# Another timing issue, or is it.......



## 68greengoat (Sep 15, 2005)

Bear with me, this description may take awhle....
'73 455, .30 over, mild cam(no specs on the cam)

Initial problem, I wanted to fix a miss that I was hearing from both sides of the engine, both sides of the exhaust. Replaced plugs with A/C's, new cap/rotor, replaced vaccum lines, checked plug wires( I replaced them a few years back, Accel 8.8s), installed Pertronix III late last fall and have a Accel Super Coil(at least 7-8 years old). Ran a tank of gas thru it this spring. Running fine down the road just hear the miss in the lower gears. Not noticeable at highway speeds.

Decided to check the timing. In the past, earlier this spring, I timed it without a light. Advanced it until I heard pinging and backed it off until it stopped. Ran good until I would start it when hot. Backed off timing somemore until it started good. Timing was set way off the chart, well over 12deg, that's as far as the indicator goes. Seemed to run pretty good tho.

Today I went to time it with a light. Had put about 120 miles on today and started the timing procedure when I got home while the engine was still at operating temp. Pulled and plugged the vaccum line off dizzy, hooked up timing light on #1 cylinder and loosened the dizzy hold down bolt(normally loosen the bolt after the motor is running, not sure why I didn't this time). Dizzy never moved when the bolt was loosened. Went to start it and it would fireup and die instantly. What the heck... Thought the dizzy had moved, so I played around with that. Could tell when it was too advanced when it turned over hard and could also tell when I didn't have enough in it. 

Finally got it started. But it ran like crap and the tach was jumping all over the place. Kept reving it and it was popping but it finally cleared out and idled. Set the initial timing at 10deg and had to turn the idle up signifcantly to keep it running(1000rpms per manual). After reinstalling the aircleaner and reconnecting the vaccum line, idle increased to 1200, dropped it back to 1000. The missing seemed to have quit and it had a consistant lope.

Test drove it. Ran thru the gears and it seemed to take off fine. Punched it at 55 and it seemed to be doggy. Stopped and let it idle for about 5 mins, took off and the tach was jumping around and running rough. It cleared itself and ran fine. Did the same thing after I shut it down in the garage. After 5mins of sitting, had a tough time starting(turned over fine) and ran like crap until it "cleared out" again. Shut it off and to me smelled gassy.

Question:
1. Is 10 deg of initial timing correct for a "mild" cam, or should it be advanced more? Initial timing on this seems to make a difference on performance. Advance it too much and it seems to dog on the low end.

2. If the timing is alright, is the carb running too rich now and needs to be adjusted?

3. Any other thoughts?

Liked mentioned earlier, this all started when I retarded the timing a bunch from it's intial setting. Just a guesstimate 15deg plus. *Would being advanced so much cause the missing?......*

Sorry for the book. I just wanted to give you all the info I had to help me diagnose the problem......:willy:


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## Rukee (Feb 8, 2007)

Pull the cap and check the wires inside for the pertronix unit, sounds like it might be an issue. I'd at least check it out.


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## 66tempestGT (Nov 28, 2009)

sounds like crappy luck. timing wont cause it to flood. BUT why did you all of the sudden decide to check it. was it running rough before this. your timing wont just randomly get out of adjustment.


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## 66tempestGT (Nov 28, 2009)

sounds like trash in the carb. the carb also just doesnt all of the sudden get out of adjustment.


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## 68greengoat (Sep 15, 2005)

Rukee said:


> Pull the cap and check the wires inside for the pertronix unit, sounds like it might be an issue. I'd at least check it out.


I'll look at the wires tomorrow. Maybe a wire was rubbed bare.



66tempestGT said:


> sounds like crappy luck. timing wont cause it to flood. BUT why did you all of the sudden decide to check it. was it running rough before this. your timing wont just randomly get out of adjustment.


I checked it because I was having a noticebale miss on both sides of the motor. I thought having the timing set wrong could possibly cause this. Like I mentioned, it was advanced way more than the manual said it should be. It didn't do it by itself, it was done on purpose. Just thought that might be causing the miss and wanted to set it to specs to see if it helped. Set to specs it's tough at times to keepit running correctly.

I know the carb doesn't just go out of adjustment, but with the timing advanced so far I thought the extra fuel the carb may be putting out would be needed with that setup. Now that the timing is backed off, I thought a rich carb could pose a problem. I could be way off base on my thinking, that's why I posed the questions......

