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mark pollard · Guest

I am doing my first rebuild of a 16v engine and am puzzled by the cam profiles. The inlet lobes seem to have two different profiles - is this wear or is it normal? The exhaust lobes appear to be a bit 'pointy' - on a 8v this would be a sign of wear - is it the same on the 16v?
If the shapes indicate wear, does anyone have any good cams for sale (standard or uprated)
Thanks,
Mark

tvatavuk · Posted: Sat Jan 08, 2005 12:03 am Post subject:

There are few 16v out there that have cams in perfect condition. You can take a look and see how high are they, usually one lobe is more worn then the other on the same cam shaft.
16v in good condition are hard to find these days
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Tino Vatavuk
Little black dress which replaced Alfa Romeo 33 S 16v Permanent 4 GMo

paddy granger · Alfa Sprint Joined: 12 Aug 2003 Posts: 248

Hi tvatavuk, is it just the 16v engines that suffer from this problem, or also the 8V engines? At what kind of km's do the problems usually start?

Ben_nz · Posted: Sat Jan 08, 2005 6:54 am Post subject:

A mechanic told me that Alfa boxer engines (in general) tend to 'chew out camshafts', the 1.7 (8v) slightly more than the 1.5. When my motor was pulled apart after a timing belt failure, it had worn cam lobes, some quite bad and some hardly worn at all. This was a 1.7 8v engine from an s2 33. The motor had about 130,000kms on. Presumably the amount of wear depends on whether the car gets regular oil changes, and I have no idea how well my car was treated before I got it.

Matt Stolton · Posted: Sat Jan 08, 2005 7:04 pm Post subject: Variable valve Timing

The 16V do have slightly different inlet lobes, i.e. of the two lobes per cylinder, one is slightly thinner and taller, whilst the other is broader and shorter.

My 16V project had cams (we believe Autodelta) that had this effect eccentuated still further. Along with the injector pointing more behind one valve than the other, you effectively get one air/fuel valve, and one air valve. At high RPM, with this funny valve asymetry, this helps breathing, but helps maintain torque at lower RPMs.

Check a workshop manual for the correct specs, in case you do have genuine wear, but there is some asymetry to the standard cam profile on a piston by piston basis. The exhaust valves are sysmetrical IMHO.
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Regards

Matt

Ex Alfa 33 'GTA' (P4 with Knobs On)
Now cruising in a 166 3.2 Ti!!

tvatavuk · Posted: Sun Jan 09, 2005 3:42 pm Post subject:

Hi Paddy,
AFAIK all boxers are, but those with hydro lifters chew them better Sad

.
_________________
Tino Vatavuk
Little black dress which replaced Alfa Romeo 33 S 16v Permanent 4 GMo

mark pollard · Guest

Thanks for the comments guys. I think I need 1 exhaust camshaft and 1 inlet.
Can anyone help?
I am also putting this request in the 'For Sale' section
Mark