uh oh, stumbling, sounds like a diesel

[rich weyand]

Ok, distributor did roll back about 1", but I couldn't move it without loosening the bolt. What is the proper way to tighten it down so it doesn't happen again?

Going to be properly timing it this weekend

Sent from my SCH-I605 using Tapatalk

Excellent.

Happened to me once, too, which is how I knew to tell you to check it. The distributor will always wander retarded if it moves, because the shaft rotation is trying to pull it retarded.

 

[flyboy1100]

So what it probably did, it was a little loose, it rolled back and tightened itself under the clamp and why you had to loosen it back up. Just get it where you want it, make sure the clamp down is over the dizzy housing and snug it up with a 9/16 open end wrench if you don't have a dizzy wrench. It's a little difficult to get back in there and under the dizzy housing without the dizzy wrench, but using the open end wrench you should be able to get on the bolt enough to snug up the bolt over the clamp.

I have a dizzy wrench but it didn't fit well under the vacuum advance. I was able to get a ratcheting 9/16 in there.

Oh and vacuum advance works too with a mity vac, no idea if its working on the carb port or if it's even correct port. I took pics and will post them this afternoon

Sent from my SCH-I605 using Tapatalk

 

[HotRodPC]

Excellent.

Happened to me once, too, which is how I knew to tell you to check it. The distributor will always wander retarded if it moves, because the shaft rotation is trying to pull it retarded.

Yep. It's just retarded !!!

I do believe I made this suggestion to him with my first response to this issue because he said he had just set the timing and had it running good. It's a bit common for this to be the problem if someone has recently set the ignition timing. He's not the first that this has happened to.

So it appears everyone in this thread is fixed up now? 1 was firing order was wrong, and 1 was retarded timing.

 

[Driver4r]

I have a dizzy wrench but it didn't fit well under the vacuum advance. I was able to get a ratcheting 9/16 in there.

Oh and vacuum advance works too with a mity vac, no idea if its working on the carb port or if it's even correct port. I took pics and will post them this afternoon

Sent from my SCH-I605 using Tapatalk

the small hose in my pic is the right spot

 

[HotRodPC]

You're about to start a huge argument when you ask where the vacuum line goes for vac advance. Some say manifold vac, some say ported vac which is a dead vac circuit until you come off idle then it comes to life. That's where I hook vac advance to. Ported Vacuum.

 

[rich weyand]

[huge argument in part follows] Look, I'm 60 years old. I started playing with cars in 1969 at age 16, on cars from the early 60's. No such thing as ported vacuum. All vacuum advance units connected to manifold vacuum. Why? Because that's where they go.

When did ported or timed vacuum come in? With emissions controls. You know, the stuff that lowered compression and horsepower and performance and throttle response while cleaning up emissions in the 150 million or so cars on the road. Why? Because they measured idle emissions, because cars sitting in traffic jams in LA and DC and NYC were causing lots of pollution. And running retarded at idle helps that. It lets some of the charge into the manifold while it is still burning, which runs the exhaust manifold hotter and gives some after-burning of emissions in the manifold.

So, if you want better performance and throttle response, and you aren't going to be sitting in traffic jams in LA or DC or NYC for hours, and you don't need to undergo emissions testing, then use manifold vacuum.

Another data point. If you look at Edelbrock carb diagrams, the ports are labeled "timed vaccum (Distributor vacuum advance port for emissions controlled engines)" and "manifold vacuum (Distributor vacuum advance port for non-emissions controlled engines)".

Or you could read this: http://www.corvetteactioncenter.com...ported-vs-manifold-source-vacuum-advance.html

Or you could, just maybe, you know, for grins, and to prove me wrong, take five seconds to pull the vacuum advance line off the ported vacuum port and connect it to the manifold vacuum port, and then drive it for a while. Notice how crisp the off-idle response is now? Hmm?

 

[HotRodPC]

TOADJA !!! NEVER ASK where to hook up Vacuum Advance on a forum !!! NEVER

 

[Driver4r]

[huge argument in part follows] Look, I'm 60 years old. I started playing with cars in 1969 at age 16, on cars from the early 60's. No such thing as ported vacuum. All vacuum advance units connected to manifold vacuum. Why? Because that's where they go.

