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Deals and Appeals => Appeals => Topic started by: csheff on August 14, 2020, 05:12:13 PM

Title: GT 500 - need your help with ideas on what could be wrong
Post by: csheff on August 14, 2020, 05:12:13 PM
Need more ideas on what to check. My 67 Gt-500 was running great on the freeway going 70 coming home the other day when it just sputtered,  spit almost like out of gas then a pop and died.
Everything under the hood looked ok, dry I ck'ed if I was getting gas, was. After I let it sit a while I tried to start seemed like it wanted to but nothing. Had it flatbed home.
Since I have ck'ed the condenser ck'ed good but replaced it anyway. Coil seemed to ck ok, I get spark. I tried starting again and it feels like it wants to start but just won't.
Help guys what am I missing? I'm assuming it's electrical.
Title: Re: need your help with ideas on what could be wrong
Post by: shelbydoug on August 14, 2020, 05:18:04 PM
Check it with a timing light to see if it is firing on time. The results will tell you a lot.
Title: Re: need your help with ideas on what could be wrong
Post by: trotrof1 on August 14, 2020, 05:57:39 PM
Its either fuel, spark , or compression. I assume your fuel is OK , not degraded. you should have a good strong spark at the plug. If that checks out good pull out # 1 spark plug and rotate the crankshaft with a ratchet on the dampener crank bolt to # 1 TDC marked on the dampener. check to see if #1 piston is at the top of its travel the moment the mark on the dampener touches TDC. Take a maker pen and mark the dist housing where the #1 tower is on the dist cap. \ Pull off the dist cap and see if the rotor is pointing exactly at # 1. IF the timing marks, the distributor and # 1 piston dont line up exactly the timing chain might have jumped . If they do line up ok then go back and check fuel and spark again. This is just a basic check you would normally do on any engine. All my cars are small blocks so somene else here might be more familiar with 428 issues.
Title: Re: need your help with ideas on what could be wrong
Post by: Greg on August 14, 2020, 06:18:56 PM
You probably have a gas issue.  It is the fuel pump or filter.

If you have spark, pour gas in the bowls through the horns and see what happens. 
Title: Re: need your help with ideas on what could be wrong
Post by: Coralsnake on August 14, 2020, 06:32:47 PM
Boiling ethanol comes to mind if it was warm out
Title: Re: need your help with ideas on what could be wrong
Post by: 557 on August 14, 2020, 06:36:28 PM
Quote from: Greg on August 14, 2020, 06:18:56 PM
You probably have a gas issue.  It is the fuel pump or filter.