I just filled it with premium today too. Don't think that's the problem since this all happened when I was "about" to make some changes. It would have had to been impeccable timing, but in my world, that's entirely possible....


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## Rukee (Feb 8, 2007)

too far advanced will not cause a miss, just pinging and hard starting. A carb can not compensate for a rich or lean condition, it just runs what it's jet'ed for/at.
If you have a miss on both sides then I would be looking at the pertronix unit, distributor, plug gap or the coil first.


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## 66tempestGT (Nov 28, 2009)

After 5mins of sitting, had a tough time starting(turned over fine) and ran like crap until it "cleared out" again. Shut it off and to me smelled gassy.

its flooding


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## Rukee (Feb 8, 2007)

66tempestGT said:


> After 5mins of sitting, had a tough time starting(turned over fine) and ran like crap until it "cleared out" again. Shut it off and to me smelled gassy.
> 
> its flooding


Who's car are we talking about here?? 66tempestGT's car? Or 68greengoat's GTO?


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## 68greengoat (Sep 15, 2005)

66tempestGT said:


> After 5mins of sitting, had a tough time starting(turned over fine) and ran like crap until it "cleared out" again. Shut it off and to me smelled gassy.
> 
> *its flooding*


I haven't looked into it yet, but I must have impeccable timing. I wonder if something happened on my way home b/4 I started making adjustments. Float sticking? It runs fine on the road, just not so good when I shut things down and try to start it again. Maybe the float isn't closing?
Just popped the hood and smell nothing in the carb. I know when my lawnmowers float sticks open it floods the carb .


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## 66tempestGT (Nov 28, 2009)

"In the past, earlier this spring, I timed it without a light. Advanced it until I heard pinging and backed it off until it stopped. Ran good until I would start it when hot. Backed off timing somemore until it started good."

this is a very reliable way to set the timing. its not a bad idea to look inside the distributor cap to make sure everything is ok, but ignition problems rarely "clear up" when you raise the rpms. possibly a small piece of trash in the needle and seat holding the float open slightly. my dad would take a small hammer and peck on the carb some to try and dislodge it. LOL


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## Too Many Projects (Nov 15, 2008)

Troy, the new Pertronix III is made for a certain ohm coil, like .032, or something and I doubt the old Accel coil is a good match. You may be damaging the Pertronix with it. Go online to Pertronix and look at the Flame Thrower III coil and see what ohms it runs at to match the Ignitor and then check the coil specs. And be sure the dizzy is grounding, I remember them stressing that as very important. I just installed the same conversion in my Camaro and can't get a coil for it. Pertronix got a bad batch from the Chinese screwballs and sent them all back. It will be May before I can get a proper coil.....


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## 68greengoat (Sep 15, 2005)

Too Many Projects said:


> Troy, the new Pertronix III is made for a certain ohm coil, like .032, or something and I doubt the old Accel coil is a good match. You may be damaging the Pertronix with it. Go online to Pertronix and look at the Flame Thrower III coil and see what ohms it runs at to match the Ignitor and then check the coil specs. And be sure the dizzy is grounding, I remember them stressing that as very important. I just installed the same conversion in my Camaro and can't get a coil for it. Pertronix got a bad batch from the Chinese screwballs and sent them all back. It will be May before I can get a proper coil.....


I believe the coil I'm running now is this:
ACCEL 140001 - ACCEL Super Coils - Overview - SummitRacing.com at least it looks just like this. I can't verify if it has any manufactor's number on it since the car is not in my garage.. It's sitting at a mechanics garage who works out of his house. I've had it there before. I though I had it fixed after I got it running and beat on the carb with a hammer yesterday, well not exactly that drastic, to free a sticky float. Put 40 miles on, everything worked fine, let it sit for awhile and started it fine again. Today started fine, ran for 10mins on a fast idle. Out of nowhere, it started missing. Picked the kid up from school and I had a tough time keeping it running while sitting. Backfiring like crazy. Got back on the road, ran fine, drove to the mechanics, idled fine for quite awhile, then started missing again. He said it was pouring gas into the carb. It was backfiring thru the carb, out the exhaust, you name it. 

It's so bad now that it wont clear out. Let it sit for a few hours to get new plugs since they were soaked, installed them, tried starting it, backfired instantly and runs way too rough to attempt to drive. I would have thought sitting there for a few hours and new plugs it should have run good for 30 seconds anyway. Checked the plug wires for the 3rd time, everything seems to be in the right place.

I thought after sitting so long and popping like it still is that maybe the coil is going bad? Timing chain skip? Or maybe, it's just loading the carb with fuel that much.

