I am rebuilding my car, and in the process, am running a fair amount of hardline. As the title suggests I'm considering hardlines for my oil coolers. First, I only run SS hardlines because I don't like aluminum's propensity to work harden, and also, I like SS's corrosion resistance for E85 and methanol fuels. SS is probably overkill, but when comparing tubing prices, the difference isn't significant enough to sacrifice my OCD peace of mind. So on to the questions:

1) Would 1/2" (-8 AN) lines be too small?

Almost all kits I've seen run 5/8" (-10 AN). Before my tear down, that's what I ran. The reason I ask is that 5/8" tubing is significantly more difficult to work with than 1/2".

2) Should I not use hardlines for the coolers at all? Why?

Some will probably say that the flexibility provided by conventional hoses is necessary to allow for flex, but being that the coolers are rigidly mounted to the chassis, which I'm reinforcing, I wouldn't think that a need to compensate for any significant deflection would arise. I could be wrong, hence me asking. Were I to do this, lines to and from the engine would be flexible to allow for deflection there.

Any other input is more than welcome.

Thanks.

 

-10 is the minimum. For long lengths (such as oil cooler relocated to trunk) I'd go with -12.

Hard lines would be okay as long as the cooler is hard mounted to the chassis, the chassis never flexes at all, and you run flex lines to the engine because the engine WILL move, even with solid mounts.

Trying to run stainless line that large is fit only for a masochist. I don't see how aluminum would have any issues related to the fuel used. You're still using aluminum rotor housings and front cover, no?

 

Thank you for the input. If I may, what makes you say that? Is it that you think (or know from experience) the smaller lines would create too much of a pressure drop?

That's what I figured as well. I absolutely agree that the engine will move and that flex lines to and from it need to be able to deflect well.

You're not lying. It's amazing how much harder it gets to work with at those sizes.

Coated (from the factory) aluminum housings, sure. I'm hoping my front cover doesn't get to see much fuel. Mainly, I am concerned with methanol and ethanol fuels and corrosion. While the jury is still out on long-term use of E85 and how corrosive it is, straight methanol has shown to eat up any aluminum that it has prolonged exposure to. Of the two factors cited in using SS as opposed to Al, I'm more concerned with the work-hardening. Corrosion resistance is really more of an added benefit than a design requirement.

Thanks again for your input.

 

I'm just going by what I see production wise. There's nothing special about the intake manifolds, cylinder heads, engine blocks, or oil cooler lines on flex fuel engines.

I agree methanol is nasty stuff. Ethanol is much more pleasant to work with as a motor fuel and as an oil diluter. M85 cars, as I recall, required special oil to deal with the contaminants involved with methanol. E85 cars just run regular gasoline-engine oil.

Too bad about the whole ethanol-is-a-controlled-substance thing.

You do see a lot of special fuel fittings and such for "alcohol" powered cars. That's because in the US at least when you say "alcohol" in terms of motor fuel you are almost exclusively speaking of methanol. One or two people do run their cars on ethanol just to prove a point but it ends up being a huge hassle because of the BATF.


(I hate working with even 1/4" stainless!)