Triumph Repair: Spitfire Rust and Mileage, rear wheel bearings, spitfire 1500s

Question
Hi,

I was wondering if you knew whether I could put 15% ethanol has into a Triumph?  This isn't E85 -- that has 85% ethanol, but in Iowa, the middle grade of fuel is much cheaper, 15 cents a gallon, but has the ethanol.  Ideas?

Also, do you have suggestions on where to troubleshoot the engine to increase its fuel mileage?  The engine is in pretty good shape and I just don't know where to start to help get the mileage back up.  It's running in the mid to high 20's right now.

Cheers,

Thomas

Answer
Thomas,

Mid to high 20s for a Spitfire isn't terribly bad.  I've had people claim that low-30s is possible.. but that depends upon a lot of things.

There shouldn't be any problem with with the emissions blend of gasoline.  Keep in mind that the alcohols (methyl and ethyl) do not have as much energy per gallon as gasoline, so fuel mileage will take a hit right there.

As to improving mileage... from an absolute standpoint you get more efficiency the higher the compression ratio goes.  The downside is that higher compression requires higher octane or you'll beat the engine to death.

During the 1970s Triumph lowered the compression ratio on most of the Spitfire 1500s to 7.5:1 to allow the cars to run on lower octane (ie, cheaper) gas.  Some of the cars escaped the factory with 9:1 compression, as did the MG Midgets that also used the 1500 engine.

It's still worth doing the basics that apply to any car.  Make sure the ignition components are in good shape and properly adjusted.  Ensure the carb components are in good shape and again that the mixture is properly adjusted.

Grease and adjust the front wheel bearings and grease the rear wheel bearings on a regular basis.  Keep your tires properly inflated.

Cheers,

Jim