Crankcase Ventilation System

[Eleven]

Would anyone post a photo of the PCV plumbing on an SV with a Weber? I think I have a duff valve but also think I have it plumbed wrong. Car idles crappy.
I have a Sunbeam Specialties intake manifold with the Weber.
Side tappet plate tube to the intake manifold.
Oil fill pipe to the air cleaner. The flame trap is located on the oil fill pipe. (This arrangement looks wrong because there is no way for excess oil to flow back into the engine.Wonder if it should be on the side plate. One side of the flame trap is such that it connects to a hard tube meaning you cannot attach a hose to it but you can the other side if that makes sense.
I cleaned the PCV valve a few years ago (didn't put that many miles on it since) but it is on the intake manifold and downstream from the valve cover oil fill and the flame trap.
As a side note, which got me thinking about this; When reving the engine up, I noticed the flame trap (attached to the oil fill) was being pushed out as crankcase pressure increased.
Anyway, a good photo of a correct system will go a long ways. Thanks for any help!

 

[husky drvr]

Tracy,

Your description sounds correct for installation. The flame trap should be rotated so the connection to the oil fill is on the bottom. Has the flame trap been cleaned?

There is a section in WSM 145, Engine, pages 33 and 34 that describes the PCV system, along with cleaning and testing.

Do you have the original AC PCV valve or has it been replaced with something else? If it's a replacement, it might be designed to operate in reverse to the OE AC valve, which would cause your poor idle quality.

You might also consider a compression test with your mention of high crankcase pressure. I suppose it might be possible you have possible stuck rings due to storage.

Hope this helps,

 

[Eleven]

Thanks Don! It is the original AC PCV. I have cleaned it but not sure how good it is. As to the rings, the car has been used this summer and it has a new head on it. The compression is close to 150 across all 4. The flame trap needs to be rotated, thanks for that!
I looked at the manual but it didn't help with the plumbing. I will run through their tests and clean the flame trap. The idle problem has been a long term issue in a way. I just found out that it has flat top pistons and maybe a little hotter cam. Not sure about the cam. (I could measure but that is a pain in the flame trap)
I know there is a Datsun one that folks have used. Agree that there is no way to tell if it is a good match or not.
Cheers, stay safe and thank you!

 

[Tim R]

I don't know what the SS manifold is like but the curved Weber manifold that Alpine Innovations sell for their DGV conversion does not use the PCV, you fit a blanking plug into the threaded hole. On our Weber equipped cars we vent both the tappet chest and rocker cover to atmosphere on pipes that go down to the bottom of the engine in the transmission tunnel. The cars have been like this for a very long time with no problem. You can feel the air pulsing if you put your fingers to the pipes but there are no fumes or oil leaks caused by doing this. At one point we had a 'catch tank' intending to catch any oil that came out but it was not necessary.

Tim R
.

 

[alpine_64]

The compression is close to 150 across all 4.

How do you measure compression.. Plugs out and WOT?... Should be closer to 175

 

[Eleven]

plugs out. I have no idea how old the mill is or the state of the rings. Doesn't smoke, good oil pressure and the numbers are pretty even so am leaving it alone.
What is WOT?

The SS manifold is okay and decently made but lack a water heating jacket. Given the little I drive the car, I might do what you have done but am going to install a replacement from NAPA and see if the idling is any better.

Thanks fellows!

 

[Billm]

Wide open throttle. While cranking the engine over for a compression test, one should hold the carb linkage so the butterflies are wide open.

 

[hartmandm]

Photos previously posted to the forum by another member. Not sure if these are of any value for your setup.

Mike

 

[Eleven]

Yes, I did the compression with the throttle wide open. I thought it would be higher with the flat top pistons but we all get old I guess.
My set up is the same as the photos. The help with the set up but do bad things to my self esteem... The shine, no dirt. Even the break reservoir is perfect for gawd's sake!!!!!
Thanks again fellow for the help. I replaced the PCV, will see if that does any good. Suspect I need to look at the Weber jetting if the PCV does help. The set up in there now was with the old one that may have been leaking air.