What cam to Use?
Someone once asked ”What cam should I use in my Aurelia?”. Having done a fair amount of research into Aurelia cams, the answer isn’t totally clear. So here are some recommendations:
- start with a fresh engine. Many engines struggle with low compression and while smooth, are not up to factory standards. So too, certain componentry in the valve train get significant wear, and are not up to snuff. Getting it all back to factory standards is the first course of business.
- get carburetors up to standard. Many period carbs now suffer from wear around the spindle shaft, and leak air, thus making accurate tuning and setup difficult. So too, carb jets may not be accurate and been modified over time.
- consider electronic ignition for better combustion at all RPM.
- start by using the factory cam – the cars are remarkably well tuned and engineered to run with the factory cam. Setting them back to the way they were designed is the correct thing to do.
- if you want more performance, identify why as precisely as you can. In that way, the correct performance enhancements can be selected.
What cams to choose from?
Lancia made several different cams for the Aurelia. The early ones vary largely by timing only, with a bit more lift on the the B22 cam, which is the hottest of the stock factory cams. The later stock cams in the s.5/6 B20 and B24 use the earlier B10 lobe profile, but have a bigger base circle and revised lifters to reduce cam wear.
Of the aftermarket cams, the original Nardi is too radical with extreme exhaust timing. It revs freely but is not a good street cam. There are many Nardi replacement cams made in Italy which are modified and "detuned" to be more usable. There is also a cam made in Italy for Cavalitto, which he sells as between a stock cam and the Nardi. On paper, it seems too extreme for the street, but Cavalitto says not. In America, Megacycle used to make a fine cam for the Aurelia. Not sure if they will still do this.
How hot an engine ?
Which cam to use depends on what engine you want to have and how you want to use it. Each car has different needs, and the engine should be designed to address those. I have had experience with three Aurelia engines, two with modified cams and they all perform quite differently.
In my B20 restoration, the engine was stock with a B10 cam. Compression was increased a bit, to 9:1, and period welded headers were used. The flywheel was lightened a bit, electronic ignition fitted. The car is quite tractable, revs freely and has plenty of upper end power. No need for a change in cam, the engine was fine.
I once had a B20 4th series with a Nardi setup. It had the Megacycle cam, a nice cam that raises the performance modestly. In general, I was very happy with this car, it would pull to 5300 in 3rd gear up long Colorado hills forever. It also passed my “Chicago” test – able to pull from a stop in 2nd gear, with performance balanced nicely between revving and pulling down low – better than the stock cam, but still keeping low end power. The Megacycle cam keeps the Lancia character and opens up the breathing somewhat. Both Steve Snyder and Ed Godshalk have used that cam, and pull past 5000 RPM without any problems.
An engine was built for a B24 Convertible, to give increased power and torque. It had the following:
- Pistons – 9:1 compression
- Carbs – Nardi setup, redone
- Ignition – electronic
- Cam – new one by Dema in California.
- Exhaust – stock
- Flywheel – lightened to 15 1/2 lbs
- the engine pulled very well from 4000 on up, and would bury the tach (over 6000) in 3rd without a problem. It kept making power high up. The cam and carbs worked
- power arrives at around 3700rpm, a bit over 75 mph, not suitable for slower expressways.
- lighter flywheel made gear shifts much smoother. The gears just “snick” into place, and that older 6th series “lag” is gone.
- on the dyno, there was power loss when the oil got quite hot around 200 degrees. Thus the oil cooler on the Flaminia.
The initial goal of this engine was to get some performance, and it did that. The resulting engine ran very close to a Flaminia 3C 2.5 engine, a worthy goal. While breathing better, the use of electronic ignition and probably a superior cam profile gets this Aurelia engine to that level. But over time, the "boy racer" aspect of the engine became tedious, and a single carb was put on. Probably would have changed the cam back to stock later. So be careful - some engine upgrades leave the Lancia character behind. Beware of going too far.
10.14.06, rev'd 6.6.2017