Author |
Message |
doc hopper Samba Member
Joined: December 08, 2006 Posts: 588 Location: California
|
Posted: Thu Oct 24, 2013 3:20 pm Post subject: Blow By Symptoms Giving Mixed Signals? |
|
|
In an earlier post I was discussing the blow-by in my 1679 engine, (oil coming out the crank pulley onto the deck lid) but having read more on the Samba site here is my confusion:
The engine (all Gene Berg parts, built by Clyde Berg) has 60,000 miles on it. Never runs hot (verified by Berg dipstick sender (s) )
Meticulously maintained (oil changes, tune ups, valve adjustments)
Has full flow with HP-1 filter and 1.5 quart sump, 30 wt Penzoil
Built with a modest 6.8:1 compression
Performance is good, mileage is good
If the rings are worn enough to be causing blow by, shouldn't I also be burning oil? No evidence of this such as tell tale blue smoke, in fact it doesn't smoke at all.
Shouldn't it also be running hot at freeway speeds?
Last compression test : 115,110,100,115 _________________ "Honesty hath no fence against superior cunning" |
|
Back to top |
|
|
VeedubPastor Samba Member
Joined: September 03, 2009 Posts: 761 Location: Maryland
|
Posted: Fri Oct 25, 2013 10:24 am Post subject: |
|
|
All these engines have blow-by. That is why the crankcase is ventilated.
How is your crankcase ventilated? _________________ 1971 Super Beetle - Daily Driver
Solex H30/31 & 034 distributor (yeah, I know)
Stock thermostat & flaps
Stock air cleaner and emissions equipment |
|
Back to top |
|
|
doc hopper Samba Member
Joined: December 08, 2006 Posts: 588 Location: California
|
Posted: Fri Oct 25, 2013 2:36 pm Post subject: Blowby |
|
|
The crankcase is ventilated in the usual way for a stock set up (stock carb, stock aircleaner) vent tube from the bottom of the air cleaner to the tube on the oil filler that goes down below the sheet metal to the street. _________________ "Honesty hath no fence against superior cunning" |
|
Back to top |
|
|
Northof49 Samba Member
Joined: July 22, 2013 Posts: 1759 Location: Winnipeg, Manitoba, Canada
|
Posted: Fri Oct 25, 2013 2:38 pm Post subject: |
|
|
If you take the cover off the breather / oil cap, are you feeling much pressure generated? If there is a lot of blowby, I would think you would feel the pressure of the leakage there. _________________ 1958 Karmann Ghia owner |
|
Back to top |
|
|
doc hopper Samba Member
Joined: December 08, 2006 Posts: 588 Location: California
|
Posted: Fri Oct 25, 2013 2:54 pm Post subject: Blow By |
|
|
In order to cure the problem of oil slinging out of the crank pulley onto the decklid I put a vented valve cover on the 1-2 cylinder head.
I ran a hose from the valve cover to the evaporative control nipple on the air cleaner (stock vw air cleaner).
This took care of the oil slinging, but at highway speeds the oil was now being blown out of the air cleaner all over the side of the engine compartment.
I now have the valve cover venting to the oil filler nipple that goes down to the street.
Anyway... same question... shouldn't I be experiencing overheating, oil burning and so on with this much blow by? _________________ "Honesty hath no fence against superior cunning" |
|
Back to top |
|
|
Northof49 Samba Member
Joined: July 22, 2013 Posts: 1759 Location: Winnipeg, Manitoba, Canada
|
Posted: Fri Oct 25, 2013 3:00 pm Post subject: |
|
|
I don't know, but there are oil control rings and above them are the regular rings. Sure sounds like you are getting blowby if there is oil blowing out the vents at high speed. Was it always this way? _________________ 1958 Karmann Ghia owner |
|
Back to top |
|
|
doc hopper Samba Member
Joined: December 08, 2006 Posts: 588 Location: California
|
Posted: Fri Oct 25, 2013 3:03 pm Post subject: Blow by |
|
|
Began about 10,000 miles ago at 50,000 miles. _________________ "Honesty hath no fence against superior cunning" |
|
Back to top |
|
|
borninabus Samba R&D Dept.
Joined: May 18, 2006 Posts: 4532 Location: Arizona Highways
|
Posted: Fri Oct 25, 2013 4:47 pm Post subject: |
|
|
What did a leak-down test say about that #3 cylinder that is out of the 10% compression range? _________________ 71 Ghia A/S - 88 Van A/T - 13 JSW TDI 6M/T |
|
Back to top |
|
|
jwold Samba Member
Joined: September 30, 2008 Posts: 2088 Location: Portland, OR
|
Posted: Mon Apr 28, 2014 10:39 am Post subject: |
|
|
Check to see if the bolts that hold your case together are tight. |
|
Back to top |
|
|
|