Date: Fri, 14 Dec 2007 09:47:38 -0800
Reply-To: David Kao <dtkao0205@YAHOO.COM>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: David Kao <dtkao0205@YAHOO.COM>
Subject: Re: Knock Knock ?
In-Reply-To: <83FCC0B7-205F-46CC-8C9E-7FEB62582E2A@xochi.com>
Content-Type: text/plain; charset=iso-8859-1
Perhaps the pistons were incorrectly installed? It happened to me
once to my 1971 AC Beetle when a mechanic rebuilt my engine.
He had the pistons all in reversed direction. As a result the engine
lacked power and there was a not quite obvious knocking noise.
Another mechanic took the engine apart and confirmed the error.
Just my guess, a mistake very unlikely but possible. This is very
hard to diagnose without taking the cylinder heads off.
David
--- Michael Diehr <md03@XOCHI.COM> wrote:
> Stump the chumps: I've got an 85 auto with a rebuilt engine with
> about 5000 miles on it. It's running ok overall (mpg around 17-18 in
> fast california driving), but power seems a bit off (even for vanagon
> standards).
>
> The problem: The engine makes a ticktick sound at around 3000 rpm
> that was definitely not there in the prior engine.
>
> It sounds a bit like ping, but the behavior is not always ping-like:
> * only happens under 1/2 to full throttle under load
> (consistent with ping)
> * it's worse at altitude and cold
> (backwards? ping is usually worse at sea level on hot days, right?)
> * not obviously connected to the octane of fuel.
> (inconsistent with ping)
> * the frequency of the tick noise sounds like it may be happening on
> 1 cylinder only
> (e.g. unlike ping, it doesn't seem to decrease in frequency when
> you add more
> throttle, just the loudness increases. When i've driven cars
> with ping,
> usually the ping frequency is dependent on throttle/load too)
>
> It has rebuilt injectors that were flow tested at witchhunter. The
> valves have never been adjusted, and I *think* the shop that installed
> the engine (to which i'm unable/unwilling to go back to them...a long
> story) may have replaced the distributor and messed with the mixture
> adjustment screw, as well as putting in a new (rebuilt) ECU. I'm
> running mobil 1 15/50 w/mahle filter.
>
> Ideas? I'm having a real mechanic look at it, and would like to make
> sensible suggestions...
>
____________________________________________________________________________________
Never miss a thing. Make Yahoo your home page.
http://www.yahoo.com/r/hs
| 
