Timing/Ignition questions.

[Fredensborg]

Vacuum leak or idle screw adjustment.

I looked all over, and I'm almost certain there are no vacuum leaks. Every available vac port has something plugged in, or it is capped off. I will start looking at the idle adjustment business as you and Mister 4x4 suggested. Now I have to wait till one of my little helpers gets home from school to man the gas pedal for me!?

 

[Don C]

Turn the idle adjustment screw in until it will run, then begin the idle mixture screw adjustment process as outlined by Eric.

 

[Fredensborg]

Stupid question.... should the nipple on the vac advance on the distributor be close to straight, drivers side, or passenger side when timing is "close".

 

[Don C]

Stupid question.... should the nipple on the vac advance on the distributor be close to straight, drivers side, or passenger side when timing is "close".

It could be any place, depending on how it was "clocked" the last time the distributor was installed.

A timing light is the only way to tell.

 

[Mister 4x4]

It really kind of depends on how the distributor was clocked when it was installed.  If it was dropped in originally toward the driver side, then it might wind up closer to the center as you advance the timing.  If it was in the middle, and you need to advance the timing it'll wind up closer to the passenger side.  If you wind up with nowhere to go (and haven't gotten to the sweet spot yet), you might need to pull the distributor and re-clock it in order to have enough adjustability.  I'd wait until you find out if you hit the limits of adjustability before worrying about having to do that.

Pushing/rotating it toward the driver side [if it's in front] is basically turning it counter-clockwise, which will 'retard' the timing (bring it close to TDC and into "After TDC" numbers).  Pushing it toward the passenger side is clockwise, is advancing the timing, and will increase the number of degrees "Before TDC," which is the normal side of things.  The area of 14-16* BTDC is what you're shooting for, and which will feel like the sweet spot once you get all of the other settings closer to where they need to be.

You can cycle the throttle by pushing the top of the linkage plates back toward the firewall yourself... or wait for the little helper so they get a chance to have some fun helping Dad.     ::thumb::

Hope that helps!

 

[Mister 4x4]

Stupid question.... should the nipple on the vac advance on the distributor be close to straight, drivers side, or passenger side when timing is "close".

It could be any place, depending on how it was "clocked" the last time the distributor was installed.

A timing light is the only way to tell.

Ya beat me to it, Brutha!  Well done!  ::thumb::

 

[Fredensborg]

Well, I checked the timing while it was running at around 2000-2500 rpm and it was way high. Like 24° or so BTC. But that was with the vac line to the distrib still hooked up, so that was advanced timing probably?

I get it running, adjust the idle arm screw as low as it goes (and stays running), then you are supposed to adjust the mixture screws in until it starts to falter correct? I've backfired this baby a few times here, I hope I'm not wreaking anything!

 

[Mister 4x4]

The distributor is 'curved' to advance the timing even further as the rpms rise (that's part of where the vacuum comes in, along with centrifugal force fighting against the internal springs).  Chances are, you're probably not far off, but you can't be sure until you get the idle down to 750-ish, and can put a timing light on it to set it properly.

You won't wreck anything - you're on the right track.  Remember - subtle changes... don't take any big swings at it.  Bring it all down gradually, and you'll have an easier time getting it right.

 

[c9zx]

Well, I checked the timing while it was running at around 2000-2500 rpm and it was way high. Like 24° or so BTC. But that was with the vac line to the distrib still hooked up, so that was advanced timing probably? "

It is not way high. Take the RPM to 3000, set the timing for 36 BTDC with the vacuum line plugged, set the carb mixture screws to 1.5 turns out from all the way closed, make sure the idle speed screw is turned CW enough to be active, and see if it will idle. Depending on what is in the distributor for a curve you may need to do some work there as well. Chuck

 

[Mister 4x4]

That's one way to do it.  Setting the timing is normally done at idle speeds, but there's no reason why it can't be done at higher rpms.  It's kind of a 'backward' way of doing it, but it'll work - Chuck knows his stuff.  ::thumb::

 

[Don C]

That takes the mechanical/centrifugal advance slot size into consideration without having to disassemble the distributor. Good idea Chuck :goodpost:

Plus, nice way to do it when it won't idle down.

 

[Stanglover]

Having not re-read the entire post, I did not see mention of the choke plate being completely off and the engine at operating temperature. I assume this to be the case, but...........

 

[midlife]

Many vacuum leaks can't be seen. The best way to find leaks is to use starter fluid or other flammable materials and spray it around the carb base, intake manifold, etc. If the engine speed varies when spraying, then there is the vacuum leak. There's no other explanation (other than carb failure) not to have the car idle below 1000 rpm.

