'89 Fifth Ave

[NoCar340]

If you're going to pry it apart, use as wide a putty knife as you can find, preferably brass if possible and as thin as possible. Don't pull on the handle at all, just use the side of your closed fist to gently "hammer" it into the gasket space. Let the blade do the work, but don't go in really far. It should come apart fairly easily after just about an inch or so. There are dowels on the phenolic body you don't want to hit, so start at the back of the carb and be patient.

Soaking it in mineral spirits for a while won't hurt anything and may really help soften up that gasket.

 

[Monkeyed]

Here's actually a pretty decent discussion on the ported v manifold vacuum advance question.

http://www.hotrodders.com/forum/ported-vs-manifold-vacuum-advance-scenario-151264.html

This was more of the "i have been messing with engines since the late 60s and was a professional mechanic for 30 years, so have probably built, tuned and modified more engines than most here...when the ported vacuum cars started showing up out here in cal. to meet smog regs. i would ALWAYS switch them to manifold vacuum-every customer would come back and say "HOLY CRAP, what did you do to my car, it runs tons better."...go with MANIFOLD VACUUM-->ALWAYS..."

versus

"Respectfully disagreeing ... ported vacuum was NOT a stop-gap for emissions. It was a drivability choice enacted by the manufacturers given the lower compression of the early smog-era vehicles.

On the other hand, if you have a high compression engine, you can use manifold vacuum to get extra initial timing that backs off a bit under load, then the mechanical puts it back in as you increase RPMs.

The bottom line is that the vacuum signal you use is simply another way of tailoring the ignition curve to match the engine's needs. One isn't "right" and the other "wrong." This debate is much like the vacuum secondary carb vs. the mechanical secondary carb. There is no "right" answer, only what is best for your application...

Proper vacuum source --> always. There are no absolutes...I don't mean to neglect your experience in the industry, but as a former engineer/consultant for Rochester Delphi, I was constantly required to know the latest and most advanced combustion physics on the planet."

 

[NoCar340]

Wow, I don't even think the Rochester guy gets it. Ported vacuum goes from nil to full manifold vacuum the second the throttle moves, unless there are some Rochester carbs out there that do it differently than the QuadraJet, all Holleys, and every Carter on which I've ever worked. The only reason it's even ported (a.k.a. "timed") is to keep the idle stable. If you look at any vacuum fitting on the carburetor, it ends in the throttle body. The ported fitting's passage is above the throttle blades, the continuous vacuum ports are below it. I've run vacuum advance both ways due to necessity when using an ESA/ELB carb now and then over the years, and other than chasing the idle all over the place when routed to continuous vacuum, I've never noticed a performance difference either way.

I can absolutely guarantee you that if you run your vacuum advance from a constant source rather than the ported fitting, your idle will be 700RPM at one stop and 1,500+RPM at the next, and vacillate to various points in between depending on the moment. It's really, truly annoying on a manual trans, by the way.

 

[kkritsilas]

I would think that if a ported vacuum wasn't needed, they would have just put the vacuum port on the intake manifold (like for the power brake booster) and done it that way. However, at idle, you don't want any added mechanical or vacuum advance (just the initial, or static advance that you adjust with the timing light and the vacuum port on the distributor disconnected/capped off), hence the need for ported/timed advance.

I have heard of divorced advance as well (honestly can't remember where); is that yet another name for ported/timed advance?

Kostas

 

[NoCar340]

I have heard of divorced advance as well (honestly can't remember where); is that yet another name for ported/timed advance?

Kostas

I don't know, but I expect it's much happier advance now than it once was. :icon_biggrin:

I've never heard the term; apparently it's archaic enough that even Google can't find it.

 

[Jack Meoff]

I don't know, but I expect it's much happier advance now than it once was. :icon_biggrin:

Bank account reference? :laughing7:

 

[kkritsilas]

I did some poking around Wikipedia, and found this:

"On some vehicles, a temperature sensing switch will apply manifold vacuum to the vacuum advance system when the engine is hot or cold, and ported vacuum at normal operating temperature. This is a version of emissions control; the ported vacuum allowed carburetor adjustments for a leaner idle mixture. At high engine temperature, the increased advance raised engine speed to allow the cooling system to operate more efficiently. At low temperature the advance allowed the enriched warm-up mixture to burn more completely, providing better cold-engine running."

This is in the article on Ignition Timing. I can see this being called "divorced vaccuum advance", as the switch will separate the vacuum advance based on engine temperature, hence, "divorced".

