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mcguan.2
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I just bought a '73 Jensen that had not run in over a year. After rebuilding the carbs, changing the fuel in the tank, etc., I started her up. Immediately I noticed oil spewing out from a hose attachment directly beneath the rear carb, on the engine block, next to the starter motor. Obviously a hose is supposed to go on that nipple, but where would it go to? And what does it do?

Judson Manning
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Congrats on gettting her started - now comes the fun part!

A "1973" model could have either  late MkI or early MkII block.  Both blocks have a crankcase vent in that same general area.  A MkI engine has no oil cap on either cam cover, the MkII has the oil cap on the intake cam cover. 

Oil laden vapor coming from a MkI vent is normal as the MkI cars all had an external oil separator.  Oil laden vapor from a MkII vent suggests too high an oil level or excessive blow-by caused by worn rings.

mcguan.2
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Thanks for the help. It must be a mkI. There's no engine oil filler on either cam cover; it's in a different spot. My concern was the amount of oil that was coming out of the vent and the direction it was pointing. The oil was coming out as if you put oil in a large syringe and slowly depressed. Not a really strong stream, but definitely a stream. Also, the direction of the vent, since there is no hose on it, was pointing onto the starter coil wiring. So, I have two questions. 1. Do you think the stream will subside as the engine warms up? Maybe it was just because the car had been sitting so long? 2. If I attach a hose to the vent, is there some direction I should point it so it's not shooting all over the starter coil?

Judson Manning
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Verify it is not the oil pressure gauge take-off fitting located in the same area.  No it wont stop regardless of which fitting it's coming from.

It is a common modification to pipe the later MkII vent down the side of the engine as very little oil comes out of this opening.  The MkI is a different story.  Piping a MkI vent under the car will lead to an engine quickly running out of oil.  The vent needs to be piped to the oil/vapor separator mounted on the firewall next to the battery so the oil can drain back to the sump.

 

Jensenman
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It sounds to me like the oil pressure gauge fitting since a vent should not have a stream of oil coming out! The oil pressure tubes are famous for becoming brittle due to age and heat and then cracking or breaking off. I wouldn't recommend running the engine until it's repaired because 1) it will empty the crankcase eventually 2) hot engine oil can be flammable.

mcguan.2
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Thanks for all the help, fellas.  That's what it was -- the oil pressure fitting that feeds back to the pressure gauge.  It had in fact become brittle and probably cracked off while I was re-installing the carbs.  It had recoiled back to the other side of the engine so I couldn't initially see it.  All fixed now and she's running well. 



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