# CIS-basic, injectors



## Dr.Jeff (Oct 30, 2013)

I just read another post here about installing CIS injectors on a different head, and it raised a related question:
On the early Mk1 CIS "basic" systems, are the non-air shielded injectors (e.g. '80 1.6 Rabbit) interchangable with the air-shielded injectors (e.g. '84 1.8 GTI)? That is to day, can the shields and / or injectors from one be switched with the other? For example, install the non-air shielded injectors into a air-shielded style head. If so, which parts need to be swapped or modified?
Thanks.


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## dogzila22 (Apr 1, 2008)

You can use RD or PL injectors with holders, but 9a injectors is different thread


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## nbvwfan (Aug 15, 2007)

Early to late CIS can all be interchanged, even Porsche and brass Mercedes, you have to just use the right holders and lines.
Use search or check Google for fitment cases of what has been run.


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## Dr.Jeff (Oct 30, 2013)

The reason I was unsure, I noticed the holders (insulators) are NOT interchangable between the two heads (1.6 non-air-shrouded and 1.8 air-shrouded). They have different outside diameters and thread size.

So if the early 1.6 injector is to be used on the later 1.8 head, I guess you just retain the later (air-shrouded) holder/insulator in the 1.8 head, and fit the early 1.6 injector into that holder?

Seems like the early (non-air-shrouded) injector is a difficult fit into the later (air-shrouded) holder. Does anything need to be done to convert them?
Thanks to everyone for any help.


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## Shavarsh (Jan 12, 2014)

Also working through a similar situation, interested to hear some responses


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## nbvwfan (Aug 15, 2007)

The holders are relatively inexpensive.
Buy a set of each and try them out.
Without knowing what you have, you are playing a guessing game.
1.6,1.8 8V,1.8 16V, 2.0 16V, Merc's, and Porsche all have the same basic dimensions.
The heads, shrouds, retainers, and metering passages are what is different, application to application. 
If it is a CIS item, it will probably fit in a CIS system, though with some experimentation.
Do some more research, or do some bought component trial and error.


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## rabbitnothopper (Oct 19, 2009)

some lambos and ferraris used cis


i dont know why you want to go with air-shrouded injectors if you are not using an air-shrouded head
just get some bosch mercedes 047 brass injectors and be done with it


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## nbvwfan (Aug 15, 2007)

^ :thumbup:
I am running the brass Mercedes.
They have a lower crack open pressure, are cheap, and don't seem to have the rusty pintle syndrome.


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## Dr.Jeff (Oct 30, 2013)

"rabbitnothopper", Perhaps you missed the point of this thread. As I stated in the beginning, I am running a air-shrouded head. The question was about the fitment of injectors in the air-shrouded head.

My air-shrouded head did not have any injectors in it. I have a new set of injectors in a NON air-shrouded head and attempted to install team with the air-shrouded holders into the air-shrouded head. But for some reason the injectors did not fit into the air-shrouded holders properly. So I was wondering if possibly a different type injector is used with the air-shrouded set up (compared to the NON air-shrouded).
As my injectors are new I see no reason to buy another set IF both heads use the same injector (again, that was my question).

If I understand correctly the actual injectors should be the same for either head (please let me know if that is not true). Therefore I just purchased a new set of air-shrouded holders to see if that is where the problem is. However I have been away and unable to try them yet.

While I appreciate the suggestions for using alternative injectors from other vehicles, etc., it does not answer the question at hand.
Thanks, Jeff


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## bugsinmyteeth (Feb 8, 2006)

If this helps answer, there are two different injectors for VW CIS heads. There are 3 different plastic inserts, different for 83 only air shrouded and for 84- on air shrouded and a thrid type for earlier non-shrowded. They all take the exact same injector seal. Early injectors will fit all off them. The later (84- on) air shrouded heads had injectors with a small aluminim cap that somehow affects the air flow. You can pull off and remove the caps and the later injectors will work fine on all the heads. If yours are not fitting I would also check the seals. You should run new seals preferably the green viton seals (last longer). You often have to lube them with glass cleaner or spit to help them fully seat in the injector cups. You do have to push pretty had sometimes, but make sure they are corectly centered so you don't force and break the plastic cups.


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## Dr.Jeff (Oct 30, 2013)

"bugsinmyteeth", thank you...that helps a lot.
I had pretty much concluded about the injectors being the same. However I did not realize the '83 has unique holders. My 'air-shrouded' head is in fact a '83, and things were not fitting. Based on what you said, I guess it is because I don't have the right holders. The new holders I bought must be the '84+ model, and naturally my early (non air-shrouded) holders won't work. So I think I need to find the correct holders for the '83 head.
Thanks for your help, Jeff


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