Kostas

 

[NoCar340]

Thermostatic vacuum switches were pretty common on early emissions-era cars, including Mopars. They're almost a lock on a feedback-carb application. The easiest way to "fix" those cars is to replace the carburetor and run the vacuum advance directly off the ported fitting. Feedback carbs can be made to run well without the emissions controls, but it's not really worth the amount of effort.

 

[Monkeyed]

probably should have checked first.. I bought 2 of these brass thermoquad floats,

http://m.ebay.com/itm?itemId=111210753974

OEM Carter #s 21-249, 21-252; Chrysler #3780155

those should work right? Right..?

 

[NoCar340]

More than likely, yes. I don't think there were too many variances in the floats, even though there were several part numbers. That being said, you might have wanted to check with a local auto supply. I think I paid about that for a pair.

 

[Monkeyed]

More than likely, yes. I don't think there were too many variances in the floats, even though there were several part numbers. That being said, you might have wanted to check with a local auto supply. I think I paid about that for a pair.

I offered them $20 for a pair, and they accepted, so Great Success! I remember seeing that the brass and plastic floats were interchangeable, but didn't think there might be different types. Lord knows, I've made mistakes like that before, you'd think I'd learn!

 

[Monkeyed]

as far as checking, around here, unless you're buying something they don't know anything about nothin', and if you are, they magically become 100% certain with out a shadow of a doubt about everything, either way they're wrong half the time. :angry7:

 

[Monkeyed]

not that I'm bitter :sunny: lol

 

[Jack Meoff]

as far as checking, around here, unless you're buying something they don't know anything about nothin', and if you are, they magically become 100% certain with out a shadow of a doubt about everything, either way they're wrong half the time. :angry7:

Sounds like the quality customer service I get up here.

 

[NoCar340]

The parts counterman is a dying breed. I'm one of the last that started out on honest-to-God paper catalogs, back when a DOS-based invoicing system (which did nothing for lookup or inventory control) and dot-matrix printer seemed like NASA technology to the customer. Internet? Microsoft Windows? That was all gee-whiz "someday tech" back then; I cut my teeth writing invoices on those carbon-dupe machines that required the jab of a pen to advance the invoice.

In the last store I ran, I had "catalog day" for the trainees, when they weren't allowed to use the computer cataloguing and had to go to "the books." They dreaded it, but became damned-good counter staff. Training at Advance, AutoZone, O'Reilly's et al consists of the supervisor overlooking the transaction and zapping the trainee with an electric cattle prod every time they finish with, "Do you want fries with that?" :eusa_doh:

 

[NoCar340]

I actually got fired from Advance Auto Parts for being too good at my job. I scared the hell out of my manager, who was both incompetent at both management and auto parts, and convinced I was out for his job.

 

[Monkeyed]

Training at Advance, AutoZone, O'Reilly's et al consists of the supervisor overlooking the transaction and zapping the trainee with an electric cattle prod every time they finish with, "Do you want fries with that?" :eusa_doh:

That about hits the nail on the head! My wife's neon was throwing a check engine light, I told her to take it up to Advance and have them hook up a code reader to it, and to NOT under ANY circumstances whatsoever buy ANYTHING they try to sell you based on the reading! Good thing too, or she would have left with a downstream O2 sensor that day!

 

[Monkeyed]

It had been running rough and had a Crank sensor code, I told her it wasn't that, but she was convinced by the counter people, so I said fine, and replaced it for her, no change in the way it ran. She wasn't convinced, I called it in as defective, and got another free one to replace that one with. still no difference. Replaced the Cam sensor, it's ran fine ever since

 

[NoCar340]

The flip side to that argument: Guy comes in looking for a TPS. It's pre-OBDII and not showing a light. I asked him what it was doing, and he told me, "It runs great but when you throttle it in gear, it falls on its face." I told him it wasn't the TPS, it was the fuel pump. Guess which is cheaper? He bought the TPS, but I told him if he plugged it in, it was his to keep. He tried the "defective" bit, so I looked up the specs and showed him with a multimeter that not only was the TPS I'd sold him fine, so was his original. I wouldn't take it back since it had been plugged in and tested fine. He stormed out, angrier than a wet hornet, and went across the street. I called them 20 minutes later and asked. He'd bought a fuel pump, for $17 more than mine. Jackass.

 

[Jack Meoff]

A guy I work with went to Jiffy Stooge for an oil change.
$29.99 special.
$115 out the door.
They sold him an oil pan flush!!?? Among other ridiculous things.
It's not like they're pulling your pan and you're getting your car in 15 minutes
That's what they do though....they prey on the people who don't know.