the only free time Ive had to fire it up, get up to temp, then check have been after 10pm all week on the exception of when I drove it to work on the 25th.

I'm hoping I can mess with it today after yard work, but I'm not holding my breath as I've got plenty other things to catch up on in the house.

 

update...

Went out before yard work. i misspoke earlier, Im hooked to ported vacuum, therefore it's not pulling anything at idle while hooked up.

In the process however, I found a drip coming from the trans, coming off the front UJoint.

I'm tired of this crap. Lol

 

A drip? My car has a sheet of cardboard under it to soak up the “drips”. Don’t stress over this.


As for the distributor, just move the vacuum hose from the ported fitting to a manifold fitting. Takes less time to do it than to type it.

 

It's my understanding though that it'd run worse going full manifold..especially with the low vacuum. I used to run full manifold, but when chasing vacuum I was corrected about that (again, as much as I understood)

For the drip..yeah, I park over cardboard as well. It just seems like even though everything is new..its always something..lol

 

How do you figure having ported vacuum (zero vacuum at idle) would be worse than having big cam low manifold vacuum (way more than zero)? Sorry, but whatever you read, heard, assumed, or whatever is incorrect.

Please forgive me for this, but it seems that you do not have the knowledge necessary to sort this out, and really need help. This forum can provide that help but you have to be open to actually listening and applying the advice given.

 

That's where my frustration is coming from. Checking the timing is a 10 minute process - max. That's assuming the car doesn't have a functioning choke and needs babysitting to start up.

And yes, OP, you want manifold vacuum. Whoever told you to run ported gave you bad advice (that's typically a smog thing). Unless the vacuum canister is bad, causing a vacuum leak, or isn't providing as much advance as its supposed to (due to your low idle vacuum), everything should be better with manifold vacuum advance. You already said the engine wants more timing, but you're getting hard starting when you give it what it wants. Manifold vacuum advance fixes that.

 

No offense taken. The issue I have is this isn't some 500 car with a mild cam and an engine I can swap in and out if I screw up. It's a 1 of 2500, numbers matching car with pistons that I cannot order new off the shelf I go too far. So I'm being extremely cautious to put it lightly.

In switching to manifold vacuum, I'm assuming I'll need to retime.. correct?

 

Set dwell to established setting DISCONNECT and plug vacuum advance to set timing next in that exact order. Next, reconnect vacuum advance followed by A/F mixture ratio.

 

per the card, the dist. is already at 30°(?) Dwell..which is an entirely different aspect than what I'm used to (used to electronic, not points)

 

Dwell = Contact points setting. That piece where it’s written in at 30* means they established their readings based off a dwell angle of 30*. Personally, my engine I’d tune it again at the established dwell of 30* at the established RPM (you’re setting the contact gap point). Next, follow the ESTABLISHED procedure to set your timing (vacuum advance disconnected & plugged). Reconnect vacuum advance to manifold vacuum and adjust A/F mixture ratio.

 

Gotcha. Well, I'm hoping to be able to have a bit more time this week to be able to mess with the car. So provided that happens, I'll reset with manifold vacuum. I need to tidy up the plug wires/engine bay anyway..so this'll just better serve as an excuse to do so.

 

Suggestion. Do some reading/research on ignition timing and the role of the vacuum canister function. Engineers base dwell, timing & A/F mixture to achieve optimal performance within a range of three primary driving conditions: Idle, Cruise & WOT. It’s basically your acceleration curve but also your deceleration curve. Keep that in mind when considering the role of the vacuum advance canister at idle, cruise & WOT. You need to dig in a little deeper on ignition timing. Once the light bulb goes off, and it will, you’ll appreciate what TDC means in relation to dwell, timing, A/F mixture and the role of the vacuum ADVANCE.

 

Pffft. I have a car that's one of 377, so I know about rarity. Rare or not, all the basics apply.

No you do not need to do anything after setting the initial timing at idle. Do that with the vacuum advance disconnected and capped, then connect it to full manifold vacuum. Easy peasy.

Increased timing (to a point) = lower operating temperatures.
Retarded timing = higher operating temperatures.

 

..but when you cut your teeth and used to working on those 500 dollar cars, this makes you rethink some things..haha.

 

500 dollar car? That sounds like the value of a 1970s era car 30 years ago. The one I have was around 50K new in 2006.

