DJ Dep
refugee from the other place
Ewwwwww...but then we wouldn't be saving the planet and being green.
I agree with Guru....use a road draft tube like in the good old days. Why suck all that gunk back in the engine????
PCV valves instead of breathers?
- Thread starter Yellow73SB
- Start date
Ewwwwww...but then we wouldn't be saving the planet and being green.
I agree with Guru....use a road draft tube like in the good old days. Why suck all that gunk back in the engine????
JPhil
Huh?
I don't mind running a PCV, I just want the car to quit smoking & using oil. It just started doing it this spring.
Last week I unplugged the PCV valve from the breather & ran it a couple days to work & back (about 100 miles total, both city & 60 mph county roads).
No difference in the smoking. Then I put a clear tube from the PCV to the carb with a loop down by the dipstick and ran that a couple days. Only had a few drops of oil in the tube.
Did a leakdown test yesterday, I'm running from 10% to 3% leakdown. Interestingly, the 3 plugs that showed signs of oil fouling had lower leakdown rates than some of those that didn't (3%, 4%, & 5%). The 10% one actually looks to be leanest & cleanest of all of them, but it's not bad. At least now I think it's not rings making the smoke...
I seem to be just a tad on the lean side on most of them, do you think changing to an easier breathing PCV would change the mixture? It seems to me it would, although I didn't think about that till I pulled the plugs. I did that last year to try to reduce the oil misting on the valve covers.
Next weekend I will replace the valve guide seals on the 3 cylinders that show oil fouling.....Hope that does it.
Last week I unplugged the PCV valve from the breather & ran it a couple days to work & back (about 100 miles total, both city & 60 mph county roads).
No difference in the smoking. Then I put a clear tube from the PCV to the carb with a loop down by the dipstick and ran that a couple days. Only had a few drops of oil in the tube.
Did a leakdown test yesterday, I'm running from 10% to 3% leakdown. Interestingly, the 3 plugs that showed signs of oil fouling had lower leakdown rates than some of those that didn't (3%, 4%, & 5%). The 10% one actually looks to be leanest & cleanest of all of them, but it's not bad. At least now I think it's not rings making the smoke...
I seem to be just a tad on the lean side on most of them, do you think changing to an easier breathing PCV would change the mixture? It seems to me it would, although I didn't think about that till I pulled the plugs. I did that last year to try to reduce the oil misting on the valve covers.
Next weekend I will replace the valve guide seals on the 3 cylinders that show oil fouling.....Hope that does it.
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Not sure if it’s cool to quote this here, but it may help.
Phil
Not trying to initiate an endless debate or wow anyone with pointless molecular activity or even reinvent the English language, like happened over there, but here is a post of mine from another forum.
Here is a simple test I did on a decent engine not using oil. Perhaps you could compare to your engine. I use it for a fast and easy blowby test.
Phil
Not trying to initiate an endless debate or wow anyone with pointless molecular activity or even reinvent the English language, like happened over there, but here is a post of mine from another forum.
Here is a simple test I did on a decent engine not using oil. Perhaps you could compare to your engine. I use it for a fast and easy blowby test.
Had a few minutes to take some pics today.
I’m not suggesting which method is best for any purpose, just use what works best for me on this car since I don’t race and don’t want to reinvent the wheel.
This should dispell some of the beliefs/posts that there is no fresh air being introduced into the crankcase and/or that the crankcase will run under a vacumn with a pcv.
The car is a 77 with original engine, a bit of a cam, old alum intake, recurved dist, de-smogged qjet, headers with dual cats, oem pcv and air cleaner. The engine has 72,000 plus miles on it. The only change to the pcv system was the addition of stainless mesh material, into the valve cover baffles, (pot scrubbies from the grocery store), to aid in the condensation of oil vapor.
The proper test for engine blowby, uses a very expensive flow meter such as this.
http://www.j-tecassociates.com/Engine inline2005.htm
I just used a half decent vacumn gauge.
The connection
The gauge, engine not running
The engine at 750rpm
The engine at 3000rpm, no load
Stainless mesh in baffle
Pics are self explanatory.
There is a fairly constant vacumn from idle to 3000 rpm, so the pcv valve seems to be adjusting itself as designed.
Without a flow meter, fresh air intake can’t be measured, but it definitely will ingest fresh air.
What someone that has never tried this may not know is that the vacumn took approximately 20 seconds to go from 6 at idle to 0 after shutdown.
My conclusion is that the rings are in pretty decent shape for this old a motor.
When I next have some time, I’ll try it on the road with the gauge and post the results.
Here’s some more info to mull over.
Had a little time to get some reading on the road today. Traffic was pretty heavy, so I didn’t get a lot.
I connected my “lower than atmospheric pressure gauge” (because Z-man and FB007 contend vacuum does not exist) the same as before, to the oem passenger valve cover breather tube.
I taped the gauge over the shadowband, so it’s not as clear as should be with the bright Florida sun behind it.
At startup and idle I got the same reading of 6”
After the engine got to full temp (180°) it went up to 7”
At 2000 rpm steady cruise it went back to 5”
At 2500 rpm steady cruise it stayed at 5”
At 3000 rpm steady cruise it stayed at 5”
At 3500 rpm steady cruise it dropped to 4.5”
At 4000 rpm steady cruise it stayed at 4”
Traffic wouldn’t let me cruise at any higher rpm
Half throttle acceleration thru 1st, 2nd and into 3rd stayed at 4”
Full throttle acceleration brought it to .5# pressure.
Thru all of the cruising rpm’s the needle stayed pretty steady.
At WOT acceleration, thru the gears, there was a lag of 3 or 4 seconds to reach pressure.
kwplot34
Heart Attack
Ewwwwww...but then we wouldn't be saving the planet and being green.
I agree with Guru....use a road draft tube like in the good old days. Why suck all that gunk back in the engine????
I dont like running all that crap back through my motor,hot air,gasses,oil,moisture and who knows what else,so i vent mine out the bottom of the car,with the help of a vacuum pump
mrvette
Phantom of the Opera
Some of us vent naturally without assistance....
:rofl::sweat::tomato:
:rofl::sweat::tomato:
