Smoking #1 cylinder on My Ford 3000 Diesel

[mtodd101]

Hello
I have a 1966 3 cylinder diesel that is burning through a quart of oil in about a 20 minute period. I did an in frame rebuild over the winter. New piston, rings, rod bearings, pins and had the head rebuilt. surfaced, guide, seals, valves. I set the valve lash per my manual. So i got it back together and it smokes and bleeds oil out the exhaust pipe. Everything I read say the rings need to seat themselves so mow like crazy, keeping an eye on oil level. Eventually the smoke oil slow but don't stop. I removed the Exhaust manifold and the smoke and oil are coming from #1 cylinder only, the others are dry. tried to do a compression check, but my gauge only bounced up to about 220, but wouldn't hold the #, so compression is in question. I took the head off today thinking I'll find broken rings or something, but the rings looked good. The piston looked good except for some discoloration on top. there's no play with the piston in the cylinder, so I don't know how the oil is getting passed the rings. There was oil on top of the piston. I'm probably going to take the head back the the machine shop and have them look it over. The head gasket looks almost new. There isn't any water in the oil or oil in the water. Not sure what to do next. I added some photos I took today. maybe someone will see something I don't Thanks. Sorry for the length. Matt

 

[90cummins]

It's unlikely the head. You need to pull that piston out & check the rings.
90cummins

 

[mtodd101]

Hi 90cummins. Thanks for the reply. I did pull the piston and it looked find. Some discoloration on top but looked fine. The rings looked good also. Not sure how "seated" rings should look. They were loose like I had just put them on the piston. Not sure where to go from. Matt here

 

[Dataway]

Obviously you aren't new at working on engines ...so, trusting your opinion of the rings ..... if that was a gas engine I just built I would immediately be looking for a missing valve seal on the intake side, or a problem with the intake side valve guide.... that seems like a ton of oil to be passing rings. I'd guess it's being sucked in to burn that much oil ....but while I know gas engines quite well, no so much diesels, and I don't know how much oil that engine carries in the valve spring seat area to make it available for leakage into the cylinder.
JohnnyB

 

[mtodd101]

Here's a Video of the tractor running without the exhaust manifold on. Matt

 

[Dataway]

Well if you are confident it's not the rings, then the next logical culprit will be the valve system (assuming there is no crack in the head/block that would allow passage of oil into the cylinder ......probably unlikely). If it's possible on that engine, visually check for a valve stem seal, see if it looks the same as the other cylinders with no problem. If I was confident it wasn't the rings/cylinder then I would pull the springs/valves on that cylinder and inspect the valve seals and guides.

Before you give up on the cylinder/piston, I'd check the cylinder dimensions, make sure it's round and that there isn't much taper. You didn't mention if there was any work done to the cylinders. On a gas engine, typically if a rebuild warrants new pistons and rings, then cylinder work would be necessary also, or you end up putting round pistons in not so round or straight cylinders.
JohnnyB

 

[mtodd101]

Hi Johnny. Thank for your reply also. So your thinking is that the intake is possibly sucking oil into the cylinder and then out the exhaust valve? Could that have anything to do with the valve lash setting. Could I have that way out of spec. I did check and reset the lash before I took off the head. they weren't as tight as they should have been, but made no difference as far as smoking.

 

[mtodd101]

Hi Johnny. I didn't check the cylinder bore before I put new rings in. Should have, but didn't have the tools or the knowhow to do that. In hindsight I probably should have split the tractor and done a rebore. The money and experience wasn't there for the undertaking. The old piston and rings looked bad and in some, rings were missing. The tractor smokes more now than before and never went threw the oil like it's doing now. I've order a bore gauge and will check for roundness in that cylinder before I put the piston back in. As far as the valve seals go, I have a full set of seals but haven't ever done any valve work myself. I do have a valve spring compressor. Is that the only tool I would need? I might as well put the new seals on both valves while it's taken apart. Thanks again for taking the time to help. Also have another video. Not sure if they help at all. Besides the smoke, the engine kind of throttles up and down. Not sure what causes that. Matt

 

[Dataway]

Actually old pistons and rings that have conformed to the shape of old cylinders could easily smoke less than a new piston in a old cylinder. A service manual should have the specifications for cylinder taper, bore, out-of-round, etc. that is acceptable. A valve spring compressor is all you should really need to remove the springs and valves. It would take the proper tools, or an experienced hand to check the valve to guide clearance, suffice it to say the valves should fit the guides and move easily up and down, but have very little, if any, slop side to side. I can't comment on the valve seals as I've never worked on that particular engine so I don't know what they look like or how they are installed, but typically they will fit over the top of the valve guide and hug the valve stem, but not so tightly that it provides much resistance to movement.

And yes I would tend to believe that the engine is sucking oil in through a bad intake valve seal/guide and from there it would make it to the exhaust port. Again... I am assuming that the cylinder is not so out of spec that it could be the source of the oil. Since a diesel can almost burn oil ... some of the strange throttling up and down behaviour could be that cylinder burning, or attempting to burn the oil as fuel .... some other members here more familiar with diesel engines will hopefully chime in on that possibility.

Hate to say it, but, checking the cylinder condition and measurements before installing the new pistons and rings would be an absolutely "must do". If cylinder wear, taper, size (O.D.) etc. are out of spec it could make the new piston and rings pretty much pointless as far as "refreshing" the engine. Again, hopefully a tractor mechanic will chime in, but on a gasoline engine, any engine block ready for new pistons and rings would almost certainly be ready to have the cylinders re-machined to the next oversize.

These comments are just general guidelines and guestimates, not being a diesel mechanic I can only go by my experience with gasoline engines.
JohnnyB

 

[90cummins]

Did you home the cylinder when your replaced the rings??
90cummins