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Arshloch

Noticed some oil burning today.

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I have noticed a small cloud of bluish/grey smoke today while in heavy traffic. It seems as if I let it sit at hot idle for a minute or so the motor pops a smoke cloud as I step on the gas while taking off. No oil burning at other speeds or deceleration otherwise. It holds steady 23 inches of vacuum at idle, probably sucking all that oil in.

My guess would be that the valve guides are just about to expire, right?

Second, carburation....

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wonderful clouds of blue smoke on deceleration. Because the M10 is slanted, there is oil at the base of the exhaust valve seals and guides. Deceleration increases the vacuum and sucks that oil into the combustion chamber.

Blue smoke on acceleration is most often worn oil-scraper rings.

Regards,

John N

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Nah, mine doesnt smoke like a Trabant on deceleration. Only at first when I hit gas after letting it idle, a single puff no more nor less. There is a very small amount of gray upon firing up. I run synthetic 20 w 50m and just switched to a 2bbl. With these oldies as soon as you start mess around all other bloody problems seem to pop out.

Well, I'll do a leakdown test eventually.

May also be:

Diluted oil - will change that,and look for pieces of piston rings

valve guide seals

Head gasket

Broken ring - unlikely- it would smoke all the time

Overly rich mixture/fuel puddling (running a dry intake), just switched to and jetted a 32/36 weber

Cant be: PVC is venting into a catch can.

Driving like this here is considered a crime, almost like killing puppies.

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Well, I'll do a leakdown test eventually = yes more like now

May also be:

Diluted oil - will change that,and look for pieces of piston rings

valve guide seals = yes - do that now also

Head gasket = better hope not, but your cylinder leak test,

and a cooling sysltem pressure test would be revealing

Broken ring - unlikely- it would smoke all the time = see above

Overly rich mixture/fuel puddling (running a dry intake)

just switched to and jetted a 32/36 weber = and yes again -

dumping unburned gas at the wrong Air/Fuel mixture doesn't help

Cant be: PVC is venting into a catch can. = that's the first positive

of the bunch

what do the spark plugs say ?

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My plugs actually look perfect, mixture, everything checks out fine, etc.

But, one peculiar thing is that I found some deposits at the base on the spark plug ground, which appears to be other than normal gas deposits -burnt oil additives. There is a pattern for that too: cylinder #1 has no deposits, #2 very small, #3 more, #4 even more. Not sure if one can attribute to the temperature irregularities within the cylinders, but it seems as the oil makes it there through the valve steam seals because of the natural tilt of the motor and oil puddling mostly at the rear of the head. Also, noted that it burns more oil on start up when the car is parked with the right side on the curb - again more oil on the intake side of the head.

It did also had some carbon build up on the valves when I acquired the car due to the oil on the valves, which is diminished into nothing- thanks to synthetic oil, hard driving, good quality gas, and no PCV. There was some leakage in there already for sure!

I am pretty sure it's either of the 2

either the steam seals

or both, the seals and guides

I want to get a buddy to check if it puffs any smoke on downshifts. But so far I have not seen a single puff of smoke while it drives, only bloody clouds of it on take off.

This video illustrates exactly the problem with a ford 5.0:

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