 

no, I'm saying that's what I'm coming from prior to this car. From the pure Roadkill mentality of "don't get it right, just get it running" to now Im having to change my entire way of thinking.

 

OK, I can relate to that. I bought my Cutlass for $700 (choice between the car and a 286 computer) and have maybe $10k total invested over the years. Hard for me to comprehend the dollars that are being tossed around these days.

 

Lol you ain't kidding

 

Well, if you want to understand what & why you’re doing what you are doing start with learning the relationship between the crankshaft, the camshaft, the timing chain, the distributor (shaft), the # of lobes on the top of the distributor shaft and how each lobe effects the opening & closing of the points and the collapse of the electric field to the primary windings of the ignition coil. Dig deeper. You’ll get this - a light will go off eventually. If not, dig deeper.

 

Yeah, I'm definitely a research guy. Engines have always intrigued me, but the math is intimidating (obviously until you do it enough).

Sometimes with this car, especially with the engine..i catch myself researching too much rather than just trying/applying. I forget how rowdy the last engine I built was, but then I could replace it with no issues too if I screwed up.

 

I would not call this a performance setup. At these settings the engine will be lazy and run warmer.

 

I was told it was going to be curved to my combo. I can't remember what all I was asked to provide for that to happen..but it was enough that it felt like a thorough job was being done. Though again, I've never had a distributor restored/recurved

 

Alright, switched the vacuum source around and it seemed to run even better, however once again..once warm it stumbles.

It has 20° initial, the vacuum advance gives me 8° and ive got 12° mechanical. Air cleaner was still pretty warm but not nearly as hot (though it could be psychosomatic) but then again, my priority is the stumble/how it runs. My question is, with that giving me 40° total, is that too much? In my past experience, 32-36 was ideal without the vacuum advance, and a total around 50° was ideal..but I'm A. drawing from memory and B. coming from SBM with electronic ignition (similar to HEI) and not points.

 

This is such a long winded thread....

Two very specific questions for you:
(1) What is your timing set to - exactly?
(2) What is your exact measured vacuum?

I've seen several of your threads. I'm not about to review them all. You need to be certain you can pull a STEADY vacuum when performing your vacuum reading. Rock solid STEADY vacuum. What is your vacuum reading and can you perform the test defined in the upper left-hand corner of this chart? You should NOT see ANY variance in vacuum - it should be STEADY. If you witness a vacuum reading which drifts back & forth over a range of 4" - 5" Hg you need to set your vacuum to a STEADY reading adjusting your A/F mixture.

 

Timing is 20° Initial, with vacuum unhooked and capped. I have not read the vacuum since this thread started, but it was about 8hg at idle fully warmed up with the most variance being an occasional 1/2 swing..but even then vary random and not frequent at all. I have gone over every vacuum line, I have disconnected and capped all lines from the carb/intake other than the gauge, no change. The only time it gets better is when idle RPM is increased whether that be from carb or timing.

 

20° initial says nothing about your timing. I asked about your timing. I'm not sure what you're talking about. What is your timing set to? 10°BTC, 12°BTC? Unless you're running the largest cam known for that engine and you're running 1/4 miles @ 5.5 seconds, you can't be pulling 8"Hg.

Again, I'll ask - what is your timing set to?
What is your vacuum? Measure it w/ a vacuum gauge. I'd consider 14" - 15" w/ a big gnarly cam if you're running 1/4 mile runs. But I don't believe you have a 1/4 mile performance cam in that car. What is your measured vacuum? And, make sure it's steady. Rock steady. You should be pulling exactly what it states in the chart I provided. The lowest I'd expect to see if you have a loping cam is maybe 12'Hg - 14"Hg. If you're measuring 8"Hg you have a serious vacuum leak - somewhere.

 

20° BTDC is where my inital timing is at. Beyond that, maybe Im just misunderstanding. I have measured vacuum on two separate gauges and Im at 8hg. Where we're at with the vacuum issue is that not only was the cam not degreed, but the cam is designed for a 10:1 compression engine and this doesn't have that..meaning the machine shop missed the mark. The intake gasket has been changed multiple times, the carb/base gasket has been changed multiple times, lines have been changed, completely unplugged, etc.

I sent the car elsewhere to have the cam degreed, however the guy who was going to do that called and said he could tear it down and cost would go up, but he thought the car ran too well to have the cam off that far.