If you have spark, pour gas in the bowls through the horns and see what happens.
+1 prime it....
Title: Re: need your help with ideas on what could be wrong
Post by: trotrof1 on August 14, 2020, 06:42:00 PM
I had to drain my tank out last year because of a fill up of bad gas. It does happen.
Title: Re: need your help with ideas on what could be wrong
Post by: csheff on August 14, 2020, 06:47:37 PM
I'm getting fuel, bad gas was a thought as I did fill up shortly after leaving but drove 30 miles before this happened.
Title: Re: need your help with ideas on what could be wrong
Post by: trotrof1 on August 14, 2020, 07:02:05 PM
Pull out a plug and see if its wet possibly indicating a spark issue. You could put a breaker bar on the crank to see how much play there is in the chain . Roll it both directions to see how much travel before dist rotor moves.
Title: Re: need your help with ideas on what could be wrong
Post by: Greg on August 14, 2020, 07:04:28 PM
If you have fuel squirting (it can't be a dribble) in the venturi's then you have spark issue. 
Title: Re: need your help with ideas on what could be wrong
Post by: KR500 on August 14, 2020, 07:14:51 PM
Quote from: csheff on August 14, 2020, 06:47:37 PM
I'm getting fuel, bad gas was a thought as I did fill up shortly after leaving but drove 30 miles before this happened.
Check for spark, use spark tester or a spare spark plug. Make sure you have a strong spark. If not check coil resistance, points, rotor, cap, wires, ect. Check the timing! Once in awhile the distributor drive gear pin will shear off. Seen valve stem pieces break off and get by the oil sump bypass and lock up the oil pump, shears the distributor drive gear pin off. Remove dist. cap , crank the engine, see if the rotor is rotating. No = drive gear pin sheared or timing chain /gear problem Timing gear/chain can jump if worn badly. Check compression. Timing chain/ gear out of time= low compression. Make sure you have good fuel and pressure. Good luck
Title: Re: need your help with ideas on what could be wrong
Post by: trotrof1 on August 14, 2020, 07:22:31 PM
Eric the car guy on youtube has a straight forward video on checking timing chain slack. 7 degrees of movement would be max limit.
Title: Re: need your help with ideas on what could be wrong
Post by: JWH on August 14, 2020, 07:26:53 PM
Sheff, I had this exact same thing happen under exact same circumstances. Turns out it was the coil. My car died in the middle lane of the highway at rush hour. Thankfully it started one more time and if I kept the revs up (3,000 rpm) it would not die. I managed to make it home and then pffft, that was it. I installed a new coil and everything was good. I think you can get a decent coil at the parts store for $20-$30 so you are not out a lot if it is something else.
      I also like the thought of checking the fuel filters in your carbs for junk. Good luck and let us know what fixes things.
Jeff
Title: Re: need your help with ideas on what could be wrong
Post by: s2ms on August 14, 2020, 07:40:54 PM
+1 on suspecting the coil, especially if it's a repop yellow top. I've had the exact same issue a couple times.
Title: Re: need your help with ideas on what could be wrong
Post by: propayne on August 14, 2020, 08:12:21 PM
Suck, bang, blow...
Title: Re: need your help with ideas on what could be wrong
Post by: trotrof1 on August 14, 2020, 08:25:03 PM
Are we talkin cars or the brothel .
Title: Re: need your help with ideas on what could be wrong
Post by: 557 on August 14, 2020, 08:33:24 PM
Both...
Title: Re: need your help with ideas on what could be wrong
Post by: csheff on August 15, 2020, 10:27:21 AM
Jeff I suspected the coil but it ck'ed ok, will get one and try first.
Title: Re: need your help with ideas on what could be wrong
Post by: shelbydoug on August 15, 2020, 10:39:35 AM
Coils can check good when cold. When the engine gets hot, they won't fire correctly. That's called an intermittent coil. You need to try a new coil to confirm. No other way to do it.
Title: Re: need your help with ideas on what could be wrong
Post by: Dan Case on August 15, 2020, 10:47:14 AM
Is the ignition switch okay? I had one fail internally once in a 1960s Ford. Was the last thing I checked.

Title: Re: need your help with ideas on what could be wrong
Post by: shelbydoug on August 15, 2020, 12:55:57 PM
Quote from: Dan Case on August 15, 2020, 10:47:14 AM
Is the ignition switch okay? I had one fail internally once in a 1960s Ford. Was the last thing I checked.

+1. They like to fail in the run mode. So the car will fire up but then die as you release the key into the run position.

There are no outward signs and all you can do is use the shop manual procedure to test the switch.

I just threw out three of them. One was a recent failure this year. Why I was keeping the others, don't know.

So I've had the car since 1972. It's on it's forth starter switch and only has 23,000 miles. I think it's time that is the factor but I should probably stop hitting them with the 40# sledge hammer.  ::)
Title: Re: need your help with ideas on what could be wrong
Post by: 67350#1242 on August 15, 2020, 09:36:59 PM
One more thing to check - tachometer.  The run circuit passes through it.  An open tach will cause similar problem. You will have spark during crank but goes away during run.  The tach can be bypassed by pulling the leads and plugging the 2 harness leads together.
Kurt.
Title: Re: need your help with ideas on what could be wrong
Post by: Drew Pojedinec on August 15, 2020, 11:06:39 PM
Quote from: shelbydoug on August 15, 2020, 10:39:35 AM
Coils can check good when cold. When the engine gets hot, they won't fire correctly. That's called an intermittent coil. You need to try a new coil to confirm. No other way to do it.

Have had the same issue with coil and other ignition components.
Driving fine and poof. Dead.
Fires fine cold dies hot.

Duraspark magnetic pickup would die this way too. Makes it hard to troubleshoot for sure.
Title: Re: need your help with ideas on what could be wrong
Post by: shelbydoug on August 16, 2020, 07:30:37 AM
Quote from: Drew Pojedinec on August 15, 2020, 11:06:39 PM
Quote from: shelbydoug on August 15, 2020, 10:39:35 AM
Coils can check good when cold. When the engine gets hot, they won't fire correctly. That's called an intermittent coil. You need to try a new coil to confirm. No other way to do it.

