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Discussion Starter #1
Hello All
Since I bought my 2600 in November I have been monitoring an oil problem and now I am seeking your advice.

The previous owner rebuilt the engine at great expense about 5000 km ago. The engine runs well and does not foul plugs or have any quirks. I have noticed that after running on a trailing throttle down a hill for example and then accelerating visible oil smoke is emitted from the exhaust. It seems to be heavier smoke around town at slower speeds.

A friend who followed me recently said it also did this under heavy acceleration although I have not noticed this from the drivers seat.

It is not brake fluid. It does use some engine oil. I have not done a lot of km's but it is probably about a litre per 500km.

If it was my Austin Healey with these symptoms I would diagnose valve stem seals.From the parts manual the 2600 does not seem to have stem seals. Is that right?

I would appreciate any advice on this.
 

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Yes, it is correct that the 2600 does not have valve stem seals on the exhaust valves and therefore burns oil, which is most prevalent when you were off the throttle on a downhill stretch and start to accelerate again. Although not pretty, this behaviour is normal (and, from an environmental perspective, seem to have been acceptable at the time -- same as the factory not supplying an oil vapour separator for the valve cover in S1 cars).

What you didn't talk about is what oil you're using and what the oil pressure is (cold and warm, under load and no-load conditions).

So, as expectations for what pollution and smoke is acceptable has changed over time, so did some of the technology: I bet that if you currently are using 10W-40 oil and switch to 20W-50 (or a modern equivalent for classic cars such a Redline oil) much of the smoke will go away.
 

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Discussion Starter #3
2600 Oil

Thanks Reudi,

I haven't changed the oil yet as the previous owner told me had just changed it in readiness to sell it (he loved his 2600). In my Healeys I use Penrite 40-60 which is a classic car oil made in Australia. Do you think this would be OK or maybe a bit heavy? The Healeys love it -doesn't leak out and doesn't burn.
 

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I cannot comment on Penrite oil (no experience with it) -- but if push comes to shove, I'd try another oil (or other oils, i.e. several tries) before even remotely considering ripping the engine apart once more.

Oil pressure of 50-56 PSI on a warm engine is OK (50 is the minimum according to Alfa Tech specs).

As I recall, Alfa also specified oil consumption of 1-2 liters/1000 km somewhere (a value I found quite high), but I can't find the reference at the moment. How much oil does your engine consume and is it within that range?

And, BTW, have you checked compression and are you sure the rings have seated (and therefore seal) properly after the engine work was done?
 

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How much oil does your engine consume and is it within that range? ...are you sure the rings have seated (and therefore seal) properly after the engine work was done?
I agree, if the rebuilt engine only has 5,000 Km (3,100 miles) it may just need to be driven. Two liters per 1,000 Km may improve with increased mileage. Also, check for oil leaks. When I bought a new 164-S over 22 years ago it burned 1 quart every 1,000 miles and still does 130,000 miles later but perhaps it burns less and leaks more now.

With older cars they seem to smoke less with synthetic oil but I'd run conventional oil for the first 10,000 miles or so.

Oil is cheap; rebuilding a motor is not!
Mark
 

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Discussion Starter #7
Thanks all for your input and sharing your knowledge and experience. I will change the oil to make sure it has a suitable type and do some more tests. I will report back in due course.
 

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Discussion Starter #9
Thanks Rogerspeed. I can certainly confirm that I have been treating it like a recently rebuilt motor without specifically knowing what the factory run in procedures are.
 

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It would be very helpful to know what is your understanding of the way to treat a recently rebuilt motor. There are widely varying opinions on this.

The factory prescribes certain max speeds in each gear during break in. Others of us tend toward higher cylinder pressures than this approach will produce.

It might be interesting to note that Lycoming specifies that the engine NOT be operated below 75% power for a certain number of hours.



Thanks Rogerspeed. I can certainly confirm that I have been treating it like a recently rebuilt motor without specifically knowing what the factory run in procedures are.
 

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Discussion Starter #11
I have always followed the practice with new engines of varying the revs from mid range to high by using different gear ratios, not using maximum revs at all and not running the engine at low revs in high gears. I have tended to use this engine in the range 2500 to 4500 RPM.
 
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