What should I check next?

Posted By: 70Dart499

What should I check next? - 03/24/13 10:24 PM

I'm having a problem with the car, and I need some help with a possible diagnosis. I went to the track yesterday for a two day race, and the car ran great all day, but then this morning on the first time run, the car broke up really bad and almost died, I thought maybe a plug wire was off, so I checked & the wires were fine, I pulled the front and rear bowls off to check for trash, I found a couple of very small pieces, so I thought maybe that was the problem, so I went up for the next time shot and the car almost died when I hit the gas and would barely run under any amount of throttle. talked to a knowledgeable local engine builder, & he suggested we check for a broken valve spring, we did, and they were all OK. I loaded up and came home, changed the plugs which were old, an that didn't help much either, I have a temp gun, so I went around and checked all of the headers and I found that #4 & #6 are cold and apparrently not firing. Question is what else should I check, the plug wires look OK from the outside, so what is the next thing to check?

Posted By: VernMotor

Re: What should I check next? - 03/24/13 11:10 PM

compression test- leak down. ohm test wires look at cap.

Posted By: MR_P_BODY

Re: What should I check next? - 03/24/13 11:51 PM

It sounds like a ignition problem more than anything..
start checking ALL of the ignition system.. I would
look at the coil first.... JMO

Posted By: 70Dart499

Re: What should I check next? - 03/25/13 12:30 AM

You guys are pretty much thinking the same thing that I was. I couldn;t belive it, the car ran great yesterday, and then this morning, it just ran like crap. It did pop through the exhaust a few times yesterday in the shutdown, but I just figured that it was becuase I hadn't changed the plugs in a while. Maybe it was a warning sign?

Posted By: Cab_Burge

Re: What should I check next? - 03/25/13 12:48 AM

Pull the valve covers on both sides, let us know what you find

I hope all is good

Posted By: 70Dart499

Re: What should I check next? - 03/25/13 12:50 AM

Quote:

Pull the valve covers on both sides, let us know what you find I hope all is good

Already did that, had a very knowledgeable local engine builder take a look for me while I was still at the track and everything checked out OK.

Posted By: Hot 340

Re: What should I check next? - 03/25/13 12:53 AM

If its an old carb it might have a blown power valve....the older ones didnt have blowout protection for backfires.

Posted By: bonefish

Re: What should I check next? - 03/25/13 03:39 AM

did you look at the plugs.somtimes that can tell you alot.

Posted By: 70Dart499

Re: What should I check next? - 03/25/13 04:00 PM

Quote:

did you look at the plugs.somtimes that can tell you alot.

Yes, that was one of the first things I did, the dead cylinders looked wet and the others just looked old and due for a change. I changed all the plugs out, and the two dead holes didn't pick up. I'm going to start out by changing the wires on the two dead holes, and if that doesn't help, I've got a spare coil I'm going to try. If none of that works I guess it will be on to the distributor.

Posted By: Dodgeguy101

Re: What should I check next? - 03/25/13 04:09 PM

Quote:

Quote:

did you look at the plugs.somtimes that can tell you alot.

Yes, that was one of the first things I did, the dead cylinders looked wet and the others just looked old and due for a change. I changed all the plugs out, and the two dead holes didn't pick up. I'm going to start out by changing the wires on the two dead holes, and if that doesn't help, I've got a spare coil I'm going to try. If none of that works I guess it will be on to the distributor.

I would think if it was a coil, the problem wouldnt be the same 2 cylinders having a problem. Something mechanical,

Posted By: Guitar Jones

Re: What should I check next? - 03/25/13 04:21 PM

Quote:

Quote:

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did you look at the plugs.somtimes that can tell you alot.

Yes, that was one of the first things I did, the dead cylinders looked wet and the others just looked old and due for a change. I changed all the plugs out, and the two dead holes didn't pick up. I'm going to start out by changing the wires on the two dead holes, and if that doesn't help, I've got a spare coil I'm going to try. If none of that works I guess it will be on to the distributor.

