Unusual Oil Leak ??

[PatO]

Well I made it through last winter and part of the summer without any oil spots on the garage floor. But sure enough eventually I found a new oil drip.  In short order I found some oil running down the drivers side rear of he engine onto the starter and header. To make a long story short I eventually isolated the leak to a small vent hole on the bottom of the distributor housing, not at the seal where the shaft meets the block. This I'm certain of.

I've attached a picture of a distributor unit very similar to mine and pointed out the hole in the housing.

I've searched the internet on this and there is very little on the internet regarding oil coming from the distributor housing. Some discussion on excess crank case pressure but I have my pvc valve and hose installed properly, along with a push in breather on the valve cover on the other side of the engine. I see no oil anywhere else.

Not wanting to try to figure out how to disassemble a distributor and figure out where the oil is getting by - my inclination is to just buy a new distributor.    That is of course if someone has dealt with this sort of thing before and can share their experience with me ???  Anyone else ever have this issue.

Thank you!

[Chryco Psycho]

How well is your PCV system working , pressure could be pushing oil past the bushing in the dist but this is the first time I have heard of a leak there .

[MoparLeo]

When you say push in breather is it a factory/sealed type or open at the bottom.
Is your engine equipped with a factory type top end, meaning stock type air cleaner, stock type oil filler and push in breather that is connected to the air filter housing ?
A picture is worth a thousand words.
On a stock system excess crankcase pressure ( normally an engine with worn piston rings) that could not be evacuated by the PCV valve would bypass to the air filter through the breather hose in the valve cover to air cleaner.
Stick a toothpick in the distributor housing hole and spray the rear of the engine liberally with brake cleaner and immediately blow of all areas with a pressurized air hose to dry.
  Or also add some fluorescent dye to the oil and recheck any leaks with a black light to trace the origin.

[Bullitt-]

I could imagine a leak at the oil pressure sending unit spraying on the distributor as more likely.    

[PatO]

Thank you for the replies!

Over the past couple of weeks I've thoroughly cleaned the area. I'm real sure the sender isn't leaking, I've taken a clean paper towel around it and all over it and didn't find a trace of oil.

Below are a couple of pictures of my motor taken this afternoon. On the passenger side is what a refer to as the breather that I have in valve cover. On the drivers side I have a hose running from the pcv valve to a fitting on the air filter bottom.  As you can see it is not a stock set up.     I think I have adequate breathing for the crank case. The motor has 600 miles on it. I don't see oil from the breather or the dip stick tube.  But I'm not an expert either.   

What I did do this past Sunday was to re-clean the back of the engine and then tape a folded up paper towel to the underside of the distributor, a diaper so to speak. I took a road trip for about 20 minutes and after the engine cooled a bit I removed this diaper.  There was oil on the paper towel, a nice sized spot.  No oil on the distributor clamp or anywhere else. Today after taking the pictures I put my finger over the hole in the housing and it was wet with oil. The car hadn't been run since I turned it off on Sunday.

Not having seen a diagram of a distributor I'm wondering if there is a bushing or o'ring or other sort of seal in the distributor that has failed.

If the weather holds, I try the diaper trick again and take the car out for a half hour run and see what I find.

Thanx again.

[JonH]

Your pcv valve should be connected to full manifold vacuum. Pulling crankcase fumes into the intake and fresh air entering via the breather on the other valve cover. This should solve your issue....

[Chryco Psycho]

The PCV has to be connected to the base of the carb to function correctly , there is no vacuum inside the air filter to draw off the pressure .  Tus the engine is pushing the pressure out any opening it can find !

[PatO]

Unfortunately for me I have a rather aggressive cam and my house is at 6500 feet in altitude. Difficult to get a decent idle with the pvc plumbed to the base of the carburetor.

At the time I was getting the car running again I debated on getting one of those adjustable pcv valves so I could could restrict the vacuum loss to after the throttle was being opened. I tried the hose into bottom of the air filter cause I was thinking if there was any positive pressure in the crank case it would get by the pcv valve and into the air cleaner.  Seems like that would be a bit of wrong thinking on my part   I may not understand how exactly the spring/valve work inside the pcv valve.

I was wondering if I took both the breather and the pcv valve off and left the top of the engine open to the atmosphere for a short drive it that would tell me anything? But then again the distributor already has oil in it.

found this thread also:

https://forum.e-bodies.org/engine-transmission-and-rear-end/4/engine-oil-in-distributor/20175/msg252433#msg252433


Right now I'm thinking the adjustable pcv valve would be less expensive and a whole lot easier than replacing the distributor.

Really appreciate the comments and helping me think this through.

[PatO]

Saturday was a nice day here so I took my time and checked out my engine a bit more carefully. I found that the breather in the passenger side valve cover had oil in it. The small ring of holes on the bottom of the breather has a foam backing and I could clearly see it was pretty oily. Not enough to drip , but close.  The actual pvc valve had oil in it as well. I've spend few hours on the internet to try and get my head around what I was doing wrong. Clearly, I was out at first base on this matter.

Today, I determined that my engine idles real steady at 10" of vacuum.  I've seen a number of threads elsewhere about a 1980s Mopar era PCV valve, #4343581 that supposedly works on built engines that are idling at a lower vacuum than stock.

Has anybody had experience with any pcv valves for this sort of application?  I'm still thinking about the adjustable valve but if I could simplify things I may try that route first.

Thanks again. 

[MoparLeo]

https://auto.howstuffworks.com/positive-crankcase-ventilation-system.htm

[B5fourspeed]

Rick Rehrenberg sells good distributors on ebay.I would email him about your issue and I am sure he would have some ideas