Have had the same issue with coil and other ignition components.
Driving fine and poof. Dead.
Fires fine cold dies hot.

Duraspark magnetic pickup would die this way too. Makes it hard to troubleshoot for sure.

This is largely a "coil in a can" issue. The newer style flame thrower boxes don't seem to have the issue but they stick out like a sore thumb on a "classic or period correct" set up.

It's no doubt shorting and grounding internally and maybe just boiling the oil in the can.

There are those that will claim the Ford yellow tops are the most dependable and you can't kill them. Then you will notice a box of them in the stash.


Some of these items are really ancient technology items. Like Shelby says "anything can happen. A blown gasket. A 5 cent washer."

Like with a Holley, a 008 o-ring goes and you could be on fire?


"You pays your monies and you takes your chances?"  ;)


My Ukrainian Grandmother would always say, "OYE DUGGIE!". Now THAT'S grassroots wisdom!
Title: Re: need your help with ideas on what could be wrong
Post by: csheff on August 16, 2020, 12:08:02 PM
Tried a new coil and still no start, seems like it wants to but no start. Going to have to dig a little deeper now. Will take no. 1 to TDC and go from there.
Where is the best place to buy the ignition switch that's correct? I will test that.  Trying everything  I can before tearing into motor.
Title: Re: need your help with ideas on what could be wrong
Post by: shelbydoug on August 16, 2020, 12:43:59 PM
Quote from: csheff on August 16, 2020, 12:08:02 PM
Tried a new coil and still no start, seems like it wants to but no start. Going to have to dig a little deeper now. Will take no. 1 to TDC and go from there.
Where is the best place to buy the ignition switch that's correct? I will test that.  Trying everything  I can before tearing into motor.

You have two choices on the switch. Motorcraft and Standard. Both I would say are very heavy duty and about equal. Either is still available from a standard auto parts store.

The only caution is that there is a difference between a '67 and a '68 switch. So just make sure you get the proper part for the application.

Make sure your connections are snug under the dash. I take out the ash tray and radio and just work through that space. That space is adequate.


You may want to take the coil wire out of the distributor cap and have someone turn the engine over. I always want to see the coil throwing the spark. Look out though. The spark hurts if it grounds through you. That I am highly experienced at. I had curly hair at one time. Now it's very straight.
Title: Re: need your help with ideas on what could be wrong
Post by: csheff on August 16, 2020, 05:41:23 PM
Doug, what is the difference between the 67 and 68?
Title: Re: need your help with ideas on what could be wrong
Post by: shelbydoug on August 16, 2020, 05:53:28 PM
Not entirely sure. I think there is an extra wire on the '68. I have both but haven't put them side by side.

Now you reminded me why I was saving the bad '68s. For comparison. It's on the list of things to do but you know what happens with lists?
Title: Re: need your help with ideas on what could be wrong
Post by: Krelboyne on August 16, 2020, 07:40:41 PM
1967 ignition switch would have a threaded stud on the back.
Title: Re: need your help with ideas on what could be wrong
Post by: JWH on August 16, 2020, 10:39:41 PM
I am sorry if I missed this in a previous post, but are you running points? Or Pertronix?
Title: Re: need your help with ideas on what could be wrong
Post by: csheff on August 17, 2020, 08:26:17 AM
JWH, I am running the dual points.
Title: Re: need your help with ideas on what could be wrong
Post by: sg66 on August 17, 2020, 12:52:59 PM
I've had the defective coil issue and trust you've confirmed they work on another motor?

