[T3] On a 73 T-3 SB fuel injected auto trans pinging

Jim Adney jadney at vwtype3.org
Tue Dec 12 11:46:45 PST 2017

On 11 Dec 2017 at 12:55, William J wrote:

>  Also on Samba I'm being told that the injector seals of the kind that
> are sold by most on-line and FLAPS only last 2 years before drying out
> and cracking providing a leak . Mainly by one fellow who says you
> should use green CIS viton O'ring type . Last ones I got from bus depot
> and they looked just like the one VW sold like they were molded black
> rubber , by molded they have a small ridge around the center. 
>  I replaced mine in 2009 and just looked and see no cracks . He claims
> it's the fit around the injector tip that is the issue . What I see
> once compressed they seal around the tip/ yellow plastic cover and the
> base of the injector . I cannot rotate mine or move any injector one
> bit. . He also said  seals that sit unused are shot 

Probably about half of mine are still originals. I see no problem continuing to 
use them. I hate the idea of replacing that square cross section seal with a 
round o-ring. I'm concerned that we'd then be asking it to seal against the 
unmachined cast surface out at the edge of the machined recess.

It's certainly possible that there are unreliable aftermarket parts. That's just 
another reason to keep using the OE stuff as long as it's good. I NEVER 
replace old parts with new just so they'll be new. There needs to be a good 

BTW, Viton is great stuff: good chemical resistance and good high temp 
performance, but unusable at low temps, say below freezing. (Remember the 
Challenger Space Shuttle!) Not really a good choice in general, but it's 
important to understand that there are actually dozens of formulations of 
Viton, as well as hundreds or thousands of other kinds of elastomers.

>  I was also told you can't use or find thin enough gasket paper to
> replace the gasket on both sides of each runner to intake plastic
> spacer. 

The original paper wasn't anything special. It was very thin and it does not 
appear to be any kind of gasket material. I use regular typing/copy paper; it 
works just as well as the OE stuff did.

>  I also wanted to ask if you have 4 of the runner to IAD hoses and
> maybe the injector  tip seals ? and if so what would they cost. I can
> find then on-line yet the shipping is a killer. 

I don't think I've ever had to replace the air runner sleeves, but sometimes, if 
you're rebuilding an engine that's been put together carelessly, or you've just 
realigned the runners, you have to snug the sleeves up with cable ties for a 
few years to give them a chance to assume the new shape.

For the injector tip seals, if you can squeeze one and it can collapse without 
cracking, it's still good. I reuse them many times.

For the outer "seals", they last forever, unless you get a gas leak that soaks 
them. Then they expand and break the phenolic alignment blocks. The 
alignment blocks are the only part I've had to replace very often. The swollen 
outer seals will recover if you let them sit for a few months. The gas 

Jim Adney, jadney at vwtype3.org
Madison, Wisconsin, USA

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