I'm getting a flatbed tomorrow to bring it to another mechanic who works on old cars on a regular basis and loves Q-jets and thinks they're the best carb since sliced bread. He rebuilt the carb 6 years ago or so. He also said the pertronix modules are good units. 

Where the car sits today, he thinks q-jets are junk. Wants me to ditch it and put a Holley on. That aint happenin'...

Frustration level is constantly rising........

Thanks for the info Mitch, I'm going to take it with me tomorrow.....


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## Too Many Projects (Nov 15, 2008)

90% of the time backfiring is an electrical/ignition problem. Carb flooding will just drown the engine.


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## 68greengoat (Sep 15, 2005)

Tell ya what Mitch, I agree, to me it seems to be more than just a carb issue. Although, that still may be part of the problem.....


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## Rukee (Feb 8, 2007)

Drag it over here, I'll fix it for you.


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## 68greengoat (Sep 15, 2005)

Wish I could, Ruk. Wish I could........


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## 68greengoat (Sep 15, 2005)

Too Many Projects said:


> Troy, the new Pertronix III is made for a certain ohm coil, like .032, or something and I doubt the old Accel coil is a good match. You may be damaging the Pertronix with it. Go online to Pertronix and look at the Flame Thrower III coil and see what ohms it runs at to match the Ignitor and then check the coil specs. And be sure the dizzy is grounding, I remember them stressing that as very important. I just installed the same conversion in my Camaro and can't get a coil for it. Pertronix got a bad batch from the Chinese screwballs and sent them all back. It will be May before I can get a proper coil.....


The coil rating is supposed to be .32 ohms or greater. That Accel super coil should do the trick if it hasn't gone bad. Like you mentioned, could be a ground wire. Whatever it is, it's getting worse and worse. Like I mentioned, it's not even driveable at this moment... Need to call the "guy" with the flatbed. $$


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## Too Many Projects (Nov 15, 2008)

You get anywhere with this ?


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## 68greengoat (Sep 15, 2005)

Hey Mitch,
It's at the shop right now. Last I heard, he can't look at it until tomorrow. Had it towed last Friday. He has to get a motor in a 'Stang first, then he can dig into mine. It's a tranny shop that does general mechanical work too for any year car. They rebuilt my tranny about 6 years ago. I trust him. He's been around old cars for many years. Will update when I find something out or it's fixed....


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## geeteeohguy (Feb 2, 2008)

I agree, Rukee. I'd love to have a look at it myself. Gas fouled plugs tell me that there is at least a carb issue. It may have ignition/timing/issues as well. I have experienced very over-advanced timing producing misfire and rough running. It can also damage an engine. When the plug fires the mixture and the piston is still on it's way up the bore, bad things happen. 10 degrees BTDC base timing would be the MAX I'd want to run on this engine. More like 8 degrees BTDC. Has anybody stuck a vacuum guage on this thing to see if there are valve issues???


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## 66tempestGT (Nov 28, 2009)

it will be interesting to see the outcome. gassy plugs makes me think carb. backfire out exhaust says ignition. backfire through carb valve timing or crossed wires or ??????. good luck. i hope you find something simple, or at least cheap. :cheers


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## Too Many Projects (Nov 15, 2008)

Back-fire thru carb.........flat exhaust cam lobe from new, junk, oil.....


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## jetstang (Nov 5, 2008)

Your needle and seat in the carb are junk/sticking. You hit it with a hammer and it seated and ran great. Then it hung up again and is running bad, hmm, same issue, needle and seat. Rebuild the carb or swap on a good one.
If it ran good, then bad, then good in the same configuration and you didn't change anything, it's not timing, or misrouted wires. It's probably carb. May be timing jumped or burnt valve. May be old nasty gas, is it fresh gas? Likely there is a bunch of crap in your tank that got to the carb.
I'm pretty sure Protronix stole all there ideas from the major manufacturers, so I assume an Accel coil will work fine. Backfires kill powervalves on Holleys, what do they do to Q-junks? 
When you turn the car off if smoke comes out the top of the carb, the needle and seat is leaking, any smoke indicates a leak.


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## 68greengoat (Sep 15, 2005)

geeteeohguy said:


> I agree, Rukee. I'd love to have a look at it myself. Gas fouled plugs tell me that there is at least a carb issue. It may have ignition/timing/issues as well. I have experienced very over-advanced timing producing misfire and rough running. It can also damage an engine. When the plug fires the mixture and the piston is still on it's way up the bore, bad things happen. 10 degrees BTDC base timing would be the MAX I'd want to run on this engine. More like 8 degrees BTDC. Has anybody stuck a vacuum guage on this thing to see if there are valve issues???


