what an amazing piece of mechanical enginering...

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

What you you think this engine is worth? $2-300,000? If the cars go for over a $1,000,000???

Paul

Did you look at the 917 Chassis pics. Looks like they stuck those chassis together with chewing gum.

http://www.pbase.com/917carl/image/21035442

Those welds look like mine!

That engine is a thing of beauty. I just spent the last half hour drooling over the pictures. Maybe I can justify building one to make Nickies for it? Do you think I can fit that in a 914 :-)

Charles Navarro
LN Engineering
http://www.LNengineering.com
Aircooled Precision Performance

Here is a picture of the 16cyl engine that was design also for the 917.
I think that at that moment Porsche decide to go with Turbo power for the Can-Am 917 instead of the 16cyl.

Quilmes

One more view 917 16cyl engine.

Not only is it 16 cylinder...it looks like twin plug too. That means 32 sparks to coordinate...

Is this the 1190 hp Can Am engine we have heard about?

I think I'll go into autozone and ask for a distributor cap for one of those just to watch them all run around trying to figure out WTH I'm talking about.

Sort of like taking the Cheby 350 powered 240D to the Mercedes Dealer for an oil change...

OMG....look at that dizzy. finding ign problems must be a nightmare....i bet it idles smooth though. Not like my 914 definately.

MFI too!

at the factory museum, they have an aluminum frame/chassis hanging on the wall....I must have stared at it for 10 minutes straight

slide valve intakes... woohoo.

towle,

let me know what you find on the 8... I've been looking for some blueprints on the type 771 2.2L SOHC engine, but most of the pics i can find are on the 3L DOHC engines.

Have you seen these 8 banger 2.2 pics ?
http://www.pbase.com/9146gt/factory_racing...parts_907engine

I think I read once that the flat-16s crankshaft was so long that it flexed too much. It created lots of unwanted vibrations and they were afraid it wouldn't hold together for race distances. Made a lot of power though. The two in the pictures are the only ones ever made IIRC.

I saw that 917 frame at the Porsche museum too. The curator took it off the wall and let me hold it (it was a slow day and we were the only people there.) Only weighed about 20–25kg I think? REALLY light. But no, the welds weren't very pretty.

you guys SUCK! it took 5 posts before someone posted about putting the engine in a 914. time to turn in your CLUB card

Helium making the chassis lighter? I don't think so. Yes, helium is lighter than air, but by the time you pressurize it, your probably looking at the same mass as atmospheric pressure (14.7 psi/1 bar) air in the tubes would be. Now what would be lighter is if they sucked all the air out of the tubes and made it a vacuum.. less mass in the tubes, less mass overall.

The reason why the put helium in the tubes is because the welds need it on the backside to be stronger. "Perge" is the term used to weld tubing that needs to be structurally strong, stainless is one metal that REALLY shows a difference. When you purge those metals, if fact any metal for that matter, the opposite side that would normally be exposed to oxygen now is sheilded by the inert gas, making the back side of the weld look almost like the front side.

TIG welding, which is sometimes refurred to as Heli Arc, is what they had back in those days. The company that came up with the TIG welder was called "Heli Arc Co.". Now I would assume they named their company that because they first used helium as the inert sheild for welding, but thats not the reason why TIG welding is refurred as Heli-Arc. Kind of like "Vice Grip" or "Allen wrench", they are name brands.

The drivers were nerveous because they were in an 800hp car that weighed ~1700lbs and had horrible aero dynamics. Vic Elford finally became their test driver, and with his rally experience, he, more than any other driver, helped develop the 917's.

Thinking back to the glory days of Riverside, I recall seeing the pressure guage on the chassis when walking the pits. I seem to recall that it was not just the 917 that pressurized the chassis', but other Porsche prototypes as well. I still see the image of the cockpit in my mind, but I don't recall which car (can you blame me 30+ years later!!)! Chassis *looked* like aluminum. BTW, a very approachable George Follmer standing next to his car in the garage eagerly answered my questions. Ahh, such fond memories.

Andy

Sammy, now that makes sence to pressurize the tubes and have a gauge like Andy just mentioned. If a crack developed, then the pressure would leak out and the gauge would reviel that problem.

