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Discussion Starter #1
1979 350 with 20,000 on the rebuild. No modifications other than dual exhaust with no converter. No smog equipment other than PCV valve and it seems okay. 4 barrel Q-Jet. Engine runs stong, no misses.

I drive the car some what hard and then park it. If I come back about twenty minutes - couple of hours later and start it, the right bank smokes for about four seconds. The amount of smoke is substantial. The smoke is light gray with an ever so slight blue hue to it (almost no blue). There is no smell of antifreeze and it doesn't smell of burning oil either.

If I drive the car easy and start it about twenty minutes later, there is no smoke; only does it if I have gotten into the throttle. While driving, there is no noticable smoke, even at full throttle.

I pulled the spark plugs today and saw that the back right plug was all gunked up and black in color. I put a new plug in it and went down the road for a hard throttle session. Came back 20 min later and the smoke came back.

I did do a compression test of the right bank and they were all right around 110 psi. I do not notice oil consumption nor coolant consumption.

What do you all think could be the problem. (carb?)
 

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Hi Chris, I would check the valve seals. Were the stock O-ring types used for the rebuild or the after market "umbrella" type? Sometimes when the valve seals are bad, you will smoke after the engine has sat and restarted and then it clears up. Much success with solving the problem! :)
 

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Hey just a thought...........i have had it in the past on a couple of cars......disconnect the brake booster vacume line,Take it for a real hard thrash..(remember the brakes will be crap :)......then see what happens,The booster?master cylinder could have a leak
and its dripping brake fluid into the manifold THEN sucking it mainly into that cylinder
The smell you kind of described and the greysh smoke sounds very familiar,Also check ya fluid level in the master cylinder...Process of elimination
Let us know
Gav
 

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Hey just a thought...........i have had it in the past on a couple of cars......disconnect the brake booster vacume line,Take it for a real hard thrash..(remember the brakes will be crap :)......then see what happens,The booster?master cylinder could have a leak
and its dripping brake fluid into the manifold THEN sucking it mainly into that cylinder
The smell you kind of described and the greysh smoke sounds very familiar,Also check ya fluid level in the master cylinder...Process of elimination
Let us know
Gav

I checked the fluid level in the master cylinder and it is about an inch low, but I have not checked that in years. I pulled the vacuum line off of the booster and the inside of the line is dry. Would this eleminate the brake fluid theory or should I pull the line and take it for a drive anyway? Thanks for the input.
 

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Discussion Starter #5
Hi Chris, I would check the valve seals. Were the stock O-ring types used for the rebuild or the after market "umbrella" type? Sometimes when the valve seals are bad, you will smoke after the engine has sat and restarted and then it clears up. Much success with solving the problem! :)
Don't know what type of seals are on it. I have done a valve stem seal job in the past on another car, so I could do that again. Very cheap, but I will try other things first. I spent a couple of hours on here tonight and got some other ideas. I am going to look at the distibutor cap and plug wire to see if it is firing. I don't think there are any misses, but I could be wrong.
 

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Hi.....i would disconnect the vacume hose and go for a thrash :) just remember the brakes won't work very well
you wont necessarily see drips of fluid in the hose,when the motors idleing there is vacume that will suck the fluid into the manifold
Gav
 

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Check the exhaust side of the head on the outside for oil wetness. A leaky stem seal will allow oil in the exhaust and it will ooze out onto the head from where the manifold meets the head.

OE design is the umbrella on the springs and stem seal between the stem and retainer. Removal of the umbrella will allow oil onto the guide/stem if an umbrella stem seal is not used.
 

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Discussion Starter #9 (Edited)
Okay, I pulled the brake booster line and went for a full throttle run. I came back about 30 minutes and started it and it still smoked.

Also, checked the exhaust manifold gasket area for oil and found nothing but normal dirty engine smudge from valve covers (not excessive)

Also, put a timming light on the hole in question and the wire is firing.

Here is a picture of the smoke, I hope this will help.

 

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Discussion Starter #12
110 psi is pretty low - a leakdown test will tell you where your compression has gone.

:beers:
After watching people do compression tests on youtube, I think I did mine wrong. I only took the spark plug out of the hole I was testing. On the videos, everyone was taking all of the plugs out so the engine can spin faster. What is the correct way? All plugs out or leave them in, or does it not matter?
 

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Removing all the plugs will allow the engine to turn faster to get a better reading. Opening the throttle will prevent drawing fuel into the cylinders.

From reading your post, I'd say the valve guides and seals need replacing.
 

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Okay, I pulled the brake booster line and went for a full throttle run. I came back about 30 minutes and started it and it still smoked.

Also, checked the exhaust manifold gasket area for oil and found nothing but normal dirty engine smudge from valve covers (not excessive)

Also, put a timming light on the hole in question and the wire is firing.

Here is a picture of the smoke, I hope this will help.

That looks like a head gasket leak...
 

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Discussion Starter #16 (Edited)
Thanks for all of the ideas. I will check the vac line to the trans tomorrow and see if there is mosture in it.

If it's a head gasket, sure would be a nice time to upgrade the heads and cam. :yes: Now the hard part is saving up enough green backs.:(

I have learned so much from this forum and the more I read, the more I discover I don't know.
 

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Discussion Starter #17
If you have an automatic check the vac. line to the modulator.Could be getting trans. fluid in it also.

Bingo!!! Thank you, thank you, thank you. I pulled the vacuum modulator line of the number 8 intake runner and out comes fluid. Went under the car and pulled the line from there and lots-n-lots of fluid. Thanks for you advice. No I will go to the transmission thread and try to figure out how to replace it.

Thanks,
Chris
 

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Discussion Starter #18
No more smoke! B&M Vacuum Modulator did the trick. Picked it up at Summit today and tossed it on. Very happy. Thanks for the advice.:hurray:
 
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