Intermittent puff of blue

[73LemonTwist]

I have a lingering issue that is puzzling me, and maybe one you folks have an idea. Its a mystery puff of blue from the exhaust.

On start and warmup there is not evidence of blue in the exhaust. Under normal operation their is no evidence of blue in the exhaust, and the plugs are looking pretty clean - no evidence of oil buildup on the plugs.

When I take the car out for a run after its been sitting for an extended period or idling in the driveway for an extended period (ie tinkering with the carb), at the first stop light after the engine rpms have been up to a city cruise for a few blocks, I get a very distinct cloud of blue. its not a puff, but a noticeable (and embarrassing) cloud.

It happens once and then will not occur again until its next extended period of sitting. It seems to occur that first time you let off the throttle back to an idle.

The car has a PCV but no EGR valve. Compression is good and balance between cylinders is good.

I am baffled - ideas to check?

 

[Fran Blacker]

Sounds like valve seal or maybe guides if heads have many miles on them.

 

[dodgeboy440]

I have a lingering issue that is puzzling me, and maybe one you folks have an idea. Its a mystery puff of blue from the exhaust.

On start and warmup there is not evidence of blue in the exhaust. Under normal operation their is no evidence of blue in the exhaust, and the plugs are looking pretty clean - no evidence of oil buildup on the plugs.

When I take the car out for a run after its been sitting for an extended period or idling in the driveway for an extended period (ie tinkering with the carb), at the first stop light after the engine rpms have been up to a city cruise for a few blocks, I get a very distinct cloud of blue. its not a puff, but a noticeable (and embarrassing) cloud.

It happens once and then will not occur again until its next extended period of sitting. It seems to occur that first time you let off the throttle back to an idle.

The car has a PCV but no EGR valve. Compression is good and balance between cylinders is good.

I am baffled - ideas to check?

Hi Lemon Twist !
Perfect recipe for a cool summer
Beverage …. Lemon…

Now to the Mopar matter …
Assuming your lil dodge doesn’t have a “dispensary card “ for smokin…. Lil pun… sorry couldn’t resist .

I vote for valve Guides & Or Seals …

probably a little of both , if a seal
Has lost enough elasticity to let oil seep into the chamber it may give you the Puff The Magic Dragon on startup …
Have you tried any of the
“Seal Swell” Or “Engine Restore”
Products ? They May Give You Some Relief !

Men Of Mopar
The Brotherhood of Muscle …

Good Luck !

John

 

[69 Sleeper Bee]

As Fran above stated it probably is valve guide seals or guides. It will only get worse over time and then start showing up on plugs. Probably going to need to have the heads worked on and hardened seats put in if not already done.

 

[73LemonTwist]

This engine hasn't been opened up - has 83,000 miles on it. I would have thought steam seals would give a more consistent oil consumption issue, and certainly evidence on startup.

I have had Mobil 1 high mileage oil in it for the last year or so, hoping to provide a little bit of "swell" to the old seals....

 

[dadsbee]

"Swelling" them won't do any good when they're lying at the bottom of the stem..

 

[1967coronet]

Pull the valve covers and check the seals.
Use a small screw driver ect to see if they are still soft and flexible.
Check each one.
If they are brittle you need to replace them.
If they seem to be in good condition run a compression test.
Oil smoke if that's what it is most times is coming from the head down or head gasket or rings.

 

[pnora]

If is original miles and never worked on it needs seals. Back in the day valve seal replacement was an everyday shop repair. We did 100's of them.

 

[dadsbee]

All you need is a piece of rope and a valve spring compressor.... and of course a new set of seals.

 

[diesel_lv]

I've only had 1 vehicle do that, my '86 Toyota pickup w 230k miles at the time. Pulled valve cover, pulled plugs, screw in air adapter and fill cylinder w air pressure, remove rocker arm and valve spring, replace stem seal and reinstall. No more smoke. Sold it w a little over 320k miles and smogged better than a new fuel injected car. I know our Mopars w shaft mounted rockers are a bit more work but it's a 1 day job.

 

[pnora]

With no A/C I could do both sides on a small block in 3 hours. Add a hour for A/C.

 

[69 Sleeper Bee]

This engine hasn't been opened up - has 83,000 miles on it. I would have thought steam seals would give a more consistent oil consumption issue, and certainly evidence on startup.

I have had Mobil 1 high mileage oil in it for the last year or so, hoping to provide a little bit of "swell" to the old seals....

If you have 83G on that motor then as we say in the south " You done damn good son "
I am pretty certain then it is valve seals / guides at the very least. I would be thinking a head job is in order and maybe more once you get into it. That is a lot of miles on these old motors even with proper maintenance.