I don't think at 10 deg it's over timed. I was running it way advanced than it is now and had no problems. Like was said by Ruk earlier, when it was too advanced, it turned over hard. I backed it off until it started good and no pinging. That left the timing advanced off the indicator. Indicator goes to 16deg. _It has a mild cam for whatever that is worth._ When I timed it to 10 deg I had to really crank in the idle screw to idle at 1000rpms which is spec for that motor. I past a certain point where it's bypassing something, beyond a secondary something maybe? I understood what the mechanic was saying didn't understand the terminology. Basically, one of the reasons it's dumping a bunch of fuel in the carb is because the idle screw is turned in so far. It thinks the car is doing 50 when in reality it's just supposed to idle. I shouldn't have to crank the idle screw in so far. So, something is causing that issue.
I put a vaccum gauge on the line at the dizzy. No vaccum. Which is good unless the line is coming from a port with constant vaccum. Some on this forum have recommended doing that for full advance right away if I remember, 1 mechanic didn't. :willy: Didn't talk about it with the current mechanic..
Checked a line from the carb to the intake, disconnected at intake. 10 psi at idle, 18psi at full advance. That's all I've done......



66tempestGT said:


> it will be interesting to see the outcome. gassy plugs makes me think carb. backfire out exhaust says ignition. backfire through carb valve timing or crossed wires or ??????. good luck. i hope you find something simple, or at least cheap. :cheers


It's backfired from both. Mainly exhaust(alot). Checked wires 3 times. Had a second set of eyes the last time. Wires are good. Basically, little or no response from throttle at this time. Tough to keep it running. Put in new plugs, cap, rotor this spring.



Too Many Projects said:


> Back-fire thru carb.........flat exhaust cam lobe from new, junk, oil.....


Ran good all day(a week or so ago), 100 + miles. Tried starting to adjust timing while still hot, start, die, start, die etc........ All these issues started b/4 I made any adjustments. Cam could have crapped out. Changed oil this spring with Rotella 15w-40.
Problem got worse and worse as time has gone on to the point where I'm at today.



jetstang said:


> Your needle and seat in the carb are junk/sticking. You hit it with a hammer and it seated and ran great. Then it hung up again and is running bad, hmm, same issue, needle and seat. Rebuild the carb or swap on a good one.
> If it ran good, then bad, then good in the same configuration and you didn't change anything, it's not timing, or misrouted wires. It's probably carb. May be timing jumped or burnt valve. May be old nasty gas, is it fresh gas? Likely there is a bunch of crap in your tank that got to the carb.
> I'm pretty sure Protronix stole all there ideas from the major manufacturers, so I assume an Accel coil will work fine. Backfires kill powervalves on Holleys, what do they do to Q-junks?
> When you turn the car off if smoke comes out the top of the carb, the needle and seat is leaking, any smoke indicates a leak.


Gas is fresh premium. Accel coil should work fine. Plenty of umph for the Pertronix module. I love my Q-junk. So does the guy working on it....

Plugs were red when I changed them. One indication of ash deposits that CAN be caused by gas additives. I used 16oz of Maximum 104 octane boost per tank of fuel last fall. Tank wasn't completely empty when I would refill and add more boost. Maybe way too much boost had accumulated. It is my understanding that octane boosters are tough on a fuel systems. From erroding coatings in the tank which dislodges particles that can plug a carb to rubber fuel lines to the carb itself. Needless to say, I'm not going to use them anymore.

I'm "hoping" all I need is a rebuilt carb and maybe a new coil or even a dizzy. 

I appreciate everyones input and will post up what they find. May sneak down there today and see if they've started looking into it. I need to get 50# of birdseed out of the trunk anyway...:lol:


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## 66tempestGT (Nov 28, 2009)

did it only start backfiring after you changed the plugs? you know the distributor on a pontiac turns counterclockwise. opposite of a chevy. just throwing that out there.


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## 68greengoat (Sep 15, 2005)

Welllllllll, the mechanic just called. Car is done, being fixed that is. Nothing major! Whew... Turns out to be a bad wire supplying power to the coil. It was getting intermittent power. Carb is fine. Vaccum advance wasn't working, so he replaced that. Mechanical advance was the only thing working. They timed it to 10deg. I'm getting 39deg total now. Sounds like it was alot less with the vaccum not working. I'm going to find out what rpm the total timing is coming in. I'm gessing once the vaccum advance was fixed they could time it properly and were able to back way off on the idle screw and eliminating the flooding of gas...

