Tuning Woes

[tharrold 10]

I apologize if this is a basic question...but I have been searching the forums for quite some time, and it's now time to ask for some help.

 

I have a '69 Automatic, with a 302, no AC.

 

I've always been able to hear an occasional cylinder miss when idling, and the exhaust has always had a strong smell (I assume that means I've been running a bit rich).

 

Now, this is the year to finally do that full tuneup...

 

Bought a Pertronix ignitor, and installed. Went well, no apparent issues.

Didn't seem to help with the miss, but car ran fine initially.

 

Bought cap, rotor, plugs, wires, fuel filter. All basic stuff, right?

 

After changing all of the above (gapped plugs to .040), car starts fine, but dies in reverse or drive (low idle, under load)

 

OK, so out comes the timing light and tach.

 

Checked timing - WOW, way off - not even on the scale.

 

Found TC, and made sure my balancer hadn't moved, or timing chain jumped, etc. (I had replaced timing chain about 5000 miles ago, so I doubt it was the crappy factory gears).

 

Set timing to 10BTC.

 

HUGE steady misfire at high RPM only. still idles fairly smooth.

 

Checked compression. All cylinders at about 130, but 5 and 6 were at 120. All seemed to hold compression, no slow leak.

 

Checked carb vacuum - 17-18", very steady.

 

Noticed carb is leaking a small amount of oil on the passenger side. tightened carb a bit. Again, manifold vacuum was good, so not sure if that is a major issue right now. (assume oil is from pcv...)

 

So, here I am. Car fires up fine, idles good. After it warms up, I set idle to 950, set timing to 8BTC, and then put it in drive...it LOOKS like it would be idling at about 600 in drive before it starts to sputter and die.

 

One thing - I noticed that with the timing light on, and rev'ing to 3-4000RPM, the timing seems to increase, but only to about 12BTC. Shouldn't it jump to about 30-34?

 

Could I be looking at a vacuum advance issue? It's not manifold vaccum, so mechanical?

 

Am I adjusting things in the wrong order? I always assumed you set high idle, adjusted timing, then worried about low idle...

 

Please...any thoughts or suggestions are appreciated.

 

Thanks in advance.

:oops:

[tharrold 10]

I apologize if this is a basic question...but I have been searching the forums for quite some time, and it's now time to ask for some help.

 

I have a '69 Automatic, with a 302, no AC.

 

I've always been able to hear an occasional cylinder miss when idling, and the exhaust has always had a strong smell (I assume that means I've been running a bit rich).

 

Now, this is the year to finally do that full tuneup...

 

Bought a Pertronix ignitor, and installed. Went well, no apparent issues.

Didn't seem to help with the miss, but car ran fine initially.

 

Bought cap, rotor, plugs, wires, fuel filter. All basic stuff, right?

 

After changing all of the above (gapped plugs to .040), car starts fine, but dies in reverse or drive (low idle, under load)

 

OK, so out comes the timing light and tach.

 

Checked timing - WOW, way off - not even on the scale.

 

Found TC, and made sure my balancer hadn't moved, or timing chain jumped, etc. (I had replaced timing chain about 5000 miles ago, so I doubt it was the crappy factory gears).

 

Set timing to 10BTC.

 

HUGE steady misfire at high RPM only. still idles fairly smooth.

 

Checked compression. All cylinders at about 130, but 5 and 6 were at 120. All seemed to hold compression, no slow leak.

 

Checked carb vacuum - 17-18", very steady.

 

Noticed carb is leaking a small amount of oil on the passenger side. tightened carb a bit. Again, manifold vacuum was good, so not sure if that is a major issue right now. (assume oil is from pcv...)

 

So, here I am. Car fires up fine, idles good. After it warms up, I set idle to 950, set timing to 8BTC, and then put it in drive...it LOOKS like it would be idling at about 600 in drive before it starts to sputter and die.

 

One thing - I noticed that with the timing light on, and rev'ing to 3-4000RPM, the timing seems to increase, but only to about 12BTC. Shouldn't it jump to about 30-34?

 

Could I be looking at a vacuum advance issue? It's not manifold vaccum, so mechanical?

 

Am I adjusting things in the wrong order? I always assumed you set high idle, adjusted timing, then worried about low idle...

 

Please...any thoughts or suggestions are appreciated.

 

Thanks in advance.

:oops:

[MikeStang 247]

If it's only going up a few degrees, I would take a vac pump and hook to vac advance, start the car, then pump the vac pump a few times and check timing again and see what total is....almost sounds like vac advanceis shot, or the dizzy is messed up...try that,then take some carb spray and squirt it around the carb base and the manifold, if motor idles up, you found your culprit...

