Date:         Tue, 18 Dec 2007 08:30:45 -0500
Reply-To:     Dennis Haynes <d23haynes57@HOTMAIL.COM>
Sender:       Vanagon Mailing List <vanagon@gerry.vanagon.com>
From:         Dennis Haynes <d23haynes57@HOTMAIL.COM>
Subject:      Re: Knock Knock ?
Comments: To: md03@XOCHI.COM
In-Reply-To:  <EB332026-249F-4B2C-8793-92F96FD59668@xochi.com>
Content-Type: text/plain; format=flowed

So, how did the mechanic adjust it for running lean? The O2 sensor should be
in control. The adjuster on the AFM only has alimited effect at idle. Off
idle it will not make a difference and if it does, go back to the O2 sensor.
How far was the timing off? I think the lack of exhasut gaskets would be a
major issue.

Dennis


>From: Michael Diehr <md03@XOCHI.COM>
>Reply-To: Michael Diehr <md03@XOCHI.COM>
>To: vanagon@GERRY.VANAGON.COM
>Subject: Re: Knock Knock ?
>Date: Mon, 17 Dec 2007 07:31:49 -0800
>
>Thanks for all the Sherlock Homes who replied with theories.
>
>Update:   the mechanic says the timing was off and the motor was
>running lean, and that it's been adjusted and is running much better
>now.   He also noted that the PM (previous mechanic) didn't put
>gaskets on the exhaust headers.   He also said he'd not been able to
>hear the knock/ping/tap noise, which is not surprising since I
>couldn't hear it either on the drive into the shop.  (Don't we love
>our vanagons?!!?!)
>
>I've not yet driven it yet, but it sounds like with luck that it's not
>anything terrible like reversed pistons or broken rings.
>
>I guess it's not clear how much damage I may have done by running lean
>for many hundred miles, but I was aware of the issue and was trying to
>baby it...
>
>Rocket J Squirrel:  this perhaps explains some of our MPG
>differences?  A dangerously-lean condition on my engine giving me
>18MPG.    I guess there's no free lunch...
>
>
>On Dec 14, 2007, at 4:30 PM, Scott Daniel - Shazam wrote:
>
>>Bingo on the small exhaust leak !
>>A small one can sound like a tick tick tick  sound all right,
>>And waterboxer exhaust pipes like to warp, contributing to  gasket
>>leak,
>>and the pipes crack sometimes too.
>>
>>-----Original Message-----
>>From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com] On
>>Behalf Of
>>Dennis Haynes
>>Sent: Friday, December 14, 2007 3:27 PM
>>To: vanagon@GERRY.VANAGON.COM
>>Subject: Re: Knock Knock ?
>>
>>A tick tick sound under load could be something as simple as  and
>>exhaust
>>gasket leak or more complicated as piston slap or even a broken
>>ring. A
>>compression or leak down test may be able to locate the offending
>>ring.
>>Piston slap would more likely be due to a piston installed backward
>>or a
>>size tolerance problem between the cylinder and piston. A bad wrist
>>pin
>>bushing can also cause noises but that like a rod bearing is usually
>>as
>>load is reduced.
>>
>>Dennis
>>
>>-----Original Message-----
>>From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com] On
>>Behalf Of
>>Michael Diehr
>>Sent: Friday, December 14, 2007 11:02 AM
>>To: vanagon@GERRY.VANAGON.COM
>>Subject: Knock Knock ?
>>
>>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...