Help! Stalling once car is warmed up

[mcampbell26915]

Hi i am still relatively new to restoration and this forum so I apologize for any mistakes I will probably make.

I am having a very hard time with my 72 302. It starts up right away and idles "ok". Some days it will idle perfectly other Days it will sound a little rough but never too bad. The problem is that when I let the car warm up for a while and drive it around about a mile or so it will stall. It will start right back up sometimes but only last another 10-15 feet before stalling again, then after that I need to wait a while before it will start again. It is really weird to me because it runs fine for that mile or so and then just out of no where it will stall. If anyone has any idea what this could be I really would appreciate the help. Here are some things to consider :

Back of intake manifold is leaking oil

Rear differential is leaking

Engine shakes(broken motor mount I'm assuming)and runs more rough when in gear

Very random fits of running rough and running perfect

Burns white/blue smoke ( burning coolant)

very rarely will puff some black smoke out of exhaust

Newish 500 cfm holly carb

New battery

New alternator

New intake manifold

New plugs and wires

Idle and mixture screws set

Timing set ( 14 )

New exhaust

Newish coil ( bought it used )

I'm sure I'm forgetting a couple things but I will include them if they come up

Any help would he greatly appreciated I want to think I am relatively close to being able to drive this thing around but it's so unreliable that I don't want to take it out in fear that it will randomly just die with no warning like it's been doing. Thanks in advance for the help.

Matt

 

[nailpounder]

give your vacuum advance on the distributor. a quick check pull of the cap and put a vacuum on the hose and see if the advance is working . just a thought .i had something like that happen to me once .needed a new distributor or the choke is sticking or out of adjustment

 

[jb73Mach]

Burning coolant? Head gasket could cause all kinds of performance problems. Is there any coolant in the oil? Any oil in the radiator?

How are your plugs? Clean and gapped properly?

 

[JimNiki]

Hi matey...

If this engine is of unknown condition since you've had it, this is what I would do... Assuming it's not your daily driver.

Fix all obvious leaks.

Confirm the dizzy is not worn and reliable

Confirm the carby is not worn and reliable

If still have issues

Pull heads off to confirm no obvious Leaks or cracks ...check valves also

Replace with new gaskets

Pull sump off and check for metal fragments

These last points sound a little full on, but under the circumstances, that's where the issues may lie.

It's basically a process of elimination.

That with the quick and easy

I wouldn't drive it in case you are doing damage to the engine...

Your pistons could be trying to pump coolant... If there's a minor crack in a head and it gets worse, you'll blow the engine...

 

[Jeff73Mach1]

a vacuum leak, an improperly adjusted Choke, bad distributor cap/rotor/wire, bad coil, a few degrees to much initial timing, and a potentially blown head gasket. In that order is how I would investigate. There are some parts that should not be bought used and a coil is one of them-when they are bad they usually work until they heat up.

 

[matrixx]

a vacuum leak, an improperly adjusted Choke, bad distributor cap/rotor/wire, bad coil, a few degrees to much initial timing, and a potentially blown head gasket. In that order is how I would investigate. There are some parts that should not be bought used and a coil is one of them-when they are bad they usually work until they heat up.

+10

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[jbojo]

a vacuum leak, an improperly adjusted Choke, bad distributor cap/rotor/wire, bad coil, a few degrees to much initial timing, and a potentially blown head gasket. In that order is how I would investigate. There are some parts that should not be bought used and a coil is one of them-when they are bad they usually work until they heat up.

+10

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Totally agree with the above. My first suggestion was going to be the coil.

 

[judge]

I have seen a bad condenser exhibit the same symptoms. Had intermittent coil problems at times, but the intermittent coil would cause loss of acceleration and just bog down. I'd try a new condenser go for a ride.

 

[Jim and Jutta]

I had similar issues years ago with my 351, it turned out to be the coil overheating, it was just old.

 

[Mikes73]

Yup what they said, I would swap the coil first, then the condensor. I've had a few bad coils display the exact problems you are having, usually Accel's.

 

[matrixx]

There's probably a reason the coil was "used".

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[c9zx]

It sounds like there are a number of problems. What is the LIST number on the carb choke housing (ex. 4412-S). there are several 500 cfm 2Vs with wildly different calibrations (street vs.race). Is the coolant level actually dropping? A cooling system pressure test would confirm an internal coolant leak and may help locate it. A cylinder leak down tester may be used to identify which cylinder(s) are leaking if that is the problem (pressurize the cylinder with the radiator cap off and watch for bubbles in the radiator reservoir, be patient it may take several minutes to reveal a small leak).

Chuck

 

[mjlan]

Dude! You have a lot going on. With multiple potential issues affecting the engine, you might have start from the ground up to figure out what's happening...

Anecdotally, I fought with one if my cars not wanting to run and after messing with it for weeks finally changed the condenser and it solved the problem.

