# A lot of smoke



## Bluedog (Aug 8, 2018)

I have a 1966 GTO. 389 .60 over, Edelbrock Performer intake, Edelbrock AVS carb, HEI, stock cam and a four speed.
This project has been ongoing for over ten years. A few months ago I finally fired her up and she ran great.
I continued to work on the interior and fix minor things directly thereafter while firing her up now and then. 
I took her for her initial drive for a few miles and all was well.
A few weeks ago I noticed white smoke with the distinct odor of fuel starting to come from the exhaust.
I recently relocated out of California and have just now got back to working on her. 
Upon firing her up the smoke has increased greatly. After fiddling around I figured that I would replace the 20 year old carb with a new Edelbrock AVS 650.
She fired up immediately but began to run very poorly with an extreme amount of smoke coming from the exhaust as well as between the intake and head. 
After removing the plugs I found that all eight were extremely fouled. 
After cleaning them I fired her back up. It ran great for about a minute and again began smoking and missing terribly. Plugs fouled again.
Sooooo, clearly I am getting more fuel than is being burned by the plug. Plug wires are new. Assuming all eight plugs didn’t decide to die at once what are your thoughts considering the smoke is the same with the old carb and the new one? I have not touched the AF ratio. 
I apologize for the dissertation.


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## BearGFR (Aug 25, 2008)

White smoke... as in really white? Not gray? Not black? Smoke from burning oil will tend to be gray, smoke from running on way too much fuel will be black.
If that's the case, then more than likely it's steam - as in you've got coolant leaking into the chambers somehow. If it's also leaking smoke from between the intake and the head, my first suspicion then would be badly leaking intake gaskets. Try snugging down all the intake bolts first --- don't go super crazy tight because it's possible to twist one off, then you'll have a bigger problem.

Bear


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## BLK69JUDGE (Jun 10, 2010)

whimpy spark?
got a full 12volts going to the distributor from the fuse box 
and
12 gauge wire ?


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## pontrc (Mar 18, 2020)

X2 with Bear sounds like coolant


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## Bluedog (Aug 8, 2018)

The smoke is more gray than white but really smells like fuel. The plugs being as black as they were look lIke fuel. 
The smoke from the intake confuses me. Those bolts on the intake are tough to get to with the carb on but I can get a wrench on them and they are pretty snug. I thought the gasket should be air right. If smoke can get out I assume air can get sucked in. 
I know I have 12 volts at the choke. I gave some thought to a weak coil not supplying enough spark thus fouling the plugs. Not sure if there is such a thing. 
It sure sounds like it is loaded up. Like a very aggressive cam. That is until it won’t run anymore. 
Its all quite frustrating. I put new wheels and tires on her a couple months ago because I thought I was done with the motor.


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## pontrc (Mar 18, 2020)

The smoke on the intake is probably coming from the exhaust cross over from the middle. Did you check timing the distributor could have moved?


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## PontiacJim (Dec 29, 2012)

White smoke can also be transmission fluid if you had had an automatic - but ain't going to happen with a 4-speed. But since you say it is grey and plugs are wet, sounds like flooding issues.

Choke fully opening?

You may have too much fuel pressure. Some of these replacement fuel pumps put out too much pressure which will unseat the needle/seat assembly in the carb. The AVS wants 5-5.5lbs fuel pressure. So I would check my fuel pressure first.

Your float level could be too high. Sometimes it can be best to drop the float just a tad bit lower than what the spec states. The AVS, like the AFB, should be easy enough to pull the top and check. You can also take a peak into the carb to see if you see anything amiss or loose. Factory assembler may have been having a bad day.

You can check your timing, it won't hurt, but I don't think it will clear up a set of wet plugs. If the spark were weak, then I would think the engine would quit/shut down rather quickly when the plugs got wet as that would snuff out a weak spark.

What is the gap on the spark plugs? I know with the HEI you can run wider, but just to try something, gap them at .035" to tighten them up. A wider gap requires more electrical energy and a tighter gap requires less. It certainly could be the HEI itself or any of the individual components within it. Is your HEI aftermarket or factory?

Smoke coming from the intake - maybe oil leaking past the valve cover gasket under the valve cover lip and collecting on the intake, and when the exhaust crossover gets hot, it burns off the oil. If this is it, it will have a smell. You did not say where the smoke was coming from - ie center, middle, end? I assume 1966 "093" heads. Maybe a wrong intake gasket or mismatch between the 1966 heads and later intake - just a thought.


