Is some blowby normal?

Slowmotoring

Slowmotoring

Member
im just getting the model a out for the year now that spring has finally sprung and the salt is washed off of the roads. I have noticed some oil is coming out of the oil filler neck and there seems to be a lot of air blowing out that seems to be bringing some oil vapor along with it. Is this somewhat normal? Ive seen some model a’s with what looks like a vent tube off of the filler kneck that vents underneath the car. Thats why im not sure if this is “normal” for the a’s or if i need to look into the possibility of a broken or seized ring. I have not done a compression test yet.
 
Slowmotoring said:
My bad. I jumped the gun with my post. I have now found that this has already been discussed. Back to the garage now.....
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No question is a bad question unless you ask it over and over again.

Oil breather, will also keep the fire wall cleaner. Venders sell several different styles.

Enjoy your car.
 
Slowmotoring said:
im just getting the model a out for the year now that spring has finally sprung and the salt is washed off of the roads. I have noticed some oil is coming out of the oil filler neck and there seems to be a lot of air blowing out that seems to be bringing some oil vapor along with it. Is this somewhat normal? Ive seen some model a’s with what looks like a vent tube off of the filler kneck that vents underneath the car. Thats why im not sure if this is “normal” for the a’s or if i need to look into the possibility of a broken or seized ring. I have not done a compression test yet.
Click to expand...

That’s called a draft tube, a GOOD idea.
 
Rings are not a perfect seal even less so when worn. Pistons goes up, pull air in thru the vent tube, pistons go down push air out thru the vent tube.
 
redmodelt said:
Rings are not a perfect seal even less so when worn. Pistons goes up, pull air in thru the vent tube, pistons go down push air out thru the vent tube.
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With 2 pistons going up and 2 going down, the overall volume of the sump doesn't change. Any gasses exiting from the breather are purely the result of blowby, which as has been said, is inevitable.
 
I just got done doing a compression test. Cylinder one had 58psi the rest had 60psi. I installed the draft tube after doing the compression test. Weather is nice, its getting driven...
 
Off topic: When we were cruising our sail boat, there was a boat nameed "Blew-by-U" I guess they thought is was fast. Whenever there are two sailboats in the same water going the same direction, it is a race.
 
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