I'm sooooo glad it was something simple. If I had the car at home when it basically stopped running, I "might" have been able to track the bad wire down myself. But, since it wasn't, I didn't want to pay for 2 tows if I couldn't find it.. Electrical issues can be a pain in the rectum. Amazing how much hassle it caused..........

Time to go get her......

Thanks again to all.....:seeya:


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## geeteeohguy (Feb 2, 2008)

Hope that does it. The vacuum advance on your engine SHOULD be hooked up to direct manifold vacuum, not ported. The engine should slow sown with the line disconnected and speed up with it connected. It was engineered that way to let the engine run advanced (and cool) at idle speed. The fact that yours was non op, and maybe hooked up wrong, would be one reason the carb took so much idle screw to set the idle speed. Good luck! Also, engine vacuum is normally read as inches of Mercury, or hg. Sometimes kilopascal's. You should have at least 14-15 inches of vacuum at idle with a mild cam. Stock engine, 18-20 inches. Low vacuum can be a sign of other internal issues. Hope it runs great for you!!!!


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## 68greengoat (Sep 15, 2005)

Yeah, the psi was a shot in the dark. I didn't feel like going out and looking at the gauge to be sure. Just found the gauge after 30 years!

Unless they changed it, the VA was hooked to the carb and not the manifold. If it's still the same, will ask them about it. But, if they're good mechanics they should have changed it on their own. I was told, by the 1st mechanic where the car died, the manifold vacuum was connected to a vacuum port on the carb. Vacuum to vacuum.

When I take a reading, should I connect the gauge to the manifold and not the carb? Or, does it matter? If the line going to the dizzy is from the carb, should I move the line to the manifold and plug the carb port?


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## 68greengoat (Sep 15, 2005)

Car's back. They did a bunch of vacuum work. Basically, closing off a bunch of fittings. Took out a vacuum connection on the manifold, plugged it and plugged the fitting on the carb so I don't have a line going from vacuum to vacuum anymore. All that's left is the line from the PCV to carb and carb to dizzy..... 10deg initial/39deg total, all in at 2000rpms.

Seems to run great. Going to put some miles on it today, just because.....


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## geeteeohguy (Feb 2, 2008)

Manifold vacuum is just a term. It is vacuum that you can feel with your finger over the end of the hose with the engine at IDLE. (PCV is an example). It does NOT have to be a hose connected to the manifold....it can also be connected to the carb, valley pan, or elsewhere. The carb has fittings that are BOTH manifold vacuum (At or below the throttle plates) and Ported vacuum (Above the throttle plates). Ported or venturi vacuum increases as the engine is speeded up. Manifold vacuum DECREASES as the engine is sped up off of idle. Most all Pontiacs use manifold vacuum to supply the vacuum advance on the dizzy to help keep the engine cool at idle in traffic, etc. The manifold vacuum supply source on my '67 with Q-jet is on the drivers side of the carb, at the front. Yours should be the same.


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## 68greengoat (Sep 15, 2005)

Thanks for the Vacuum 101 Course. Hopefully, others are learning too at my expense.
Yep, I'm set up the same as yours.......
Thanks for all the info, Jeff..... Have you been doing any of this??!!


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## Too Many Projects (Nov 15, 2008)

Glad it was something simple. I had a strong feeling it was electrical. There was a car on the dyno last year at the Camaro Club meet that started backfiring bad and I advised him to get off and find the electrical problem, he didn't listen and it damn near blew the blower and dual quads off before it quit completely. He thought he blew it up. Turned out to be the master cutoff switch on the tail light panel was bad and arching, supplying intermittent power to the ignition....


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## 68greengoat (Sep 15, 2005)

Too Many Projects said:


> *Glad it was something simple*. I had a strong feeling it was electrical. There was a car on the dyno last year at the Camaro Club meet that started backfiring bad and I advised him to get off and find the electrical problem, he didn't listen and it damn near blew the blower and dual quads off before it quit completely. He thought he blew it up. Turned out to be the master cutoff switch on the tail light panel was bad and arching, supplying intermittent power to the ignition....


Thanks Mitch, that makes 2 of us. First issue I had with the motor in the 7 years I've owned it. Guess I can't complain.......


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