SBC 283 problems. Wierd...

Got a wierd one...

My 283 in the 64 Chev is running really rough. Spitting, backfiring, popping, no power. Thing is, it only does it after the car has been running for a while. It does not seem to be directly related to the engine temperature. I drove it about 15 miles up to a friends house the other night & it was fine all the way to the highway (about 2 miles from the house) Then about 5 miles up the highway, I started to feel it getting rough. When I got off the highway, it was back to running shitty again.

I have checked fuel supply (filter, fuel pump, carb was rebuilt 2 weeks ago) Changed timing chain the other day, new wires, checked all plugs... I was trying to set the timing today & it seemed to not be able to make the timing light flash every time, & the skips in the idle (not regular, intermittent) seemed to correspond to the times when the light wouldnt flash. While doing this, I noticed that the (+) terminal of the coil was really hot. Could I have a bad coil maybe?

The only thing I did recently before it started running like this was change the alternator, but even with the alt disconnected & running off the battery, it does the same thing.

 

2 things I'd try.

You said fuel filter...the original filter is in the carb I believe. So if someone put on an external inline filter, maybe they left the small carb filter still in the carb fitting?

Next time it acts up, try just a hot jumper from batt to plus side of the coil to see if you are not getting constant voltage to the coil. Such as a break in the resistor wire, a bad terminal someplace, or a dirty ign switch

Just don't leave the jumper on very long at all, because the full running/charging voltage of 14v will burn up the moving arm on the points.

 

Try a coil.

 

You should have an inline resistor .right ? if not you will burn up your points .will run ok at idol but not while driving .

 

Try examining your distributor cap. You do not say you replaced it so you may have some arcing or carbon tracking in the cap. The spark will travel across the cap to the wrong plug. Examining real close you can see thin black lines on the surface of the inside of the cap. You can also have the same tracking across the rotor. Also check for cracks in the cap and rotor.

lg
no neat sig line

 

Oops. Forgot to mention that. I did a FULL tune up about a month and a half ago. (plugs, cap, rotor, points, wires, fuel filter)

 

condensor?

 

Please consider pouring a bottle of Seafoam, some down the carb idling fast with the rest in the tank.

pdq67

 

Well it does not have the white mopar style ballast resistor. I guess the resistor is in line somewhere. I dont know where on that car. I was looking for it today. I was thinking... I could just run a new wire from the ign wire at the key switch, then just send it through an external ballast resistor, up to the coil (+). Obviously just cutting out the old wire. Could this work?

 

New as well...

 

AWHILE BACK A FREIND OF MINE WAS HAVING SIMILAR PROBLEMS, AFTER HE TUNED IT, I FINALLY REPLACED HIS " new" CONDENSOR WITH THE OLD ONE AND IT RAN FINE AFTER THAT, SO THE NEW CONDENSOR WENT BAD IN JUST A FEW MILES

 

The "ballast resistor" is hidden in the harness on GM cars. I would not suspect it being a problem. I've had an ass load of GM cars running the resistor wire and never heard of one failing. I've had conventional ballast resistors go bad and the engine would not run. They are either good or they are bad.

I would try another coil. I have had problems with coils that act up when they get warm. You say it's not heat related but it only happens after it has run for a while. To me that says that it is heat related.

 

Hmm.. Just seems wierd to me. It's running like it's WAAYYY the hell out of time. Backfiring through the carb & everything. Would the bad condensor cause that? I guess a new set of points is cheap enough to try... SOmebody else also mentioned the coil, & the one on here is pretty old. Maybe I should just give that a try. But of course, it's Sunday, & everything closes at 5.

 

Well what I meant by "heat related" is that it doesnt seem directly related to the coolant temperature. The car runs at like 165 & it can get up there & be running fine for 20 minutes at that temp before it gets shitty. Now the temp of the coil could be a different story, so I should look into that after work tomorrow. Maybe just get a new one since the one on there is so damn old. I guess that means I didnt really do a Full tune up huh? haha

 

Oh wait, it's monday! Maybe theyre open

 

I would recommend changing the condensor as well. I have experience with an engine running poorly with a bad condensor and the symptoms are similar to yours.

 

Lets go back to the basics.

Go through and check your firing order to make sure that you don't have a couple of wires crossed. It's real easy to get 5 and 7 crossed up and almost every one of us who runs or has run a sbc has done it at one time or another.

Make sure that all of the plug wires are tight in the cap and tight on the plugs and make sure that none have laid up against the exhaust and gotten burned and are arcing.

I'd still check inside the cap especially if you have had some hard rain lately as there may be moisture in the cap. Also check to make sure that the holder for the condenser and it's screw are tight. If that is a bit loose it will act similar to what you described especially under a hard pull.