One other thing to check is if you have any vacuum leaks. I had a rubber nipple blocking off a vacuum port on a Holley once that had dry rotted causing a similar experience. Visually everything appeared ok installed on the car and I only found it when I pulled the carb off to open it up and check inside.
Title: Re: need your help with ideas on what could be wrong
Post by: 67350#1242 on August 17, 2020, 02:16:26 PM
You can run a jumper from battery + to coil +.  Try to start then.  If it does the problem is ignition switch, bad tach, or open wiring from ignition to coil.  Don't let it run too long with the jumper.
Kurt
Title: Re: need your help with ideas on what could be wrong
Post by: JWH on August 28, 2020, 06:15:55 PM
Just checking in, any success getting the car back on the road? If so, what was the fix?   
Title: Re: need your help with ideas on what could be wrong
Post by: csheff on August 28, 2020, 09:59:24 PM
Not yet JWH, haven't had much time lately. Going to do some work on the car Sat.
Title: Re: need your help with ideas on what could be wrong
Post by: csheff on August 29, 2020, 01:46:43 PM
Ok, I have found by turning the car over, the dist. turns but I cannot feel the #1 piston come up. I thought gear on Dist but if it turns the gear is there. What am I missing?
Title: Re: need your help with ideas on what could be wrong
Post by: trotrof1 on August 29, 2020, 02:52:29 PM
So you have presumably eliminated fuel or spark as the problem so next  put a compression tester on it and see what pressure reading is. I cant imagine the piston not moving but you can carefully insert a wooden dowel or something similar into the plug bore and slowly turn the crankshaft by hand. When #1 piston is at the top of its travel check the timing marks on the dampener to see if at TDC. Then check to see if dist rotor is pointing exactly at # 1 on the cap. Might be 180 out so rotate crankshaft one time and recheck if necessary. I think the crank bolt is 15/16. Also when viewing the marks on the dampener rotate the crankshaft both directions and make note of how many degrees of movement free travel to see condition of timing chain. Just a process of elimination is all. Report back with your findings.
Title: Re: need your help with ideas on what could be wrong
Post by: Bob Gaines on August 29, 2020, 04:29:25 PM
A quick way to check for TDC without compression testors is to use finger or thumb over the spark plug hole as I am cranking the (more like tapping) and when the piston pushes compression out (should feel it and hear the woosh) I start to verify TDC by way of the harmonic balancer markings. Not that this way is better but typically faster to see if further more in depth evaluation is needed. If you rotate the engine and no compression from spark plug hole then you know that you definitely need more evaluation. Best of luck with solving your problem.
Title: Re: need your help with ideas on what could be wrong
Post by: csheff on September 01, 2020, 03:42:53 PM
Compression tested ok if 150 -180 is good. checked play in rotor again and noticed I could spin all the way around with a little force. Rotor is good and not cracked. Decided to remove points plate to look underneath. Things seemed to look good there. weights still in place. So is it possible the pin on gear on Dist. sheared?
Title: Re: need your help with ideas on what could be wrong
Post by: Greg on September 01, 2020, 03:53:44 PM
Quote from: csheff on September 01, 2020, 03:42:53 PM
Compression tested ok if 150 -180 is good. checked play in rotor again and noticed I could spin all the way around with a little force. Rotor is good and not cracked. Decided to remove points plate to look underneath. Things seemed to look good there. weights still in place. So is it possible the pin on gear on Dist. sheared?

Bingo, sounds like you found it.  Pull the distributor and look, you should not be able to spin the rotor button around if it is seated properly.
Title: Re: need your help with ideas on what could be wrong
Post by: trotrof1 on September 01, 2020, 04:01:04 PM
If you are saying that you can physically spin the dist rotor and the dist shaft rotates also, then yes pull the unit out and look at the gear on the shaft. I think a previous post noted a possible rollpin issue. I dont think a detached drive gear would fall off the shaft but just be gentle when pulling the dist out.
Title: Re: need your help with ideas on what could be wrong
Post by: KR500 on September 01, 2020, 07:26:37 PM
See reply #10
Title: Re: need your help with ideas on what could be wrong
Post by: csheff on September 01, 2020, 08:47:28 PM
Rodney, what thru me on Dist pin was it spun when being turned over. But won't be 100% until Dist was s pulled and looked at
Title: Re: need your help with ideas on what could be wrong
Post by: Greg on September 01, 2020, 10:14:23 PM
Quote from: csheff on September 01, 2020, 08:47:28 PM
Rodney, what thru me on Dist pin was it spun when being turned over. But won't be 100% until Dist was s pulled and looked at

