The guy that put the engine internals together says "The rings are not seated yet end the smoking is normal. Just give it a couple hours of work"

[mm lindquist]

I purchased a kubota 3830 in 2007. The mechanic from kubota told me to start the tractor let it idle for one minute then take it to 1300 rpms for the warm up. He said the oil pressure is too low below a thousand rpms. I've overhauled hundreds of refrigeration compressors with insert bearings. The standard was always 10 psi for every 1000 rpm for that type of bearing.on a piston type engine the only time I experienced the problem your describing was using Chrome moly rings and it did stop using oil after a while. We bought a 1994 carry. It smoked from day one. At 40000 miles it stopped and I gave the car away at 350 thousand miles and it still didn't use oil between changes. I would use the tractor. If there is a problem it will get worse not better. It sounds like your mechanic knew what he was doing other than riding the brakes.

 

[sportscarclinic]

90 Comments and counting... Looks like we're creating a nice compendium of all the reasons why an engine will smoke and have low oil pressure.

Did anyone mention on the oil pressure front mention worn out lifter bores yet?
On the smoke side, what about a sticking enrichment solenoid on the injection pump?

 

[jimux]

This is a great thread.

Absolutely…great hearing so many pro players and group thinking!

 

[sd455dan]

It sounds like one of the rings is either broken or wasn't installed at all.

90 Comments and counting... Looks like we're creating a nice compendium of all the reasons why an engine will smoke and have low oil pressure.

Did anyone mention on the oil pressure front mention worn out lifter bores yet?
On the smoke side, what about a sticking enrichment solenoid on the injection pump?

A stuck enrichment would have the exhaust smell of unburned diesel, Not burned engine Oil.

The exhaust smoke Has been stated as burning of engine oil not incomplete combustion of diesel fuel
after asking the OP.

 

[sportscarclinic]

A stuck enrichment would have the exhaust smell of unburned diesel, Not burned engine Oil.

The exhaust smoke Has been stated as burning of engine oil not incomplete combustion of diesel fuel
after asking the OP.

Got it, I missed that. So add this possibility to the list of "confirmed as *not* the reason for the smoke in this instance". Now just need to 'exclude' 50 more.

 

[Dman1981]

I have overhauled literally thousands of engines never had one belch oil out exhaust Perkins cat Cummins ford kubota duetz guy either soaked them in engine oil which I never do or he put it together with the block looking like in picture then what you have is failure to communicate

 

[LouNY]

Quite a bunch of noise on this thread.

One, just run it and work it long enough to see what it is going to do.
get it up to temp (with a thermostat installed) and put a load on it.

Two, don't idle the engine at low rpms for now, keep it up at 1100-1200 rpm.

Three, is it doesn't clear and run right after half an hour or so being worked then it's time to start trouble shooting.

Start with a compression check and then a leakdown test.
After getting those results you can then decide what needs to be torn down and checked.
Without them you are peeing into the wind.

The smoke could oil and it could be fuel,
fuel could be injectors or timing.

10 psi oil pressure on a hot engine at very low rpm may be just fine,
that is one reason many manufactures went with lights instead of gauges.
Many low oil pressure switches actually activate in the 5-7 psi range.

 

[sportscarclinic]

Is there any way to do create a poll on this forum thread? At some point maybe we'll get an actual answer from the OP. If we do, it'd be interesting to see whether a majority opinion was correct.

I'll cast my vote for wrong size bearing shells installed, allowing excessive oil to be slung onto cylinder walls, overloading oil control rings.

 

[etpm]

I always thought that diesel engines needed higher oil pressure but I don't know just how much higher. I was shocked that my 1992 Toyota V6 pickup is supposed to have only 6 psi oil pressure at idle when warm. 10 psi at idle for a diesel seems in line, but I don't know. What do typical small diesel engines run?
Eric

 

[rocco611]

10 psi per 1000 rpm is a general guideline I heard a lot .I have always considered that an oversimplification. Most engine manufacturers have published standards for oil pressure. A lot of has to do with size or oil passages design of the oiling system and volume of oil displaced by the pump. My Harley twin cam has single digit oil pressure at idle, low restriction oil filter and just enough volume to keep the top end lubricated. that is normal for a twin cam. What's normal for one engine isn't necessarily acceptable for another. your engine should have more pressure at warm idle. The low pressure alarm is also letting you know its not normal.