Cam Gear on for lifter R&R

[QSHIPQ at aol.com]

Javad:
Let's be clear here.  In the case of the 3B motor, there is no rear cover to
worry about, the rear cover is the cam cover, so an unobstructed "up" of the
exhaust cam can happen, with no risk to the "procedure" whatsoever.  The cam
seal makes this a "not recommended" procedure, cam seals should be done on
every cam removal IMO/E, it's just too cheap to pass up.  If the cam comes
out, a new cam seal goes on, even if you are doing just the cam timing chain
on the 3B, you went from a 15USD procedure, to a 20USD procedure.  Can you
"reuse" a cam seal?  Sure, but we're talking a couple hundred bux worth of
lifters so:  A) the cam seal is a fraction of the total cost, and B)
necessary lifter replacement would dictate this cam seal isn't recent.

WRT 10v cars.  I've done lots of them over the years, and looked for ALL
shortcuts to these procedures, and I weigh these shortcuts in terms of risk
vs benefit, as well as the "can it be done".  I've lost 1 woodruff key in 20
years of... woodruff keys, so that reasoning doesn't make sense to me (sears
sells nice flex magnets to grab those, btw).  Looking in detail at your
procedure, I see a couple of problems that would indicate to me that this
procedure assumes such a high risk of damage, that it isn't a valid
procedure.  IF you are leaving the TB on the cam gear so as to not have to
retension the TB (what I'm reading with the duct tape on the belt to hold it
onto the cam gear), then as you lower the cam onto the number 1 journal you
are adding an off center loading of a steel cam to an aluminum front cam
journal.  The REASON you are leaving the TB on the cam gear is that putting a
previously tensioned timing belt on the cam gear after cam install is a
B*TCH.  Why?  Cuz it's tight.  Thinking this thru, which cam cap goes on
first in your procedure?  What is that doing to the loading of the front cam
journal?

If you follow the Audi procedures, ALL cam journal caps are torqued to spec
BEFORE the Timing Belt Tension load is added.  In YOUR procedure, you're
ADDING TB Tension load to the front cam journal/s BEFORE you have even
installed the cam journal caps.  I wince as I reread that.

Billet steel cams and cheap audi aluminum castings don't mate well under load
Javad.  Using any cam journal to tension an installed cam belt causes stress
on very delicate aluminum caps.

Javad, I read what you are doing is just wrong.  If I can't convince you, I
hope your machinist can.  The 15nm cam journal tightening sequence in the
Bentley manual is the only documentation needed here.

Major no-no Mr Shadzi.

Scott Justusson



In a message dated 1/9/02 12:36:47 AM Central Standard Time, JShadzi writes:


Removing the cam gear is a less than 1 minute job for me, infact, I have
built a tool to lock the camgear in place so that it can easily be loosened
and torqued without rotation.  But, in the occasion it does not need to be
removed, I would rather complete the procedure with the cam gear in place,
and a piece of duct tape also ensures that the cam belt never comes off the
gear, and that the woodruff key can't fall down into the lower crank pully,
BTDT.

Anyway, your posts didn't say "the cam gear should be removed for so-and-so
reason", you said "it can't be done", and I wanted to point out that that
specific statement was incorrect.  Generally, if it has been more than 60-80K
miles, I also would recommned that the cam gear be removed and the seal
changed.

Regards,
Javad