[T3] Knock Knock

[Keith Park]

that sounds like valve train, it doesnt change as the oil pressure comes up
so it isnt a pressure fed bearing.

Keith


Topnotch Restorations
topnotch at nycap.rr.com
http://www.a383ina68.addr.com/radiorest/main.htm
71 Squareback  "Hothe"
65 Notchback  "El Baja Rojo"
93 RX7  "Redstur"
87 Golf  "Winterat" RIP
01 Sentra SE "Boremobile"
 

-----Original Message-----
From: type3-vwtype3.org [mailto:type3-vwtype3.org-bounces at lists.vwtype3.org]
On Behalf Of Sean Bartnik
Sent: Saturday, September 16, 2017 7:14 PM
To: type3 at vwtype3.org
Subject: Re: [T3] Knock Knock

Just to add my impression since the character of the noise doesn't always
come across in video (though I think this one does a good job).

It's a very metallic hammering type sound.  Sounds deep; not like valve
noise.


> On Sep 16, 2017, at 6:51 PM, Daniel Nohejl <d.nohejl at gmail.com> wrote:
> 
> Over the last few weeks, we've been trying to diagnose a noise....
> 
> In Madison, I thought I noticed what sounded like a loose valve. A day or
so later, we discovered that the connection between our heater box and
muffler was loose. We tightened it and applied some muffler repair and the
noise vanished. Now, we have a new louder noise that has emerged over the
last few weeks. It's been hard to diagnose as the noise is generally loudest
at cold start and for the 10 or 15 seconds the engine is running before the
high idle kicks in. To properly diagnose, I had to pinch off the AAR hose at
the air cleaner so I could get a low idle for a longer period. I also
required the assistance of Sean, whose ear has proven indispensable more
than once. Anyway, here are the other general characteristics of the noise:
> 
> 1. The noise is loudest at idle
> 2. Above idle, it sounds like a loose valve.
> 3. While cruising, it can barely be heard, even when driving next to a
concrete divider on the highway.
> 4. After letting off the gas, the noise doesn't return until just above
idle. It definitely doesn't start up right after getting off the throttle.
> 5. It's clearly coming from the 3/4 side of the motor.
> 6. All valves are correctly set, there's no excessive side play (solid
rocker shafts), the springs are fine, etc. I've run the motor several times
with the valve cover off and everything looks right. 
> 7. After unplugging the spark plug wires at #3 and #4, it's clear that the
issue is at #3. With the #3 wire unplugged, the noise diminishes by a good
80%
> 
> Here's a video (credit Sean) that does a great job of capturing the noise
> 
> https://youtu.be/sxs1yrFLPl0
> 
> I know what all of this suggests, but I'm curious if what I'm describing
rings any other bells for anyone. Or, if we know what it is, can it be fixed
without splitting the case????
> 
> Thanks, 
> 
> Daniel
> 
> 
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