Vac Advance is toast on my distributor--repair?

[hberdan]

Looks like the vacuum advance is out on my distributor. Any way to repair this, or should I just replace it?
What is a rebuilt one going for these days?

[Petros]

It might be possible to repair it, but I do not think anyone has attempted it yet. You can buy just the vac advance, very costly new. In my experience most used one are just as bad. I go through the wrecking yard remove them and test them, most are bad. When I put a working used one on my car, it does not last long. the rubber diaphragm is very old, and does not last once it starts getting used again.

It will run fine without it, it just means your part throttle economy will not be as good. That is like at fwy speeds where the vac is high, it allows the spark timing to advance to improve economy. Unless the emission controls cuts it out, which is most of the time.

[hberdan]

The car seems to run fine-- but with some loss to mpg and acceleration, compared to years past. (Tercel wagon acceleration, an oxymoron) I imagine this happened a while back and I just got around to diagnosis a couple of days ago when I was doing some tune up work. All winter the mileage has been bad, so I replaced the plugs, did a valve adjustment, new valve cover gasket, replaced a couple of cracked vacuum lines, checked the timing---and then noticed that the advance was no longer working...so you're saying I should just not worry about it?
Can I change it out with a used one, without removing the distributor from the engine? I have a spare used distributor that came off one of my since-gone parts cars, and I've never checked to see if the VA works.

[4wdchico]

Last I checked Rock Auto and Amazon both sell the Standard Motor Products P/N VC360 for less than $60. If you go to the RA website and enlarge the picture of it there is what appears to be a ND brand stamp on it, making it an OE part.

[xirdneh]

o'reillys has them for 53.00 plus tax
rockauto for about the same plus shipping cost
i have replaced them just removing distr cap
could probably be done without removing it with a little practice
sometimes the screw that holds it on does not come off so easy

[Petros]

I find it easiest to replace them by removing the distributor, which is easy, but does require you to re-time it. Likely it can be done without removing the dist, but if you have not done it before it will be a bit frustrating I think. You know how to check if the vac is good don't you? suck hard on the advance vac port and you will see the arm pull into the unit. If you can suck air through it, diaph. is bad.

If you carefully mark the location of the distr at the slotted base where you adjust it to set the timing, you should be able to get it back in at the same timing position.

[hberdan]

Thanks Petros, those were my next two questions! I went thru my spares this AM and found the used but complete distributor with the vac advance, which came right off after removing the cap and the set screw. I'll clean all the gunk off before I try to test it, though! Yuck. With the typical leaky distributor oring and the bottom position of the thing, it's mighty greasy.
Looks like it would be easy to install one without moving the distributor out of position, if I can get the arm to cam enough to set into that pin properly.

[hberdan]

o'reillys has them for 53.00 plus tax
rockauto for about the same plus shipping cost
i have replaced them just removing distr cap
could probably be done without removing it with a little practice
sometimes the screw that holds it on does not come off so easy

If this used one is also no good I'll put in a new one. I think these days any extra mph is useful, and $60 is only a bit more than a tank of gas...(!!) Yesterday, I only looked at the Toyota OE parts; the vac advance was $155!

[hberdan]

I've not gotten around to replacing the vac advance yet, but even without that the car is getting 28mpg on mountain roads! Not bad, all things considered.

[takza]

My last good tank with the wagon came in at 35 mpg....no vac advance...but with the timing advanced some. A problem was a rough idle though. Was running 0W30 synth oil with synth gear oil. 0W30 synth probably not a good idea....started to use some after 5-6K miles.

[dlb]

My last good tank with the wagon came in at 35 mpg....no vac advance...but with the timing advanced some.

takza, do you remember what your timing was set to at this time?

[hberdan]

My last good tank with the wagon came in at 35 mpg....no vac advance...but with the timing advanced some. A problem was a rough idle though. Was running 0W30 synth oil with synth gear oil. 0W30 synth probably not a good idea....started to use some after 5-6K miles.

I'm running on Kendall 5-W30 GT-1® High Mileage Synthetic Blend Motor Oil, replacing the 10-W40 Valvoline semi synthetic I've been using for years. Oil is being used at about the same rate as with the Valvoline. Engine sounds good.

[hberdan]

Last I checked Rock Auto and Amazon both sell the Standard Motor Products P/N VC360 for less than $60. If you go to the RA website and enlarge the picture of it there is what appears to be a ND brand stamp on it, making it an OE part.

Finally got around to getting one--Oreillys wanted $103, Rock Auto wants ++shipping $$--but as you wrote, the Amazon part is only $53 with free shipping, no tax, and it is EXACTLY an OEM part. ND brand, box says made in Japan. Can hardly wait to get it in the dizzy and go for a drive!

[deejay1272]

My last good tank with the wagon came in at 35 mpg....no vac advance...but with the timing advanced some.

takza, do you remember what your timing was set to at this time?

I'm currently advanced to about 18-20 deg BTDC. This, with my working vac advance, takes me up to a very aggressive advanced timing when vacuum is high. Currently I'm getting around 36 mpg on the freeway - no complaints about that!

(In combined city/hwy driving, I'm at about 31 mpg usually...). I don't typically use up a full tank in city driving, but I bet my economy is pretty bad for in town driving - maybe ~22-25? That's why I usually take my EFI Honda Civic for in town trips if I can. It gets somewhere near 30 in the city (39 on the hwy!).

[danzo]

hberdan have you installed the new vac advance yet? What are your before/after ignition readings? I'm thinking of replacing mine, as I'm not getting enough advance much above idle.