For the corvair engine, I need to make 4 spacers of 2 different thicknesses to go between the head and the intake runners. What material should I use? Delrin? I need something easily drilled as I am making the spacers in a limited work shop.

Phenolic material.
Its basically thick formica.

Obtain it at a shop that sells woodworking tools.
Its also used for table saw safety plates etc...

You should be able to find it online...
Simple to drill with hand tools.

http://www.rockler.com/product.cfm?page=17...filter=phenolic

Rich

you should also be able to get it from MSC or McMaster Carr...

McMaster has it, but it aint cheap. I need a section of 1" and 1/2". What temp level should I have?

The stuff does not melt easy.
Head temps in that area should not be more than 400 degrees.

Rich

400 is a problem in that the material is max rated at 266F. There is some mil spec stuff rated to higher, but it is $80+ for a small section.

Here's a dumb idea that might get a quick and dirty answer......

Got a running 914? It's aircooled and probably has an intake area temperature close to the corvair.

Run the 914 until it is warmed up.

Using a meat thermometer touch test, get readings on one or more of the intake mounting studs and on the aluminum next to the spacer.

Due to the cooling effect of the incoming air, I betcha the temps aren't too bad in that area.

Other choice might be a thick chunk of fiberglass like a circuit board. Best is epoxy resin The glass is rough on tools though.....

Hmmm.... looks like Ultem (polyetherimide) is in the 300-400 degree range.....

http://www.modernplastics.com/march05/wdtempaluxII.html

Hey, look up a local plastics supply house. I bet Harrisburg has one. Prices may be cheaper....

Phoenolic is probably the best but the temp may make it too expensive. Aluminum probably will be the cheapest.

If a head gets to 400 degrees, it melts...at least it will drop a seat.
Worst case is 350.

The lower temp stuff should be fine.

Rich

Ah, 6061-T6 was very cheap compared to all phenolic and plastics. I got 1 x 2.5 x 12" and .5 x 2.5 x 12" shipped for $24. This should not be too hard to machine with my tools. I use my lathe as a mill from time to time

A hole saw will also work on aluminum but you will need to clean out the groove while it is cutting and use a lubricant to keep the teeth from loading up. A bar of soap will work in a pinch. I have a wax that comes in a cardboard tube that I use on the bandsaw blade and the sanding belts and disks to keep them from loading up.

The hole saw will be the cheapest large hole maker.

We use phoenolics on the turbo subys and you can touch the intake after a hard run and it is barely warm and sometimes actually cool.