Vacuum advance not working

[Anonymous]

My father told me that my vacuum advance isn't working when we were dropping in my engine and getting it to run. Is this pretty easy to fix? Would this cause a slight stutter when accelerating? The engine will stutter a little bit usually when I'm cruising around 20mph and try to accelerate to 30, but it catches pretty quickly and runs fine. Seems to do this at all times, warm and cold.

 

[pedal2themetal45]

HI
YES its an easy fix. just a couple of screws and its just hooked over a lever. pull the cap pull the screws and its out.
Tim

 

[CZLN6]

Howdy All:

Leditions- There are two places to check for your inoperative vacuum advance. The 1st is the carb and SCV. The 2nd is the distributor.

Start the car. Remove the vacuum line from the distributor. Work the throttle as listen and feel for suction. If you hear/feel it, it is likely not the carb/SCV.

Reattach the hose to the distributor and now remove it from the carb. Now suck on the hose while watching the vacuum advance arm between the cannister and the distributor. If you can feel movement as you suck, great. If you get a "no more" feel you likely have a stuck advance plate. If you can suck endlessly, you have a bolwn vacuum diaphram inside the cannister.

Check it out and report back- please.

Adios, David

 

[Anonymous]

I'll have to try it tomorrow morning after work. Thanks for replying. If it does turn out to be a blown diaphram, would I be able to just replace the vacuum advance canister on the side?

 

[Anonymous]

well I was outside sucking on a cigarette and I figured I might as well try the hose thing. I do believe that I have a blown diaphragm. I had no resistance on the hose from the distributor. The question is, would that be causing me the stuttering problem? I drove it a little more to get more to the story, and at lower speeds (ie 15 - 20) the car almost dies when just accelerating however, while at higher speeds (ie. 45 - 55) it stutters during acceleration but isn't hardly as noticable as 15 - 20 mph. The funny thing is that it has actually died 3 times when pulling into the parking lot at work. It hasn't happened anywhere else but at work, like the car hates going as much as me.

 

[pedal2themetal45]

HI
Another thing to look at would be the axcelator pump, Look down the carb (motor off) and see if when you move the axcelator linkage there is a shot or stream of gas going down into the carb.. if not the axcelator pump is bad that can also cause a stumble..
tim

 

[CZLN6]

Howdy back:

If you do have a blown vacuum diaphram, your engine is suffering from a vacuum leak. On a good diaphram, the vacuum applies pressure, pulling against the diaphram. If the diaphram is leaking, it is, in effect, a vacuum leak.

Try driving the car with the vacuum hose to the carb dissconnected at the distributor and plugged. You may need to add an additional 5 or 10 degrees of initial advance for test purposes. If this solves, or at least, imporves your driving stutter, you will know you are on the right track.

Replacing the cannister is possible, but not easy. A new cannister will be hard to find and relatively expensive. By that I mean that the cannister will be about $20, while a complete rebuilt distributor will be about $50 (NPD). Changing the cannister is best done with the distributor on a work bench. This is a great time for a general cleaning, checking and lubing too.

Adios,

Adios, David

 

[Anonymous]

Is there another distributor that we can use for these 200ci? I might as well upgrade if there is one available? or are we stuck with using the factory distributor for now?

 

[Anonymous]

The advance diaphram was shot on my '62 144--the only trick is to take the old one with you to the parts store. Then depending on the year of your car you may have to look uo the oldest small six combo they have in the catalog. then start comparing yours to the pics. I got mine the next morning for around $12 from autozone. The only trick to changing it is the clips and screws are very small and awkward to get at--use magnetic srcew driver and good needle nose. Car will run MUCH better.

 

[Anonymous]

or try one of those parts places

sure I paid a little more at NPD but they got it right first time

 

[CZLN6]

Howdy Back:

Ledition- Yes, you could upgrade by using a distributor from '68 or later. The '68 to somewhere in the early '70s are point type, but incorporated centrifugal advance and a ported vacuum signal (no SCV) for vacuum advance, as do all other distributors that follow. After '75 electronic units began to appear. Ported vacuum will definitely work better with your carb combo.

