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Hey everyone, I just had quite a few items fixed on my '73 Coupe and it was running well until the other day. I went out to start the car and it took awhile for me to start and I had to keep my foot into the gas pedal to keep it running. When it was running, it was running rough like it was missing on some cylinders and it was puffing white smoke pretty good. As soon as I let off the gas pedal it would die. The engine would lope and vibrate quite a bit as well. I did fill up about 3/4 of the tank with 100LL avgas about two months ago but I had driven it about 50 miles or so on that fuel with no problems. The mechanic that I took it to did advance the timing a little bit more than stock and said 100LL would be good to run. It seems to me that it could be an ignition problem and I haven't ruled out fouled plugs as I know from flying general aviation aircraft that we have to burn off the deposits on plugs from time to time. Anyone have any idea what it could be? Thanks. 

 

Captain Morgan

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Sounds like a blown head gasket. I'd check around heads when cold if you'd see some fluid, and check radiator level.  Did you replace or removed heads recently?

73 modified Grande 351C. (Finally back on the road woohoo!) 

71 429CJ. ( In progress )

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The mechanic replaced the radiator hoses and filled the collant system. How would I diagnose a blown head gasket, compression check? I haven’t replaced or removed heads. I don’t think they’ve been touched since 1973. 😂

Edited by Captain Morgan
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When I got my car 30+ years ago, I got the exact same. It would run on few cylinders and smoke white and would go crazy smoking when car was getting to temp.

On mine it was bad news, one of the cylinders wall had a crack letting coolant enter the chamber. But it would start fine. As yours already has problems to start, you might be lucky and that it's just a blown gasket.
No matter what the problem is, thick white smoke is very likely burned coolant, bad timing would give you some black smoke as fuel would not be burned the way it should. Not white.
If you have drove a bit since the repairs, open the caps on valves covers, you might find "mayonaise", if you check your oil, you might see drops of water on your stick, if you check your plugs, at least one of them will probably look very bloated with deposits and even dripping coolant. You might also see "rainbow" on coolant at radiator cap.


I know some ethanol gas formulas can have lots of moisture in them, which would also burn white, so I hope this is the case for you. A simple plugs cleaning, filling with good gazoline would then fix but if car doesn't run fine after that, I'm afraid the only way to know whats going on is to open the engine...

73 modified Grande 351C. (Finally back on the road woohoo!) 

71 429CJ. ( In progress )

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Ok, so I went out to start the car and video the symptoms. I also looked around the base of the heads and I didn’t see any evidence of coolant. The car started up fine and chugged a little bit but it seems that it’s a fueling/ignition problem because it is smoking out both sides and it’s a straight duel exhaust. Let me know what you guys/gals think. Thanks.

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Doesn't really look white fumes to me at least not on this video. The way I recall them, they are way thicker, whiter and you'd have a cloud behind car.
This looks more like a too rich condition and may be a tad of oil burning on one bank.
I'd start by removing every plugs and clean them (or changed them if they are old) and set their gap. Then check timing.

73 modified Grande 351C. (Finally back on the road woohoo!) 

71 429CJ. ( In progress )

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Thanks for your reaponses. If I want to change plugs/wires and distributor, what are good ones that work well in our Cleveland motors? I have a stock 2v engine and I don’t plan on more power, just as close to original as possible. 

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Start with the simplest thing. I would start with the carb,  make sure the choke is opening ,and the float and power valve are functioning properly .

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I do not think anyone answered how to check for blow head gasket. most automotive parts houses have the tester they loan as long as you buy the test liquid. It is a rubber bulb pump that you put some of the test liquid in the chamber and pull a vacuum on the radiator. if it changes color you have exhaust gas in radiator so blown gasket.

Gaskets can be put on backwards. They are marked FRONT. So put on as marked if you have to change. 

 

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When a man is in the woods and talks and no women are there is he still wrong??:P

David

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