CIS Cylinder head question

[Peter Jones]

Mine uses the two piece brass and plastic combo.

I've got these bits on the way from the very helpful people at http://www.germanautoparts.com


Upper fuel injector holder. Brass.
Threads into cylinder head and holds injector. Requires lower half and seal ring below. One required per injector.

Lower fuel injector holder.
Plastic.Snaps onto brass upper holder. Requires seal ring below to seal against cylinder head. One required per injector,

Seal ring, lower fuel injector holder. 16.5 x 19.5 x 1.5mm
Seals lower plastic injector holder to cylinder head. One required per injector

Seal ring, fuel injector.
Upper (large, thick), at top of injector, between injector and upper injector seat. One required per injector.

Seal ring, fuel injector.
Lower, (small, thin), at bottom tip of injector, between injector and lower injector insert. One required per injector.


All these bits can be found from this page http://www.germanautoparts.com/main....maingroup=Fuel

Just thought it would be handy to other CIS travellers to see all the bits laid out.

GermanAutoParts also has the unshrouded injectorholders as well as the one piece plastic holders.

Thanks for the tip about the aux air line, that sounds like a convenient place to attach the plumbing.

Pete

[twin eng, twin turbs]

I'm not sure why the GX is so low spec, it's CR is something like 8.5:1 and the cam is only 250 degrees duration.

Yep there should be o rings at both ends of the injector, I've got all of them new ready to go. There's another o ring in the head under each of the plastic insulators.

Pete

You are right about the GX being of low performance, it runs a milder cam,9.0:1 compression and 38mm inlet valves instead of 40.5mm inlet valves found in DX series 1800, which is the best 1800 8v for tuning due to its larger bowl area in the inlet port. I blocked my injector air shrouding port in the back of my head with a 1/8'' BSPT plug when i had the original CIS injection system on my MK2 and it made no difference to the drivabilty at all...

[Peter Jones]

You are right about the GX being of low performance, it runs a milder cam,9.0:1 compression and 38mm inlet valves instead of 40.5mm inlet valves found in DX series 1800, which is the best 1800 8v for tuning due to its larger bowl area in the inlet port. I blocked my injector air shrouding port in the back of my head with a 1/8'' BSPT plug when i had the original CIS injection system on my MK2 and it made no difference to the drivabilty at all...

Yeah mine was blocked off when I got it. I've never run it the way VW intended.

With all the seals stuffed and one non-shrouded injector fitted I'm guessing there was all sorts of horrible vacuum leaks between the ports.

My plan is to get it all sealed up and back to factory and work from there.

Pete

[Peter Jones]

Made up a new outlet plate. I'll hook it up and let you know how it all works out.



Pete

[Peter Jones]

The new bushes, insulators and seals arrived today.



Might actually be able to make some noise this weekend.

Pete

[Alex1983]

Made up a new outlet plate. I'll hook it up and let you know how it all works out.



Pete

Pete, I've run into the exact-same problem with my '88 DX head. I bought a polished and ported DX head from the UK and when it arrived, it was missing the plastic vacuum connector. The 'old' head has a metal pipe pressed into it instead (so I can't just transfer the connector across).

Can you provide any guidance about how you got on with the solution pictured? Where did you get the fitting from and was it easy to press in...? It looks very effective.

All help/advice welcome!

[Peter Jones]

That all worked fine.
I made the aluminium plat myself and the brass fitting was from Enzed.

The fitting screws into the plate, by the looks of it, it's 1/4" BSPT

I've got the taps to cut the thread of Enzed could tap a plate for you too.

Pete

[Alex1983]

Hey Pete... I'm not sure if this breaks a record for the longest-ever time to respond to a thread on this forum, but... I don't suppose that offer of a plate and fitting is still open? Obviously I'd be very happy to reimburse you handsomely for your services!