Can we talk about Small Block ignition timing?

[ArdWrknTrk]

I would always start with a 'tune up'.

3500 miles seems like nothing though.

Although a tune up with Autolite plugs is what put me off them.

Changed plugs, rotor and cap.

Had a miss that wasn't there before.

Changed the rotor back. Still there.

Changed the cap back. Still there.

Pulled the plugs and TWO insulators were not crimped tightly.

So NEW is not necessarily GOOD.

I'm sticking with NGK until they bite me too.

Axial play, or torsional play?

Any side to side wiggle of the shaft is a problem.

This was mentioned in reference to a DUI dizzy recently, where the guy went to an old points distributor and a Pertronix unit because poor oiling ate the shaft bushings.

Pages 1 & 2 of Scott's recurve instructions.

http://www.reincarnation-automotive.com/Duraspark_distributor_recurve_instructions_index.html

http://www.reincarnation-automotive.com/Duraspark_distributor_recurve_instructions_page-2.html

[Gary Lewis]

Pages 1 & 2 of Scott's recurve instructions.

http://www.reincarnation-automotive.com/Duraspark_distributor_recurve_instructions_index.html

http://www.reincarnation-automotive.com/Duraspark_distributor_recurve_instructions_page-2.html

Good find on Page 1, Jim. Together that's a good resource. Where should we book it, Dano?

Cory - Before you do your tuneup you might try running the engine at night w/o lights on. Sometimes a bad plug wire will show up. I've seen the engine compartment look like Las Vegas with all the sparks. But sometimes it takes spraying the wires with water to get the action started.

And don't forget to adjust the idle air/fuel mix on the carb. Perhaps that's off.

Last, see if you can dial in more initial advance w/o the engine kicking back when you start it or with pinging under load. More initial will help the bottom end power.

[ArdWrknTrk]

Good find on Page 1, Jim. Together that's a good resource. Where should we book it, Dano?

Cory - Before you do your tuneup you might try running the engine at night w/o lights on. Sometimes a bad plug wire will show up. I've seen the engine compartment look like Las Vegas with all the sparks. But sometimes it takes spraying the wires with water to get the action started.

And don't forget to adjust the idle air/fuel mix on the carb. Perhaps that's off.

Last, see if you can dial in more initial advance w/o the engine kicking back when you start it or with pinging under load. More initial will help the bottom end power.

Gary,

I would ask Scott if he's okay with hosting it here, with accreditation and a link back at the very least.

Scott works hard to be the best there is (as you do) he deserves to be rewarded for his efforts.

Another document you need is the Crane adjustable advance instructions.

Jegs has them on their site.

It's important to follow them to the letter.

 

[Gary Lewis]

Gary,

I would ask Scott if he's okay with hosting it here, with accreditation and a link back at the very least.

Scott works hard to be the best there is (as you do) he deserves to be rewarded for his efforts.

Another document you need is the Crane adjustable advance instructions.

Jegs has them on their site.

It's important to follow them to the letter.

I need to call Scott tomorrow anyway, so I'll ask him why he hasn't joined. He said he would. But his pages are just that, HTML/CSS pages, so don't lend themselves to embedding here. In other words, I think the best thing we can do for Scott is to link to them.

As for the Crane document, that is a PDF so is easily downloaded and then embedded in either a post or a page.

One approach for both would be to create an Ignition folder in the Resources folder/section of the forum. Another approach would be to add another tab to the Documentation/Electrical/Ignition page and capture both the Crane doc as well as links to Scott's pages.

(Or, we could do both - create an Ignition entry in the Resources and have a link to a page in Documentation.)

Thoughts?

[ArdWrknTrk]

I need to call Scott tomorrow anyway, so I'll ask him why he hasn't joined. He said he would. But his pages are just that, HTML/CSS pages, so don't lend themselves to embedding here. In other words, I think the best thing we can do for Scott is to link to them.

As for the Crane document, that is a PDF so is easily downloaded and then embedded in either a post or a page.

One approach for both would be to create an Ignition folder in the Resources folder/section of the forum. Another approach would be to add another tab to the Documentation/Electrical/Ignition page and capture both the Crane doc as well as links to Scott's pages.

(Or, we could do both - create an Ignition entry in the Resources and have a link to a page in Documentation.)

Thoughts?

The URL is the old RHP domain.

I don't think he even has them on the Parkland Performance site.

Inquire why not.

Ask him if he would move them, and if you could then link it and drive some traffic to his site.

I would gladly pay $155 (or whatever it is) for a custom curved distributor, if I had to replace it anyhow.

