advice required
i have an austin somerset 1200cc it is blowing out blue smoke all the time ,the plugs are black and and wet when removed ,yetwhen i put on the compression meter it is registering 100, is it possible for the oil ring to fail on the pistons and still hold its pressure, there is no rattles or tapping when running [the engine has been stood for a few months and the oil was very sticky when removed]
before i start to strip the engine down is they anything i could do to remedy it or any further tests i could carry out
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could it be valve stem seals allowing oil to leak down the valve stems ,if compression is ok it is a possibility
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oil control rings control amount of oil given to scraper and compression rings,if that fails all rings will fail so suspect either valve guides or seals
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Steve
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Probably oil rings gone. They depend on being flexible enough to exert pressure on the cylinder bores at all stages of travel. If they're worn they won't stop oil from passing them, if they're gunged up they can't move enough to seal. You did say that the drained oil was a bit 'sticky' , This could mean that the rings are a bit 'stuck' as well. Try some decent oil and a good long run. Chances are that a rebore is on the cards.
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Before you do anything, check and clean the crankcase breather. (from tappet covers I think to open air.. )If blocked you will get crankcase pressurisation = oil consumption..
Then it is possible if the oil was very dirty the rings have siezed. Try running flushing oil thru it.
These are all easy and relatively cheap...
madf
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If this was just valve stem oil seals then the car would belch some white smoke at start up after an overnight rest and again on engine over-run i.e. going down hill with your foot off the throttle. A blue dirty haze can be overfueling. You mention 100, do you mean PSI this engine was 7.5 to 1 compression so I would expect 120/130 Psi warm and oiled. With the oil filler cap removed is there a lot of gases excaping yo free air due to ring blow by. Regards Peter
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Further you say black and wet. If the wettness eveporates it's petrol not oil. Was this car an SU or a diagram stomberg. Regards Peter
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99% sure that Somerset far to early for valve stem seals. Sounds to me like gummed up rings after being left. Warm it through do an oil change with something fairly high in detergent, we used to use diesel engine oil for this & see if they'll free off. Pretty sure that the Somerset had 4 rings as well. 100PSI not bad for an engine thats been standing as the valve seats will be fair from perfect.
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Yes I agree and there is a liquid, who's name escapes me, that you can pour into the pots to soak the gunge off the rings. The Sommerset was made from 1952 to 1954 so as you say it may not have valve stem oil seals but I think I remember the 1953 Morris Oxford having seals and gear ( Tuftnul ) driven cam/push rod shaft. Available in Black. Regards Peter
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I wouldn't rush into any major engine work, at least before you try giving it a good flush-out and run to see if the oil control rings free off. Those old long-stroke engines (Somerset had the first of the immortal BMC B Series IIRC) aren't shot just because they start to burn a bit of oil.
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If the oil is really black and gummy and you think the rings may be stuck, I'd try something stronger than just flushing oil in the sump. Pour some parafin into each plug hole, and crank the engine over slowly by hand - it has a handle, presumably. Leave it overnight. Then give it a burst on the starter with the plugs out to expel any remaining parafin, and refit the plugs and start up. Run it a few minutes, then drain the oil, and refil with cheap oil with a flushing additive. Let it run for 20 minutes or whatever it says on the can, then drain, and refill with better oil with detergent, eg oil for diesels. Fit a new oil filter.
If that doesn't free the rings nothing will, or else it is simply bore or valve guide wear and needs an overhaul.
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cheers cliff i will try out the things you mention (heres hoping ) i will let you know if it works
regards andy
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100 p.s.i.sounds a little low to me.You could try the old trick of temporarily sealing the rings with oil.Take a note of your compression readings,then put about ten mls of oil in the bore,through the plug hole,and repeat the comp.test,do on all cyls.If there is a significant increase in readings the rings are not sealing properly.
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