Intel's Ronler Acres Plant

Silicon Forest

Sunday, March 9, 2008

Motorcycles using a car engine

So I had this idea when I was a kid of building a motorcycle using a small automobile engine, and even though I am older and should be wiser, I am not. I still want to build one. Originally I wanted to use a 3.5 Liter aluminum V-8 engine, originally developed by Buick and later sold to Triumph and Rover. The same engine was used in the TR-8 and in the first V-8 powered Rovers (Land & Sedans). 3.5 Liters may sound like a big enough engine for a car now, but at the time (mid 1960's) it was minuscule. Muscle cars were using 427 cubic inch behemoths. 427 cubic inches translates to 7 Liters, twice the size of the little V-8 I had fantasies of using.

Nothing ever came of my idea, but several other people have been bitten by the same bug and gone off and actually built them. There is even a company building and selling them. They are monstrous brutes and I imagine they would be a thrill to ride. They have got to be heavy, though, and that means you have to be careful with them, especially at slow speeds.

The main motivation for using a car engine in a motorcycle is cost. Car engines are mass produced in far greater quantities than large motorcycles. You can get a great deal more power for a lot less money. Another advantage is reliability.

Factory produced motorcycles are built like airplanes. Everything is light weight, specially designed for this one purpose, limited quantities, and very expensive. Highly stressed machines like this require fastidious maintenance. One little error and a five thousand dollar engine goes up in smoke. On the plus side you get a high performance machine that will fly through the curves, compete with jet aircraft for acceleration, and stop on a dime.

But what if you just want a cheap bike that will boot, scoot & boogy? I'm thinking you might be able to get away with a motor and tranny from a Geo-Metro. I mean 70hp out to be enough for a bike, eh?

11 comments:

Anonymous said...

most 600cc and bigger motorcycle engines make 70 HP and more and are much lighter....and actually meant to fit in a motorcycle. the only reason to put an car engine in a bike is to be.....well, weird.

DAVE WALLS said...

hi, I.VE RECENTLY INSTALLED AN AUSTIN A30 800CC MOTOR INTO A ROYAL ENFIELD FRAME MY FRIENDS WONDER WHY I GUESS BECAUSE IAM A BRIT MACHINIST LOVE OLD VEHICLES AND IT WAS FUN

Anonymous said...

Hi Guys;
I have a 1969 bike with a Ford 2ltr inline 4 cylinder engine. It drives with a centrifical clutch to a 90 degree gearbox, to convert to a chain-drive. It rides on 13 inch car tires and wheels. It's a big cruiser type motorcycle that is slightly larger than a HD Road King. Kids toys just get bigger when you "grow up" !

Charles Pergiel said...

Anonymous: we need a picture!

coco said...

Hi Guys;
I am thinking on putting a 4 cylinders car engine with manual gearbox on a bike frame.
But i was wondering of how could i shift the gears without losing contact with the steering bar.

Do you have any idea?

Charles Pergiel said...

Originally motorcycles used hand shifters. You could try that. Or use an automatic transmission.

Mayur Bhoir said...

hands off to the bike builder

marty said...

dont give up
use aluminium car engine across the frame
fit pre unit gearbox and either a extended input shaft or a idle shaft.
use the original clutch.
you then have foot change like all bikes should be and a hand clutch.
it does work.
i built bsa a10 extended frame,honda 750 front forks, reliant (dont laugh) 700cc engine,extended input shaft
no problems getting it taxed etc or insurance

Dutchlarry said...

Built a chopper using a Subaru 1800 boxer-engine, with an automatic gearbox. Will never use an automatic on a bike again though. Way too scary. Made a trike using an 1800 Subaru as well, using a manual box. That was far better to control

Charles Pergiel said...

Brilliant! Using a Subaru engine and gearbox would mean minimal drive train work. A sprocket and a chain, eh?

Clive Eswards said...

just completed a bike using imprezza turbo with auto box.
it will be street legal from tomorrow.
i'd love to post some pics but dont know how!
Clive Edwards