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Blue smoke
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Old-Nail
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PostPosted: Tue Mar 20, 2007 11:38 pm    Post subject: Blue smoke Reply with quote

When I start up my Austin Somerset it starts up quite easily but does issue a fair amount of blue smoke.

As I understand it this could mean either worn bores or stuck piston ring(s) or perhaps worn valve guides and/or hardened sealing rubbers.

My question is - what is the best (quickest) way to find out which of those is the culprit?

The obvious one is a compression test I suppose but just in case it is a sticking piston ring or two is there anything I can drop in the bores to help out?
If the engine does show low compression on all cylinders am I to assume it is goosed or having been stood for twenty years that things have just gotten a little stuck?

The top and bottom of it is I don't want to have to remove and have rebuilt an engine that might yet serve a few more years.
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buzzy bee
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PostPosted: Tue Mar 20, 2007 11:51 pm    Post subject: Reply with quote

Hi

Does it stop smoking or does it smoke all of the time when it is run?

How much oil is it using?

I would be inclind to say that if it smokes only on start up, it will be the valves/inlet oil seals, but if it carries on all of the time it may be the bore or rings. Now have I got that the right way around?? Confused Embarassed I think so, but am sure someone will clarify it!!

Cheers

Dave
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Rick
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Location: North-west UK

PostPosted: Wed Mar 21, 2007 8:44 am    Post subject: Reply with quote

Is it just on startup, then clears to be ok for the rest of the time its running? if so it may just be worn valve guides or seals (do they have valve seals like on the A Series??) allowing oil to trickle down overnight.

If it is continuous then it may be rings, either worn or perhaps stuck a bit.

Have you changed the oil recently with a good quality oil? sometimes really old oil, perhaps contaminated through years of standing with water and fuel, can thin it down and cause oil to get in the bores. If there is a crankcase breather somewhere, have a look to make sure its not blocked.

A compression test wouldn't harm, perhaps after letting it run for an hour or so to warm through properly (is it on the road yet? if so take it for a long drive)

Rick
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Various 1920s-1960s - Austin, Morris, Commer, Dodge etc.
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buzzy bee
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PostPosted: Wed Mar 21, 2007 8:54 am    Post subject: Reply with quote

Hi

I am glad I was right in my thinking!

Cheers

Dave
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Old-Nail
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PostPosted: Wed Mar 21, 2007 11:12 am    Post subject: Reply with quote

That's the difficulty I'm having in diagnosis.

It's not roadworthy yet so can't take it for a run, and I can't gauge oil consumption because it never goes anywhere!

The smoke lessens as the engine warms up but is still detectable, and I've never been able to run it for more than five minutes or so as the enclosed area it is stored in gets so 'fumey'.

Now that the wind has dropped outside I'll go out and have a good look at it to make sure of the breathers etc, and perhaps warm it up and change the oil.

Another factor that might contribute is that the carb has been off at some point as evidenced by the red instant gasket smeared everywhere and the pick up from tickover isn't clean, although the smoke does smell like oil and not rich mixture.
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Rick
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PostPosted: Wed Mar 21, 2007 11:17 am    Post subject: Reply with quote

I'd be inclined to warm it up as best as possible, drop the oil and replace with a good 20/50, do a compression test and see how it looks from there. Oil thins badly if fuel has got in it, same with moisture, following lots of brief engine runs over a period of time.

If the pick-up from idle is hesitant, have a look at the accelerator pump on the carb and see if its sticking. I had this with my green Devon, that is a '53 and has the same carb as on the Somerset. The pump was sticking, I freed it up and its better now. Also check that you have the correct N5 or N8 plugs in it, anything else (especially the modern plugs that have the insulator sticking out a little from the bottom of the plug) don't help these engines run well at all.

Rick
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Old-Nail
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PostPosted: Wed Mar 21, 2007 8:26 pm    Post subject: Reply with quote

Ok chaps i've been outside all afternoon beggering about with the Somerset.

I can confirm that the blue smoke persists even after warming it up for ten mins, in fact when I rev hard and release - rev and release it does a fair impression of those Indian smoke signals they used to have in the westerns.

The oil does look thin so I will change that next and check what plugs have been put in it replacing them if needed.

What puzzles me is that the bodywork and chasis are very very solid, almost as if the car wasn't used much in the rain, but the engine is not original.

