JD 4020 Excess Smoke/Rocker Oiling Issue?

Hello everyone,

This is my first post, but I have been lurking for a while now.

Long story short, the engine builder who rebuilt our diesel 4020 engine (ten years ago) didn't do it correctly, and the front timing gear popped off, allowing the valves to make acquaintance with the pistons haha. I installed all new components (timing gear, pushrods, etc.) had the head milled/inspected. Everything it put back together, timed correctly and it fires right up.

The issue I am having is that the engine smokes a little more at idle than it did before, and it smoke a lot more on acceleration (then clears up at constant RPM). I have tried loosening each injector and each one makes a difference (so it is running on all 6), one injector had to be replaced with a new one too. Any thoughts on this?

The other issue I have is it doesn't seem like any oil is making it to the top end. On any other engine you would see the oil running off of the valvetrain components, etc. On this one there doesn't seem to be much if any. The rocker shaft is aligned on the pin and the hole that I think supplies oil seems free. I blew air into it and I could her the air in the oil pan area. Any thoughts on this?

-Will

Check to see if the rubber plugs are in the end of the rocker shaft, they get hard and will move in. The rear one can move enough to cause the oil to run out the rear of the shaft and not lube the rest of the rockers. The new ones are a bear to get in and if you can move the old plugs at all replace.

Ok so that is a point of contention that I had reassembling the rocker shaft. In the valvetrain explosion, the end cap of the rocker arm assembly came off. I actually ordered a new end cap and the rubber plug. I did not, however, put that rubber plug back in, because it would have interfered with the oiling hole. I don't even know why the rubber plugs are there, as the end caps have plenty of press fit to prevent any oil leakage. I'll take the rocker arm assembly off and see what I can discover. You would think that oil would come out of somewhere though?

-Will

The shaft should have either the rubber plugs, having a cotter pin to stop it from coming out OR the steel cap. chris

Pull the rocker shaft and crank the engine to
see if oil is coming to the head.
As someone else said it's either/or on the plugs.
If there are small holes in the ends for cotter pins,
rubber plugs should be used. Otherwise steel plugs
are supposed to be used.
Look through the shaft to be sure an old plug hasn't
slid over the oil entering hole.

10-4 That is what I thought! I checked the oil with the rocker shaft off and when cranking it comes out in splurts, but that is to be expected at the slow crank speed/that high on the engine. The rocker shaft is also not clogged and air shoots out of it in just the right places. I put it back together and called it a day, it seemed to be getting some oil. The black smoke also seemed to lighten up a little bit...

-Will

Early or late and precleaner above the hood?

No precleaner

It is a steel cap style, so no rubber plugs to go bad. I took the rocker shaft off and the oil does shoot out while cranking but it definitely has a pulse (like a fuel pump). The rocker shaft also holds air pressure and shoots air out of the right holes.

When reinstalled, it just seems like there isn't enough oil flow/maybe none. It is certainly no small block chevy with oil flying everywhere.

So must be a side console? If so, look for a canister/filter on top of the air cleaner, has this ever been changed? Part number AR51923.

I wouldn't worry about it then if your oil pressure is OK?

Side Console, yes. Let me look into this. The only air filter I am aware of is the one in the air cleaner housing that is accessed by removing the side panel. That gets blown out every season.

-Will

Going to check the OP and report back. I'll throw a gauge on it tomorrow.

-Will

The oil will come in spurts that is because the only comes out as the hole in the cam lines up this is at the rear cam brg. you should check the inj psi setting all should be very close to the same

It does come in spurts, the machine makes 30psi idle. I think it will be ok...

-Will

I have the same oil issue. How has your unit been running with weak oil to the rockers. Any issues. I've been battling this for some time now. already replaced rocker assembly once. looking for ideas.