bad engine blow-by

twooheight · Jan 13, 2011

I got myself an LB1714 that has a few issues. First was it was really hard to start. 3 new glow plugs later it is much easier to start. I used Kubota glow plugs as they were only $11.36ea instead of $42ea for ones from the Kioti dealer. I can provide Kubota p/n if anyone wants. the second and more major issue is the blow-by. The case is being pressurized to the point it has blown the valve cover gasket out and was spraying oil about a foot out the side of the engine. I took the valve cover off and ran the engine for a couple minutes to watch the valves to make sure they were opening correctly, they were. I am left to believe that I have either a broken or stuck ring (i was told it sat for several years). Does anyone know if the pistons can be pulled out the bottom or does the head have to come off? I have been trying to find a service manual for the thing so I would at least have the torque specs but have had no luck thus far. Any help would be greatly appreciated.
Jerry

Willl · Jan 13, 2011

I know of no engine that you can pull pistons out the bottom without removing the crank.

Not saying it can't be done, but I have never heard of such a thing.

Myself, I'd pull the head and pull the pistons out the top.

PoorMansCat · Jan 13, 2011

How long have you ran it? Has it been worked, or just ran with no load? One thing you can try would be to pull the injectors, fill all cylinders with MMO. Allow the engine to sit for approx. 5-7 days. If possible, jack up one rear wheel and spin the wheel every couple days with it in gear to move the pistons thru their bores...
Before putting the injectors back in, use the starter motor to spin the engine over and clear all the MMO out of the cylinders. Install the injectors and try it again.
If its carbon/rust that stuck them, that will usually do the trick.

jake98 · Jan 13, 2011

too much oil in it?

kjung17 · Jan 13, 2011

Poorman's application of marvel mystery oil will certainly correct a stuck ring. If not, you'll need to pull the head and take a look around. I have had 100's of pistons out, always from the top. Is this a sleeve engine?

twooheight · Jan 20, 2011

I can try the MMO trick. I do not know if it has been run under load by the previous owner. The only load I have put on it was loading and unloading it from the trailer. I changed the oil and filter thinking may be the guy had put too much oil in it but that was not the case. I have managed to pull pistons out the bottom before without removing the crank, not saying it was easy but i was doable. I don't know if it is a sleeve block or not. I would assume not since it is an iron block, but I don't know. I have seen several references to the LB1714/1914 that suggest they are somehow basically the same as the old Kubota B17/20 models. A couple years ago I was trying to locate an owners manual for a B20 and had seen reference to it then. Now that I am trying to find info on my LB1714 I am again finding references of that nature. Any thoughts? I'm afraid to pull the head for 2 main reasons. 1) availability of a replacement head gasket, and 2) torque specs for head bolts.

PoorMansCat · Jan 22, 2011

twooheight said:
I can try the MMO trick. I do not know if it has been run under load by the previous owner. The only load I have put on it was loading and unloading it from the trailer..

Sometimes when an engine has a stuck ring, just starting it up and running it "unloaded" doesn't help. But on occasion, you can go ahead and put the engine under a load by working it, the ring will unstick and seal up.
But, try the MMO trick, it had worked many times in the past.
One other thing, is the crankcase blowing an oil vapor out, or is it steam? Does it immediately rise up from the tube and disappear or does it linger in the air and have sort of a cloud?