Here's a tip on "blow-by". First, you can't tell if an engine, any engine, has high CC pressure by just the smoke out the filler cap or road draft tube. The pressure needs to be measured with the proper tool, a manometer, and by the proper method, different manufacturers have different methods of checking, like plugging the road draft tube and running the pressure out of an orificed fitting, leaving the road draft tube open and putting a tool on the filler, or just measuring the pressure straight out of the road draft tube. You can't guess unless the air/smoke out the tube is whistling like a teapot, then it is probably fair to assume the engine has excessive cc pressure. Every engine is different. They might be consecutive s/n engines off of an assembly line or two of the same engines rebuilt buy the same guy using identical parts, they will be different in their performance, smoke out the tailpipe, cc pressure, etc. Injectors and the valve set can't cause excessive cc pressure, I take that back, an injector can cause high blow by if, in the case of a bosch pintle style injector, which the multi is, fails in the open position. It can burn a hole in the piston, but there will be other symptoms evident BEFORE you even think about looking at blow by. If an air compressor is causing high cc pressure, you will see excessive oil in the tanks at your post trip inspection...you are doing that, correct? Excessive cc pressure is usually indicated by having big oil leaks at places that are weak links, the pressure trying to vent itself will follow the path of least resistance, usually front and rear main seals, tappit cover gaskets and valve cover gaskets. Bottom line, if the engine is not using oil, remember, the multi does not like to idle, it WILL slobber out the manifold and drip all over the side of the engine, run them hard, they like that, you don't have massive recurring oil leaks or there isn't an issue in the way the engine is running, like missing and lots of smoke that smells of oil out the pipe, you 95% do NOT have high blow by.
Here's something to throw out there on smoke out the breather. A spun bearing will cause heavy white smoke out the road draft tube or filler. It will not make pressure, just lots of smoke. I have seen, I don't know, 20? engines come in with a complaint of smoke out the breather and found that a cam bushing or main bearing was spun. No other symptoms in the way of engine operation, no unusual knocking, nothing. Sometimes these engines have been running thousands of miles before this was found. I went out on an industrial 855 once that was in a mobile drill rig. It had a complaint of a smell coming from the engine that was making the operator feel sick. A main was spun. The operator told me it had been like that for a YEAR but they couldn't put the machine down until I went out to look at it.
Just a seed to plant
