blow by question

[ddettloff]

Mild build 318 lot's of vapor coming out of breather and pvc when I disconnect it.
No smoke coming out of exhaust.
when pvc connected there is a lot of vapor coming out of breather.
If this was a ring problem wouldn't I see smoke from exhaust.
The compression is low approx 110 lbs per cylinder any thoughts.

 

[teringer]

was it reringed or bored out?

 

[Treblig]

Mild build 318 lot's of vapor coming out of breather and pvc when I disconnect it.
No smoke coming out of exhaust.
when pvc connected there is a lot of vapor coming out of breather.
If this was a ring problem wouldn't I see smoke from exhaust.
The compression is low approx 110 lbs per cylinder any thoughts.

This is an interesting question and would like to hear a good (logical) answer because my 69 Barracuda smokes a little also and I might try the breather troubleshooting method!!! So here's a FREE BUMP for you.

Treblig

 

[TrailBeast]

You both need to be sure your PCV valve and lines are clear and flowing.
Valves are pretty cheap, so it might be wise to replace them and see if the problem persists.

I recently had the opposite problem with a valve, where the PCV could have sucked up the entire BP spill.

 

[moper]

What does the bottom of the oil filler cap look like? Is the PCV wet with oil? Is there more or less vapor when the engine is at operating temperature? How often (and far) do you drive it?

 

[pishta]

if you have a lot of vapor, it may just be a back log of water vapor, a normal byproduct of combustion and condensation. A breather routed from the base of the aircleaner and a working PCV would seal it all up. Id throw in a can of seafoam and clean it all out, then a bottle of Marvel UCL. Compression rings could be gummed up but oil rings may still be functioning as well as exhaust valve seals.
Grammas old Buick Apollo never went more than 5 miles a week until me and my dad blew it out on a spirited run on the highway. That thing left a steam trail for 5 miles. replaced PCV, Ran like a champ afterwords, changed oil was like tar.

 

[nm9stheham]

You can have poor compression rings and good oil rings and have blowby into the crankcase but no real smoke fromt he exhaust.

Your 110 psi compression readings will depend on the cam you use as well as the compression ratio of the pistons so that may or may not be meaningful.

I would check the compression rings as follows: Take a compression reading on each cylinder after setting overnight. Then squirt some oil into each cylinder and retest right after the oil and see if the reading increases after the oil; if so, then the compression rings are likley not sealing well, or the ring grooves are worn, or both.