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## Lemans guy (Oct 14, 2014)

You obviously have a leaking intake manifold gasket that must be replaced. But first, while it is running I would check what I could to see, verify any head gasket leaks. You can run a cylinder leak down test, also observe coolant for bubbles or oil or use one of the tester kits that you do at the radiator cap.

If you feel the head gaskets are good, I would replace the intake gaskets, as Bear and PJ were discussing. This is a known that you can’t keep going with, the intake gaskets also seal coolant passages, and when they get into the cylinder you get white smoke and rough running after an initial ok startup. The coolant starts seeping in and it makes a mess of your mixture also, and blows out the tailpipe.

Is the the smoke on the intake near the coolant passage?.....

either way that gasket must be replaced.....and with the correct one, as PJ said

good luck you will get it!


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## Lemans guy (Oct 14, 2014)

I should have also mentioned that as coolant leaks into a hot cylinder it blows back the steam into the intake and dilutes the mixtures which causes more misfiring, and that means more unturned fuel and more fouled and wet plugs....and gas smell.

This is just one possibility from a leaking intake gasket.....which you have.

So what appears to be too much fuel, can be caused by the leaking intake gasket,..maybe.

If you have bad head gaskets do it all together,...hate for you to pull the intake and have to go back for the heads. But all your symptoms could be from the leaking intake gaskets.


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## Bluedog (Aug 8, 2018)

It is a basic aftermarket HEI I picked up from Summit. The plugs are at .035.
The intake leak is coming from the center ports on both sides. 
This is what the plugs look like after cleaning them and running for three minutes.
I agree that the intake leaks have to be fixed. I’m going to get after it right now. Hopefully I can get out of this with just a gasket set. Doubt it. 
Argh!


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## PontiacJim (Dec 29, 2012)

Bluedog said:


> It is a basic aftermarket HEI I picked up from Summit. The plugs are at .035.
> The intake leak is coming from the center ports on both sides.
> This is what the plugs look like after cleaning them and running for three minutes.
> I agree that the intake leaks have to be fixed. I’m going to get after it right now. Hopefully I can get out of this with just a gasket set. Doubt it.
> ...


Definitely wet. What kind of spark plugs are those? Is it the equivalent to the R45S?


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## BearGFR (Aug 25, 2008)

Center ports are actually part of the crossover passage that's used to heat the underside of the intake. That's just more exhaust you're seeing, but it also tells you for certain that the intake isn't completely sealed.

It's very possible, perhaps even likely, that you've got multiple problems going on here and also probably that you're going to have to go through the process of identifying and correcting them one at a time until you find the 'magic bullet'.

You've got an advantage over all of us in that you've "been there in person" and have witnessed first-hand the transition between "running great" and now. There's a logical explanation for what's going on, you've just got to find it. Time to go "Dick Tracy" on it (does anyone even remember who that was?)

In general, start with thing that are easy and inexpensive to do, progress towards the more difficult/more expensive until you solve the mystery.

Based on the limited information we have coming just from what you've said, if it were me I'd tackle getting the intake sealed up first and pretty soon get to running a leakdown test on it to find out if you've got cylinder sealing issues - because of the smoking. 

Check the condition of your oil. Something that looks like a chocolate milkshake is an indication of coolant leaking into it from somewhere. 

Remove the radiator cap, and run it until it gets warm enough to ensure the thermostat is open. Bubbles and exhaust smell mean that combustion gasses are finding their way into the cooling system so hope it's "only" a head gasket and not a cracked head or block.

Pull the dipstick and take a good long whiff. If you smell gasoline then the thing is probably running rich enough that fuel is washing past the rings and getting into the oil --- this is bad because it thins the oil, and bearings don't enjoy that very much. If that's going on, then correcting it is a priorty - check your float level, condition of needle and seat, install a gauge and measure your fuel pressure at the carb inlet (ought to be no more than 6psi) , install a wide-band air/fuel meter (either portable/hand-held or permanent). 

A proper leakdown test will tell you not only how well each cylinder is sealing, and if one or more has excessive leakage, where from (rings, intake valves, exhaust valves).

To run a test you'll need a source for compressed air and a leakdown tester, a way to "lock" the crank (I use a big pair of locking pliers on the flex plate), a fully warmed up engine, and some time.

If you're a tool-head/gear-head like me who just loves having an excuse to get something new, consider investing in a borescope camera. You can use that to "look around" inside the cylinders and intake ports.


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## Bluedog (Aug 8, 2018)

Thanks guys. The borescope sounds awesome. 
I am in the process of pulling the heads. Given the amount of gray smoke being generated I want to see where the coolant is coming from. 
Will keep you posted.


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