forum | |||
oil pressure is gone above 3800 rpm (volvo penta 3.0 from 1996) | General | |||
Engine coupler | General | |||
Volvo 4.3 Engine Rebuild | General | |||
Engine News from Genmar | General | |||
Usage of motoroil | General |