I have a 966 that was low on hp and had a lot of blow-by. I overhauled it one winter and the next summer it had plenty of hp, but still had bb and oil cunsumption. The next winter pulled her apart again and found no internal problems. The rings seated just fine. There was some black streaks on the cylinders on the injection pump side, about one inch thick, going from top to bottom. Honed the cylinders and installed new rings and assembled rest of tractor. Now we are chopping silage and it's like you can't breath sitting in the seat with so much bb. It's doing the same thing it did before. Now the tractor was run in on the dyno after both overhauls. What could be the problem? It is a steady stream of bb coming out the breather. Any ideas would be appreciated. Getting tired of rebuilding this thing.

does the tractor idle a lot? if so thats your problem just needs worked! but keep in mind it is going to have some blow by and without a cab you are going to catch it in the face.

So is that just the nature of the beast? Cause my 1466 that i also overhauled doesn't burn a drop of oil and the blow-by is very minimal. The 966 has a lot of bb when under a load. The tractor idles some, but not much. It is usually always working hard. Dad is just getting tired of breathing bb when chopping.

we have had our's since right after paint dried (before i was born) and it has had blow by for as long as i can remeber and it has never been overhauled. It still runs strong so i guess it is just the way it is.
how much oil is it burning?

Under load it burns little to no oil, but when doing light jobs it burns about a quart every four hours of opperation and slobbers. I guess we are gonna have to live with it.

i think there may be a fix to that let me get back to you on it we had an 806 doing the same thing i believe i will look into and let you know

I will wait to hear from you. Thanks

Which engine is this 414 436 or 466 how many inches is the blow by when it blows down the oil cousumption sounds a bit high to me also may want to send off a sample to know whats goin on that way

Had a couple 966's in the past. They had more blow by than a 1086 or any of the others. 1440 combine with the 436 non-turbo was the same way. Talked to the best IH mechanic around and he said those series non-turbo had the most blow by he knows of.

Yeah thats what my old boss told me and he has been with IH for 30 years. I guess we will just deal with it. Hasn't burned any oil since we started chopping and the blow-by doesn't seem as bad now. I guess she just wants to be worked all the time.

Sorry it took me forever to get back to you. That is defiantly common as far as the blow by goes. The oil is not good. You called it best thing to do is just operate the tractor above half throttle. it helps keep the seals lubed so the oil doesn't leak down. hope this helps let me know if you need any more info on it i will do my best!

Thanks buddy. I think we will just work her hard and keep an eye on the oil level. I put a hose on the breather tube, so it dumps the vapor closer to the ground and that seems to help.

your injectors or fuel injector pump might be bad on the 966

Had both pump and injectors rebuilt when I did the overhaul.

Had both pump and injectors rebuilt when I did the overhaul.

Did you use break-in oil to seat the valves properly? My mechanic said that I should use two doses of break-in oil after an overhaul. He also said the best thing for a fresh overhaul is to lug it pretty good and avoid a lot of no load conditions. I'm still trying to find something to do with mine that won't scratch the paint lol.

Have the valve seals been replaced?

If you have an air compressor and a graduated regulator and gauge, make an adapter to go into the intake. Put in about 20 lbs air into the intake you want to take off the valve covers, you can then tell when the valves are on overlap. You will have to turn and hold the engine off overlap, If you set the regulator to a certain pressure it will work just like a leak down tester, just leave it at that setting. You mark the dampener, pressurise, wait 30 seconds and write down the pressure. Turn 120 degrees then do it again, 6 times, and if three values are out of line you know which hole it is. I have a manometer and an adapter that goes in the dipstick hole. If you have that much blow-by and oil consumption I would be looking at valve guides, intakes for the oil consumption, and exhaust for the blow-by.

The head was rebuilt also with new guides, valves, springs, and keepers. I think it's all going by the piston rings. Used SAE 30 engine oil and broke it in on the dyno. I am not going to tear into it again. I have a 6BT Cummins that might find a new home:D

hmmm,im not sure what the case would be then?does it overheat?

received a 903 cummins that had shorter bolt and allowed turbocharged intake air in to valve cover causing lots of blowby, one possibility. we used to bring engine idle up to 1000 rpm to warm up, reason old fuel injection systems did not generate high(full, design)injector popping pressure, this would have fuel dribble from injectors during idle and wash cylinders. raising engine speed increased fuel inj. system pressures. check thermostat, load is heat, tolerances close up, seal up. low idle temp(faulty thermostat) could allow increased clearences and blowby at idle.

very true

Doesn't overheat. 180' is normal operating temp.

hmmm??does it run ok at full throttle under a load?

not to sound smart but did you check the bore is it within spec? is it possibly out of round?

what are you talking about?

the bore is 414 non turbo

what are you talking about?

the bore is 414 non turbo
As in bore, the piston sleeve or engine block. aka the hole where the pistion runs up and down in. is it withing spec or out of round. He said he overhauled it, honed the cylinders and put it back together. if the cylinder is bigger then the piston and what the rings can expand to, your gonna get blowby. He said that there was an oil streak on one side of the "bore", aka cylinder which would lead me to possibly believe that the cylinder if you look at it from the top down is in more of an egg shape rather than a circle, and the piston isnt fitting properly. they make bore guages that you stick in the cylinder measure and make sure the cylinder is indeed a true circle.

Yeah it runs great at all engine speeds. When we honed the sleeves, we did check it with a bore scope and it was near perfect. Well within the specs. Also checked ring gap and that was fine also. Maybe it's just the nature of the beast. Starts very quick and easily, has plenty of power, doesn't burn oil or slobber when being worked hard. Only has oil burning and a lot of blow-by with light loads, like baling hay or pulling grain wagons.

Sorry, meant to say bore gauge, not bore scope.

Try a quart of Lucas Oil (http://www.lucasoil.com/products/display_products.sd?iid=25&catid=7&loc=show). Worth a try. I use it in everything. Works great IMO.

lucas oil products is the best oil to run,rotela 15w40 is ok,but lucas makes it last longer