intake insulators on the carrera motronic?
 

I noticed in the parts diagram that the 3.2 intake uses the phenolic insulators much like the carbs. I am converting a CIS engine to the Carrera intake. Do I need to use the insulators or is this just a case of German over-engineering?
Thanks,
Jim S.

You should use them as they also have a cut out in them to help the injector clear the head. They are cheap to boot!

Cheers

thanks Jeff.

Another question...are the intake studs for the CIS runners sufficient length for the Carrera flanges and the insulators?
Jim S.

I go both ways on this. A phenolic block is a fantastic insulator, so now all the heat in the head it kept in the head and cannot migrate to the intake. The intake is usually a piece with a very large surface area that can radiate out heat, why trap all the heat in the head when you can move it upwards to the intake and let it out of the motor? I have seen old school vintage star mazda cars run in 90 degree ambient and freeze up the intake at idle. These are old school rotary motors with alu intakes and weber carbs, they freeze about 1/4 inch off the block all the way up to the trumpets. I dont think you need phenolic blocks on a 911 motor.

Probably not, the Carrera intake studs are really long.
I don't know how thick the CIS or Motronic runner flange is, but I have a custom intake on my carrera engine with insulators and an 8 mm flange. With that in place the studs are long enough for 2 nylock nuts.

Kid962 / Magnus,
Thanks for the info.
Looks like I need to spend some more time thinking this through.
Jim S.

I think someone has the insulators on eBay fairly cheap for both CIs and Carrera Intake

Thanks North Coast. I'm tracking the ebay option.

Safe...do you know which length studs are on your engine?

35 mm on my 84 engine.

Thanks Magnus!