I like the idea of having both another folder, and a tab for ignition.

Anything to make those resources more available.

[Gary Lewis]

The URL is the old RHP domain.I don't think he even has them on the Parkland Performance site.Inquire why not.Ask him if he would move them, and if you could then link it and drive some traffic to his site.I would gladly pay $155 (or whatever it is) for a custom curved distributor, if I had to replace it anyhow.I like the idea of having both another folder, and a tab for ignition.Anything to make those resources more available.

I think there's a way to clone the whole page and put it on our site if he doesn't want to migrate it to his new site. But of course we'd give him credit. I'll ask.

 

And let's plan on doing both the belt and braces approach - add the info to the Documentation/Electrical/Ignition page and put a link to it in the Resources/Electrical folder on the forum.

[LARIAT 85]

The truck definitely has a miss, and I need to take a step back and give things the KISS treatment...keep it simple stupid...

Make sure your spark plug wires are routed correctly. As strange as that sounds, it makes a difference. If certain wires are too close to each other, they can crossfire and cause an engine miss.

There are two different firing orders for a 5.0/302: there is the standard firing order and the 5.0 H.O./351 firing order. The spark plug wires are routed slightly different between the two.

 

[Rembrant]

The truck definitely has a miss, and I need to take a step back and give things the KISS treatment...keep it simple stupid...

Make sure your spark plug wires are routed correctly. As strange as that sounds, it makes a difference. If certain wires are too close to each other, they can crossfire and cause an engine miss.

There are two different firing orders for a 5.0/302: there is the standard firing order and the 5.0 H.O./351 firing order. The spark plug wires are routed slightly different between the two.

Rick,

Wires are all routed OK and firing order is checked and correct. All good there. I replaced all the plugs, wires, cap and button this morning and it was running a little better for sure. I then bumped the base timing up to 16btdc, and it works better here too. The problem I'm having now though is that the idle is not as smooth as it was. Before, my tach needle was rock solid. Now it's bouncing a little bit.

I put the timing light back on, and you can see that the timing it bouncing way advanced. It reads on the 16, but bounces way ahead. I should note here also that I put some oil in the upper advance shaft in the distributor (below the little felt that's in there).

Vacuum is reading 16" at idle. That was with no air cleaner on it. When I put the 5.0 dual snorkel intake back on it, the idle goes from 800 up over 900.

So my base ignition jumping way ahead...is that my centrifugal advance? When I've checked it previously, when set at 12btdc, it was always pretty steady.

[Gary Lewis]

Rick,

Wires are all routed OK and firing order is checked and correct. All good there. I replaced all the plugs, wires, cap and button this morning and it was running a little better for sure. I then bumped the base timing up to 16btdc, and it works better here too. The problem I'm having now though is that the idle is not as smooth as it was. Before, my tach needle was rock solid. Now it's bouncing a little bit.

I put the timing light back on, and you can see that the timing it bouncing way advanced. It reads on the 16, but bounces way ahead. I should note here also that I put some oil in the upper advance shaft in the distributor (below the little felt that's in there).

Vacuum is reading 16" at idle. That was with no air cleaner on it. When I put the 5.0 dual snorkel intake back on it, the idle goes from 800 up over 900.

So my base ignition jumping way ahead...is that my centrifugal advance? When I've checked it previously, when set at 12btdc, it was always pretty steady.

It seems that your curve starts coming in just above 800 RPM, so any increase in idle speed gets more advance, which may increase the idle speed.

And where do you have your vacuum advance connected - ported or manifold vacuum?

But the increase in RPM with the air cleaner on suggests that your air/fuel ratio is lean. The air cleaner tends to enrichen the mix slightly. And your vacuum at idle should be closer to 20", which may also be due to a lean air/fuel mix.

[Rembrant]

It seems that your curve starts coming in just above 800 RPM, so any increase in idle speed gets more advance, which may increase the idle speed.

And where do you have your vacuum advance connected - ported or manifold vacuum?

But the increase in RPM with the air cleaner on suggests that your air/fuel ratio is lean. The air cleaner tends to enrichen the mix slightly. And your vacuum at idle should be closer to 20", which may also be due to a lean air/fuel mix.

Gary,

Vacuum advance is currently disconnected.

Right, so I'll play around with the idle speed and adjustments to see if I can get it to stop bouncing.

I wonder if the centrifugal advance is now moving too easily since I oiled it? Any time I played with it previously it wasn't advancing until a much higher RPM. Maybe it was sticking before and now that it's lubed up it's swinging out to full advance at too low an RPM?