Author Topic: Wtb injector shims  (Read 3149 times)

April 25, 2021, 11:57:32 am

mitch_04

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Wtb injector shims
« on: April 25, 2021, 11:57:32 am »
I'm looking for injector shims for my 82 1.6 NA Rabbit. I put new nozzles in and my pressure is 2300-2500, quite a bit above the 1800 spec.



Reply #1April 25, 2021, 03:07:52 pm

ORCoaster

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Re: Wtb injector shims
« Reply #1 on: April 25, 2021, 03:07:52 pm »
If your pressure is higher than spec then you can carefully sand down the shim you have to make spec.  I would suggest oil and a honing stone or some wet sand, sandpaper of 360  grit followed by more sanding with some 600.  Others might tell you to go all the way to 3000 but I won't.  Make figure eight designs to get an even face on them.

I just replaced all four nozzles on my 1.6 Caddy and I can really tell the difference in performance.  I had the same amount of fuel in the jar from four nozzles as I did from ONE of the old pissers. 

I had to adjust the turbopump to compensate for different fuelling afterward.  But it runs and pulls so much smoother now that I kick myself for not thinking the nozzles were the problem long ago.  140 K on the engine and I thought the injectors were replaced when the PO rebuilt the engine.  He spent 3600 on doing that, sent it all the way back to Ohio to have it done.  Then he put the crappy injectors he removed back in it. 


Reply #2April 25, 2021, 04:11:46 pm

RustyCaddy

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Re: Wtb injector shims
« Reply #2 on: April 25, 2021, 04:11:46 pm »
Here are a couple of sources.

Have used these in VW style Bosch injectors:

https://mercedessource.com/store/search?keys=shims

Haven't purchased from these folks, but again, seems like shims for Bosch injectors in Mercedes and VW applications are pretty close to the same thing:

https://www.ebay.com/itm/203192731140?hash=item2f4f3b0604:g:3dMAAOSwVZxfuxZW

Not mine or anyone i know personally.


Reply #3April 25, 2021, 04:46:31 pm

mitch_04

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Re: Wtb injector shims
« Reply #3 on: April 25, 2021, 04:46:31 pm »
Appreciate the responses! I considered sandi g them down, but was concerned with keeping them flat. Never thought to use a knife sharpening stone with some oil... Makes sense.

Would you all just balance them at the same PSI (2300) or drop all the way to spec (1800)?. I considered dropping them all to 2300 then running them for a season and checking again.

Reply #4April 25, 2021, 10:11:30 pm

ORCoaster

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Re: Wtb injector shims
« Reply #4 on: April 25, 2021, 10:11:30 pm »
Spec on a 1.6 NA  is 130 bar or 1886 psi.  Are you sure you have the right bodies on the injectors and springs inside?

Almost sounds like you have 155 bar injectors. 

If you can spring for the variable shim kit I think you will find it most helpful.  There is a spec somewhere deep in my brain that equates a 0.5 mm to some value of Bar but I can't dig it out right now. 

Having the ability to shim with various thicknesses will help you get as good of a balanced set of injectors as you can.


Then there is the method of changing the timing to compensate for the higher pressure.  That can be tricky in that you really don't know how many mm to advance the timing to get those higher bar nozzles to go pop at TDC.  Those of us that run turbos have the higher pressure injectors so we run more advance. 

I see 95 mm in a lot of threads here and I think that is for the 1.6 and if a turbo 1.9 I believe it is 1.05.  Not certain about those numbers but you can check me with the search on this site. 

If it were me, being cheap and having three good ways to check the time on the engine I would install what you have and adjust timing to make it run its best and see how it goes. 
« Last Edit: April 25, 2021, 10:17:09 pm by ORCoaster »

Reply #5April 25, 2021, 10:19:33 pm

mitch_04

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Re: Wtb injector shims
« Reply #5 on: April 25, 2021, 10:19:33 pm »
I'll have to double check the bodies, but the engine is a 1.6 NA and it's the ones that came in the car. Someone else could have swapped them or something. I'm not around them at the moment, but I'll check later on. Does it say directly on the injector how many BAR it is?

Reply #6April 26, 2021, 03:33:04 am

fatmobile

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Re: Wtb injector shims
« Reply #6 on: April 26, 2021, 03:33:04 am »
You can also sand the spring.
 I put it in a drill press and bring it down on a flat piece of sandpaper.
Doesn't take much but I can't remember how much to take off per PSI.
Tornado red, '91 Golf 4 door,
with a re-ringed, '84 quantum, turbo diesel, MD block

Reply #7April 26, 2021, 11:12:30 am

libbydiesel

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Re: Wtb injector shims
« Reply #7 on: April 26, 2021, 11:12:30 am »
I also sand the spring.  I typically install shims until all injectors are at or closely above the target pop pressure.  I then sand the spring of the ones above the target pressure to get them all within 10 psi of each other.  I torque to a lower torque setting when checking and use a higher torque after all are where I want them.  The higher torque will raise the pop pressure slightly so take that into account.  The result is smooth running.  I have not use a drill press in the past for sanding the spring (I've just done it by hand), but I certainly will use the press in the future.  Great tip. 

Reply #8April 26, 2021, 01:52:10 pm

ORCoaster

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Re: Wtb injector shims
« Reply #8 on: April 26, 2021, 01:52:10 pm »
Yes on the injector bodies themselves there is a stamped number with bar clearly written after it.  You may need to clean the bodies of rust and oil to see them.  But they are there.

Reply #9April 27, 2021, 12:48:10 pm

mitch_04

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Re: Wtb injector shims
« Reply #9 on: April 27, 2021, 12:48:10 pm »
Thanks for all the help. The injectors are stamped 130 bar. I had previously emailed Giles about shims and I'm going to just send them up to have him shim them for me. I like doing stuff myself but I just need to speed this process up a bit so I can enjoy the car.

 

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