I would think if it was a coil, the problem wouldnt be the same 2 cylinders having a problem. Something mechanical,

Could be the cap or wires, did you look at the cap for carbon tracking? Could also be a vacuum leak, intake gasket maybe?

Posted By: viperblue72

Re: What should I check next? - 03/25/13 04:26 PM

Im guessing you checked the lash to make sure a camshaft isn't going flat?

Posted By: 70Dart499

Re: What should I check next? - 03/25/13 04:56 PM

Quote:

Im guessing you checked the lash to make sure a camshaft isn't going flat?

I didn't have a set of feeler guages at the track, so no. I will check the lash at some point if I can't find anything electrical. Just a question though, wouldn't a cam going flat be more gradual? I mean the car ran great except for the little popping out of the exhaust, I mean the ET's were right where they usually are given the weather, Sat at 5:00pm and the next morning it wouldnt get out of it's own way. Ive never personally dealt with a cam failure but I would think it would be more gradual.

Posted By: bonefish

Re: What should I check next? - 03/25/13 05:00 PM

put an old plug in the wire then ground it and have someone turn it over and see if it sparks.first disconect the other wires from the dist.so it doesnt start.

Posted By: Mr.Yuck

Re: What should I check next? - 03/25/13 05:32 PM

Quote:

put an old plug in the wire then ground it and have someone turn it over and see if it sparks.first disconect the other wires from the dist.so it doesnt start.

yeah start at the easy place 1st. If you had a broken spring or wiped cam you hear some etra noise, you can also pull ur dip stick and see if it has some "glitter" on it.

Posted By: 70Dart499

Re: What should I check next? - 03/26/13 02:01 AM

Check the ignition stuff over this evening, and everything seems OK, I'm borrowing a leak down tester from a friend tomorrow, and we are going to check the comp. Im thinking its a blown head gasket since the two middle cylinders are dead. I'm kind of hoping thats all it is, becuase I can fix it in one or two evenings work.

Posted By: sixpackgut

Re: What should I check next? - 03/26/13 02:39 AM

blow air into cylinders

Posted By: rickstershemi

Re: What should I check next? - 03/26/13 02:46 AM

i broke 3 fins (for lack of a better term) off the reluctor in my MSD Dizzy once after a hard landing on a higher than normal wheelie.....instantly ran like crap with three cyl down...????

Rickster

Posted By: sixpackgut

Re: What should I check next? - 03/26/13 02:56 AM

Quote:

i broke 3 fins (for lack of a better term) off the reluctor in my MSD Dizzy once after a hard landing on a higher than normal wheelie.....instantly ran like crap with three cyl down...????

Rickster

amazing

Posted By: 70Dart499

Re: What should I check next? - 03/26/13 03:03 AM

Quote:

i broke 3 fins (for lack of a better term) off the reluctor in my MSD Dizzy once after a hard landing on a higher than normal wheelie.....instantly ran like crap with three cyl down...????

Rickster

I pulled the dizzy cap and I didn't see anything broken, but I thought for sure I would?? Anyway, the leakdown test tomorrow will tell the tale, and if it's not low on comp we will go from there.

Posted By: rickstershemi

Re: What should I check next? - 03/26/13 03:06 AM

Quote:

Quote:

i broke 3 fins (for lack of a better term) off the reluctor in my MSD Dizzy once after a hard landing on a higher than normal wheelie.....instantly ran like crap with three cyl down...????

Rickster

amazing

go figure.....found three cold header tubes trying to figure it out and when we went to ck the cap/rotor....found them lying in the dizzy

MSD did swap out a brand new dizzy at zero cost

Rickster

Posted By: jamesc

Re: What should I check next? - 03/26/13 03:29 AM

Quote:

Check the ignition stuff over this evening, and everything seems OK, I'm borrowing a leak down tester from a friend tomorrow, and we are going to check the comp. Im thinking its a blown head gasket since the two middle cylinders are dead. I'm kind of hoping thats all it is, becuase I can fix it in one or two evenings work.

from your description the head gasket would be my first guess, if this has aluminum heads the head may need repair.

