[Vwdiesel] Injector Seals

[mark shepherd]

I make it a point of always reusing heat shields. Not because of the money, 
although if you are experimenting with the injectors it can add up over 
time; but because I believe that a shield can for a few reuses at least, 
develop a better seal than first use.

I always use a 19mm nut, a 3/8" ball bearing to reform the shield, and a set 
of clamp pliers to give a repeatable redeformation.
They do not need to be redeformed quite to the same extent, but about 0.5mm.
I rest the shield upon the injector and use my thumbnail as a gauge to check 
the gap.
The lower face of the shield has unique machine ridges around, which help to 
seal the shield to the ledge on the head. Unfortunately, the shield being 
hard, furrows the head!
 Every new shield cuts it's own furrow and so actully wears the ledge away, 
so I always put the same shield back in the same hole.

I am actually on the 10th reuse with these! I do not advocate this, but can 
thus say safely  reuse for 5 times.

Just for those who insist on single use only; I'd like to ask how many 
single use shields have leaked, and how many have leaked to the point of 
sealing up the threads with carbon?
For me with these shields, effectively used 40 times between them, only 3 
uses have required resetting, so that makes them statistically more reliable 
than new IMO...

On the GTD site I posted a picture of 8 shields, four had had a single use, 
and four  had been used 8 times.
No one took up the challenge to segregate them, not even those claiming it 
could destroy an engine to use more than once....
Pathetic really  ;o)

Regards,
Mark


----- Original Message ----- 
From: "mark shepherd" <mark at shepher.fsnet.co.uk>
To: "vw fans" <Vwdiesel at vwfans.com>
Sent: Monday, April 11, 2011 10:34 AM
Subject: Re: [Vwdiesel] Injector Seals


>
> testing
> ----- Original Message ----- 
> From: "James Hansen" <jhsg at sasktel.net>
> To: "'Dave Cook'" <davevw at yahoo.com>; "'Audi-VW-Diesels Group'" 
> <Audi-VW-Diesels at yahoogroups.com>; "'VW Diesel Group'" 
> <vwdiesel at vwfans.com>
> Sent: Monday, April 11, 2011 6:13 AM
> Subject: Re: [Vwdiesel] Injector Seals
>
>
>>
>> Yes, they need to be new, or at least reformed.  What i mean is, the new
>> seal will have a touch more dish in it than a used one.  They have some
>> preload in their shape, so when the injector pushes down on them, the
>> springiness of the seal squishes under torque and maintains sealing 
>> pressure
>> against the nozzle through heat cycles, etc. as the injector moves 
>> slightly
>> through those heat cycles.  Used ones have less shape, hence less 
>> preload,
>> and may leak, filling the injector threads with carbon, seizing it to the
>> head, killing threads on the way out, etc..  You can reshape them with a 
>> big
>> centerpunch and a block of wood- just bop them a little bit to the nozzle
>> side, and they will mimic new ones.  I've done this lots.  You can grind 
>> one
>> yourself with a drill and a grinder.  Chuck the punch stock, preferably 
>> some
>> cold rolled, and grind to a point, to match the injector seal body shape.
>> It doesn't take much, and they can crack... so careful, or anneal them
>> first. (bring to a red normalizing heat, then let cool very very slowly)
>> -james
>>
>> -----Original Message-----
>> From: vwdiesel-bounces at vwfans.com [mailto:vwdiesel-bounces at vwfans.com] On
>> Behalf Of Dave Cook
>> Sent: April-10-11 6:56 PM
>> To: Audi-VW-Diesels Group; VW Diesel Group
>> Subject: [Vwdiesel] Injector Seals
>>
>> Someone please tell me it is ok to reuse injector seals!
>>
>> I am very close to having the engine hooked up!  It is all bolted into 
>> the
>> car, just working on hooking up fuel, coolant, clutch, etc etc lines and
>> wires.  If possible, I might be able to crank it tonight!
>>
>> I noted when I was cranking over the engine that I could hear compression
>> leaking around number 1 injector.  So I went to tighten it and it was 
>> only
>> finger tight.  Well, all the other injectors are also loose so I popped 
>> them
>> out to take a quick look.  All were ok, but I kinda thought the seals 
>> needed
>> to be new every time they were installed.  Good thing I checked, though, 
>> as
>> number 4 didn't have a seal in there at all!
>>
>> I could pull a seal out of another head, assuming that is ok to do...
>>
>> I could get some tomorrow afternoon probably, but have to work late 
>> tomorrow
>> and Tuesday so it will be a few more days before I could try to start it,
>> and I'm rather impatient!
>>
>> Dave Cook
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