I did a bit of detective work today and found that on the back of the drivers sun visor the car and engine number are stamped on a plate there and the engine in the car doesn't match it.
What I can't know is how long ago the engine was changed, but given the cars seeming lack of use for a good many years I can't see it wearing out two engines!

The mileage says 25000 but the speedo isn't connected so may have been that way for years?
Another odd thing is that this car was registered in November 1953, and yet it has no heater installed, according to the Austin counties magazine this was virtually unheard of on a home market car by that time... the plot thickens!
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buzzy bee
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PostPosted: Wed Mar 21, 2007 10:29 pm    Post subject: Reply with quote

Hi

Was the replacement engine new when it was put into your somerset, or was it allready used?

Could it be that it did a few miles or had a hard life before being matched to your car?

Cheers

Dave
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Rick
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PostPosted: Wed Mar 21, 2007 11:29 pm    Post subject: Reply with quote

Hi Nail

I was doing exactly the same thing this afternoon, sending smoke signals, again with a 1200 BMC engine, but this time in the Devon p/up! I drained out the old fuel and put fresh in. I can get it to fire up on choke, but it dies almost straight away, and puts out a lot of white stuff from the exhaust.

Compression test is next for me I think, these engines are prone to head gaskets going Rolling Eyes so could be what I've got, although the engine actually sounds sweet as anything when it runs, and with new plugs fitted, runs well, just conks out, and puts out a bit of smoke (although I think the smoke thing is improving slowly the more I run it).

Is your replacement engine a BMC gold seal unit, or perhaps a s/hand replacement lifted from another car at some point? perhaps the original one was run short on oil, or boiled at some point, hence the switch in the dim and distant past?

The oil in mine is very poor I think. Its clean on the dipstick, but feel it between 2 fingers and there is little 'body' to it, so I suspect its been contaminated over the years.

RJ
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buzzy bee
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PostPosted: Wed Mar 21, 2007 11:41 pm    Post subject: Reply with quote

Hi

Bet you are going crazy, having the thought that the head gasket may be dicky on this pickup too! Shocked

Cheers

Dave
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Old-Nail
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PostPosted: Wed Mar 21, 2007 11:47 pm    Post subject: Reply with quote

A few months ago I went looking at a genuine 10k mile Morris Minor that was literally stored in a barn since the old lady owner gave up driving.

The farmer had put in fuel and a battery and started it up to sell it, when I went down it was putting out an enormous amount of white smoke, but a mechanic mate of mine said it would clear and wasn't anything to worry about, just a consequence of standing for so long.

That sounds like what you have Rick, I suspect the more you run it the better it will get whereas my smoke is blue Crying or Very sad

I either need a good replacement engine or a company that can re-con this one, either way it's got to be put right.
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buzzy bee
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PostPosted: Wed Mar 21, 2007 11:51 pm    Post subject: Reply with quote

Hi

I agree, if Ricks smoke is white, it could be water/condinsation, that has buit up during storage.

Cheers

Dave
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Old-Nail
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PostPosted: Thu Mar 22, 2007 12:08 am    Post subject: Reply with quote

If anyone hears of a suitable replacement engine for mine (including the 1622 Cambridge unit) let me know!
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Rick
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Location: North-west UK

PostPosted: Thu Mar 22, 2007 8:46 am    Post subject: Reply with quote

Yeah if I can persuade it to run long enough, without enveloping us completely in smoke/steam, it may just clear. When I first started it, there was a lot of oily-like deposits spitting out of the exhaust, but that has lessened quite a lot and its just smokey stuff.

I don't mind if the gasket wants doing, it'd make a change from doing the Ford one!!!!

Rick
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UKdave2002
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PostPosted: Thu Mar 22, 2007 3:21 pm    Post subject: Reply with quote

A common symptom of valve guide wear is a blip of smoke when the throttle is closed quickly, you often see this if you are behind a car and they are changing gear.

With the throttle closed and a cylinder is on its induction stroke its much harder to “suck” an cylinders worth of air /fuel into the cylinder (as the carb butterfly is closed a depresssion is created in the cylinder) so any wear in the valve guides will tend to suck oil in via the inlet valve stem. This is why many cars have an additional rubber oil seal just on the inlet valve.

Dave
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