There are a lot of types of PVC. I have used it to replace aluminum on a shifter handle before. I don't remember what type it was, but it was lighter and cheaper then aluminum. http://www.mcmaster.com/ has a lot of material. You might be able to ebay the aluminum.
P grade Delrin. Easy to work with. resistant to gas, oil etc.... and can be had in different thermal grades. As mentioned before McMaster carr has it. Fitysix
long as it doesnt fall apart or breakdown with the use of fuel and oil around it. i have the corian counters in my house but the wife wont let me pour gas on them to see if they melt..........
Delrin might be okay. It's easy to machine and similar to nylon. Teflon is super easy to machine, but very expensive and it has the problem of "flowing" over time when you bolt something down tight on it. It tends to kind of squeeze out and get deformed slowly. They used to make a lot of carb spacers out of phenolic resin filled with linen. It looks shiny brown with a cloth pattern in it on the top and bottom with layers of cloth stacked up inside it. It holds its shape well at high temperatures. Phenolic is easy to machine, but smells horrible when you cut it and puts out big smoky clouds of toxic fumes. It's good stuff, but I hate machining it because of the toxic fumes. If you can flood it with oil, you can keep the fumes down sometimes. Don't breath the fumes -- they'll mess you up. Read about the toxicity of it before you work with it, and you'll probably decide to use something else.
the stuff you are referring to is called Micarta. i keep a couple small scrap chunks in my toolbox for seating bearing races and whatnot. it's suprisingly strong and stable stuff; as i've not been very gentle a time or two applying persuasion with a 40 oz hammer on one side of it.
I had prepared a lengthy response, and then lost it all when I went to put the kids to bed so here's the short version. I manage an injection molding operation and have a plastics engineering degree. I would not use the Delrin. It has a higher CLTE(coefficient of Linear Thermal Expansion) than aluminum, meaning it will expand and contract more with thermal changes. This could lead to breaking over time. Also, aluminum is more resistant to chemicals. You have the aluminum and really, it's not that much harder to machine. If it were me, I wouldn't use the plastic, and if you're hung up on it, I would look for something with a higher melt temp. I process that material in the 400F to 440F range. Not real high for an underhood application. Just my opinion.
I have seen ALOT of drag racers use marine grade plywood to make carb spacers. I even saw a couple of sheetmetal tunnel rams that had plywood tops. I wouldnt mention it if I hadnt seen it with my own eyes. The claim is that the plywood has better insulating properties than even the phenolic. I never asked anyone how well they held up over time.
funny this should come up after i was recounting working with micarta as a kid in my dad's knife shop. i remember smelling that acrid smoke from that shit for the rest of the day after helping him out there. he used that as well as corian on his knife handles and both hold up VERY well. i would think you are safe using that corian as a spacer provided it doesn't react too much with the fuel and oils related to these engines.
I used corian for carb spacers on my racing outboard with no problems. I just made a set of spacers for my tri power but this won't be running for awhile. Dupont says its good up to 350 farenheit, the only thing I'm not sure of is if it will become brittle after alot of heat cycles. The outboard does not get as hot or get used nearly as much as a car will. It does vibrate more though.
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