 

[Fredensborg]

Well, I checked the timing while it was running at around 2000-2500 rpm and it was way high. Like 24° or so BTC. But that was with the vac line to the distrib still hooked up, so that was advanced timing probably? "

It is not way high. Take the RPM to 3000, set the timing for 36 BTDC with the vacuum line plugged, set the carb mixture screws to 1.5 turns out from all the way closed, make sure the idle speed screw is turned CW enough to be active, and see if it will idle. Depending on what is in the distributor for a curve you may need to do some work there as well. Chuck

 Right on, I'll give this a try tomorrow. Ran out of time tonight.

 

[Fredensborg]

Having not re-read the entire post, I did not see mention of the choke plate being completely off and the engine at operating temperature. I assume this to be the case, but...........

Choke plate? You mean the flapper on the front of the carb? It was open a bit, but not wide open....I don't think. As for operating temp, it was warm. I started it several times, and had it ideling at 2000ish rpm for a a few mins at a crack. 

Many vacuum leaks can't be seen.  The best way to find leaks is to use starter fluid or other flammable materials and spray it around the carb base, intake manifold, etc.  If the engine speed varies when spraying, then there is the vacuum leak.  There's no other explanation (other than carb failure) not to have the car idle below 1000 rpm.

I put a vac gauge on it while it was in a high idle, was around 20 " hg. When the idle dropped, right before it died the gauge was at around 9" hg.

 

[midlife]

That suggests to me, still, that at low idle, your vacuum leak is still there. 9" is very low for a stock engine.

 

[Don C]

That suggests to me, still, that at low idle, your vacuum leak is still there.  9" is very low for a stock engine.

+1. Something like a failed diaphragm in your power brake booster will result in a huge vacuum leak. Just because each fitting is capped or has a tube on it doesn't mean that the other end of the tube isn't open or the tube isn't split or cracked. A bad or missing PCV valve will cause a huge vacuum leak.

The gasket(s) on the base of the carburetor have to be in good condition and the carburetor fasteners tightened (but not over tight). And these are only a few of the possible vacuum leak sources.

And, if your choke doesn't open when the engine is warm, the engine will never run right.

 

[Stanglover]

Having not re-read the entire post, I did not see mention of the choke plate being completely off and the engine at operating temperature. I assume this to be the case, but...........

Choke plate? You mean the flapper on the front of the carb? It was open a bit, but not wide open....I don't think. As for operating temp, it was warm. I started it several times, and had it ideling at 2000ish rpm for a a few mins at a crack. 

Yes, if the choke is on (closed) by even just a bit, the engine will rev higher until the engine reaches FULL operating temp, or at least until the choke reaches it's set point if that makes sense. I'm not at all familiar with Edelbrook carbs, but I guess the principle is the same.

Many vacuum leaks can't be seen.  The best way to find leaks is to use starter fluid or other flammable materials and spray it around the carb base, intake manifold, etc.  If the engine speed varies when spraying, then there is the vacuum leak.  There's no other explanation (other than carb failure) not to have the car idle below 1000 rpm.

I put a vac gauge on it while it was in a high idle, was around 20 " hg. When the idle dropped, right before it died the gauge was at around 9" hg.

 

[Don C]

You are correct, Edelbrocks have a similar fast idle setup connected to the choke mechanism.

 

[Fredensborg]

That suggests to me, still, that at low idle, your vacuum leak is still there.  9" is very low for a stock engine.

+1. Something like a failed diaphragm in your power brake booster will result in a huge vacuum leak. Just because each fitting is capped or has a tube on it doesn't mean that the other end of the tube isn't open or the tube isn't split or cracked. A bad or missing PCV valve will cause a huge vacuum leak.

The gasket(s) on the base of the carburetor have to be in good condition and the carburetor fasteners tightened (but not over tight). And these are only a few of the possible vacuum leak sources.

And, if your choke doesn't open when the engine is warm, the engine will never run right.

It does have a different cam, so its not totally stock .... I'm just not sure the lift or duration of it because I didn't put it in.also .030 bore      When its running, I don't hear any sucking other than into the carb. The gaskets are fresh, and its tight.

 9" was literally just before I shut the key off to prevent it from backfiring, my best guestimate.. I can hear the idle coming down quick, so I kill it to prevent backfire. Keep in mind this is me by myself running from the front of the car to the drivers seat as necessary. PCV valve is in working order and has a fresh hose.

I'll have to inspect all the vac lines next time I start working on it.

I'm stuck at work the next couple nights, so I wont get to mess with it for a couple days...