 

This is making some sense - some, but not much & if what you said is true, the cam was not degreed, you're in a world of dog doodoo.
You have a 69 442 400G block - what carburetor do you currently have mounted on the car?

If I'm not mistaken a stock 400 should have timing set ~7.5° BTC at 850rpm with auto trans (with or without A/C) & 2.5° BTC with manual trans. Your timing is set to 20°BTDC and you're pulling 8"Hg vacuum? Wow. I'm at a loss of words. Sorry.

 

Currently, I have a Jet Stage 2 Qjet. However with a Holley, it was the same thing. Timing was set with vacuum unhooked and plugged, and revving up until the mark on the balancer stopped moving, to which the distributor was turned until it aligned with zero (note: assembly shop showed a "new zero" on the tab) with dial back indicator set at 34° (total timing). Once it idled back down, I found I was at 20° BTDC initial. It idles in park around 900-1000 RPM (Factory tach is pretty suspect), though this engine is also not stock. It's bored .040" over, has an Erson TQ50 cam, and has been "zero decked" (the last part is where I'm thinking the machine shop screwed up)

 

Your initial may not be 20* because of your idle speed of 1k+ rpm, the distributor is already starting to advance at that rpm. Based on your distributor spec you posted, it should have stopped advancing with 22* of mechanical at 4k rpm, giving you 34* total. Which means your initial should be at 12* below 900 rpm. Drop your idle speed to 750 rpm and then see where your timing is. Your hesitation may be due to when the accelerator pump actuates with relation to opening the throttle.

 

I'll give it a shot. The thing shakes like no tomorrow IIRC with an idle much lower than where it's at. It already has a bit of a shake to it.

Also though, in all that..arent I just making the vacuum problem worse?

 

The engine should not shake much at idle, it could be caused by a misfire, valves not adjusted properly, the idle a/f mixture is off, or a combination of these. You aren't going to leave the idle there, your just checking what your initial really is by reducing the idle speed and seeing if the timing drops. Reduce the rpm until the timing stops retarding and note that. If the reducing the idle does cause the timing to drop then the distributor spec is correct, if not then we need to get more specific on what your total is and at what rpm it stops advancing.

 

As said, that is a pretty lazy advance curve but may be starting to advance a couple of degrees. I am betting it won't like a 750 rpm idle speed. I personally like my idle where you have yours, 900 to 1000 rpm in park with even a mild cam. The shake at idle reminds me of my 81 Delta 88 I had years ago with a stock Olds 307 with a leaking choke pull off. I couldn't believe a new choke pull off made it idle so much better.

 

A few things to keep in mind. There is a difference between wide open throttle (WOT) total and max possible advance. At WOT, you should be 32-36, and you are. You're at 20 + 12 = 32. At WOT you don't pull vacuum, so the vacuum advance doesn't play into anything.

When you aren't at WOT, you've got a partially closed throttle, which pulls more vacuum, adding in the advance. You need this, because you aren't running a full load of air/fuel. It doesn't burn as fast and you need more time to complete the burn - hence the increased advance.

The stumble is likely fuel. I'm guessing you aren't running a wideband O2 sensor? Easiest thing to check is whether your accelerator pump is adjusted and working properly.

 

We are trying to verify if the distributor spec is correct and go from there.

You are correct, but lets get the mechanical timing verified and straight before we jump into the vacuum advance.

 

I've had the accel pump suggested, especially with the carb on it (Jet Stage 2 Qjet). I am not running a wideband. My to-do after Nationals is to get the exhaust done and take it to be dyno tuned (with wideband)..so that someone much more qualified than myself can dial the carb/timing/etc in rather than just my seat of the pants/not-professional experience.

FWIW, from a slow roll I matted it and it kicked me sideways for the first time. Though, as I was driving through town, it slowly got worse and worse (the stumble). I put a quarter turn more fuel in prior to headed home from the church and it didn't seem to be nearly as responsive, so I'll pull that back out.

 

What exactly are you referring to?

 

No if he was at 20* according to the distributor spec sheet, he should be 20+22=42 at 4000rpm where the timing should stop advancing. Then you add the 14* of vac advance under light throttle would put him at 56, probably too much advance for his engine.

 

Sorry..a quarter turn out on the mix screws.

 

Those 2 screws your fiddling with only affect idle a/f settings, once you are out of the idle circuit, they do nothing.