For your problem, when it quits, you need verify that there is adequate fuel and strong spark. Either the ignition is giving up or the fuel is not there (assuming that there's compression)...

 

[mcampbell26915]

Thanks guys a lot! I'm going to start with the quickest and easiest fix that everyone seemed to have mentioned and get a new coil. Wires and plugs should be good because I just replaced the wires 2 days ago and the plugs in October. I'll replace the plugs again because it's only about 20 bucks. I'll get a new coil and plugs soon as I can and then post my results. If there are any other ideas people have other than what has been mentioned please let me know so I can narrow down the solutions even more. Here are a couple more things to consider that I didn't mention in my last post:

The choke is manual

I took out the AC compressor and pully and belt , but left the AC lines because I couldn't get them off .

I can't nor can any of my helpful friends get the distributor out. It's too stuck in there. I am barely able to turn it when I loosen the bolt, but it definitely won't come out or I would have already replaced it.

Thanks again, I'll get those plugs and new coil and update

Matt

 

[matrixx]

If you say the engine runs "good" at times. and the top of distributor has new parts (cap, rotor, points, condensor) then I wouldn't lean to heavily of messing with it. The Dizzy will come out its just been in the same position for many, many years.

 

[mcampbell26915]

Ok so I just replaced all the spark plugs and the coil, and it is still doing the same thing. It will idle pretty well at times when I adjust the choke correctly ( I have to keep changing the choke every couple minutes that it's running, probably just because the car is warming up) but it will idle pretty well in park and neutral . But as soon as I shift it into gear the whole car shakes and starts going crazy - shaking, dropping rpm and rising rpm without warning, it sounds very in even, and then after the car is thoroughly warmed up it will die just like before. It can start again, but when I put it in gear after an increasingly shorter amounts of time it stalls . It's getting gas , spark should be good I just replaced wires plugs coil and the cap looks new , ( can't be more then 10 months old). Vacuum might be the issue, I'm not sure I hear much of a whistle, I'll try the carb cleaner trick and see if the Rpms kick up so I can see where/if I have a leak. I have to let my car cool down before it will idle properly again though so I will be posting my results sometime today hopefully. If anyone has any other ideas as to what's going on that would be awesome. A couple more things to mention - yes the coolant level is dropping, I just added a little more. It doesn't seem to be dropping too fast because I filled it about a week ago and I just checked it today and it was missing probably about a cup and a half of coolant. To answer somones question, yes there is oil in the coolant I think, because it's a slightly murky muddy color, not to much so that it's opaque but there is a hint of oil. Also I do think there is coolant in the oil because last time I changed the oil about a 1/3rd of a cup of coolant came out before the oil started coming out ( coolant sinks because it's more dense ). So yea I know that's not good at all but I want to figure out what is causing the car to not stay running . I would really rather try all the quicker and easier fixes before I get into fixing really big issues like the head gasket and heads and things like that. If I need to I will but obviously id rather try the other things first. Thanks again everyone.

Matt


Sounds very UNeven* not " in even" , sorry typo.


one more thing I forgot to mention, it only puts out blueish white smoke occasionally, today I ran It for a while and it didn't burn any. But a couple days ago it burnt a lot. So it goes back and forth. Thanks

 

[Jeff73Mach1]

I would bet that you have a vacuum leak at the front or rear of the intake manifold. You will have to pull it and replace the gaskets and reseal the ends with RTV to fix it. Typically an oil change is added at this point. Oil in the coolant and vice versa means a blown head gasket or cracked block. Usually it is a blown head gasket.

Surprisingly, changing head gaskets is a relatively easy job that can be done with hand tools in an afternoon. When working on a car with hydraulic lifters and factory positive stop rocker arms, there isn't much in the way of adjustment to worry about. You can remove the intake and all brackets attached to the heads, but don't undo hoses or wiring (besides the upper radiator hose) Everything can be pulled and tied up out of the way simplifying reassembly.

If you run it with coolant in the oil, you'll destroy your engine before too long. A hundred bucks worth of gaskets, fresh oil and coolant and you may get many, many more years of life out of it.

 

[matrixx]

If there's a busted head gasket I'd most definitely repair that first. The smoking, rough idling/driving, thay engine probably has enough compression to run when cold but when heated up the metal expands and your lossing even more compression.

Like jeff said its not like a modern car, its pretty simple, hardest part will be manhandling those heavy iron heads off the engine and sitting them on the floor.

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[c9zx]

I think you should stop driving the car or even starting the engine. Bearings and oil pumps do not get along with anti-freeze and water. You can buy a compression tester for $25 and up. This will allow you to Identify which cylinder(s) has a problem. It sure sounds like a blown head gasket to me. If it is, change them both and check the deck of the block and the sealing surface on the head as well as the bores for hairline cracks. Get that problem fixed and move on to the others. Just an opinion.

Chuck