glenahan at vfemail.net
Thu Jul 31 16:14:36 PDT 2008
On Jul 31, 2008, at 11:58 AM, Mark R wrote:
> The "tick" is the camshaft (or rocker arm in something like a small
> block chevy) "hitting" the top of the lifter. In other words, the
> lobe doesn't always remain in contact with the "top" of the lifter
> as it should (with the obvious thin coating of oil in between). If
> you picture the "tick" as a hammering type of action, you'll
> envision what's going on. The wear is the surfaces of top(s) of
> the lifter(s) and the cam lobe(s).
> Why does this occur? History- lifters used to be manually adjusted
> and the "lash" was set by shims or some other adjusting
> mechanisms. This was a maintenance item and required packaging so
> that this was possible to routinely adjust. Also, with tighter
> emissions regulations, having it only adjusted periodically meant
> that all other time, the timing wasn't optimal. This is especially
> troublesome in a lean-burn emissions configuration.
> The fix which allowed for tighter engine packaging, improved
> performance over time, and improved emissions- lifters which self-
> adjusted. they do this by being "pumped up" (thing of them as
> being elongated) by oil pressure (and volume). Hence the term
> "hydraulic lifters."
> If they don't "pump up" as designed, the lash becomes greater, wear
> increases, and valve timing is off. Again, many cars can go a long
> time in this state before anything catastrophic occurs.
> Respectfully, I believe if there's a tick, there IS increased wear
> occurring versus a valvetrain which isn't ticking. I fully agree
> that for a lot of people and budgets, it might not be enough wear
> for a lot of concern.... which is what I suspect Grant's comment
> really meant.
> Hope this helped!
> Mark Rosenkrantz
> On Thu, Jul 31, 2008 at 11:25 AM, <jlagnese at massed.net> wrote:
> I was under the impression that lifter tick, caused by hydraulic
> lifters not full of oil, simply decreased efficiency since the
> valves were not opening fully.
> So where is the wear? The top or inside of the lifter? The cam?
> Anytime there is not enough oil someplace, things do wear!
> ---- Original message ----
> Date: Thu, 31 Jul 2008 10:39:27 -0400
> From: "Mark R" <speedracer.mark at gmail.com>
> Subject: Re: lifter tick
> To: "Grant Lenahan" <glenahan at vfemail.net>
> Cc: quattro at audifans.com
> >I respectfully disagree with Grant. Lifter tick DOES increase
> wear. That
> >said, Audis seem to tolerate it for a LONG time, so it might not
> be worth
> >the expense and trouble of replacing the lifters. In other words,
> the harm
> >is typically minimal, but it is there.
> >If you fixed it with different oil or a solvent... then it's fixed.
> >Hydraulic lifter tick is caused by "crud" (deposits) in the lifter
> (s), low
> >oil pressure, incorrect weight of oil, etc. The first step is
> always to
> >either try a solvent, switch oils (weight, type, brand), oil
> filter brand,
> >etc. If that solves the problem, then there's no problem
> remaining! =)
> >Mark Rosenkrantz
> >On Thu, Jul 31, 2008 at 8:01 AM, Grant Lenahan
> <glenahan at vfemail.net> wrote:
> >> ignore it - it does no harm
> >> On Jul 30, 2008, at 10:09 PM, Rick Cone wrote:
> >> > My 89 Audi 200 has a rather noisy lifter tick. I "fixed" it
> with a
> >> > quart of Lucas, but what is the real fix? Is there any adjustment
> >> > in the valvetrain of these things?
> >> > Rick A. Cone
> >> >
> >> >
> >> >
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