Here are photographs of both sides of the engine bay of a roadster that ran at Bonneville.

Yes it's the same car, and there hasn't been an engine change between the photographs. This is the format the car ran on the salt.

Identify the engine.

A semi-flathead V8?!

turboed.

in Ford Blue.

Pass. side looks like an OHV Chevy.

Never saw anything like that.

Bizarre, huh?

Beyond strange.

I'm trying (and failing) to see just how it would even work, let alone why it was done.

There's a logical reason for it, but it takes a bit of lateral thinking (and an understanding of the classes that they compete in at Bonneville).

I've been trying to imagine half of the engine as part of the turbo, making the boost for the other (powered) half. Maybe a creative way around displacement restrictions?

Clutching at straws here.

It's not 'merely' a flathead V-8 with an OHV conversion on one side to facilitate the fit of the manifold/plumbing/turbo and still fit underhood? Strange...

I've been trying to imagine half of the engine as part of the turbo, making the boost for the other (powered) half. Maybe a creative way around displacement restrictions?

Clutching at straws here.

You're referring to a split cycle or hot side/cold side engine (one bank becomes a piston compressor for the other bank that sometimes runs in 2 stroke mode) ... but no, it's not one of them ... however your second thought is leading in the right direction.

I found a few web pages of Weird Engines, and I may have fun in the Trivia section with them.

It's not 'merely' a flathead V-8 with an OHV conversion on one side to facilitate the fit of the manifold/plumbing/turbo and still fit underhood? Strange...

Nope

You're referring to a split cycle or hot side/cold side engine (one bank becomes a piston compressor for the other bank that sometimes runs in 2 stroke mode) ... but no, it's not one of them ... however your second thought is leading in the right direction.

I found a few web pages of Weird Engines, and I may have fun in the Trivia section with them.

I keep looking at this thing and it looks like a Chevy small block with one side converted to a flathead - which I can't make any sense of. I see what looks like a GM alternator(on the wrong side), what looks like a GM valve cover, A distributor at the firewall, and something which almost looks like another distributor( without wires) at the front where some Fords have it.

Can you even convert an OHV to a flathead?

OK, the only thing I can think of is that someone figured out how to do this in order to run in two different classes with the same engine, maybe with a swap out of heads? It would change the displacement, but it still makes no sense to me.

In fact, I can't imagine it running at all - seems to me the thing would be so out of balance that it would shake itself apart.

I'm officially stumped.

is it possible that these two styles of engines arent using the same crank shaft?

i mean obviously it seems like they are completely different motors... one seems like a... slightly modified chevy v8

the otherside... i dont recognize one bit...

is there an H style engine...? like VW makes W8's is there an H configuration? in which 2 different fuel types or 2 different style motors could coexist?

is it possible that these two styles of engines arent using the same crank shaft?

i mean obviously it seems like they are completely different motors... one seems like a... slightly modified chevy v8

the otherside... i dont recognize one bit...

is there an H style engine...? like VW makes W8's is there an H configuration? in which 2 different fuel types or 2 different style motors could coexist?

Nope. There's just one crank in the engine, and there's just one engine block.

OK. One hint. The car runs on the lake beds in "F Class".

I'm about to go away for a day or two. I'll post the answer when I get back.

Let's see, "F-class" in the Senior Citizens Timing Association is 2.01 to 3.00 liters in displacement, or 123 t0 183 cubic inches. I'm guessing he's somehow running on only one bank of cylinders at a time to stay under the displacement limit and in an overhead valve class, then switching to the other bank to run a flathead class. How he keeps that thing balanced I don't know...

Almost there ...

Wow, that is cool...and strange. I have no idea in creation.

Chris

Almost there ...

okay well im sure if the whole motor is functional... i wonder if he uses each side to his advantage... isnt ohv more efficent at high rpms? then flat head for low rpms?

similarly to a dual cam vehicle...

I was going to guess that the OHV side of the motor is nothing but a giant air pump

that runs the blower... but I guess I was way off. I love stuff like this, that is one

super cool idea. Kudos for creativity.

Considering that I see no exhaust plumbing whatsoever for the flathead side of the engine, I would say like Sly says, the OHV side of the engine is being used to force air into the turbocharger strapped to that side of the engine, meanwhile the actual power is being made on the flathead side of the engine. That way the entire engine is fully functional, but it is technically only "running" on 4 cylinders, the other four just act an air pump to supply air to the forced induction system, which keeps the guy in the displacement rules.

OK, here's the story.

First of all, it is a SBC running as a an odd fire 4 cylinder so that it can compete in a sub-183 cu inch class. The side with the Ford flat head does nothing but provide a mount for 4 spark plugs.

If you look at the photo showing the Ford flat head side, you'll notice a plate bolted to the intake manifold to close the manifold on the side that isn't being used. You'll also see a rectangular plate under the flat head. That plate blocks the water jackets and keeps the oil from coming out the pistonless cylinders on that side. The con rods for the unused bank have had the small ends cut off the rods as close to the crank as possible, and the big end portion is fitted onto the crank with the normal bearings to control the oil feed and so that the remaining con rod on each journal will stay in place. The Ford head is bolted to the blanking plate and then to the chevy block and is used simply as a place to mount 4 spark plugs so that the electronic ignition that expects to have 8 plugs connected to it will work properly.