Posted By: poppaj

Re: What should I check next? - 03/26/13 05:06 AM

I still would think it is ignition, sounds like is not firing on those cylinders at all. I would change cap,rotor and wires first. A blown head gasket would more than likely have water in the oil or be throwing some water out the headers. poppaj

Posted By: jamesc

Re: What should I check next? - 03/26/13 05:08 AM

Quote:

I still would think it is ignition, sounds like is not firing on those cylinders at all. I would change cap,rotor and wires first. A blown head gasket would more than likely have water in the oil or be throwing some water out the headers. poppaj

not if it's blown between the cylinders which is a common failure point...no water there

Posted By: RodStRace

Re: What should I check next? - 03/26/13 05:25 AM

I think we can agree that it's not a fuel problem...
Is the battery fully charged? Check for spark at 4 and 6.
What changes have been made recently, no matter how unrelated?

Posted By: dennismopar73

Re: What should I check next? - 03/26/13 12:52 PM

Start with timing,and rotor phasing!! bet the spark is 'blowing off, balancer may have slipped as they do and thus the spark blow off,
start from fresh pull it upon number 1 , check the balancer!!!!
then the rotor phasing!!

I will bet you have more than 1 or 2 cyl that is running colder!!

Posted By: CHAPPER

Re: What should I check next? - 03/26/13 01:28 PM

Quote:

Quote:

Check the ignition stuff over this evening, and everything seems OK, I'm borrowing a leak down tester from a friend tomorrow, and we are going to check the comp. Im thinking its a blown head gasket since the two middle cylinders are dead. I'm kind of hoping thats all it is, becuase I can fix it in one or two evenings work.

from your description the head gasket would be my first guess, if this has aluminum heads the head may need repair.

If #4 and #6 plug wires aren't crossed, I would suspect the head gasket blown between those cylinders.

Posted By: Guitar Jones

Re: What should I check next? - 03/26/13 01:49 PM

Quote:

Quote:

Quote:

Check the ignition stuff over this evening, and everything seems OK, I'm borrowing a leak down tester from a friend tomorrow, and we are going to check the comp. Im thinking its a blown head gasket since the two middle cylinders are dead. I'm kind of hoping thats all it is, becuase I can fix it in one or two evenings work.

from your description the head gasket would be my first guess, if this has aluminum heads the head may need repair.

If #4 and #6 plug wires aren't crossed, I would suspect the head gasket blown between those cylinders.

I guess I read it wrong, I thought it was 2 & 6, I would have to agree, do a compression test. All the other ignition stuff would affect other cylinders also, not just 2. Process of elimination, eliminate everything else except what would only affect 2 cylinders, and in this case 2 adjacent cylinders.

Posted By: TheBlackCar

Re: What should I check next? - 03/26/13 02:23 PM

Problem is in carb. Its dumping fuel and the manifold is directing it into those two cylinders.

If it were a head gasket, it would be popping up thru carb as pressure passed between cylinders.

Good Luck

Posted By: 70Dart499

Re: What should I check next? - 03/26/13 06:20 PM

Quote:

Problem is in carb. Its dumping fuel and the manifold is directing it into those two cylinders.

If it were a head gasket, it would be popping up thru carb as pressure passed between cylinders.

Good Luck

I guess I forgot to mention that it is popping out of the carb a bit

Posted By: 70Dart499

Re: What should I check next? - 03/31/13 07:07 PM

Well, got the head off today and its not good. The head gasket was blown, and the head has a decent size gouge where the gasket blew. So I guess I will have to have that one resurfaced, and I assume I'll have to pull the other one and have it resurfaced also. I hope not, but im going to call the machinist in the morning and I'm sure he is going to suggest doing both heads. I guess I will be bracket racing my pickup truck for a while, because I'm sure the machine work ain't gonna be cheap