Euro Cam Thread

[George Beston <gbeston@domain.elided>]

For anyone who has done a Euro cam conversion and been disappointed, 
you may be interested in my experience.  By the way, we are talking 
about the 105.48 cam, right?

I'm referring here to an internally dead stock 2L  Alfetta engine which 
has been "improved" by the addition of cast European-style exhaust 
headers, conversion to 40 mm Dellortos and the installation of 105.48 
cams.

Initially, the cam installation was a disappointment. The engine had 
lots of torque at the lower end of the rev range, but was breathless 
above 4500 rpm.

Turns out that the cams were timed by lining up the marks on the 
bearing caps with the cam marks.  I honestly don't know what the timing 
was, because I never checked it by measurement.

In the years since, have gone through three different timing 
adjustments.

The first was  to  the published valve timing for the 105.48 cams, 
which is LCA's of 99.5 degrees.  This was an improvement, but the 
engine still tended to have bags of torque at low rpm and to be out of 
breath at the high end.

The next cam timing I evaluated was lobe center angles of 114 degrees 
on both cams.  Overall, this was a substantial improvement, with 
somewhat less torque at the bottom end, but no sign of running out of 
breath at the red line.

The most recent timing that I have used is Intake LCA 123 degrees ATC 
and exhaust LCA 103 degrees BTC.  This is not quite as fast overall as 
the 114/114 setting, but the engine is extremely smooth and strong 
throughout the rev range.

The last two adjustments were selected with the help of Dynomation, an 
engine simulator.  If anyone wants more information about this, contact 
me off line and I'll pass along a couple of articles I've written on 
the subject for the Canadian club's newsletter.  The only warning I 
would give about using these timings is that they are fairly specific 
to the engine configuration.  Improvements in air flow would change the 
optimum timing.  Also, I would not consider these timings applicable 
for the 1750 or other common Alfa engine sizes.

By the way, the simulator agrees with those who install high lift cams 
on the intake side only. Once restrictive  emission era exhaust 
manifolds are out of the picture, there doesn't seem to be a lot of 
power to be gained on the exhaust side.  There is some, but it's in the 
"long run for a short slide" category that may only return a few more 
horsepower.

George Beston
Alfetta
1300 Spider Jr.
--
to be removed from alfa, see /bin/digest-subs.cgi
or email "unsubscribe alfa" to majordomo@domain.elided