8v71 Blow By

[RobSedona]

I.m getting blow by from my 8v71 and it shows up in the exhaust pipes just after the 2 sides come toghter. the 8v71 is in a 1966 MCI5A and has a Jake Brake Added. Thanks in Advance

[Fredward]

My understanding of blow by is it comes from combustion pressure being forced through worn rings down into the crankcase. It comes out of the crankcase breather which on my 8V71 is on the passenger side valve cover vent hose. Its just smoke coiming out of that vent tube. I don't know about your reference to where the exhaust pipes come together?
Fred (MC5A)

[ol713]

I.m getting blow by from my 8v71 and it shows up in the exhaust pipes just after the 2 sides come toghter. the 8v71 is in a 1966 MCI5A and has a Jake Brake Added. Thanks in Advance

          When you start the engine when it's cold,  what color is the smoke?
          Others here can be more specific about the smoke.
                                         Merle.

[TomC]

Some of the sure signs of problems with Detroits.  Hard to start or have to use ether in temps around 40 degrees; when it does start puts out white smoke for more than a minute; when it does start, only a few of the cylinders are firing with the non firing cylinders eventually firing; burning a gallon of oil in 500 miles or less (normal is 1200 miles on older style and 2200 miles on new style rings); lack of power; excessive black smoke on full acceleration at near sea level.  One of the nice things with a Detroit is that you can pull the air box inspection plates on the side of the block and rotate the crank to inspect the rings for worn and/or broken rings.  If you have a worn engine, highly recommend you get it refreshed to the point that it does not smoke.  The EPA is just going to get more and more touchy about that.  Good Luck, TomC