Hi all,
I have a '79 California model Spider that has been with me since 1997. Drove it for a couple of years, then took it apart for a restoration that ended up lasting 18 years... Been back on the road for 7 years now with very few problems. As I love working on the car, I'm always looking for something to do. Aside from some small cosmetic issues I could work on and chasing a couple of annoying rattles, there's not really much to do right now. However, I found out a while ago that the distributor is not original and seems to have been swapped out for a version without the vacuum advance. The car runs great with it, and I don't see an urgent need to replace it with one that has the vacuum advance, but it is tempting to see if there would be a change in performance or gas mileage. I asked the same question on a German forum, and the consensus seems to be that the benefits would likely be minimal. So I'm asking you guys: What is your take on that? I've heard the quality of the aftermarket distributors is not great, but definitely very tempted to try. Excited to hear your answers!
Thanks,
Gunther
Distributor vaccuum advance
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gschwab
- Posts: 25
- Joined: Sat Nov 11, 2017 12:27 pm
- Your car is a: Fiat 124 Spider CS2 1979 California
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18Fiatsandcounting
- Posts: 3894
- Joined: Fri Mar 15, 2019 11:23 pm
- Your car is a: 1969 and 1971 124 spiders
- Location: San Francisco Bay Area
Re: Distributor vaccuum advance
Hi Gunther, the vacuum advance only operates when the engine is at part throttle, low rpm conditions. So, essentially around town or light highway driving. It can make the engine feel a little peppier under those conditions, but if you drive hard then the vacuum advance isn't doing much and so there won't be much difference in ultimate performance.
You might get a little better fuel economy, but it would be pretty minimal like one mpg difference. Speaking of which, you should be getting in the mid to upper 20s in terms of mpg.
One simple thing you could do is just advance the static timing (at idle) just a bit. The spec is 10 degrees BTDC as I recall, but these engines are peppier with 12 or even 14 degrees advance at idle. As long as the engine isn't knocking at higher rpms under heavy throttle, you're good. If it does, you'll need to back off the timing to 10 degrees BTDC.
-Bryan
You might get a little better fuel economy, but it would be pretty minimal like one mpg difference. Speaking of which, you should be getting in the mid to upper 20s in terms of mpg.
One simple thing you could do is just advance the static timing (at idle) just a bit. The spec is 10 degrees BTDC as I recall, but these engines are peppier with 12 or even 14 degrees advance at idle. As long as the engine isn't knocking at higher rpms under heavy throttle, you're good. If it does, you'll need to back off the timing to 10 degrees BTDC.
-Bryan
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gschwab
- Posts: 25
- Joined: Sat Nov 11, 2017 12:27 pm
- Your car is a: Fiat 124 Spider CS2 1979 California
Re: Distributor vaccuum advance
Thanks for your answer, Bryan!
I generally don't drive the car particularly hard, however highway speeds here in Germany are generally a bit higher. I usually do about 80-90 on the highway, which leads to a gas mileage in the mid 20s. I should probably check the current timing, it's been a while since I've done that. Definitely tempted to give a new distributor a try...
Gunther
I generally don't drive the car particularly hard, however highway speeds here in Germany are generally a bit higher. I usually do about 80-90 on the highway, which leads to a gas mileage in the mid 20s. I should probably check the current timing, it's been a while since I've done that. Definitely tempted to give a new distributor a try...
Gunther