Author Topic: 917 180 degree V 12  (Read 42977 times)

Online Vixen

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Re: Momentary lapses of reason......
« Reply #30 on: July 06, 2016, 07:19:49 PM »
Dave,
Porsche were never as secretive as Mercedes Benz, so you will be able to find plenty of photos and information on Google. Porsche sold many 917's into private hands so their technology has be spread around. There are photos of a number of detailed rebuilds to be found. Porsche themselves have an exploded display engine in their Stuttgart museum.

Unfortunately, I think the two cross drawings you now have are all that is readily available on the web. They should be enough, when used together with the photos of piece parts, to get close enough for a scale model. You could try the guy who did that 3D animation, he may be willing to help you. Who knows?

The 917 was on my short list of possible engines before I commenced building the MB W165. I stalled at the problem of fueling the 12 separate inlet trumpets. The idea of the Can-Am version of the engine with dummy turbos and Keith's idea of a single point fuel injection using a Megasquirt ECU (who thinks up these names?) never occurred to me. I am sure that is the answer.

I now see the reason for your tag "Steamer".  That's a good looking boat and the steam plant looks excellent. I looked at your location on the map. What a coincidence, I was born in a town called Leominster near to Worcester in the county of Worcestershire in England many, many years ago.

Mike





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Online steamer

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Re: Momentary lapses of reason......
« Reply #31 on: July 06, 2016, 07:27:15 PM »
Well I'll be dipped!      A pair of Leominsterites, who like Lemans, Model Engines, and things mechanical!


Who'd a thunk!

 8)

Dave
"Mister M'Andrew, don't you think steam spoils romance at sea?"
Damned ijjit!

Online steamer

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Re: Momentary lapses of reason......
« Reply #32 on: July 06, 2016, 07:29:39 PM »
I'm sure tonight I'll have a sketch pad handy and some doodles going on about this engine. .....should be fun!

Dave
"Mister M'Andrew, don't you think steam spoils romance at sea?"
Damned ijjit!

Online Vixen

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Re: Momentary lapses of reason......
« Reply #33 on: July 06, 2016, 07:38:49 PM »
Dave,
Beware, it's a long engine. The scale may be dictated by the travel on your milling machine as much as anything.
The engine was so long that the designers were forced to move the driver so far forward in the car, that his feet were way ahead of the front axle. No safety crumple zone in those days. David Piper lost his leg when he crashed in a 917 during the filming of Steve McQueen's film Le Mans.
Those were the days when sex was safe and motor racing was bloody dangerous. How things change?

Mike
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Online steamer

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Re: Momentary lapses of reason......
« Reply #34 on: July 06, 2016, 07:58:23 PM »
I've got about a 6 x15 x 12 high work envelope....if it's bigger than that, I'm going to a smaller scale!!!

I read a report on the 917 that at the end of the Mulsanne straight, the aero force on the body was great enough to push the shell down against the drivers toes!...making going for the brakes a challenge!....if you look at the chassis on that thing..it would appear so spindly that it's amazing they could spare that much room in the drivers seat cushion!   :LittleDevil:

The other thing I noticed was that part of the tube frame was a lubricating oil reservoir?    to save weight..

HARD CORE!......

But that's what it took!   

Dave
"Mister M'Andrew, don't you think steam spoils romance at sea?"
Damned ijjit!

Online Vixen

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Re: Momentary lapses of reason......
« Reply #35 on: July 06, 2016, 08:10:05 PM »
You should have no problem with 1/3 scale on that mill bed. It's huge compared to my Austrian made Emco F1.

Apparently they pressurized the oil in the space frame, by a small amount, as a simple way to check the structural integrity of the tubes and welds. Everything did more than one job

We pronounce Leominster as lemster, what's your take on the name

Mike
« Last Edit: July 06, 2016, 08:13:56 PM by Vixen »
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Online steamer

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Re: Momentary lapses of reason......
« Reply #36 on: July 06, 2016, 08:13:53 PM »
yes   but it is manual.   I do have a DRO....but a CNC mill would be a better tool for that job

However, If I dispense with all th external fins on the engine case, it's not that bad....just a lot of work and fixturing.

What are you using for cylinder liners?

Dave
"Mister M'Andrew, don't you think steam spoils romance at sea?"
Damned ijjit!

Online steamer

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Re: Momentary lapses of reason......
« Reply #37 on: July 06, 2016, 08:18:47 PM »
You should have no problem with 1/3 scale on that mill bed. It's huge compared to my Austrian made Emco F1.

Apparently they pressurized the oil in the space frame, by a small amount, as a simple way to check the structural integrity of the tubes and welds. Everything did more than one job

We pronounce Leominster as lemster, what's your take on the name

Mike

That's funny!    We pronounce it  LEMON-STIR,......though you can bet we get a lot of people asking "Is this LEO Min Stir"?
"Mister M'Andrew, don't you think steam spoils romance at sea?"
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Online Vixen

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Re: Momentary lapses of reason......
« Reply #38 on: July 06, 2016, 08:32:33 PM »
I never got as far as designing the cylinders. The photos show the fins as being an integral part of the cylinder, just like on a Beetle.
I would have thought the cylinders and heads would be very similar to a large air cooled aircraft engine. I used a gang of slitting saws to cut the fins into the steel cylinders of my Bristol Mercury radial engines. Have a look at www.modelengineeringwebsite.com/Bristol_Mercury_VIII.html and keep clicking on the zoom button to see the detail.

Mike
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Online steamer

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Re: Momentary lapses of reason......
« Reply #39 on: July 06, 2016, 08:34:45 PM »
Will do Mike.....I'll probably go for 1144 Stress Proof.    and make them one piece as well.

Dave
"Mister M'Andrew, don't you think steam spoils romance at sea?"
Damned ijjit!

Offline Jasonb

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Re: Momentary lapses of reason......
« Reply #40 on: July 06, 2016, 08:47:14 PM »
Could you not just bolt two of these together?


And you know that once you have the engine you will have to make the chassis.

J

PS Mike did you enjoy your cycling today ;)


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Re: Momentary lapses of reason......
« Reply #42 on: July 06, 2016, 09:05:15 PM »
YUP  Saw that Jason.

Too small!....

It's already small at 1/3   1" bore will be easier to get running I think...

Dave
"Mister M'Andrew, don't you think steam spoils romance at sea?"
Damned ijjit!

Online Vixen

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Re: Momentary lapses of reason......
« Reply #43 on: July 06, 2016, 09:10:35 PM »
Well that's effectively what Porsche did when they built the 4.5 litre flat 12 cylinder engine for the 917. Many components were identical.

"once you have the engine you will have to make the chassis" Well if you start with an all enveloping body shell you may not need to do the engine at all.

Today's stage of the Tour de France was as they say "magnifique" Every stage is so different. The main title contenders were quite content to sit in the peloton group and let  Van Avermaet charge ahead all day long, as he was considered to be a 'one day wonder' and not a general classification threat.
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Online steamer

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Re: Momentary lapses of reason......
« Reply #44 on: July 06, 2016, 09:17:19 PM »
122cc.....That'll hurt you!..

"Mister M'Andrew, don't you think steam spoils romance at sea?"
Damned ijjit!