Centrifugal advance helps performance- vacuum advance helps economy.

The downside is that you may, or may not be able to use your Petronix in an upgrade distributor. It will depend on the recess in the top of the shaft, where the rotor sits.

Adios, David

 

[Anonymous]

david, about how long will those vaccuuum units last?

I changed mine about 2 1/2 years ago...but recently dropped gas milage and am now wondering if that culd be a contributing factor. I have NOT checked it as yet

 

[CZLN6]

Howdy Chad:

In the old days it seemed like they would last forever. I don't seem to have much luck with newish ones.

Some times the diaphram material just stretches out and doesn't function properly. This is harder to detect then a blown or holed one. But it usually shows up by a lose of gas mileage 1st.

Check this by removing the distributor cap, suck on the hose to the diaphram and watch the advance plate move. Then try to manually advance the plate somemore. If more then half its range of motion is left, I figure it's time to replace/renew. When you get the new one in place test it the same way and record the range of motion for future reference.

Adios, David

 

[Anonymous]

well I ordered the distributor for the 68' 200 today and it should be here tomorrow. I hope that I can use the Pertronix stuff. I'll let you know. So why is this one going to be better then the 67? The only real difference I can see is that I guess 67 and below (maybe) has the thermatic whatchamacallit thingy emissions control. I'm assuming that is the little hole on the side that has a dust cover over it. Can't wait to see if this solves all my problems or opens up a bunch more. Thanks for all your help so far.

 

[CZLN6]

Howdy Back;

Your '67 distributor is a vacuum advance only, Load-a-Matic. It is designed to work correctly with a vacuum signal from the Spark Control Valve (SCV) in the '67 Autolite 1100 OEM carb. Your two barrel Holley is designed to send a ported vacuum signal to the '68 and later distributors. Your '67 OEM distributor was not working (if at all) as designed.

There are stickys at the top of this forum about the SCV and the Load-a-Matic distributors, and how they work.

The '68 and later distributors utilize both a mechanical ignition advance based on the rpm of the engine. The faster the engine turns the more advance is supplied. It also used vacuum, but not full manifold vacuum, but from a ported source just above the venturi in the carb. It helps mileage at steady hiway speeds.

The new distributor should not only solve your lack of vacuum advance, but should be compatible with your Holley carb. YOu should notice much better driveability, economy and power.

Have you modified your Holley for use in your situation? What jets are you using? I hope you've been following wsa11's posts on A/F tuning on his #4412.

Adios, David

 

[Anonymous]

yes you can use your pertronix with the 68.,..I am using the same setup on that...altho i have a crappy carb

 

[61Futura]

I always assumed the the little hole on the side that has a dust cover over it, is for oiling the distributors bushings whenever you remember to.

 

[Anonymous]

I'm not very smart when it comes to carbs. Its kinda tough to read his topic on the air/fuel ratio, because I get totally lost. I'm trying to learn though.

 

[Anonymous]

carbs can be tricky in my opinion. You can set everything correct and still have problems because it might be dirty etc.

keep at it. dont get discouraged. You will get it....I keep telling myself this too
Chaz

ps...nice looking ride...and more pictures? looks very clean!!

 

[Anonymous]

Put the new distributor in, and the Pertronix works with it, but I had to get a new cap and roter for it (go figure). Problem still exists. hmm, I'm out of ideas. I'm going to take off the fuel filter and check it after I sleep for a few hours, just blow through it correct? After that I don't know, fuel pump? I pushed on the throttle on the carb while it was running in park and it didn't seem to hesitate, only while driving, and there is good fuel flow when using the throttle while in park. Timing is set to about +13- btdc.


You don't need to see pictures of it up close, it looks better from afar . I have TONS of pictures of the rebuild and I tried to work on my webpage but I'll have to pick and choose which pics to put in because I have very limited space.