Hole in CIS??

[wachuko]

I was installing everything back for the engine of the RS project. I can figure out if there is something wrong. Is this hole supposed to be there??



Close up



Need to figure it out so that I can finalize the work on the engine. Thank you!

[wachuko]

Ok, so it is the hole used to put an allen down there to adjust the idle. Idle mixture screw location.

Question is...Do I need to plug it?? And if so, with what??

[kerthunk]

Yup, that is the hole for adjusting the mixture. Porsche left them wide open till somewhere in the early 1980s. After that they covered them, but I believe it was to keep ordinary folks from screwing up their mixture and causing emissions issues.

Yours actually looks like it was a plugged one that was drilled out. The holes are much cleaner on earlier ones.

[Paulporsche]

You don't HAVE to plug it, but I would advise doing so to keep dirt, pieces from the sound insulation blanket, etc out of the head of the mixture screw. Some use a golf tee. I used a piece of brass tubing and I wrapped the bottom end w/ some self vulcanizing rubber tape to give it some grip on the edge of the opening. Just make sure the plug doesn't protrude too far down or it could impede the movement of the sensor plate.

[manbridge 74]

It originally had a metal rod with a loop on one end and conical rubber piece on the other.

You can sometimes find these on other CIS cars at the junkyard. Not sure if it's still available or would even help you out as your hole is irregular.

[KiwiJohn]

Plastic knitting needle cut to length, works on mine.

[jrbennett]

I've seen golf tees plugging the hole

[wachuko]

Cool! Thank you all for your suggestions!

[enzo1]