Inliners International Forums General Discussion Hi Performance That other inline layout - flat!

Greetings . . .

All this talk about 180 degree cranks got me thinking about flat layout engines.

Like the flat 8 engine in the Porsche 908 - basically two I4 blocks with a 180 degree 'flat' crank:

and two pistons on each crank arm.

With this setup there are two cylinders firing together - so the engine acts like a 'big 4' (as was pointed out in the h-pipe x-pipe post).

I guess this would require two distributors and two coils?

I thought a little about this (it's raining here in Ohio - so I am not out cutting grass).

If we number the cylinders
7 8
5 6
3 4
1 2
Then the firing order would be 1&8, 5&4, 7&2, 3&6?

Which could be accomplished with two dizzies:
/..1..\./..8..\
|3+5|.|6+4.|
\..7../.\..2../

Someone in the other thread suggested that 180 degree cranks create vibration. Is that only in a V configuration? In a flat layout it looks as naturally balanced as any inliner . . .

Rainy day musings.

regards,
stock49

PS. Just found a pic. Looks like two plugs per cylinder - but I can't see if it is one dizzy or two:

looks like two coil wires along the front.

I vaguely remember something that.

Was it a Kaiser/Frazier??

It used a 'dual coil-dual point' distributer cap from a V-12 engine (every other hole) etc.

Maybe it was something experimental, can't remember.

Nash did something funny like that?

That could be the firing order, for a 180 degree V angle (opposed) engine. Unless it was a Boxer.

Hi Nexxussian . . .

Isn't a 180 degree V and a boxer one in the same thing?

regards,
stock49

stock49, Boxers are what they refer to the air cooled VW and Porsche motors. The little VWs are amazing motors, the opposed motor will put out some outrageous hp. You have to account for their major weakness, they will pull the cylinder studs out of the casing.

I'll still take a big inline six over them.

Larry

Thanks Lgriffin . . .

I am familiar with VWs. They have an orthodox I4 flat crank with a separate crank pin for each piston. But the piston layout is such that both pairs of opposed pistons hit TDC at the same time. But there are only four cylinders.

Such a crank with 8 pins would be really long when compared to a flat crank with two pistons on each pin.

I'd have to think about the change in firing order if any.

I've always thought that all flat engines where boxers.

regards,
stock49

Dear Leroy;

That (Nash) may have been it. It was a late 40s or early 50s engine.

Larry;

The 'horizontal opposed' engines (VW, Porsche. BMW & most single engine aircraft) run millions of hours W/O any major problems.

On the 'early' VW when abused with (high compression) the studs pull out like you mentioned.

More trivia; During WW II that engine powered unmanned planes that "anti-aircraft" gunners used for practice. Most were used after hitting the ground etc.

Happy trails.

Stock49, Here's a link to what some might call the ultimate boxer engine. The Porsche 917, 12 cyl, 300 ci, turbo charged, 454 Can Am killer.

http://www.pbase.com/917carl/917_12_cyl_engine

I'm not sure of all the particulars, in fact I was thinking the 917 was an 8 cyl.. From looking at the pics, it appears that 2 cyls are on the same journal, one piston is at TDC and the other is BDC. The motor doesn't look that much longer than a 292.

I saw the 917s at Laguna Seca. You'd hear the big McLaren 454s come thundering up the hill, and then the 917 would top the hill and scream by with McLarens following.

Larry

Didn't the Tucker have a flat engine?? Can't remember the amount of cylinders though. Rear engine drive and I thought it was made by an aircraft co.

Joe;

Yes it was.

Howard Hughes was involved (in background) but it wasn't his engine.

I don't know if a 180 though.

You're right John . . .

It was a big flat six - 335 cubic inches - out of a chopper. It was converted to water cooling:


Here's a site with some sweet '48 Tucker pics:
1948 Tucker

regards,
stock49

Stock 49

No actually the Boxer and the Opposed differ in the crank layout as mentioned earlier.

The term 'Boxer' is short for 'Boxermotor' (I have seen it with various spellings and as two words as well). The term was reputedly coined by Adolph Hitler when he saw a cross sectioned prototype VW engine being motored over. He supposedly said the pistons coming together (at BDC) reminded him of a boxer punching his gloves together before a fight.

The Boxer layout is supposed to give you better dynamic balance than the opposed (what my engineer friends call a 180 degree V with its' common crank pin).

The penalty is with the more complex crank layout (generally longer as mentioned previously) you tend to run into problems with the higher order harmonics. I have read the 917s had a furious problem with the 2nd and 3rd orders, which they obviously either solved or at least beefed it up to finish the race.

I have also been told the 917 engine is in effect 2 RSR Porsche 6's joined nose to nose (on the drawing board anyway), but I don't know how accurate that is.

K;

Yea an Helicopter, I remember now.

That car was really ahead of I's time and probably why it was supressed by the "big three" auto makers.

Same as the electric & steam cars in recent times.

Happy trails.

I think it's kind of interesting that you guys in discussing this have come up with some fairly exotic engine layouts and designs, but everyone seems to either be ignoring or has forgotten our one domestic flat six cylinger opposed engine.........the CORVAIR!