124 Emissions Air Injection Plugs
It’s very common to remove horsepower robbing emission air pumps from 124 twin cam motors and the corrisponding unsightly
air injection rail down the center of the head. Once the rail is gone, there are four open holes in the center of the
head that need to be plugged which will otherwise allow exhaust gasses to escape.
I tried some the loose Fiat fasteners I had laying around and found that wheel bolts fit perfectly in the air injection
holes in the head. I drove over the our local Home Despot to try to make a match with "more attractive" Allen headed hardware
and found they only had 3 of the 4 plugs I'd need. I said, screw it - literally. I went back home, cut four lug bolts off
with a recip saw to about 1/2 inch long section, smoothed the cut ends down on the bench grinder, then with the recip saw
again, cut a slot across the top of each cut face - viola, emissions plugs! I screwed 'em in with a large screw driver and
a little loctite on the threads. I’ve actually received compliments for the more retro look of my plugs.
124 Marelli Electronic Ignition Conversion
As I write elsewhere in the site, I remain a big fan of converting vintage Fiats to electronic ignition from the standard
points style, mainly for reliability benefits and arguably hotter spark. So it is with my ’74 124 Coupe in which I run
the later Marelli stock and it is very reliable. Performance increase? Hard to say, probably some. But not having to mess
with points and starting at a flick of the key is performance increase enough for me.
This ignition was stock on the '79 and later injected cars. I know many other people who are running it on their earlier
carbed DOHC motors and I think this conversion is more common than the use of the after-market Crane ignition. They are fairly
inexpensive, readily available from a number of sources including eBay. The simple swap out of the coil and dizzy can take
less than 10 minutes. Unlike with the Crane ignition, it doesn't require gutting or any cobbled re-use of your points dizzy
should you ever want to switch back.
Two things about this conversion:
1) The distrubutor has a vacuum advance. Leave this disconnected as carbed cars have no "ported" fitting to properly run
this feature. Simply set your timing at idle to 12°-18° BTDC and it will work like a charm.
2) Some early cars will exhibit tachometer bounce with the Marelli electronic ignition. That is: the tachometer will bounce
around, generally act flaky, and pretty much be useless. Marelli specifies the use of 0.68uf capacitor in-line on the tach
wire to correct the problem. To read more about this go to my Tach Fix Page.
3) Before installation of a used electronic distributor, its a very good idea to replace the magnetic pick-up as a matter
of course. Whether it being from the dizzy living near the heat of the exhaust manifold or just plain & simple old age,
the external control wire gets stiff and brittle, but more, the two inner wires are known to fray and pull apart. Keeping
the magnetic pick-up fresh (replace every two years or so) will ensure the very reliable service these units provide.
Updated 20 Feb 2005