I save judgement till seeing the idle and higher rpm timing numbers.

 

Turning the screws out will make it richer, so sounds like you're going the wrong way? Or am I mistaken on an Edelbrock carb? I know my Holley needs to get turned in to close off the gas flow and lean out the idle. Most of the new Holley carbs want to be out about 3/4 turn to idle properly, where older Holley were 1 1/2-2 turns.
Sounds like the timing is moving around a lot? Or is the engine rpm moving around also? Need to get the timing back up from the 30 degree high reading. Not back to the 40 high, but around 35 total at higher rpm.
Still sounds like something is weird with the whole package. Either carb, timing, or valve lash.

 

Timing isn't moving around, unless I move the distributor. What I said was the engine was idling at 1600 rpm. I checked with the light the first time and it was showing 35-40 which seems high to me at only 1600 rpm. I retarded the timing a little bit with the distributor and checked it again, still at 1600 rpm and it was reading 25-30. The issue still is keeping it running if I try and lower the idle. I know where I want total timing to be, but don't think it should be all in at 1600 rpm right? That's what I was trying to say in my last post.

 

Interesting deal this afternoon. I went out and started the engine today without touching anything distributor-wise from last night when the timing light was showing about 25 on the tape at 1600 rpm. The engine started right up and ran for about 2 minutes and I noticed a little smoke. I turned it off and saw that the header tubes were glowing red again, all of them. When they were doing that the beginning of this week I advanced the timing more and that stopped. So, I moved the distributor a little more advanced, turned the idle screw up so it would be closer to 2000 rpm and started the engine back up after a few minutes of cool down time. Engine fired right up and immediately began to idle on it's own at about 2200 rpm. Didn't sound the best when running but the first time it's ever done that. I got out and put the timing light on to see where it was at. Wish I would've got a video clip of it as it went down but idle was right at 2200 rpm and the timing showed 45 btdc and the header tubes quickly began to glow again. I was lucky that a buddy had just pulled in to visit while I was moving the distributor back a little bit. I started the engine back up, this time it wouldn't stay running (big surprise) so I stayed in to keep the rpms up at 2500 while he used the light. Timing was showing 30 at 2500 rpm, headers didn't start glowing but it also wasn't running for very long. I stopped there as I had to clean up and go pick up kids from school. When we got back home about 90 minutes later, headers are cool to the touch, heads are cool also. However, the intake manifold is still hot!? Not blistering hot, but hold your hand on it for 10 or more seconds and it gets pretty hot-hot. Make sense at all?

 

I almost hate to mention this, but I better, as your description matches what a friend's engine was doing almost exactly. We tried everything to make it run, start well, and still it wouldn't idle down well, headers glowed, and when it was totally warmed up it started hard.
I finally told him we needed to pull the engine and see what was going on with either the timing chain and sprockets, or something else. When we pulled the timing cover off the timing chain had gotten on one tooth off! Pulled the chain and moved it one tooth, and bingo! Everything ran, started, and performed perfectly.

 

I hated to mention the timing gears too (he doesn't have a chain), that was earlier this month. Look back at post 1092, he has a picture, and the marks are on.

 

I just wish I understood distributors more, it almost seems like the timing is changing on me overnight. From what I and my friend saw today, the timing was way too far advanced. 45 btdc at 2200 rpm. Wouldn't that explain the terrible fuel smell? Not burning it all and having it go into the exhaust or is that logic backward? Plugs are black now. The part that I just don't get though, is when I retard the timing it just doesn't want to stay running. Only time it started and ran on it's own was when it was showing 45 btdc and made the headers glow in about one minutes time. I didn't get a chance to work on it more this evening but I did retard it some and it was reading lower but still a little too advanced when I stopped earlier today. It was advancing when I slowly revved it, my friend was reading off the numbers as I did.


As I'm sure you'd understand, it would be devastating to have to pull the engine to fix something. At this point however, it would almost be a welcome change to actually KNOW what's causing these issues! I'm obviously not a veteran engine builder, but I understand what needs to happen here. Something that should've taken an hour at most to set is basically in it's second month now.

 

What engine vacuum source, and which port on the carb is the vacuum advance connected to?

 

Ported/Timed vacuum port, left side of carb.






Can you help me understand what the reasoning is behind plugging off the vacuum line to the carb when setting the timing? What actually happens/doesn't happen by doing this? Just something I don't understand about distributors and timing.

 

You pull the line and plug it so the distributor wont change timing during setting it. Despite the name "vacuum advance", the vacuum advances the distributor all the time when idling, or cruising and vacuum is high. When you step on the throttle to accelerate, the vacuum drops off, and the timing retards to keep the engine from pinging or knocking. It's better to use the full vacuum port, rather than timed port for your vacuum signal.
Looked back at your marks in the picture, and they do line up. That should be good, but if something doesn't show up soon, I'd question if the mark is correct. I know of two cases where double roller sets (not gear drives) had incorrect marks on them, and gave guys fits. One was on a good quality Cloyes set!