Because the gear is press fit it would be possible for the button to turn, it just would not turn in sequence with the firing order therefore not allowing the spark plugs to fire at the appropriate time. 
Title: Re: need your help with ideas on what could be wrong
Post by: trotrof1 on September 01, 2020, 11:19:34 PM
I was just wondering during the crank no start condition did it want to pop back through the carb or want to stop abruptly? Or did it just sound normally just no start?
Title: Re: need your help with ideas on what could be wrong
Post by: Peter L. on September 02, 2020, 08:07:14 AM
  I had the same issue with a Boss 302. It turned out to be a bad factory tach. They run in series with the ignition system. Easy to check. Just unplug the tach and bypass it all together. Easy to check and eliminate as a possible cause.
Title: Re: need your help with ideas on what could be wrong
Post by: shelbydoug on September 02, 2020, 11:20:01 AM
Quote from: csheff on September 01, 2020, 03:42:53 PM
Compression tested ok if 150 -180 is good. checked play in rotor again and noticed I could spin all the way around with a little force. Rotor is good and not cracked. Decided to remove points plate to look underneath. Things seemed to look good there. weights still in place. So is it possible the pin on gear on Dist. sheared?

Yes. This is actually a fairly common failure on 351c's.

The reason being, that car uses rubber"umbrellas" instead of positive sealing valve stem seals.

With age, they dry out, become fragile and crumble into the oil which gets returned to the oil pan.

Eventually the oil pump sucks up enough of them to freeze  or bind up the drive gear while the engine is running.

The weakest link fails. Sometimes referred to as a fuseable link. That being the roll pins that hold the drive gear to the distributor shaft.


I've seen them just bent 90 degrees and not sheared. So probably the pump gear just bound up momentarily and cleared themselves enough. This will start a complaint about the engine "jumping timing".

The original oil pump drive shaft is a piece of hardened hex rod. I've seen  thm twisted like a licorish stick so in that case it worked as a fuseable link and twisted before the pins sheared.

People who race will tell you that they have seen the oil pressure gauge readings bounce around under high engine load. That can be attributed to the hex shaft twisting and bouncing back.

Once you go to a machined "molly" drive shaft it will no longer flex and you had better verify the integrity of the drive pins.



The other thing which COULD have significance is that the outer ring ON THE HARMONIC BALANCER, IF NOT BONDED, with age has a nasty habit of rotating 90 degrees on the hub. That's just little enough to keep the engine running, but "just a little funny".


Here's the question that will point you in the right direction on the balancer. Have YOU had the balancer rebuilt?  ;)
Title: Re: need your help with ideas on what could be wrong
Post by: csheff on September 02, 2020, 03:27:02 PM
trotrof1, I had no pop back thru the carbs, seemed like it wanted to start but just wouldn't.
Doug, THE HARMONIC BALANCER looks good from looking at it. But will know more when I get new pin though gear get it back in and try to fire up. And no on having the balancer rebuilt.

In the mean time my dist. has a C3 so must not be original one. Would original one be C5AF-12127-E? I would be interested in finding a correct one for the car with correct date if possible. Car was built Jan, 29th 67 So any date Nov, Dec, Jan?

Also when I get the correct Dist., if I have it re-curved what info do i need to set it too?
Title: Re: need your help with ideas on what could be wrong
Post by: csheff on September 02, 2020, 03:41:41 PM
Thanks Bob that is the plan
Title: Re: need your help with ideas on what could be wrong
Post by: csheff on September 05, 2020, 03:15:25 PM
Thanks everyone for your inputs.
Was a sheared pin on Dist gear. After a few brain farts it's running again. Just have to ck and adjust timing.
Title: Re: need your help with ideas on what could be wrong
Post by: Bob Gaines on September 05, 2020, 04:31:45 PM
Glad to hear that you solved the problem and reported back. Hopefully this thread will help others in the future who are searching for answers.
Title: Re: need your help with ideas on what could be wrong
Post by: trotrof1 on September 05, 2020, 05:16:49 PM
No substitute for hands on mechanical repair. Way better than just handing it off to a shop.
Title: Re: need your help with ideas on what could be wrong
Post by: Greg on September 05, 2020, 10:21:36 PM
Great job, a lot of satisfaction in diagnosing and fixing the problem.
Title: Re: need your help with ideas on what could be wrong
Post by: NC TRACKRAT on September 07, 2020, 04:55:32 PM
Hopefully, you found both pieces of the sheared pin?
Title: Re: need your help with ideas on what could be wrong
Post by: JWH on September 07, 2020, 07:15:35 PM
Quote from: Bob Gaines on September 05, 2020, 04:31:45 PM
Glad to hear that you solved the problem and reported back. Hopefully this thread will help others in the future who are searching for answers.

+1

Great to hear you are back on the road and nice work figuring it out.
Jeff