3306 fuel in oil problem PLEASE HELP

[George Poland]

Hello.
I have sewage cleaning equipment powered by a cat 3306 engine. The problem is that the engine oil (fuel gets in) after 10-15 hours of operation, about 10 liters. Fuel injections are new, the fuel pump is repaired, new sections and seals. I also assumed another used one and it is the same. Pre-pump replaced by electric. (0,2 bar) The engine does not smoke, there are no blows to the engine after firing, it works evenly, has power. Where can the fuel get? Has anyone had a similar problem and has it been fixed?

 

[Old Magnet]

What's the s/n of the engine?
Have you checked transfer pump seals?

 

[George Poland]

Yes. everything is new. pump is after rebuilt.
unless the company did it wrong ... because it is not very possible that fuel could be refilled by other means. There are similar threads on various forums, but no one wrote how it was fixed and what was the reason why the fuel got into the oil.
Engine 3306 engine model 64z28161 number 1312991


here, for example, there is a similar option but it is not written how it worked Caterpillar Forum - 3306 fuel in oil (2958) on 2008-06-10 (dieselenginetrader.com)


please help

 

[Coaldust]

No mechanical transfer pump. Retrofitted with electric. A rebuilt injection pump. Reman nozzles. It probably has a leaking fuel nozzle with a case of post-nasal drip.

It’s not uncommon to have issues with new or reman nozzles. Tell us where the parts came from. Genuine Cat or from the Dollar Store?

 

[George Poland]

the nozzles are new, non-original replacements. apart from injections and an injection pump, is there any possibility that you get fuel into the oil?
pump was regenerated by a local company with experience. In Poland there is a problem with the repair of caterpillar 3306 because it is not enough.

 

[Coaldust]

No other possibility. If it was my job, I would pull and test the nozzles. Easy to test with a basic nozzle tester.

Might be obvious like a blown nozzle tip. Those are amazing engines and will run fairly well even with significant problems.

 

[George Poland]

thank you so we will. I will write how I can solve the problem

 

[George Poland]

one more question buddy. I have 8N7005 injectors, are these the correct injectors for my engine model? in the company I was buying, they came out of the catalog and I would like to be sure if there is any mistake here.

 

[George Poland]

and if I remove the injectors, does it make sense to measure the compression pressure of the engine?

 

[ahart]

I show an as shipped part number of 100-7559 with a reman number of 0R-4340 fuel nozzle assembly. No idea what the difference is in them but they are different in some way.

 

[Coaldust]

George,

Hello. I’m sorry. I have no way to look that up for you at the moment. How’s it running? Lots of black smoke? I wouldn’t spend the time on a compression test. Well, at least until you are convinced the nozzles are good.

 

[tctractors]

Lot of suggestions been put up but a few pictures of the engine might help more, I see the 64Z tag but again a picture would help a great amount, if it is a D.I engine i would guess it to be a 3306 -2 with the large type fuel pump that has a low pressure lift pump fitted, and by your script it would sound to be by-passed?? this pump is the usual culprit to cause fuel in the oil, I will warn you that anything around a 5 to 10 liter dilution in the engine oil will take out the main bearings fast, the big end bearings will be fine but the rotating mass of the crank and rods will spin the main bearings in the block, if an injector is dropping fuel into the cylinder then I would expect to have a hydraulic lock effect on the faulty cylinder plus white smoke clouds if it ever ran, so that brings things back to the injector pump, how do you want to play it? tctractors p.s. with this amount of fuel dilution the main bearings must be near scrap, the engine will run strong with just the slight stink of fuel but i would be checking the crank.

 

[Old Magnet]

That's going to be a late s/n 3306B.
With the transfer/lift pump by-passed there are only two other sources for fuel in the oil. Either an injector problem which seems unlikely the way you describe it runs or the governor which is a hydraulic servo type using engine oil pressure. I don't know for sure but it may be possible to back feed fuel through the servo into the engine oil system. Need some more expertise here as this is much to new for me.

 

[1466IH]

Is the lift pump completely bypassed or did you just put an electric pump in line?

 

[Coaldust]

You nailed it, Old Magnet. Nothing else it can be.

 

[Cmark]

Each pump element sits on a ground and lapped spacer, circled in red. If they haven't been installed correctly, fuel will leak past here.

 

[Coaldust]

Wise words. I stress every time I change a p&b in the mud & blood. Been fortunate over the years.

 

[George Poland]

Yes. it is omitted the mechanical pump only uses electric. That one is blinded

 

[George Poland]

,,Hello. I’m sorry. I have no way to look that up for you at the moment. How’s it running? Lots of black smoke? I wouldn’t spend the time on a compression test. Well, at least until you are convinced the nozzles are good.''



it does not emit black smoke or any other. it's ok. I have to work on this equipment because I have a contract with the company and no other option. I change the oil every day or every 2 days. I hope the engine will survive it ... because in all of POLAND I found only one engine used with 6000mth. If I can't fix it, then I go in that direction.

 

[Old Magnet]

In your description early on you indicated you tried another (complete?) injection pump and got the same results. If that's the case it would seem that fuel injection issues would be the last possible cause. As was previously mentioned it would be best to get those injectors tested or replaced. At least that would eliminate one of the possible causes. If you replace them get the right ones which appear to be part number 1007559.