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XJ-6 [1972] Emmision Problem

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BruceAllcorn

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On my 1972 XJ-6 (4.2 liter engine) I am having a problem with the engine smoking. There is a carbon canister to which is attached a tube from the gas tanks, a tube (or hose) running to the engine breather on the front of the engine above the water pump, and a tube (or hose) that is open to the atmosphere. There is also a hose connection that goes from the breather to both carbs. I am getting a bit of smoke exhausting from the hose that is open to the atmosphere and I also get smoke at the hose connecting to the carbs when I disconnect it from the carbs. When I remove the oil filler cap from the left cam cover there is a bit of smoke present even right after starting a cold engine. Has anyone ever experienced this problem and, if so, what is the "fix"?
 
Usually that is blowby, as in rings and bore issues. Valve guides can cause it on start-up.
 
TOC is right. Also, if a grade of oil less than 20/50 such as 10/40 or 10/30 can do same.
 
Thanks to both TOC and LarryK for the info. I suspected something like that but since I'm not close to being an expert I prefer to defer to those, of which there are many, that know much more than me. I do use synthetic 20W/50 oil, so I suspect I'm going to have to get into the engine to solve the problem. I fugure that while doing that I will just get the whole engine rebuilt as it has been about 30 years since it has been gone in to, of which it sat for 12 years.
 
Do a compression test to see If any one cylinder is a problem, then do a leak down test to pinpoint valves or rings. These engines can be revived after sitting long term if done carefully.
 
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