[67drake]

I have a ‘69 400 in my ‘63 LeMans. The car has the original transaxle. I had it running pretty good this summer after I took a junk Quadrajet off and replaced with a known good one.
A few months ago it started to die when I would come to a stop. It was acting as if it had a vacuum leak. I went through a couple cans of carb cleaner spraying the intake and carb areas while it was running. I had a buddy bring a smoke machine over last night and no leaks found. Not even in the long vacuum line that runs back to the transaxle.
Timing is set at 9 BTDC , which is factory setting. Timing mark rock solid, no mechanical advance at idle.
I can turn the idle screw up and up, and it will still die when I put it in drive. When it was running well, I could have the RPM at about 850 in park, and it would drop down to 650 in drive and idle all day. Now I can have idle way up at 1100 in park, and will still die when put in gear.
Just checked A/F mixture screws at it’s got 15-16 on vacuum gauge at idle.
So what next? Bad torque converter? Rebuild a Cliff carb? No problem but I hate to get into this without knowing exactly what the problem is, I’m just guessing at this point.

[steve25]

With it idling out of gear drop the idle speed down to 650, does it still die then?

Is this a HEI or points type?

[67drake]

Pertronix

[67drake]

Originally Posted by steve25

With it idling out of gear drop the idle speed down to 650, does it still die then??

Next time I’m out there in the garage I’ll try that.

[sdbob]

Im Old fashion points and condenser. I can fix those. Electronics I dont know.

[67drake]

Originally Posted by sdbob

Im Old fashion points and condenser. I can fix those. Electronics I dont know.

Yeah, that’s what I run on my GTO, but the Pertronix was on the car when I bought it last year. Maybe if I get the bugs worked out I can get to things like that.

[b-man]

Maybe put a set of points in the distributor and see if the Petronics might be going bad.

Wouldn’t be the first time.

Personally I’d never trust one of those things.

[Kenth]

Originally Posted by 67drake

Yeah, that’s what I run on my GTO, but the Pertronix was on the car when I bought it last year. Maybe if I get the bugs worked out I can get to things like that.

Pertronix IS the bug.

At least check for full battery voltage to + on ignition coil when running. (Same voltage as at battery posts).

[67drake]

Is it possible that a Pertronix failure could act like my symptoms? If so, that would be OK by me as I was going to pull the distributor in the off-season to have it recurved anyway, as I’m living on the edge of detonation with this high compression engine.

[67drake]

So, sent my distributor off to my rebuilder. He started work on it last night and noticed two issues right off the bat. A ground wire is missing between the breaker plate and distributor housing, and the mechanical advance stop bushing is gone.
I was having detonation issues at WOT, as well as the erratic idle/stalling I mentioned earlier.
He’s eliminating the Pertronix and going back to breaker points for me.
His pictures aren’t the greatest, but figured I’d post them.

[steve25]

A electronic conversion does not need a grounded plate so that was not the cause of your cutting out in gear, it is needed for points though.

[HWYSTR455]

Run more initial timing, problem solved.

I know you said you turned the idle up and still had the problem, but just to say it out loud, an aftermarket cam throws the factory settings right out the window. Makes no sense to me when people run the factory initial timing with an aftermarket cam.

Factory ran manifold vacuum for many years before emissions came into play, but people still swear by using ported vacuum too. Again, makes no sense to me.



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[chuckies76ta]

Run more initial timing, problem solved. That's exactly what I was thinking. And very easy test to do. If you do run more Initial, just be aware that it will increase your total timing if you do not adjust your mechanical timing.

[HWYSTR455]

Also kills me: People say they send their' distributors off to be 'tailored to my config', or 'back to factory original'. Both will most likely never get you where you need to be, every car is different, and you have to do it yourself, using trail & error method.

Another: 'I sent it to a guy who has a machine' . Uhg. So what, it will be a well-documented poor setup.

Anyone can do it themselves using only a timing light. 4 areas, initial, total, and rate of advance. Then you add vacuum.

Use graph paper, create a graph with timing on one side in 5 degree increments and RPM along the bottom in 500 RPM increments.

With the light, measure timing from idle to about 3500 RPM, in 500 increments and put dots on the chart. Drive it, and note performance and where any issues may appear in the RPM range. Then adjust.

Pontiac iron head engines like about 32 degrees max, all in around 2500-3200, start there.

You can determine max mechanical advance by removing the springs, and blipping the throttle to see what the reading is.



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[67drake]

Gee, thanks guys.
Not my first rodeo.
Having detonation problems also. Advancing timing just aggravated the detonation on WOT.
I also had a hell of a time sourcing heavy factory springs to slow down the mechanical timing curve. I was more or less just updating an old thread I started. This is the street section also, not everyone has the fantastic talents you possess.

[HWYSTR455]

If you advance initial timing, you have to limit total timing.


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[HWYSTR455]

You don't have to use the factory springs, there are tons of kits out there.

The weights play a part in total timing too. PM Sun Tuned, he has all the correct parts, and is a wealth of knowledge.


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[67drake]

I had already thrown a set of heavy springs in it from an aftermarket kit.

[HWYSTR455]

https://www.motortrend.com/how-to/se...l-performance/

[HWYSTR455]

Originally Posted by 67drake

I had already thrown a set of heavy springs in it from an aftermarket kit.

You won't be able to limit total timing with heavier springs, it only slows reaching the total timing.

So start with initial timing, then total timing, then rate (springs).

Start with 12 initial, then take the springs completely off, start it, blip the throttle while looking at the timing with a light, see what total is. Keep adding different bushings until you get to @ 32 degrees.

Then put the springs on and check what RPM the total is reached with the light. If it's reaching all the timing before 2500, change the springs until it does.

12 - 32 = 20, So you need to limit the distributor mech advance (bushing) to 20 degrees.

I'm not pointing at anyone here, and I post sometimes for other's as well, not just the original poster.


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