[Vwdiesel] Injector Seals

[James Hansen]

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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