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Re: alfa-digest V9 #370 - cams & followers



On Thursday, March 27, 2003, at 05:31 AM, Jeff Greenfield wrote:

George -

I'm rebuilding a 2.5 V6 right now with about 105,000 miles on it. This car
has been driven enthusiastically its whole life, not abused and has had
regular servicing.

I've seen several of the V6s that needed cams and/or followers. Amazingly
both in this car show no signs of wear. (these are the stock/original 2.5
cams)
Not too unusual. My 2.5 (which I just replaced with a 3.0) had 141,000 miles on it, and it had only ONE worn cam lobe. All the others showed no visible signs of wear other than the expected mirror finish. So one of the cams was perfect. The bad lobe, though, was really bad and getting worse by the mile.



Now for the 10,000 dollar question ... I am putting some new (not reground)
hotter cams in this engine and you've got me wondering if I should replace
all the followers?
YES, absolutely. First off, Alfa Romeo won't warranty the new cams unless new followers are installed, but even if the cams you have aren't from Alfa, they have that requirement for a reason. When you pull the old cams, take out the followers one by one and feel the face of them with your finger. If you feel ANYTHING at all, the follower needs to be replaced. Some will have a ridge worn in them (usually a sign of a too-loose valve clearance), but more sinister is a slight pitting in the center of the follower face. Sometimes you can't even see it without a magnifier, but you can certainly feel it! This pitting becomes an excellent sandpaper for your new cam shaft lobes.



I'm open to opinions ... in the meantime I'll go take a really good look at
all of the old cam followers ...

Thanks,

Jeff

George Graves
'86 GTV-6
now with 3.0 liter 'S' engine
and Power Steering


-----Original Message-----
From: owner-alfa@domain.elided [mailto:owner-alfa@domain.elided] On Behalf Of
George Graves
Sent: Thursday, March 27, 2003 1:51 AM
To: alfa@domain.elided
Cc: diogenio@domain.elided
Subject: Re: alfa-digest V9 #370

Good luck. I just went through a similar ordeal and ended up buying a
new pair. Here's what I found:

It looks as if either Alfa 12-valve camshafts are not very hard or the
cam follower buckets aren't very hard (or both). Every used pair I have
looked at was seriously worn. Even the ones that came out of a very low
milage Milano engine (less than 50K) were worn. In turn, this wears the
followers (or perhaps, vice-versa. Who knows?). I also looked at a
couple of pairs of 're-grinds' which have been re-profiled to 'S'
characteristics, then re-hardened. All of these had so much material
removed from the 'heel' of the cam lobe*, that it requires one to have
custom tappet spacers made-up to get the valves to adjust as Alfa
doesn't make any which are thick enough for re-ground cams and you
can't stack them. A new pair will cost you about US$800, and you also
need to replace ALL of the cam follower buckets, both for the 6 inlet
valves and the six exhaust valves because they are bound to be worn as
well. To check, run your finger over the follower face. If you feel
ANYTHING at all, that bucket needs replacing. Some of them exhibit a
ridge where the cam strikes it, and others show pitting right in the
center. If you do not replace them, these worn buckets will abrade your
fresh cams like sandpaper.

Not good news, I know.


*When a worn cam is re-profiled, it is required that the worn part of
the existing lobe must be ground completely away. This means that ALL
the lobes must then be ground to match the worst one. This results in a
lot of material being removed. Since Alfa V-6 cams tend to wear fast,
most cams you see will have one or two lobes that very badly worn. This
is likely the reason why all of the re-grinds I've looked at had
insufficient 'meat' on the heel. Also, I have heard that many re-grinds
are even softer than the factory cams. Sperry's, for instance, seem to
have garnered a reputation for being extremely prone to wear.

George Graves
'86 GTV-6
now with 3.0 liter 'S' engine
and Power Steering


On Wednesday, March 26, 2003, at 10:41 PM, alfa-digest wrote:

Date: Wed, 26 Mar 2003 21:37:05 -0800
From: "Dennis Lusis/CPI LABS" <diogenio@domain.elided>
Subject: Wanted: Pair of good 164 "S" cams.

Looking for good used "S" cams to drop in my 87 Milano 2.5 L. Thanks.

Dennis
San Diego, CA
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