Re: alfa-digest V9 #664

[George Graves <gmgraves@xxxxxxxxxxx>]

Joe, this is typical. It's probably a worn cam lobe, although, it COULD 
be a sticky injector. One of the rules of Italian automobiles is that 
the quality of the materials and workmanship are ALWAYS inversely 
proportional to the importance of the item in question, Case in point: 
the Alfa V-6. Take the cam cover off and marvel at the intricate 
casting with it's gorgeous internal cross ribbing insuring both 
lightness and rigidity -forever!. Now look closely at the cams and 
followers. They are crucial to the running of the car, yet they are so 
soft that they wear badly, often after only a few tens of thousands of 
miles. For some reason the driver's side, rear piston's intake lobe and 
tappet wear more and faster than others. This causes a ticking sound as 
the cam lobe (whose clearance is now too great) comes in contact with 
the inverted bucket tappet on each revolution. When it first appears, 
it usually only affects the car when the engine is cold because the 
valve stem (and all metal parts) contract when cold. This increases the 
distance between the lobe and the tappet. As the engine heats-up the 
valve stem expands closing the gap and the ticking goes away. As the 
wear gets more pronounced it will eventually tick all the time. It's 
nothing to worry about, it just sounds annoying, but eventually, the 
intake valve will be so far out of adjustment that it will affect 
performance and will have to be dealt with. My old 2.5 Liter engine had 
this problem (it too used to quiet down when the engine warmed-up), and 
it's the main reason I changed it to the 3-liter but my original plan 
was to rebuild the 2.5 liter heads and fit new cams and tappets - but 
this low-milage 3-liter turned up, and was actually cheaper than 
rebuilding the 2.5's top end, so.... But anyway, as bad as it was 
before I swapped it for a "new" engine, It would still happily and 
freely rev to redline anytime it was asked to do so.

The fuel injectors on the Bosch L-Jetronic system also 'tick' slightly, 
and a sticky one is louder, but you can't generally hear  those with 
the hood closed, so if you can hear the ticking from inside the car, my 
bet's on the camshaft.


George Graves
'86 GTV-6 3.0S



On Thursday, Jul 24, 2003, at 21:28 US/Pacific, alfa-digest wrote:


> ------------------------------
>
> Date: Thu, 24 Jul 2003 13:11:21 -0400
> From: Joe Elliott <jee@domain.elided>
> Subject: 2.5L V6 ticking noise
>
> My GTV-6 has started making a noticeale ticking noise from the driver's
> side head when it's cold.  As it warms up it goes away.  Any ideas what
> broke? Should I be worried?
>
> Thanks,
> Joe
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