Crank no start? Compressor pulley seized?

[Zezima]

Went to start up my car, it idles for a while, then starts stumbling, progressively violently, now won't start again.

I can't figure it out, nothing has been wrong this whole time other than the compressor pulley was starting to grind/whine intermittently and that was about it. Air, fuel, spark, fluids, nothing seems any different now. I drove it several times today alone.

Only thing I can think of is maybe the pulley is seized up and it's preventing a start? It'll crank and crank, but only after serious coercing will it sound like it fires a couple times, otherwise it's crank for days. No amount of adjusting the fuel mixture or choke seems to matter.

Does anyone have any ideas? The tension on all the belts seem copacetic. The distributor was replaced weeks ago, spark shouldn't be an issue. Though I have also noticed that for the past month or so, it does occasionally backfire pretty violently on acceleration from a cruise. The sound of an actual gun shot, but I'm not sure if that's related.

The compressor itself has been disconnected by the way, so that shouldn't be interfering anymore either.

 

[darth_linux]

Nylon tooth on timing gear broke perhaps and now it’s completely wrong on timing?? That could explain the back firing and cranking without catching .

 

[Zezima]

Nylon tooth on timing gear broke perhaps and now it’s completely wrong on timing?? That could explain the back firing and cranking without catching .

That sounds pretty likely. I suppose the best step moving forward would be upgrading to metal timing gears?

 

[darth_linux]

Yeah, you should TDC the engine and then look to see if the rotor is pointing to the #1 tower on the cap. If it’s off by very much you’d then remove the water pump and housing so you can get to the timing cover and do a visual on the chain and gearset.

Some local wizards here can give you more/better details on this than I can, as I’ve not rebuilt an engine yet.

 

[413]

What car/engine are we talking about?

First thing is check compression, they will all be low if timing chain jumped.

You have a timing problem as noted by the backfire.

Tell us what was changed for the distributor a few weeks ago, that's a start.

What ignition? what carb?

 

[volksworld]

the compressor clutch assembly has a bearing in it...when the engine runs the pully freewheels on the bearing... when the a/c comes on the clutch locks up and causes the compressor to spin...the clutch and bearing is external to the compressor and is easily changed...when mine seized up the pully stopped turning as the belts slid across it squealing and smoking...i highly doubt its the reason for your misfires and backfires...just because you replaced the distributor doesn't necessarily mean you replaced it with a good one...points or electronic?

 

[MJFUR]

Loosen the belts on the A/C compressor and see if you can turn the compressor pulley. Then see if you can start it with the belts loosened.

 

[Big_John]

The distributor was replaced weeks ago, spark shouldn't be an issue. Though I have also noticed that for the past month or so, it does occasionally backfire pretty violently on acceleration from a cruise.

A seized compressor won't make any difference to how the engine runs or starts. The worst it would do is throw or burn the belts off. There'd be some screeching and maybe a little belt smoke... But nothing to keep it from starting.

Since you replaced the distributor fairly recently, and you've had some backfiring, the very first thing I would check is the ignition timing... Meaning it was either wrong when installed, or it has moved after it was. I'd give the distributor a crank a few degrees clockwise and see if it helps. If it does help, you'll want to check it with a timing light once you get it running.

You didn't say what the new distributor. Points? Check the gap. Electronic? Look at the pickup and reluctor and check the gap between them. Look at the inside of the cap for any cross firing, or damage to the cap and/or rotor.

Look over all the wiring to the distributor, coil etc. Make sure they are all tight and in good shape.

And just for laughs... Check the firing order (again, going back to the distributor change). 1-8-4-3-6-5-7-2.

Those are simple, first things to check that cost you nothing but a little time.

If it's not that, I'm with the others and thinking the next thing to check is the timing chain.

 

[57fury440]

You left out the "5". 1 8 4 3 6 5 7 2. Good advice from the above posts.

 

[Big_John]

You left out the "5". 1 8 4 3 6 5 7 2. Good advice from the above posts.

I kept thinking it didn't look right. LOL! Corrected to save any confusion.

