Valve stem seal

[mosu]

When I let off the gas at any speed greater than 70 mph, give it a couple of seconds and pump the gas again, I get a big plume of ego-bruising smoke. It doesn't seem to happen at a lower speed no matter how hard I try.

The Solex is leaky, awaiting the Weber, and it's secondary fuel rods are stuck shut.

Is that big plume of smoke oil getting past the seals or some kind of over-rich condition?

And why would it happen only above 70, because I figured I'd have just as much vacuum in lower gears/lower speeds?

[79Mercy]

what model vehicle?

What color smoke?

[mosu]

Argh, I always forget that tiny detail

1973 280 M110 carb-ed.

The smoke looks whitish to a vague blue-ish in the mirror, but the plume dissipates so fast it's hard to see. No smoke at any other time, except a little white mist on warmup until the choke fully releases. No mayo in the oil or coolant.

[79Mercy]

How much oil do you use over the course of say 3000 miles?

Have you pulled the plugs out to inspect their condition?

[mercmad6.3]

If it's valve stem seals you can verify it by coasting down a hill and you will see a cloud of smoke as you acelerate at the bottom. It's not unusual and not difficult to change them.
i would also keep an eye on the trans fluid level ( worn modulator,sucking trans fluid into the intake)
And the brake fluid.. (check brake fluid level and pull the vacuum line from the booster and check inside for fluid. )

[mosu]

Thanks mercmad6.3...I replaced the modulator and the booster line is clear. I guess it might be the stem seals.

I read other comments while searching the forum that they're a pain in the royal behind to change on the M110...or was that on other engines? I'd prefer to do them over winter, and keep driving like this for the summer. Other than keeping an eye on the oil level, is there any damage I'm doing other than to the ego?

[mercmad6.3]

it wont damage anything but be careful of the greenies...

[mosu]

LOL, I'll plant a tree everytime I coast downhill

[mercmad6.3]

That will work , osama is dead so the world will stop warming now.

[meltedpanda]

seals are not bad, just make sure you have the right tools to do the job. depressing the valve springe requires a proper tool and you will save a lot of cussing to make sure the one you use is quality ( ask me how I know)

[kraakevik]

If the vacuum pump hasn't been removed yet you may have a pinhole leak in the diaphragm that leaks only on extreme deceleration.

Those '73 M110's tend to have higher valve-seal leakage than the later engines--even so, you can probably drive that way for years without serious problems--1000 miles per quart is excellent oil consumption on these "juicy" engines


Tim Kraakevik
kraakevik@voyager.net
Four M110's

[mosu]

LOL, well said "juicy", Tim. If cars could make cocktails, I should be a bartender and this would be a chocolate martini.

Usage is less than a quart/1000 miles now that my fuel pump doesn't spread my engine oil as rustproofing.

I'll pull off the vacuum tubes and have a look, although they are looking as clear as a yellowed tube can look.

Thanks for the tips and suggestions guys!