New to me Mustang 940E - some problems

Hello,
I just bought a 1996 Mustang 940E (Yanmar 4TN82E-S engine). it is in good shape, and tight.
Sorry for the long post but I want to put everything out rather tan going back and forth with "what have you done", "did you try" questions....
It has one problem I am sure is going to bite me big: it smokes A LOT out of the vent tube coming out of the valve cover.
It starts fine, appears to run fine - have not had the chance to do any real work with it yet...
I did a "tune up" this weekend:
1. Replaced the engine oil/filter, added "restore" to see if it would help with rings
2. Replaced the hydro filter
3. Replaced the fuel filter
4. Replaced the air filter - very, very dirty - filter check was popped.
It smokes a bit at start-up (white) out the exhaust but after a short warm up it is clear - but it always smokes (white) out the engine vent tube - this did not change with the "tune up"
Things I know or observed:
1. It has 1300 hours but the meter does not appear to be running now
2. I got it from someone who did not take the best care of equipment - price reflected that (somewhat)
3. Has been and was running real rough when I got it because the low pressure fuel feed (between the feed and the injection pump) was leaking - ran erratically - so the thing was "randomly" fueled for who knows how long.
4. There was a LOT of oil and dirt in the bottom of the engine compartment
5. The vent tube is leaking oil
6. the vent tube smoke is not water - did the mirror test
7. There is substantial pressure on the vent tube
8. It appears to have decent power, but I have not worked it and did not know what it should feel like "new"
9. When I replaced the fuel filter it did have some water in the bottom, about 1/3 full. Also had dirt in the bowl (it is a removable bowl clear filter on this engine).
From my research everything points to rings; but I want to make sure before I tear the engine apart - could it be anything else (simpler)
Few things I do not understand and would like to know:
1. If it was rings would you expect smoke to come out of the breather and the muffler? - it is only coming out of the breather after warmup
2. I know gas engines, but how do you remove the injectors and do a compression / leak down test? - do I need to replace a seal after I pull them? - I don't want to damage them as they are expensive and harder to find than spark plugs... - is there an adapter that I will need to hook up the tester?
3. How do you do an engine RPM drop test on a Diesel? - can you unscrew the injector? - how do you measure RPM w/o a spark signal?
This will be a limited use homeowner machine so it needs to work, but will not be worked all that often and that hard - if I could limp it along for 200-300 hrs that would serve me well...
Thanks to all in advance!

Any smoke from the breather will be exhaust gas, it sounds like your rings are worn or have a scratch in a bore.
You said it still starts and runs well, if it's only a home machine, i wouldn't be too worried about it.
Newer machines actually plumb the breether tube into the inlet manifold. Even if there was blow-by, you never know as it just gets sucked in and burnt off. Is it an option for you to just plumb it back into the inlet?
The smoke at startup is normal for a diesel, when it's hot it should be pretty well clear.
If the engine was hard to start or poured out smoke all the time, i'd suggest you look at a touch up.. I understand the desire to have it run like new, but the cost may be too much to be worth a full rebuild to get it back to like new condition.

Tazza said:

Any smoke from the breather will be exhaust gas, it sounds like your rings are worn or have a scratch in a bore.
You said it still starts and runs well, if it's only a home machine, i wouldn't be too worried about it.
Newer machines actually plumb the breether tube into the inlet manifold. Even if there was blow-by, you never know as it just gets sucked in and burnt off. Is it an option for you to just plumb it back into the inlet?
The smoke at startup is normal for a diesel, when it's hot it should be pretty well clear.
If the engine was hard to start or poured out smoke all the time, i'd suggest you look at a touch up.. I understand the desire to have it run like new, but the cost may be too much to be worth a full rebuild to get it back to like new condition.

Click to expand...

I agree sounds like crank case vent smoke.
Perhaps start it and take the oil service cap off and see if it has pressure there with your hand.
Many guys in the diesel truck preformance space will vent the ccv to the atmosphere to avoid oil soaking charge air cooler boots and the cooler itself.
Let us know what you find.

oasis04 said:

I agree sounds like crank case vent smoke.
Perhaps start it and take the oil service cap off and see if it has pressure there with your hand.
Many guys in the diesel truck preformance space will vent the ccv to the atmosphere to avoid oil soaking charge air cooler boots and the cooler itself.
Let us know what you find.

Click to expand...

Hello,

No question there is pressure, if you take the cap off it will push it off.
In this engine the crank case vent just vents to the atmosphere, like a draft tube on an old car engine...
there is pressure on the draft tube as well, pull the dipstick and there is pressure and smoke there as well...

6t6cuda said:

Hello,

No question there is pressure, if you take the cap off it will push it off.
In this engine the crank case vent just vents to the atmosphere, like a draft tube on an old car engine...
there is pressure on the draft tube as well, pull the dipstick and there is pressure and smoke there as well...

Click to expand...

IMO for household/personal use I would run it as is.
maybe send an oil sample in and maybe watch the oil level in the crank case to monitor if getting fuel dilution of the oil.

oasis04 said:

IMO for household/personal use I would run it as is.
maybe send an oil sample in and maybe watch the oil level in the crank case to monitor if getting fuel dilution of the oil.

Click to expand...

I think any engine will have some blow-by, even new there will be some.
I had a machine that when it goet nice and hot, puffed a fair bit of smoke out the breather tube, it ran great, just blew a little smoke.
Keep an eye on the oil level, if it is using excessive oil, you shold have a closer look. If it's not, keep using it the way it is. Even if you change the oil sooner to hopefully prevent too much carbon build up in it.