 

[Retired auto tech]

Uh, this might be a dumb question but do you have fuel in the carb? Look down the throat and pump the throttle a couple of times to make sure the accelerator pump is squirting. Last fall my brother asked me to come over and check out his 79 Trans Am for the same problem. Cranked fine, Had spark, no fuel in carb. Checked pump pressure, zero. Installed new pump, ran for a few minutes then died. Asked him how much gas was in the tank. He said gauge showed just above empty. Added five gallons and after cranking for 30 seconds started right up and ran fine.

As my mentor taught me over 55 years ago always
Test, Verify, Repair, Retest It is better to know what needs to be fixed before you throw at lot of parts into it and still not solve the problem.
Fuel yes or no, Ignition yes or no, timing correct? Compression good? 125 psi or more. With a jumped chain your compression will be about 70lbs, you need above 90lbs before fuel will ignite.

If the engine is all original it will need a new timing chain anyways. 58 years is a lot to ask of a high wear part. Easy to check. Remove distributor cap. Line up timing marks at about 10 degrees BTDC. Put a socket and ratchet on the crankshaft bolt. Turn the crank clockwise untill you just see the dist rotor start to move. Record the degrees then turn the crank counter clockwise untill you see it start to move again. How many degrees between the two? If five degrees or less your fine. If 10 or more its time for a new chain and gears before it leaves you stranded and calling for a tow.

 

[Just Carbs]

Check the initial timing with a light while cranking it.
Replace the condenser.

 

[Sixpactogo]

Have you given any thought to your problem being fuel related? If my car would start and idle for a short time then stumble, the first thing I would wonder about is the fuel filter or sock in the tank being clogged up with rust or gunk. It sounds like you have taken care of your AC compressor issue unless you want the AC to work. If so, you will need a new bearing and possibly clutch on the compressor.

 

[Zezima]

Sorry I haven't posted in a while, one thing lead to another and life gets in the way. But it's finally driving again. It was a multitude of things at once, but the compressor did bind and lock up so bad that it was dragging the engine because it essentially wouldn't spin anymore, causing all sorts of issues. Though on top of that, the ballast resistor had failed which was causing ignition issues, and is something I should've thought of in the first place given how problematic they can be. There was also a vacuum leak at the back of the intake manifold. Fuel lines were also clogged, which in turn clogged one of the inlet jets.

Did end up replacing the timing chain, but turns out it wasn't the OEM nylon gears anyway, so I assume the previous owner already did the chain since it was all metal. The spark plugs were also fouled up bad despite the plugs being new as of last year and only having a couple thousand miles on them at most, which means there's likely blowby and oil getting in the combustion chamber, since the plugs were pretty black and gunky. I assume piston rings or valve seals?

All that being said, decided to swap carburetors, replace all 8 spark plugs, replace the points, condenser, and coil. I bought a Sanden compressor at the advice of FCBO, the Bouchillon kit, though not everything fits, so A/C is gone for now, but installed the new compressor anyway so at least the belts can spin. Also got the timing cover, water pump housing, and crank pulley painted to match the original 383 turquoise, so that's nice.

There's still a few issues here and there, but so long as I can drive it, I'm still smiling. Appreciate the input from everyone here, if I hit another wall, I'll let y'all know, but that fiasco seems addressed now at least.

I'm currently getting what I would describe as "surge," even though it doesn't seem to be actual RPM surge, but at low speeds accelerating/decelerating it's not a smooth transition and feels like it's slightly hesitating/bucking. Nothing too crazy or interfering with function too bad, but noticeable. That, and now getting some pretty intense vibrations at idle that I wasn't having before all of this went down, not sure how much is just the new carb not being tuned properly, or if the motor mounts are going out, but it's just about intense enough to be moderately concerning with how much it shakes when idling in drive with the brakes applied.

But for now, that seems to be everything. Didn't think I should make a new thread for this, since the new issues are more minor by comparison, but decided I should update and provide closure to this chapter at least. FCBO helps keep me going with the support and community though, especially since there's not exactly a lot of local C body owners out there (though I do know of at least 3 other C body fuselages in this town), so every bit helps.