[MikeStang 247]

If it's only going up a few degrees, I would take a vac pump and hook to vac advance, start the car, then pump the vac pump a few times and check timing again and see what total is....almost sounds like vac advanceis shot, or the dizzy is messed up...try that,then take some carb spray and squirt it around the carb base and the manifold, if motor idles up, you found your culprit...

[Max Power 74]

Is your vacuum advance hooked up to a ported source?

[Max Power 74]

Is your vacuum advance hooked up to a ported source?

[Mister69 10]

Even with the vacuum hooked up wrong or disconnected you should still see more advance than 2 degrees. I'd check the mechanical advance to make sure the everything is moving freely.

[Mister69 10]

Even with the vacuum hooked up wrong or disconnected you should still see more advance than 2 degrees. I'd check the mechanical advance to make sure the everything is moving freely.

[danno 128]

You can check the vacuum advance easily with your mouth. Put the hose that goes to the carb in your mouth and suck on it, you should see the timing change, it takes that little of a vacuum.

 

But the mechanical is the issue. You should have 20 to 30 degrees advance at higher revs. The weights are under the pickup plate in the disti, take it apart and see if you can see a problem. You might take the whole disti out of the engine and look at the gears as long as you are at it. Just remember exactly where it was pointed when you take it out so you can put it back in the same place.

[danno 128]

You can check the vacuum advance easily with your mouth. Put the hose that goes to the carb in your mouth and suck on it, you should see the timing change, it takes that little of a vacuum.

 

But the mechanical is the issue. You should have 20 to 30 degrees advance at higher revs. The weights are under the pickup plate in the disti, take it apart and see if you can see a problem. You might take the whole disti out of the engine and look at the gears as long as you are at it. Just remember exactly where it was pointed when you take it out so you can put it back in the same place.

[tharrold 10]

UPdate:

 

Mechanical advance seem to go to 14 degrees.

 

vacuum advance diaphram is shot - can suck air through it, it won't hold a vacuum.

 

Will replace that and go from there...

 

Can you buy a replacement diaphram, or do I need a whole new distributor?

 

 

Thanks.

[tharrold 10]

UPdate:

 

Mechanical advance seem to go to 14 degrees.

 

vacuum advance diaphram is shot - can suck air through it, it won't hold a vacuum.

 

Will replace that and go from there...

 

Can you buy a replacement diaphram, or do I need a whole new distributor?

 

 

Thanks.

[tharrold 10]

BTW, forgot to thank you guys for the suggestions. You were right on.

 

Danno, what should mechanical advance provide? I've got the distr. out, and apart, but not the pickup plate. it seems to move pretty freely. Should it be lubed?

 

BTW, the damn screws holding the diaphram - heads broke off. Now I'm trying to drill them out, as clean as possible, so I can re-tap and get the new diaphram on.

 

What a PITA. Any suggestions as to whether I should keep the factory distr. or just stop now and buy a new one?

 

Thanks.

[tharrold 10]

BTW, forgot to thank you guys for the suggestions. You were right on.

 

Danno, what should mechanical advance provide? I've got the distr. out, and apart, but not the pickup plate. it seems to move pretty freely. Should it be lubed?

 

BTW, the damn screws holding the diaphram - heads broke off. Now I'm trying to drill them out, as clean as possible, so I can re-tap and get the new diaphram on.

 

What a PITA. Any suggestions as to whether I should keep the factory distr. or just stop now and buy a new one?

 

Thanks.

[tharrold 10]

Update: Found that O'Reilly had a rebuilt distributor in stock. At only about $45, it seemed silly not to just buy the whole unit. It was motocraft, not Autolite, but it seems to be a pretty close fit. Had some issue getting the Pertronix module to fit with the right gap, but it is installed, an I now have vacuum advance!

 

Should the vacuum advance stop advancing at 30-35 degrees? It seems to go off of the scale when I rev the engine.

 

I'm about to take a test drive, and see how it runs.

 

Quick question if any of you are still reading - what is the suggested order for tuning a 302? I always thought:

 

1) high idle

2) timing

3) back to high idle

4) re-check timing

5) check low idle in drive

 

Any words of wisdom?

 

Thanks again,

 

-tjh

[tharrold 10]

Update: Found that O'Reilly had a rebuilt distributor in stock. At only about $45, it seemed silly not to just buy the whole unit. It was motocraft, not Autolite, but it seems to be a pretty close fit. Had some issue getting the Pertronix module to fit with the right gap, but it is installed, an I now have vacuum advance!

 

Should the vacuum advance stop advancing at 30-35 degrees? It seems to go off of the scale when I rev the engine.

 

I'm about to take a test drive, and see how it runs.

 

Quick question if any of you are still reading - what is the suggested order for tuning a 302? I always thought:

 

1) high idle

2) timing

3) back to high idle

4) re-check timing

5) check low idle in drive

 

Any words of wisdom?

 

Thanks again,

 

-tjh