When did ported or timed vacuum come in? With emissions controls. You know, the stuff that lowered compression and horsepower and performance and throttle response while cleaning up emissions in the 150 million or so cars on the road. Why? Because they measured idle emissions, because cars sitting in traffic jams in LA and DC and NYC were causing lots of pollution. And running retarded at idle helps that. It lets some of the charge into the manifold while it is still burning, which runs the exhaust manifold hotter and gives some after-burning of emissions in the manifold.

So, if you want better performance and throttle response, and you aren't going to be sitting in traffic jams in LA or DC or NYC for hours, and you don't need to undergo emissions testing, then use manifold vacuum.

Another data point. If you look at Edelbrock carb diagrams, the ports are labeled "timed vaccum (Distributor vacuum advance port for emissions controlled engines)" and "manifold vacuum (Distributor vacuum advance port for non-emissions controlled engines)".

Or you could read this: http://www.corvetteactioncenter.com...ported-vs-manifold-source-vacuum-advance.html

Or you could, just maybe, you know, for grins, and to prove me wrong, take five seconds to pull the vacuum advance line off the ported vacuum port and connect it to the manifold vacuum port, and then drive it for a while. Notice how crisp the off-idle response is now? Hmm?

becuase if you go off of manifold vacume, your ALWAYS GONNA HAVE VACUME, which means its ALWAYS gonna be advanced, which is not gonna help you at cruise.

Now a throttle oriented port IS gonna make a difference. Cause when your cruising its gonna advance with vacuum instead of mechanical(the weights).

 

[HotRodPC]

That's my argument. What's the purpose of Vac Advance if you hook to vacuum all the time. If you're going to do that, then you may as well just load it with all the timing via Weights and not have Vac Advance. Many of the racers do anyway. The other thing to consider, when you go WOT, you're losing vacuum, so you're actually retarding the timing when you go WOT when you should want to advance it. Point is, why build advance into the timing when you get on the throttle you're going to take it away? Hooking up Vac Advance is certainly beneficial, but it doesn't do a bit of good at idle.

 

[Skweegle89]

 

[HotRodPC]

Popcorn hell, you may as well just pack a lunch and bring a 6 pack. These Advanced Timing arguments go on forever and ever. I haven't been on a forum yet that this subject hasn't come up and everyone has a different opinion. I just about consider this topic like politics and religion. Just don't bring it up.

 

[flyboy1100]

i think I will start a new thread for my vacuum line questions......

i might also try manifold vacuum. not sure where it is hooked up now, but at idle if i disconnect the port it has no effect, so must be ported, or nothing at all. who knows on this truck!

still unsure of where to start with the timing, 8 btdc, 4btdc?

 

[HotRodPC]

You can tell a ported port by putting your finger over it. At idle no vacuum, raise the throttle a bit and you should feel vacuum until you return back to idle.

 

[Driver4r]

That's my argument. What's the purpose of Vac Advance if you hook to vacuum all the time. If you're going to do that, then you may as well just load it with all the timing via Weights and not have Vac Advance. Many of the racers do anyway. The other thing to consider, when you go WOT, you're losing vacuum, so you're actually retarding the timing when you go WOT when you should want to advance it. Point is, why build advance into the timing when you get on the throttle you're going to take it away? Hooking up Vac Advance is certainly beneficial, but it doesn't do a bit of good at idle.

exactly, depending on how touchy you have your vacume advance set, at full time vacume, its as if you stuck the lightest springs ever in your distributor.

I myself have a black/silver(light/medium) spring setup in my dizzy with the included weights, i havnt modded those yet. Then im gonna have my timed vacume adjustable vacume advance for highway cruising.

@WOT is when my weights kick in.
@cruise is when my vacume advance kicks in.

 

[flyboy1100]

exactly, depending on how touchy you have your vacume advance set, at full time vacume, its as if you stuck the lightest springs ever in your distributor.

I myself have a black/silver(light/medium) spring setup in my dizzy with the included weights, i havnt modded those yet. Then im gonna have my timed vacume adjustable vacume advance for highway cruising.

@WOT is when my weights kick in.
@cruise is when my vacume advance kicks in.

That makes sense to me, if you add timing on newer engines at cruise you can really help mpg.

So to do that you would have it plugged into a ported source?

Sent from my SCH-I605 using Tapatalk