engine and drivetrain Can valve seals heal themselves?

[Guest Anonymous]

I have a 71 02 with a lot of miles and a head that has not been removed for at least 10 years or longer. I do remember installing viton seals and new guides on the exhaust valves. The car runs great throughout the rev range except for one thing: smoke on deceleration/engine braking, which has been attributed to bad valve seals and/or worn valve guides.

The car does get regular oil changes (Kendall 20W50) and the plugs (W8DC) always look clean, white (close to the point of being too hot). The valves are set to .008 and the timing is slightly advanced (without any pinging even on regular fuel.) Invariably, the car will smoke when I am running at 60 mph and coasting down a long incline. In fact, the smoke can be so bad that I have shifted into neutral during the long coast to avoid undue attention. This smoke (blue-white) will occur during rain or shine cold or hot weather.

The car sat for about a two months since the last drive. This Friday, she fired on the first turn of the starter and we were off. The strange thing is that there was absolutely no smoke on the downhill run this time. On Saturday, I had my brother drive the car and I followed and did not see any smoke from behind either. I examined the car and noticed no smoke on repeated heavy acceleration or deceleration. What I did notice was a whisp of smoke at idle that I could not repeat. To insure that I was not merely burning off a lot of blowby - I run a catch can and a vent not to the intake) I did not change the oil, reset the timing, change the plugs, nor was the temperature a factor at 70 degrees.

Today being Monday, I have driven 4 successive days over the same stretch of road and still no smoke. What did I do right? Or what did I do wrong so that I can continue repeating it? The only thing I can think of is something has congealed or filled the voids in the undoubtedly hard valve seals.

[c.d.iesel]

yes - in your case absolutely.

Because as you said - you had new Viton seals that just

felt sleepy untill you started to put miles on the car again.

Suggest you keep up the 6-month/2000 mile oil changes (mineral oil).

Excellent example of USING a car, VS , mostly sitting or short

walks around the block.

[Mike Self]

have you checked your brake fluid level recently? White smoke on deceleration can also be a leaky master cylinder/power brake booster, allowing brake fluid to be pulled into the intake manifold and burned--with a characteristic white smoke.

I suspect, though that your low brake fluid warning light would have come on after a week or two of this, but it never hurts to check.

Or...did you have Oral Roberts or another evangelist tuned in on your radio? Perhaps those stem seals were really healed!

mike

[Guest Anonymous]

have you checked your brake fluid level recently? White smoke on deceleration can also be a leaky master cylinder/power brake booster, allowing brake fluid to be pulled into the intake manifold and burned--with a characteristic white smoke. I suspect, though that your low brake fluid warning light would have come on after a week or two of this, but it never hurts to check. Or...did you have Oral Roberts or another evangelist tuned in on your radio? Perhaps those stem seals were really healed!

mike

I have thought about this quite a bit before posting. There is no brake fluid leak everything is clean and dry. (I am not losing any fluid, but I even disconnected the vacuum hose to examine it for fluid or even the smell of fluid, and there was none.) I did not add STP, Motor Honey, CDC, Marvel or even the magic motor pellets I used to see at the local auto parts retailer. Since new (the car has always been in the family) the car has been fed on a diet of Kendall or Valvoline 20W50. I even change the oil more often then recommended and this may be responsible for the fact that the valve train looks like it was just installed. It is even possible that the more frequent changes are counter productive in that start up after an oil change involves a period with low or no oil pressure.

The car has sat before for extended times, but the oil still gets changed routinely with all of my other cars. I have not been driving the car any differently than usual in that I normally keep the revs under 4500 rpm. The previous amount of smoke was bad enough to worry about being a nuisance. There is also blow-by in the 4X 155 ft/lb2 compression but that blow-by is directed to the catch canister and away from the intake so it is not what I had been burning. And it is not the source of the smoke since it is also not directed anywhere close to a hot exhaust or anyplace that might transform liquid into smoke.

I am happily perplexed but find it hard to swallow that the valve seals would magically swell to work after years and countless heat cycles. MikeS you may find it interesting that the car is garaged a block away from an Evangelical institution and I have been known to speak in tongues during extremely heavy traffic. I also recently jump started someone on his way to church (Saturday night) but that was not with the 02. The last time I flushed the radiator in my F10, the residue looked like the dead sea. . . .

[Guest Anonymous]

Or...did you have Oral Roberts or another evangelist tuned in on your radio? Perhaps those stem seals were really healed! mike

One more thing I overlooked. I am not as religious about cleaning the windows as I once was. I can still see out of them just fine when they are not fogged with condensation. The rear window still gets an unusual amount of oily residue from the vinyl seating in the rear so that if it doesn't get cleaned, the condensation reveals many shapes and forms, including a slice of pizza with Virgin M. topping! I cleaned it before putting the window on Ebay.

[TobyB]

Me, I vote for a sticking oil ring that finally popped loose...

But yeah, sometimes getting the engine nice and warm for a long trip

(or 6) will loosen things up better than anything else.

I put in an old part motor last year, and over the course of the summer,

it went from smoking pig to... much less smokey pig.

It hadn't been run in at least 10 years...

Now, if you start evangelizing, we may have to whack you over the

head with a porcelain statue of Mary.

t

..

[Guest Anonymous]

Me, I vote for a sticking oil ring that finally popped loose...t

..

The engine has never smoked during even hard acceleration which is more consistent with ring wear or stuck rings. The plugs are always spotless, suggesting that a sticking ring or rings is a sporadic rather than chronic occurrence. I suspected the valve guides and/or seals having routinely replaced them on my other M10 engines at valve job time.