I'd also check the voltage at the coil when the car is running to make sure that there was a resistor in the line or check the coil to see if it is a resistor coil.

You might try moving the clamp for the timing light up closer to the distributor and see if it works better there. Another old trick with that style of distributor is to hook the timing light to the coil wire so that it flashes every time the engine fires. That will let it light up the timing mark when one and six fire and might make it a bit easier to see the marks.

 

resistor wire should be a looped deal running down to the starter and then back up. The resistor wire needed to be a certain length, so they ran a loop to "use-up" the wire.

 

I vote for the condensor. I bought several from the local auto supply store, which went bad right away. I ended up using either an Accel or GM Delco Remy from a dealer.

 

A coil is not considered a tune up item. Borrow one from a buddy before you buy anything.

I was having trouble with a 58 Plymouth dying and not starting once it was up to operating temps. When it wouldn't start a guy said wait right here. He came back with a big CO2 fire extinguisher, placed his hat over the carb and gave it a big long blast with frost building up on the coil. When the frost melted he said start it up...it started right up. I was convinced.

 

Coil is breaking down,next time it does it take the coil off quickly and give it a shake if it sounds like a can of pepsi real thin liquid sound or like tommy said swap it.Should remain solid

 

The one on my 66 Chevelle was in the harness as it ran across the firewall from the ign sw. to the coil. Some idiot cut mine in two when they pulled the engine. It's a normal looking wire out to the firewall. The actual resistor part of the wire is an odd looking textured white section of wire maybe a foot long that changes back to a normal looking wire before exits the harness and connects to the coil. It's all hidden in the plastic harness wrap on the firewall. I knew the length would be critical so I cut the whole resistor section out of another harness and spliced it into the existing wire. It ran like a champ.

 

replaced the coil. Wire is still heating up. I'm gonna try replacing the wire all together & putting a resistor in line. Anyone know what resistance it has to be?
If that doesnt work, I'll try the condensor again

 

My buddy Mike mentioned grounding to me & it occured to me, I put a new powdercoated frame under the car last year. Im gonna check all my grounds first. Might not be making solid ground if the powdercoat isnt ground down enough...

 

If you are still running the original 64 distributor, you gotta remember they wear out to. Check for bushing wear, wear in the point plate, sticking mechanical advance, could be where your trouble is if the other suggestions don't pan out.

 

Tip: always spend good money on the best tune up parts, buy quality, if it's cheap, it will leave you on the side of the road, and always at the worst time.
I have seen cheap 'new' parts fail time and again.

 

Yup.

Been there done that, on a '62 Beetle. Bought the Bosch stuff a week after the Schuck's stuff.

And a few years later, used to bill a few diag hours pulling 'made in Italy' caps off of Honda cars, and putting OE stuff on.

I'm a big fan of running a few simple tests to rule stuff out, and narrow down the possibilities, instead of trying to guess what a problem is from the symptoms. I've found that if I don't KNOW from either intuition or experience, that it's usually easier to spend fifteen minutes on some baseline tests. I've almost always got a fairly defined path to go down, if I haven't got an answer within that period of time.

FWIW, you have a problem with air, fuel, or spark.

Air is the engine itself; unless it's got something that's leaking vacuum hot, it probably isn't the problem. But, I'd check for loss of coolant pretty early; takes seconds to do and rules that out off the bat.

Fuel... get the car hot; do a propane test. That'll tell you if you've got a fuel delivery problem (vapor lock; gas boiling in carb, etc) when hot. Cheap, easy, fast.

Spark... grab a brand new spark plug; get the car warmed up and acting up. Shut her down, hook a plug lead to the test plug, and hold it against a grounded part. Fire the car. See the quality of spark. If it isn't good, re-do the test with the spark plug hooked to the coil wire, and use an accomplice or remote starter switch to spin the engine w/ the ignition on.

Just because parts are new don't mean they're good. Trust me on this: I work at O'Reilly Auto Parts, where we sell "A1 Cardone" brand shit to people who don't know better.

Best o' luck.

-Bill

 

You didn't say if the car ran poorly again with the different coil after it came up to temp. Did you try it to see if it still runs bad after it gets up to temp or immediately bailed because the wire felt warm? If the resistor was bad it wouldn't run and the wire would not feel warm.

That wire has a resistor in it and it will run warmer than the others but there are millions of them out there with no problems.

I thought you were chasing a poor running engine when it warms up? If you do use a conventional ballast resistor don't touch it when it's running they will burn you.

 

ooops

 

Well it was definitely running nice when I started it, but it hadnt gotten up to temperature yet. But the wire was hot, not just warm. I didnt wanna leave it running. There is definitely a problem because the wire was RED hot. (Glowing & it was smoking, also burned my fingers) I am gonna check my grounds when I get home from work tomorrow. I bet the powdercoat is causing a problem.