You don’t see this every day . .

I was visiting a shop today where the late owner restored vintage open wheel race cars, including Indy cars, sprints and midgets. His son pointed out this engine and I asked if it was an Offy. Nope, a Jag 6 cyl cut down and welded back together to four cylinders to simulate a big Offy. Apparently, there are a lot more old Indy roadster chassis than there are surviving big Offys, so people sometimes get creative to simulate the original Offy. I asked if it had run and he said it did.


Is it my imagination or is the head on backwards? These are inlet ports? Should be on the other side of the engine should they not?


That does seem all arse about. That is the exhaust side of the block as there is no oil gallery and no oil filter mount. Possibly the centre section was spun around? The crank comes out the back on the right hand side so normally this would be the exhaust side, but hey doesn’t mean it has to be.

Ah… now I see it! Indeed, it does look like the intake ports were swapped to the left side of the engine.

Dipstick hole is there on the left. I think they feed exhaust gases in from the right and petrol comes out the left and feeds into the tank; beats the snot out of using coal powered electricity.


Absolutely brilliant, mount it in the boot and pipe the exhaust up to it, then out the head into the fuel tank. Perpetual motion.

What could possibly go wrong?

Hell yeah. A true reverse cycle.

Plus the heat from the exhaust gets absorbed and reduced from the global warming contribution. I can’t believe I didn’t think of this sooner; must get on the turps more often.

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Unfortunately Kevin, it’s now in the public domain. You’ve cheated yourself out of any intellectual propery rights through your own good natured exuberance.

As they say here in NZild " Bugger" . Never mind, in my heart of hearts, I know, singlehandedly, I saved the planet. That’s ( almost ) all the thanks I need. Bit of cash wouldn’t go astray, however.

So this one didn’t get a whole lot of interest when I originally posted it. I’ll probably be going over to this shop again on Sunday for a slot car race. If I do, I’ll take a few more photos from various angles and post them.

As to the intake/exhaust swap, it makes sense given the intended use of the engine, which was to simulate an Offenhauser race engine. Offy’s had intake on the left and exhaust on the right. As to the how, I have no idea.

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Can’t be, oil gallery etc. looks way different. It must be pistons 6431

Offenhausers had the intake on the left. No reason this couldn’t be done with a Jag block and a new head.

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Offys also did away with separate cylinder heads: made working on the valves a bit of a challenge…:wink:

But never a head gasket issue…so that’s a plus