David;
One of the things I like about Westerbeke/Universal is that all the technical information (parts, maintenance, installation, tech bulletins, etc.) on their engines are free downloads from the Westerbeke/Universal website. It’s raining like a cow whizzing on a flat rock in eastern North Carolina today, so out of curiosity I looked at the parts manual for your M4-30. As originally built, the M4-30 had a breather tube that came out of the top of the valve cover and ran down the side of the engine and vented at or near the level of the oil pan. A lot – perhaps all – engines had a similar arrangement in the days before emission controls. Inside the valve cover is a metal plate that hold what appears to be a foam block breather filter. The foam block would have trapped any liquid oil splashing off the valve train and allowed it to drain back into the system when the engine was off. With a good seal on the valve seats and unworn valve guides, there would have been very little “blow by” of gasses from the cylinder and the inside of the valve cover would have been essentially at atmospheric pressure; hence negligible fluid coming out of the breather tube. If I’m correct, the M25 seems to be the current production replacement for your M4-30. The M25 shares the same breather arrangement as my M35B, which has a breather tube that exits the valve cover and is routed to make contact with the outside surface of the “air cleaner” (which is essentially a metal housing stuffed with wire mesh (think course steel wool). Breather gasses are sucked back into the engine through the “air cleaner”. Sort of like the EGR valve arrangement you find on gasoline engines post emissions regulations. Inside the valve cover of the M25 is a foam block similar to what is in your engine. In addition there is a “breather valve” whose purpose seems to be to vent air into the valve cover to prevent negative pressure (suction) from being created by the breather tube. I suspect what is happening with your engine is that the connection to the air cleaner is creating suction in the vent tube, and that the foam block has deteriorated or gotten so saturated with engine oil that oil is getting drawn into the air cleaner housing. Perhaps the current arrangement was installed by a PO, or maybe there is a service bulletin on the Universal website that covers what you have installed. (Although the manuals for the M4-30A, M25XP and M25XPA all show a similar breather tube arrangement going down to the level of the oil pan.) Anyway, I think I would try removing the valve cover and checking on the condition of the foam block, or maybe just replacing it on general principals. The part number is 301237. Rick Brass Washington, NC From: CnC-List [mailto:cnc-list-boun...@cnc-list.com] On Behalf Of David Knecht via CnC-List Sent: Sunday, April 22, 2018 10:24 PM To: CnC CnC discussion list <CnC-List@cnc-list.com> Cc: David Knecht <davidakne...@gmail.com> Subject: Stus-List universal m4-30 air filter I removed the air filter holder from my engine today to check on whether it needed cleaning and was surprised to find the filter soaked in oil and a significant amount of oil inside the housing. I found there was a tygon/rubber tube running from a fitting on the top of the engine that ended just above the air filter housing and had dripped oil such that it then ran into the case. 1. What is this tube and what it is connected to? I can’t find it in my Universal manual. Oil pressure relief? If so, why would oil be coming out of it? I had not noticed the engine oil being low, so I don’t think it is always leaking, but not sure. 2. Where should the tube go? It seems like it will create a mess whereever it goes but I presume it is supposed to drain into the the space below the engine, but it is too short to do that effectively. Dave Aries 1990 C&C 34+ New London, CT
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