Universal M30 white and black exhaust

[Josephcrawl]

Our m30 is blowing some white exhaust when under light to heavy load. Everytime I check the coolant it is low. I plan on removing the head and I'm hoping it is just the head gasket. I also plan on decoking the head and lapping the valves while I have it off. Is there anything else I should check or do while I have the head off?

Regarding the black smoke it does this under moderate to heavy load. I'm hoping it is injector dribble. The Kubota parts place I purchased the gasket set from recommended I go ahead and get an injector since the bench test labor would be the same cost as a new injector. They also said an easy way to identify the faulty injector is to remove the exhaust manifold and see which cylinder is blowing black smoke. This sounds like a rather loud undertaking on a boat but hopefully for a short period it won't be too bad.

Lastly the parts guy mentioned how frequently he sells the head for the d1101(aka m30). Apparently they are prone to cracking when overheated and that may be the coolant leak. Pressure testing was advised.

Well if anyone has advice or comments let me know.

Thanks!

[skipperpete]

Don’t run the engine with the exhaust manifold off, that diagnostic works on a tractor... but not in an enclosed space on a boat. The sooty cylinder should be obvious when you remove the head ( it might simply be overloading and they’ll all be sooty)
Definitely inspect or test the head for cracking and do a dye check if there are any suspicious areas... check the bores for scoring.

[jordanbettis]

If I were taking the head off I'd go ahead and replace the valves and injectors anyway. As Joseph says I wouldn't want to try to run the engine in the cramped, confined, poorly ventilated boat without the exhaust manifold on it.


Cracked head seems possible I guess especially if the kubota guy says it's common on that model. However I'd ask if you've had any overheating incidents that you're aware of?

[Josephcrawl]

Originally Posted by jordanbettis

If I were taking the head off I'd go ahead and replace the valves and injectors anyway. As Joseph says I wouldn't want to try to run the engine in the cramped, confined, poorly ventilated boat without the exhaust manifold on it.


Cracked head seems possible I guess especially if the kubota guy says it's common on that model. However I'd ask if you've had any overheating incidents that you're aware of?

I do not know of any over heating. The engine set for 5 years prior to my ownership. The PO had put one of those run-dry impellers on the water pump which fit poorly on the drive shaft. The impeller would sometimes sit still and not pump water. Did this cause an overheat? Certainly possible.

[Compass790]

You could just try cracking the injector line nuts one at a time to isolate the faulty cylinder but if you are going to remove head anyway no need to.
I'd just buy a nozzle& washers for the injector/s as they are easy to replace.
The injector may only need cleaning if it sat for 5 years, could be sticky needle.
Should be youtube vids on that.

[skipperpete]

While you have the head off it’s worth removing the glow plugs and testing them then refitting them with a good brand of antiseize. They often twist off when you try to get em out requiring head removal and drilling so get em out early.

[Josephcrawl]

The head is off as of today. Cylinder #1 had an oily goo on the intake manifold side others were dry. Nothing else seems visibly wrong. I've attached pics. Please let me know if you see anything obvious.

[skipperpete]

It looks like the head gasket is leaking from #2 cal into the waterway holes. Peel off the gasket and see what the other side is like. Can you post a pic of the piston crowns and cylinders

[Josephcrawl]

Can anyone tell me where to find the injector seal washers?

[jordanbettis]

Coolant makes a lousy lubricant so you need to make sure that coolant intrusion hasn't damaged your piston rings and cylinders.


Also you still need to clean off the coolant/oil goo and make sure there's nothing wrong with the mating surface there: no cracks or low spots. It might not be the gasket itself that leaked.

[Josephcrawl]

Here's a couple of pictures of the block.

[skipperpete]

Originally Posted by Josephcrawl

Can anyone tell me where to find the injector seal washers?

There was a post from Quadrille back in 2020 and he mentions new injectors with copper crush washers but my Kubota manual shows no washer however the M3-20B manual clearly shows copper washers

[skipperpete]

Oops , only one pic attached. I assume you meant the nozzle washer but later thought perhaps you were referring to the leak off banjo washers with the little pinhole in em

[Josephcrawl]

We cleaned the head surface up today and checked the surface for warping. It passed with the spec .002 feeler.

The block was not quite as flat with some areas allowing the .002 but not .0025.

Nigel Calder claims that the copper washer heated to a red heat and quenched in water will restore their malleability. I'm going to trust his expertise.

Hopefully I can find a.place to do a pressure test on Monday.

[Josephcrawl]

Well the head is back on and the engine will not start.

Bled all injectors and getting a good spurtt there.

Set valve clearance using the flywheel method tc1 etc...

Compression readings are 290 on two cylinders and over 300 on the last. Readings were taken with a poor quality compression tester that maxed out at 300 on the dial. The proper fitting was not present. We used the rubber tipped wand pushed against the glow plug port.

Torque was set with my aging uncalibrated wrench followed by the deflection gauge style for good measure.