Grey/White smoke from oil fill tube

[Caliche]

Since you feel that the rings were installed by the book and you had this smoking issue before the work was done and the head was not rebuilt, I would be checking that.
An infrared thermometer should be able to tell you if one cyl is getting hotter or colder than the others. Or all of them. Is there an overheating issue?
Maybe an exhaust valve guide leak?

 

[FNH1620]

Finally got my compression tester in from harbor freight.
Front cyl: 400psi
Mid cyl: 400psi
Back cyl: 120psi

These are almost the same readings that we got when we had the engine apart during the winter.

We are starting to lean towards something wrong with the injection pump. This is because...

First it does not start for crap on a cold start in any weather.

Second it is the same cylinder that went bad before and what are the odds that the same cylinder that went bad before would get rings that were defective?

Third: It took 13 years for the first set of rings to go bad and now this set only lasts 30 hrs. There is clearly somthing else that is not functioning properly right now.

I don't think it is anything in the valve train b/c we checked that and all was good.

Also, when we took apart the engine the first time the back cylinder had a lot of carbon build up on the top and sides. the other two pistons looked good.

 

[Hooked_on_HP]

Fuel has nothing to do with compression. When you do a compression test the fuel is shut off to all the cylinders. For some reason on these small shibura diesels it is always the rear cylinder that is the problem.I don't know if it is the way the coolant flows or the air intake design that causes the problem. If you take it back apart and measure the rear cylinder you will probably find it is bigger than it should be and out of round. Rings are designed for a specific size round bore. If the bore out of round or over sized it will not hold compression. It is like putting a round plug in a square hole. It won't seal.
Bill

 

[Hooked_on_HP]

To prove it is the rings, squirt some oil into the cyl. through the glowplug hole and do a compression test. If the compression comes up its the rings.
Bill

 

[Jerry/MT]

Finally got my compression tester in from harbor freight.
Front cyl: 400psi
Mid cyl: 400psi
Back cyl: 120psi

These are almost the same readings that we got when we had the engine apart during the winter.

We are starting to lean towards something wrong with the injection pump. This is because...

First it does not start for crap on a cold start in any weather.

Second it is the same cylinder that went bad before and what are the odds that the same cylinder that went bad before would get rings that were defective?

Third: It took 13 years for the first set of rings to go bad and now this set only lasts 30 hrs. There is clearly somthing else that is not functioning properly right now.

I don't think it is anything in the valve train b/c we checked that and all was good.

Also, when we took apart the engine the first time the back cylinder had a lot of carbon build up on the top and sides. the other two pistons looked good.

Are you sure the valve isn't leaking on #3? With a compression pressure that low I'dsuspect the valves also. I'm not saying you don't have a problem with rings but the pressure is so bad, (30% of the the other cylinders) that valve leakage should also be suspected.

 

[bigbull338]

you need another ring job on your motor an possably rebore your pistons an put in new sleeves.you have a cracked ring as others have said.if you have water in the oil you might have a cracked block.

 

[jetskier]

Finally got my compression tester in from harbor freight.
Front cyl: 400psi
Mid cyl: 400psi
Back cyl: 120psi

These are almost the same readings that we got when we had the engine apart during the winter.

We are starting to lean towards something wrong with the injection pump. This is because...

First it does not start for crap on a cold start in any weather.

Second it is the same cylinder that went bad before and what are the odds that the same cylinder that went bad before would get rings that were defective?

Third: It took 13 years for the first set of rings to go bad and now this set only lasts 30 hrs. There is clearly somthing else that is not functioning properly right now.

I don't think it is anything in the valve train b/c we checked that and all was good.

Also, when we took apart the engine the first time the back cylinder had a lot of carbon build up on the top and sides. the other two pistons looked good.

I'd check your intake tube for signs of dusting. My 1715 was dusted and the intake tube dumps right into the rear cylinder. The dust 's momentum would force it to enter that rear cylinder on the intake stroke. I think the 1620 and 1715 are the same setup. Before my rebuild it as 180psi on the rear and 380+ on the front and center. After rear was 380, front and center were 420. I just did a ridge ream and deglazing to get a cross (not a true hone). Looking back the correct fix would be to go to the next oversize since the rear cylinder bore was just a taste out of spec.

 

[FNH1620]

you need another ring job on your motor an possably rebore your pistons an put in new sleeves.you have a cracked ring as others have said.if you have water in the oil you might have a cracked block.

My engine is not sleeved so I would have to have the cylinders bored and new pistons.

 

[FNH1620]

I'd check your intake tube for signs of dusting. My 1715 was dusted and the intake tube dumps right into the rear cylinder. The dust 's momentum would force it to enter that rear cylinder on the intake stroke. I think the 1620 and 1715 are the same setup. Before my rebuild it as 180psi on the rear and 380+ on the front and center. After rear was 380, front and center were 420. I just did a ridge ream and deglazing to get a cross (not a true hone). Looking back the correct fix would be to go to the next oversize since the rear cylinder bore was just a taste out of spec.

What do you mean by by dusting?

Yes my intake tube does enter on cylinder #3

We did teh ridge ream and deglazing aslo.

I wish now we would have measured the cylinder bores.

 

[jetskier]

What do you mean by by dusting?

Yes my intake tube does enter on cylinder #3

We did teh ridge ream and deglazing aslo.

I wish now we would have measured the cylinder bores.

Dusting meaning dirt that gets past the air filter. My intake was caked with dust/oil. It was worse on the rear just because the intake entered there.