More interesting stuff on reduced capacity/cylinder count SBC engines here.

Most likely the intake is blocked off at the plenum ends rather than the runner ends to avoid turbulence & smooth airflow. Pretty sure that 'plate' where the intake meets the head is part of the original manifold- that's the way most all of these 'tunnel port' intakes are built to effectively seal to the block.

Crank must have had a great deal of balancing work done to it. I would think it would be extremely tricky to get enough heavy metal in it to account for the missing rods, pins & pistons.

The flathead-plate-SBC idea is some radical free-thinking. He could've cut the flathead down even further to save a few more pounds (flathead head is lighter than a OHV head), but keeping it whole invites all sorts of fun-to-watch head-scratching, no doubt.

Awsome thread!

I might add Mr.JamesB that you are always a welcome addition to this forum!

That Torana of yours is awsome.

Most likely the intake is blocked off at the plenum ends rather than the runner ends to avoid turbulence & smooth airflow. Pretty sure that 'plate' where the intake meets the head is part of the original manifold- that's the way most all of these 'tunnel port' intakes are built to effectively seal to the block.

If you look closely, you'll see there's one plate that's obviously part of the manifold, and a second plate (different color) that's bolted to the manifold plate.

You'll often see a separate plate used on the BBC engines when a truck block has been used. The inch higher deck height on the truck blocks (allows inch longer con rods to improve the stroke to con rod length ratio) meant that the heads were spaced further apart than on a car block, so a plate is needed to be added to fill the gap between the intake manifold and the heads.

Crank must have had a great deal of balancing work done to it. I would think it would be extremely tricky to get enough heavy metal in it to account for the missing rods, pins & pistons.

The reduced cylinder engines have a real problem with vibration and put a lot of strain on the engine. The only cure is a custom crank. Four cylinder SBC conversions (in both V4 and I4 configuration) have been used for a long time in some of the dirt track classes that have a 3 liter engine displacement limit. I've also seen a SBC head fitted to a 4 cylinder Chevy II block.

The flathead-plate-SBC idea is some radical free-thinking. He could've cut the flathead down even further to save a few more pounds (flathead head is lighter than a OHV head), but keeping it whole invites all sorts of fun-to-watch head-scratching, no doubt.

It looks like one of the light weight alloy flatheads, so the weight wouldn't have been much of an issue, but I think the flathead was used mostly because it causes the double-take (and as a bonus, it resulted in an otherwise unremarkable "F class" entry gaining disproportionate press coverage).

Awsome thread!

I might add Mr.JamesB that you are always a welcome addition to this forum!

That Torana of yours is awsome.

I like the really oddball stuff, and if you want to see oddball and creative engineering, then the Boneville cars (and bikes) are the ones to look at. You'd be amazed how many home brew OHC SBC engines have been built for speed record attempts on the lake bed. I was doing a search for information on a Ford flathead powered Nissan 200SX when I encountered the photos of the oddball Chevy.

My Torana is getting old now. It's the rarest "production" model that was produced in the entire Torana run, but as it never reached "official" production status, and was not a homologation special built for "production class" racing (the real collectors items are the ones with the motor racing heritage), it's a model that very few people know about, and those that have heard of the model have never seen one. The estimates are that less than 100 were produced, and of those, very few are left. Its value is rising rapidly, and will probably peak in about 5 years, so I'll be putting the car into storage before I move to Canada. If my wife and I decide to return to Australia in 5 to 7 years time, I'll do the full restoration and keep it (unless I get offered an astronomical price for it), but if we decide to stay in Canada, then I'll stay a bit longer on one visit home so I can do a quickie restoration (just needs new paint, carpet, recovering of the driver's seat, and new window seal rubber) and put it on the market. I've already been frightened by a price I was offered for it in its current unrestored state (and the guy admitted that he'd feel that he had cheated me if I'd accepted his offer).

At the moment, I'm gathering the parts needed for the restoration. Picked up a set of the optional factory alloy wheels a bit over a month ago. When I ordered the car, I already had a set of alloys, so I didn't order the factory wheels. These days, the alloys that I already had are themselves collector's items (a set of 4 reproduction center caps go for $250 on eBay, and a set of reproduction wheel nuts go for just a little bit less), but those wheels aren't the correct style for a period accurate restoration (they are the right wheels for '70/'71 vintage Torana, but not my '78/'79 model). Besides, the current alloys can't be balanced when fitted to the rear axle due to clearance issues that occur between the stick on wheel weights and the rear disk calipers.

Cool, that's a pretty rare beast. I hope you keep it. I love oddball stuff like that.

Now as far as that flathead powered Nissan 240SX that's funny stuff. I used to

joke around about putting a Chevy 250 inline six in my Datsun Maxima instead

of the 2.4 liter Inline-6.