Engine at all oil and over revved like mad!!

[atoll]

Originally Posted by stevensuf

Charlie, we have found diesel in the sump, you are spot on,it has something to do with either the lift or injector pump!

sounds like the lift pump/injector pump but i would still do a compression test to rule out cracked ring or faulty valve,that will allow diesel to enter sump

[goboatingnow]

From memory the Perkins 4-108 doesn't have its sump breather connector to the intake filter. I know some yanmars do alright. I seem to remember the breather is just open to the atmosphere.

Dave

[onestepcsy37]

feeling a little better now about using straight 30 oil in my 1979 4-108. but i'm going to keep an eagle eye on the oil pressure guage.

i have the original engine rebuild and owners handbooks. they specify shell rotella 30 wt for temperatures over 80 F; being in florida and heading for the bahamas i think i'll be ok. they also recommend shell rotella 20w40 for temps above 30 F so i could probably use that year round, but i can't find 20w40, only 15w40.

they say that oil pressure should be in the 30 to 60 range, depending on temperature and operating rpm. i've never seen straight 40 or 50 weight diesel lube oil, but then i haven't looked too hard either.

i also looked all over the engine manuals but could find no reference to an oil sump breather. might be because it has an oil cooler. there is a valve cover breather which feeds into the air cleaner. i'm no mechanic but i wonder if oil overpressure in the sump goes up through the galleries into the valve train area and then to the valve cover breather.

[model 10]

You might want to read up on old diesel engine oil. I'm not sure any multi-grade oil is the right spec., there are different specs for modern engines. Unfourtnatly there is not much available for the old engines anymore so you use what you can get sometimes.

[onestepcsy37]

guy - the reason i bought the rotella 30 is that on the back of the container it said that it was better suited to older diesel engines. that's the first time i'd ever seen any oil container stating that. so i bought it. been using rotella 15w40 for the past ten years i've owned the 4-108.

[fryewe]

You original post said you were starting the engine to charge the batteries. If you have been repeatedly using the engine to charge the batteries with relatively low constant load on it you may have glazed the cylinders. Glazed cylinders can result in leakage past the rings. Leakage past the rings can result in fuel in the crankcase lubricating oil.

A sticking or faulty injector will spray fuel into a cylinder when that cylinder is not on the intake stroke. The result will be unburnt fuel buildup in the crankcase.

Were you checking the oil level in the crankcase prior to running the engine or least frequently since your last oil change? Increasing level in the crankcase (smell the dipstick and feel the oil as well) is a sure sign of fuel contaminating the oil. As the level rises pressure can build up the crankcase and push the fuel/oil mixture through valve/rod passages and past the rings in glazed cylinders on the intake stroke causing the engine to runaway on the lubricating system oil.

Sounds like your engine ran away on its own diluted oil and likely shut down when the oil supply exhausted.

What caused it? If you had no sense that your engine had any significant wear problems prior to this incident I would check for a faulty injector.

[stevensuf]

we are pretty sure its the lift pump at this time, fuel is syphoning into the sump.

[bobconnie]

Im old style myself, I only use single weight oils in my older diesels. They are not to hard to find ya just need to go to a Truck dealer to get it ! Ive always used 40 wt Diesel oil in all my perkins, and they have been very good to me !! and Ive never ran a 4-108 over 1850 RPMs ever!! if that would not shove the boat I re-proped the boat !! But as I said Im old school and like my stuff to last a LONG while !! Our current boat has a 160 HP 471 Detriot, and Im useing 40 wt in it and almost never have to run it over 1500 rpms to abtain hull speed or a little better. just saying if ya have an older style engine, it needs older style lubes, and mostly lower rpms then it seems folks use these days ! Just my 2 cents

[model 10]

Yeah, truck shops in Golfito. Stock up on the good stuff before you go.

[onestepcsy37]

bobconnie - sometimes the obvious is obviously overlooked.

never thought about going to a truckstop for diesel oil. truckstop will be my next stop....

[goboatingnow]

Originally Posted by bobconnie

Im old style myself, I only use single weight oils in my older diesels. They are not to hard to find ya just need to go to a Truck dealer to get it ! Ive always used 40 wt Diesel oil in all my perkins, and they have been very good to me !! and Ive never ran a 4-108 over 1850 RPMs ever!! if that would not shove the boat I re-proped the boat !! But as I said Im old school and like my stuff to last a LONG while !! Our current boat has a 160 HP 471 Detriot, and Im useing 40 wt in it and almost never have to run it over 1500 rpms to abtain hull speed or a little better. just saying if ya have an older style engine, it needs older style lubes, and mostly lower rpms then it seems folks use these days ! Just my 2 cents

Low speed kills diesels as a general comment. Modern engines tend to have higher operating speeds and should be regulary run up to normal operating revs. ( often 2200-2500 for some )

Remember all those engineers beavered away to ' design' it so.

Dave

[captain58sailin]

We have a Chevron jobber here and can pick up any single weight oil we need, I like delo 400, 30 wt, for my Isuzu, I once spoke to the engine dealer and they recommended 15/40 wt delo 400. Maybe someone could explain to me the dynamic of a multigrade oil, I assume normal physics apply to them, so is it 40 wt when it is cold and then thins to 15 wt when you get to operational temps? Which I would assume a single weight oil would do.

[Cheechako]

Originally Posted by captain58sailin

We have a Chevron jobber here and can pick up any single weight oil we need, I like delo 400, 30 wt, for my Isuzu, I once spoke to the engine dealer and they recommended 15/40 wt delo 400. Maybe someone could explain to me the dynamic of a multigrade oil, I assume normal physics apply to them, so is it 40 wt when it is cold and then thins to 15 wt when you get to operational temps? Which I would assume a single weight oil would do.

I believe the theory is 15 w cold and 40 w hot... to allow better circulation when the engine is cold....?

[glenn.225]

Originally Posted by Cheechako

I believe the theory is 15 w cold and 40 w hot... to allow better circulation when the engine is cold....?

You are correct behaves as a thinner oil when cold, easier to crank over, pump etc and as a thicker oil when hot, more viscus.

[donradcliffe]

Originally Posted by goboatingnow

Low speed kills diesels as a general comment. Modern engines tend to have higher operating speeds and should be regulary run up to normal operating revs. ( often 2200-2500 for some )

Remember all those engineers beavered away to ' design' it so.

Dave

The engineers beavered away to design what the marketing department wanted-- "more horsepower and less weight, and it only has to last until the one year warranty expires".

Can you show statistics on how many diesels have died at low speed vs high speed (given that the loads on most moving parts are 4 times as high at 3000 rpm as they are at 1500 rpm)??