Adapting a 3.2L intake to a 911SC head

[cmonref]

Zulu_monkey,

This post is in response to your PM. Could not figure out how to attach a picture to a PM, so elected to send it this way.

The 3.2L intake is a bolt-on to the 911SC, with a twist. The CIS injector flow path is smaller than the EFI injector flow path and the path in the head needs to be milled out to adapt. The attached picture shows the intake port with the OEM black plastic spacer laid over the large port intake. Note the portion of the port to be milled. In the port is a freeze plug from NAPA to prevent small aluminum bits from getting into the port. I also used a show vac on the side where the Dremel would throw out the small pieces of aluminum. I milled out mine by hand with a Dremel.

Replace the port studs with longer ones to accommodate the thickness of the spacer. 6mm is memory serves.

The 911SC air ducting fits right over this, but you might have to slightly trim one or two port openings to clear the spacers.

It just occurs to me that I do NOT know if this work can be done on a SMALL port 911SC head.

100_1319 small.JPG

[Dennis930]

Brian,

I did the same adapting of the Carrera manifold to my 3.0 liter 930 when I converted to efi. The head intake ports were bored from 32 to 36MM when I rebuilt the engine years ago. So I had to adapt the 36MM ports to the 41MM port size of the manifold and also open up the injector path to match the Carrera manifold. I traced the Carrera intake gasket on the head intake port to see how much material needed to be removed. Then I made a go-nogo gage with a taper from 41MM down to 36MM. I added a stop line to the circumference of the gage to know where to stop. I used a die grinder with a carbide bit to slowly remove metal from the intake port, keeping a slight taper as I proceeded down into the port. I used the go-nogo gage to monitor the progress until the gage sat in to the port at the stop line. Then I carefully machined the injector path up to the trace line. Be careful to not go too far because this cuts into the available gasket sealing surface. I have some pictures to post but they are too large. I will reduce their size and post them tomorrow.

[Dennis930]

Brian,

Here is a picture of the go-nogo gage. I made it from a 2" PVC coupling and assorted adapters to install a bolt. I chucked it up in a drill press and shaped it with a file, taking measurements with a caliper until it was where I wanted it.

Then the follwong pictures show the intake port before and after, and the gage being used to monitor maching progress.

-Dennis

[Dennis930]

Additional photo: