Giant flat eight, anyone?

"RamblinRover Luxury-Yacht" (ramblininexile)
08/09/2016 at 16:02 • Filed to: None

“ !!!error: Indecipherable SUB-paragraph formatting!!! ”

DISCUSSION (21)

Sam > RamblinRover Luxury-Yacht
08/09/2016 at 16:08

I see your flat-8, and raise you 4 more cylinders -

Kinja'd!!!

HammerheadFistpunch > RamblinRover Luxury-Yacht
08/09/2016 at 16:09

Looks like an I/O-720

722 cubic inch flat 8! 400 hp at 2650 rpm

E90M3 > RamblinRover Luxury-Yacht
08/09/2016 at 16:10

It’d be nice if they had more than 3 pictures and a more descriptive ad. It looks like it’s got more than 2 exhaust ports per side, so maybe it’s a flat 6, or something.

JawzX2, Boost Addict. 1.6t, 2.7tt, 4.2t > RamblinRover Luxury-Yacht
08/09/2016 at 16:13

Flat 8.

RamblinRover Luxury-Yacht > JawzX2, Boost Addict. 1.6t, 2.7tt, 4.2t
08/09/2016 at 16:18

I thought it was a flat eight at first, then thought it was a flat four with doubled valves, then wasn’t sure again. The plug wire count wasn’t instructive either, because this is the same kind of engine you’d expect to see dual ignition on. Eh. Probably an eight.

RamblinRover Luxury-Yacht > Sam
08/09/2016 at 16:20

Yes, but tank.

RamblinRover Luxury-Yacht > E90M3
08/09/2016 at 16:21

It does have four exhaust ports and eight plug wires per side, so it’s seemingly an eight.

Ash78, voting early and often > HammerheadFistpunch
08/09/2016 at 16:22

My gramps had a Piper Comanche with one of these in it. Allegedly it was a beast. He totaled it during an emergency landing on the beach when he had to swerve to avoid...the ONLY two people on the beach for about a mile. No kidding. 1968, IIRC.

Cé hé sin > Sam
08/09/2016 at 16:23

I see your flat 12 and raise you four more...

Kinja'd!!!

Flyboy is FAA certified insane > RamblinRover Luxury-Yacht
08/09/2016 at 16:25

My experience with Continentals aircraft motors makes me say that this is a giant flat four with two valves and two spark plugs per cylinder. Or, each of those rocker covers is covering one valve. Which is more likely.

Normally, with an airplane motor, there’s two spark plugs for redundancy and to make it run better on bad fuel. So I think it’s a big flat four.

RamblinRover Luxury-Yacht > Flyboy is FAA certified insane
08/09/2016 at 16:48

That’s what I thought when second-guessing myself, particularly since I’ve seen a lot of double rocker cover setups on Continental and other radials. But, look again - it actually appears to have eight spark plugs PER SIDE. That indicates an eight, to me.

Cé hé sin > RamblinRover Luxury-Yacht
08/09/2016 at 16:54

Not exactly, it was intended for a Porsche 917!

Flyboy is FAA certified insane > RamblinRover Luxury-Yacht
08/09/2016 at 17:01

All four cylinder aircraft engines have 8 spark plugs. Especially the Continental and Lycoming modern motors. So that is why I believe it’s a 4 cyl. But yea it looks like it has 8 per side but I think the distributor might just be on that side.

RamblinRover Luxury-Yacht > Flyboy is FAA certified insane
08/09/2016 at 17:05

I can’t look at this and see anything other than a 90 degree I4 or an opposed eight, because there are eight plug wires and four pipes visible on one side.

RamblinRover Luxury-Yacht > Cé hé sin
08/09/2016 at 17:05

I was joking that the one I linked was better because it was a tank engine and much bigger.

E90M3 > RamblinRover Luxury-Yacht
08/09/2016 at 17:33

I couldn’t tell if it was an 8 or a 6, but I think you're right. Probably an 8.

I Will Always Be The Honey Badger > RamblinRover Luxury-Yacht
08/09/2016 at 18:26

Doesn’t say small or big block pattern. Any guesses?

RamblinRover Luxury-Yacht > I Will Always Be The Honey Badger
08/09/2016 at 18:36

I think the trans side of the bellhousing is the same, n’est pas? The engine side I would assume to be neither, obviously, though there are early Hemi and other adapting options available for pre-LA engines of all kinds.

kanadanmajava1 > RamblinRover Luxury-Yacht
08/09/2016 at 19:12

This is pretty interesting. It seems to be a big brother of the six cylinder version Continental tank engine (for an example AOS 895-3 was used in M41). But I couldn’t find much info that 8 cylinder version had existed. Chicago Tribune (link) had news in 1948 that new tank engines had been designed and opposed piston eight cylinder was also available.

A 12 cylinder version also existed but it was a V12 (for an example AV-1790 used in M47). The six cylinder had a displacement of 895 cid and the 12 cylinder had 1790 cid. If this engine would be related to these we could safely assume that the 8 cylinder version would have a displacement of 1193 cid (19.6 liters).

So I guess this could be an unused prototype engine. Sadly it hasn’t been stored very well and it is missing some critical parts and some are damaged.

Here’s some six cylinder version pictures.

Kinja'd!!!

RamblinRover Luxury-Yacht > kanadanmajava1
08/09/2016 at 19:17

I tried a cursory search for information and had to give up. This is very, very interesting. It’s a bargain for what it’s being listed at, even seized, I would say. With any luck it would be possible to rebuild from spare six parts. What a discovery...

kanadanmajava1 > RamblinRover Luxury-Yacht
08/09/2016 at 19:36

I’m quite tempted to ask the seller what the manufacturer’s plate says.