Smoke out of carb

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ragtop

ragtop

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I think the 225 /6 is done ?
Hard to start and puffs of grey/black exhaust smoke out of the carb.
Im stumped on this one. Tried 2 different carbs and checked the valve lash and spark plugs.
Anyone have this happen before ? possibly a cracked head allowing exhaust into the intake ?
 
A held open or burned valve will cause this.
Comp test should be #1 on the list.
 
I wonder if the nylon gear on the distributor is chewed up and has the timing events all messed up. Easy enough to check.
 
Bad Sport said:
I wonder if the nylon gear on the distributor is chewed up and has the timing events all messed up. Easy enough to check.
Click to expand...

Distributor was replaced with a electronic unit 200 miles ago.
Spark plug #5 had some carbon build up on it.
Timing chain has approx 1/4 to 1/2'' of play before dist rotor moves.
When it does finally start runs well for a mile or 2.
Had to get it towed home yesterday.
Will do a cold compression test tomorrow and post the #'s
 
If you have a compression tester like the Milton I have, the hose is a quick connect and can be hooked up to an air compressor. You can thread it into the spark plug hole and pressurize a cylinder and listen for where air hisses out. Make sure the piston is at the bottom and both valves are closed. The hissing air will clue you as to bad valves, bad rings, etc.
 
I do have the 2 piece tester.
What air psi should I use on the compressor for this test ?
 
Quick vacuum test would show something. Burned valve will wiggle like crazy, any pressure you introduce will be evident, say 20 psi. Listen to intake, exhaust and oil breather.
 
Yup, psi is not important. Also remove the radiator cap and look for bubbles.
 
Might just be outta tune. They do run by blowin **** up, you know?
 
ragtop said:
Timing chain has approx 1/4 to 1/2'' of play before dist rotor moves.
Click to expand...

Are you checking this by measuring how much the crank pulley moves, then you are at or exceeding the service limit of the chain wear. If so, I would have to wonder if the chain has jumped time. Cracks between intake and exhaust to the degree you see is not common; the cam timing being off would be a more likely cause. I would be checking to see if the #1 valves the are right with the #1 cylinder at TDC. Compression may be all screwed up if it is. (But at least it should be all hosed up across all cylinders.)

Also, a stuck valve would cause your symptoms; any sign of that when you were setting the valves?

Running well for a mile or 2 seems to imply the flooding is the issue (or a sticking valve), rather than any cam timing problems.

Be aware that high psi on a leak-down test can move a piston suddenly and the fan belts and blade too... so keep yourself clear of moving parts in this test.
 
I was just eye balling the crank movement vs rotor movement.
One set of rockers did seem more out of spec than the others but most were fairly close to spec.
 
Well, you probably are not far off with the eyeballing; the retarded timing with such chain wear would not make the car not run or hard to start per se, but it would offer more opportunity for the chain to jump timing. 'One valve out of spec' is hard to interpret; do you mean the lash was not in spec? If so, was it far out of spec?

But if the car runs OK for a couple of miles, then it sounds like a valve sticking or a fuel issue. When the car runs good, is it reasonably smooth and powerful? How old is the car, did it sit for a long time before you got it, was the tank flushed, etc.?

Run the compression check as suggested; it will not hurt to know, and if one is low, then you will know where to look. And if you do a leak down test, be aware that there will be SOME air leakage past the rings; a slight hiss is normally not a casue for alarm. A compression test is better at this point IMO, as it gives you some quantifiable info; makes sure the spark plugs are all out, and the throttle is held wide open.
 
Running OK for a few miles, then stopping sounds like a fuel problem. It probably gets rich as the engine heats up. Read up on the choke and "choke pull-off". Also insure the "heat riser" in the exhaust manifold turns freely. A "bad engine", "cracked head", and similar would be the last thing I would imagine, as most here agree.
 
Haven't been able to get to this because my son fell ill and it's been a nightmare.
Good news is he is getting better and hope to get this problem solved soon.
 
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