Perkins 4-108 Problems Continue

[Stirfryd]

I started a new thread since the lack of oil pressure issue, appears to be turning into invasive surgery. I think my oil pump is just shot. No oil pressure, and when the oil fitting was loosened on the output side of the pump at the block, no oil came out when the engine was turned over. Flushed with diesel. Oil pan clean as a whistle. That only leaves parts that you can't get to (drop the oil pan). So, I will step back for a few days and survey the breadth of the repair. Has anyone ever replaced their oil pump on a 4-108 without removing the engine? If it could be done in place, or just raised a little, it would sure be easier than pulling the engine out. I've worked on a lot of cars, just not boats with limited space underneath the oil pan. The beatings continue. Moral is not improving. Ugghhh!

[perchance]

Is it possible that the oil pressure relief valve is stuck open? Even a badly worn pump will produce some pressure. Dirt under the valve seat will not allow it to close causing a low/no oil pressure condition.

[DeepFrz]

I'm just guessing here, never had one of these engines apart, but could the problem have been caused by something you did when you replaced the fuel pump? Are the oil pump drive gears located in the same area as the fuel pump drive gears?

[beneteau-500]

yep remove sump i would say its the balancer unit has got blocked or seized

[Stirfryd]

Thanks for the respnses. Firstly, I have put about two trouble free hours on the engine since installing the Injection pump. As far as the pressure relief valve is concerned, even if it were stuck open (and I can't see how it would have opened since I had run the engine the day before with no oil press. issues), one would think there would be some output from the pump, even if very little. And since the pressure relief valve can only be accessed from the sump....well, I still have to drop the pan. The pump is driven by the camshaft. Then engine runs fine when started other than the no oil press. (shut her down immediately). I am thinking about trying compressed air back through the pump on the outlet side. What do you think?

[Stirfryd]

Perchance, can you explain? How would a valve that doesn't seal cause no oil pressure? I have zero pressure and zero flow from the pump output.

[DeepFrz]

Stirfryd, if the gear driven oil pump is driven off the same set of gears that drive the HP fuel pump (and I don't know if it is) then its worth a careful look, IMHO. At least that is where I would start. If I recall, you did have a bit of a mess in there amongst the gears. Or was that a different thread?

[Stirfryd]

Indirectly, the oil pump is off of the same gears. It would have to be, as this is a timing issue. However it is driven off of the camshaft. The camshaft is geared to the timing gears and thus the splined shaft on the injection pump. However, all I did was remove the old fuel injection pump by pulling it out of a gear (never saw the gear because it is housed), and re-inserting the pump (only one way in or out) into the gear. Inject. pump mounted up with three nuts on studs on it's machined flange directly to the block. I can't see that I may have caused the problem with this installation. The camshaft never moved and the oil pump is hard mounted to the inside of the block to keep it's gear in a fixed position to the gear on the camshaft.

[DeepFrz]

Yeah, I downloaded the service manual and took a look at it. Should have done that before my last post. Good luck.

[Mark Zarley]

As the air would have to pass through, over and around, the machined oil pump gears ,I would not count on any volume of air sufficient to clear a blocked pick-up tube making it through. If that was your thought.

[Blue Stocking]

This is a stab in the dark, having never seen a 4-108 with the sump off. Do you have an oil pick-up tube which may have come loose and dropped into the oil. On my w/beke the oil pick-up tube has a flange which bolts up over the oil pump gears, and holds them in place.

[Stirfryd]

No, probably not much air will get through, but it beats pulling the oil pan if it works. the air may also exercise the pressure relief valve. I just looked at the project and the location of the pump is right up front where it could easily be reached once the pan is lowered. looks like I might be able to get the pan down about 4-5 inches with the motor in place on the mounts. The starter will have to come off and probably the external oil lines where they leave the block so you will have room for your hand to get under the block and work. The manual is fairly clear with the directions for pump removal and inspection. While I don't relish the task, it may be more straight forward than it seemed at first. We shall see.

[Chief Engineer]

Did you or will you try my idea I posted on the other oil pressure thread?

[gettinthere]

have you contacted Trans Atlantic Diesel? They are perkins experts. Hopefully you can get some advice from them (and buy parts from them too, they are good, supportive people).

[Stirfryd]

The oil pressure problem is solved. At my age, I have already learned that 99 times out of 100, you can usually trace a problem to some sort of operator error. I decided to take a week off and think about this lack of oil pressure problem before ripping into a big project like trying to change an oil pump. It hit me a 5:00 a.m. as I lay awake with my brain on fire last Saturday morning. I have an aftermarket electric oil drain pump. I had changed the oil twice recently due to the engine making oil, and had overfilled it slightly. I had drained off a little. "did I remember to shut the pitcock on the pump", I thought to myself. And if not, would that opening to the oil pan be cause for no pressure. Yes sir, it would be. I closed the pitcock about an hour ago and fired her up. I had immediate oil pressure. Apparently the crankcase not being able to pressurize was the cause of no oil pressure. So there you have it. An admission of guilt. Thanks to all who contributed their experience and opinion. On to the next project.....

Stirfryd