How much blowby is acceptable?

sitdwnandhngon

New member

Equipment
B7100
Aug 25, 2015
45
0
0
NY, USA
I have a good deal of smoke coming out of my B7100 vent tube.

Still starts fine and runs strong though. I recently did the cam plug fix and it seems to have gotten worse since the oil pressure came back up.

I have rings and a head gasket coming, but I really don't want to tackle it just yet.

How much blowby is acceptable, and when does it become a problem?
 

Daren Todd

Well-known member
Lifetime Member

Equipment
Massey Ferguson 1825E, Kubota Z121S, Box blade, Rotary Cutter
May 18, 2014
10,887
8,519
113
Vilonia, Arkansas
Mine had quite a bit of blow by when I first did the cam plug fix. Took around five to six hours of running the living snot out of it under a heavy load to burn all the moisture out of the top of the motor. After that it seemed to tone down quite a bit. Mine was pretty obvious that the white smoke coming out was moisture and steam. If you held your hand down by it, you could catch little water droplets. :rolleyes: mine still smokes a touch, but it's hard to see unless the light hits it just right.

If it starts and runs good, then I would just keep an eye on it and see if it tones down after a bit.
 

sitdwnandhngon

New member

Equipment
B7100
Aug 25, 2015
45
0
0
NY, USA
Mine had quite a bit of blow by when I first did the cam plug fix. Took around five to six hours of running the living snot out of it under a heavy load to burn all the moisture out of the top of the motor. After that it seemed to tone down quite a bit. Mine was pretty obvious that the white smoke coming out was moisture and steam. If you held your hand down by it, you could catch little water droplets. :rolleyes: mine still smokes a touch, but it's hard to see unless the light hits it just right.

If it starts and runs good, then I would just keep an eye on it and see if it tones down after a bit.

That was kind of my thought too. I figure as long as it is starting fine then it's probably doing okay. Seems about 10 seconds on the plugs and it fires right up, even the other day when it dropped in to the 50's 10 seconds was plenty.

There is some wet stacking on cylinder #3, I'm not sure what it's from just yet, the battery that's in it prevents it from getting revved up past half throttle, so I am thinking it was run at low throttle often.

Might need to hook up an implement and go run it to clean it out.
 

Diydave

New member

Equipment
L2202 tractor, L185f tractor
Oct 31, 2013
1,635
11
0
Gambrills, MD USA
The way to figure out if it has moisture in the blow by is to disconnect the upper tube at the valve cover, and replace with a short piece of hose, pointing upward. Place a clear baggie, over the hose. If you see condensation in the baggie, it's steam. Sometimes if you smell the blowby, you can detect the odor of antifreeze in it...:D