 

[dadsbee]

My OE engine shown above was rebuilt (for $325) in 1978. I put new stem seals in 3 years ago before putting it back in the Bee, that and a timing chain and gears (although I could have let the old "silent" chain go). Runs like a top after about 70K on the rebuild and 90K before it. Std bore and still has the OE pistons and probably the cam as well.. can remember anything but the price from back when I was 16. If I was the OP I'd just do the seals and see where it gets him, no point poking the bear...

 

[pnora]

If it runs good toss a set of seals in it and drive it.

 

[Aero Warrior]

As Fran above stated it probably is valve guide seals or guides. It will only get worse over time and then start showing up on plugs. Probably going to need to have the heads worked on and hardened seats put in if not already done.

It could be guides but I'm leaning towards an intake manifold to lifter valley gasket. If it were stem seals/guides, the car would smoke every time you did a cold start of the engine. However, a hard stop at a light might slosh oil and get sucked into the intake from below. How is your vacuum? Also check your oil level and never depend on the dip stick. An overfilled crankcase will not vent properly causing a burp in the oiling system throwing oil (internally) everywhere. Overfilled crankcases can also ruin a rear main seal.

 

[R413]

Oh no, he’s gonna need to “upgrade” his car:
hi volume oil pump
20/50 oil with ZDDP
Pertronix igniter
Blaster II coil
mini starter
amp meter bypass
Optima battery
E3 spark plugs
Dynamat the whole car
LED bulbs throughout
Radial TA’s on 15x8’s
disc brakes conversion
3.55 gears
green axle bearings
Aluminum radiator
Sirius XM radio
classic auto air
Intake gasket(gasket match the heads and intake)
etc, etc!!!

just kidding! valve seals are a likely culprit here.

 

[moparwacko]

Pull the radiator cap off, then drive a new car under it, install radiator cap.
Done.

Seriously, do the seals in an afternoon then drive it.
You can always spend more money later if that's not it.

 

[dodgeboy440]

Oh no, he’s gonna need to “upgrade” his car:
hi volume oil pump
20/50 oil with ZDDP
Pertronix igniter
Blaster II coil
mini starter
amp meter bypass
Optima battery
E3 spark plugs
Dynamite the whole car
Radial TA’s on 15x8’s
disc brakes conversion
3.55 gears
green axle bearings
Aluminum radiator
Sirius XM radio
classic auto air
Intake gasket(gasket match the heads and intake)
etc, etc!!!

just kidding! valve seals are a likely culprit here.

Dontchya…..

just LUV SpellCheck…..

DynaMat Comes Up
Dynamite….
Luv Ett Dynamite The Whole
Car ….haha ….
Where’s Wiley Coyote When
Ya need him ???
Hahaha….

 

[73LemonTwist]

Oh no, he’s gonna need to “upgrade” his car:
hi volume oil pump
20/50 oil with ZDDP
Pertronix igniter
Blaster II coil
mini starter
amp meter bypass
Optima battery
E3 spark plugs
Dynamat the whole car
LED bulbs throughout
Radial TA’s on 15x8’s
disc brakes conversion
3.55 gears
green axle bearings
Aluminum radiator
Sirius XM radio
classic auto air
Intake gasket(gasket match the heads and intake)
etc, etc!!!

just kidding! valve seals are a likely culprit here.

MSD ignitor - check
Blaster II coil - check
ammeter bypass - check
Antique Auto AGM Battery - check
E3 plugs - check
Dynamat whole car - check
3.55 sure grip - check
Sirius - check
Hi volume Gates water pump - check...
PLX O2 sensors both sides - check

Got some of it done...

 

[73LemonTwist]

It could be guides but I'm leaning towards an intake manifold to lifter valley gasket. If it were stem seals/guides, the car would smoke every time you did a cold start of the engine. However, a hard stop at a light might slosh oil and get sucked into the intake from below. How is your vacuum? Also check your oil level and never depend on the dip stick. An overfilled crankcase will not vent properly causing a burp in the oiling system throwing oil (internally) everywhere. Overfilled crankcases can also ruin a rear main seal.

Interesting thought.... For years I have been getting a recurring puddle of oil under the intake manifold bolt on the rear side of the #3 intake runner. I can sop it up, and it will return, but it never accumulates enough to run anywhere - just make a pool. This summer I have been chasing the cause of inconsistent AFR. I have sensors on both sides. I can set the idle AFR to 13.5 and tomorrow it may start up and run at 14.5. I figured it was carburation, carb gasket or a vacuum line leak. Have ruled these out as sources of the AFR problem.

I can agree with the idea of new valve stem seals. After 83,000 miles the originals don't owe me anything. Just really want to avoid removing the heads - that's getting into territory I would really rather avoid unless absolutely necessary. The engine runs like a champ, so don't really want to mess with it.

Forgot to mention - manifold vacuum runs around 15".