PCV valve help

Trying to come up with a fix for leaking rear main seals on a fleet of these units, as we believe there is to much crankcase pressure being made. These units were built without a pcv valve system and only had a breather hose coming off the left bank valve cover. These engines are run on natural gas and are compressing natural gas. So, the right side of the engine is the compressor. There is a pipe plug on the carb adapter that I can pull vacuum from, as the intake is not drilled anywhere, and I can plumb a pcv valve on at the nipple of the valve cover. My question is where or how can I get a breather in the system, or do I need one? I tried using a 2 hose pcv valve, putting a small breather out off of the smaller connection, but it just acts like a vacuum leak, so that's not going to work. Would just a push in breather installed in the valve cover work? Thoughts???

Thanks.

You would just need to have a filtered breather on one side (valve cover) & the PCV over on the other valve cover. Not sure where I saw it but there was a comprehensive thread on the different PCV's regarding how much they flow cuz there was an issue with that that got that thread started. Are you sure the rear seal it not the issue. they can be a problem child & a thread yesterday was almost driveing the owner to suicide.

Remove the oil filler cap I see on there (just long enough to check) and run the engine, see if that cures the problem. If it does find a cap with a breather built in. A lot easier than figuring out a pcv set-up.

I think you better consult the manufacturer of these before you mess with adding a breather and/or pcv. ANY blow by from the right side is compressed natural gas. You might be creating a big KABOOM.

No valve cover on the right side, just the compressor head. Have tried replacing rear seals, different brands and weight oils, different oil pan gaskets all with the same results.

Thanks

There is a 5/8 nipple on the filler tube neck that originally uses a hose run down under the unit and vents. So I don't thing taking the cap off would be any different.

Thanks

The original manufacture hasn't built these units in a long time, so I don't think I could get an answer from them. I understand what you are saying about pulling the gas internal of the engine. Maybe that is why they only used a vent. Maybe by nature they are going to seep oil, but would like to find a remedy.

Thanks.

Seen this system on some industrial engines so maybe work on your integral unit, that has natural gas probably mixed in the crank case.
Run a hose from your valve cover to a catch can. From the catch can to a spot between the air filter and the carb. Lines and can all need to be sealed This could give you some negative crank case pressure, depending on how much ring leakage you have. This could, of course, can change you air/fuel ratio, so it would have to adjusted accordingly.
I've seen catch cans with filters that drop out oil vapor. The oil just drains back to the crankcase. Can reduce carb getting oiled up and detonation problems.
You could put a valve in the the line after the valve cover to limit the possibility of too much crankcase vacuum. This might occur as the air filter gets more restriction. Wouldn't want air/dirt getting sucked into the crankcase by the seals.
Depending if your process pressures are consistent or not, could change ring leakage. Might have to monitor air/fuel mixtures more often, and have a way to check your crankcase pressure/vacuum.

For my 2-cents 440_Offroader is right on. A PCV valve IS a vacuum leak (sort of) and using one will definitely affect your air/fuel mixture. I do like the idea of creating the vacuum for the PCV in the air cleaner, not under the carburetor (or throttle body) as a first try. Also related to his post, you can buy a valve in the air tool section of Harbor Freight for about $5 to "throttle down" the vacuum if needed...really any valve would do that. I also like godscountry340's idea about taking off the oil fill cap...is it puffing smoke/natural gas vapor out of it big-time? I always checked car motors for excessive blow by that way. Your symptom of blowing rear main seals does fit with your excessive blow by idea... and about every other oil seal in the motor leaking too would also fit.

PurpleBeeper I never woulda thought! I'm gonna incorpororate that in a future build. thank you!

These units just have a open air filter , no housing. I would have to tap into the air intake pipe between the filter and carb. Looks to be a great option to try.

Thanks!