Briggs blowing oil out crankcase vent

[dana a]

I made a log splitter back in the 1990's and it has an old 11HP Briggs with a 16HP V twin carb on it. I bought the engine without a carb and used what I had. It has run for years with no problems till today. The crankcase vent isn't attached to the card and when I finished splitting wood today I went to the back of the splitter and the ground was covered with oil. I shut it down and checked the oil level and none was showing on the dip stick. It was full when I started. What would cause it to suddenly start blowing oil out. I noticed the dip stick had been pushed up out of its tube also. It is held in with a tight rubber gromet.

 

[Auto Doc's]

Most likely it has broken compression rings or a badly worn cylinder allowing too much pressure back into the crankcase. A failed breather is possible, but that is rare.

 

[Tiger Small Engine]

Most likely it has broken compression rings or a badly worn cylinder allowing too much pressure back into the crankcase. A failed breather is possible, but that is rare.

A tired, worn engine. Keep the oil topped off every time you use it, and run it.

 

[sgkent]

when it happens that fast to allow that kind of blowby to blow oil out , a broken ring, hole forming in piston, broken guide etc. All be catastrophic failures of some kind. That said, one cause can be that the breather has plugged and that only thing normal gases can do is blow out thru seals so do check the breather to be sure it is good. Also check the oil to be sure it is not full of water or gasoline. Foamy oil full of water or fuel reaching a temperature where the fluid boils off can push out oil too. I would start by cleaning it up, draining the oil left to look for contaminants, filling it with new oil and doing a compression test.

 

[dana a]

Thanks for the informative replies gentlemen. I have another engine I'll use till I get this one torn apart and fixed. It makes sense to me that you are probably right that it has a broken ring.

 

[jimcat]

Head gasket blown

 

[Forest#2]

Head gasket blown

I suspect head gasket let go but ????????????

A engine model number, type and code would be helpful. (or even some pictures of the engine????)

Pull the spark plug and see if spark plug/plugs is loaded up with black carbon or oil. If so pull the head on that side and look at the head gasket if it's a twin. If a single head pull the head and inspect the head gasket if the plug is very oily or lots of carbon.
If you have a compression gauge you could check/compare compression on each cylinder, but a leak down test gives me more results.

 

[Auto Doc's]

I don't recall B&S making an 11HP twin cylinder engine. I'm still wondering how a "16HP carburetor" was mounted to this. The original description is a little confusing. The number on the engine cover are likely not correct. AKA Frankenstein build.