But just pressurizing a chassis isnn't going to make it lighter. They used helium because it was lighter than air, not because it made the chassis lighter.

Thanks for the input Andy , I wish i was alive when all this racing went down... truly and era of fast Gods and the ability to stand 5 ft from them while doing 200+mph.

Cool picture...

The first run chassises, chassii -- frames -- were aluminum, magnesium came later. The orginal design also used the frame tubes for oil piping up to the front cooler. JWA did away with that the 2nd year of the car, and individually plumbed the oil lines.

The 16 was unfeasible because of weight and size. The length of the motor would have really changed the turning moment of the car, already sketchy under Piech's no wing 'drag is bad' philosophy.

Also, the 917's life was coming to an end under FIM rules. CanAm required a much better hp/ton figure which was only gained with turbos.

As for the length of the crank on the 16, that shouldn't have been a problem. On the 12s, power was taken from the crank at the middle of the engine. Crankwise, it was like havint 2 flat sixes end to end. They probably carried over this element over to the 16 as well.

Sammy, thats some pro- picking nutting giong on here . Honestly, i re-read my posts and i apologize if i came across rude. I need to use more in my posts, cause i'm staight to the point, but not worked up about it either.

To your point about filling the chassis with air or nitrogen, i agree. (but you wouldn't want to fill it with air anyways because of possible corrosion properties. Purging it with the inert gas is a very good idea, and helium makes a great candidate. Hey, hydrogen's even lighter! To bad Porsche didn't work on the Hindinburg, they'd saved some lives with logic.

908 engine photo from Rennsport II Daytona

Here is one from a 917-30

How much weight gets added in bungs, gauge and plumbing?

QUOTE (BigD9146gt @ Feb 8 2005, 08:31 AM)

Sammy, now that makes sence to pressurize the tubes and have a gauge like Andy just mentioned. If a crack developed, then the pressure would leak out and the gauge would reviel that problem. But just pressurizing a chassis isnn't going to make it lighter. They used helium because it was lighter than air, not because it made the chassis lighter. Thanks for the input Andy , I wish i was alive when all this racing went down... truly and era of fast Gods and the ability to stand 5 ft from them while doing 200+mph.

I didn't want to mention something based on vague recollection (the 30+ y/o memories), but it was said, at the time, it revealed cracks in the chassis'. That would be a pretty important bit of info in a 200+ MPH car! Perhaps it did serve a secondary purpose, like back filling with helium/argon for welding during the fabrication process.

Camping out at RIR was great fun, in those years. Did it many times; watched many races there. I really enjoyed the freedom of walking the pits, and literally rubbing elbows with some of the great's. Shelby, Donohue, Penske, Hunt (James), Mario, Unser, Fittipaldi, Foyt, Parnelli, etc; very casual atmosphere. Lot's of celeb's too. I ran many laps there in a Shifter Kart; great fun!

Andy

The real reason that helium was used in the frame is that helium is the smallest molecule. That means that the smallest of leaks or cracks could be detected. Helium is often used for leak detection due to the small molecule size. Why not hydrogen? Well, hydrogen molecule is H2 whereas helium is He. That is helium is a single atom, and hydrogen is two atoms and hence much larger.

QUOTE (davep @ Feb 8 2005, 12:08 PM)

The real reason that helium was used in the frame is that helium is the smallest molecule. That means that the smallest of leaks or cracks could be detected. Helium is often used for leak detection due to the small molecule size. Why not hydrogen? Well, hydrogen molecule is H2 whereas helium is He. That is helium is a single atom, and hydrogen is two atoms and hence much larger.

I knew that.

QUOTE (davep @ Feb 8 2005, 12:08 PM)

The real reason that helium was used in the frame is that helium is the smallest molecule. That means that the smallest of leaks or cracks could be detected. Helium is often used for leak detection due to the small molecule size. Why not hydrogen? Well, hydrogen molecule is H2 whereas helium is He. That is helium is a single atom, and hydrogen is two atoms and hence much larger.

It hadn't occured to me, but this would be a good way to test the chassis for weld joint integrity by sniffing for helium (by using He detection equipment, of course ). That said, it would seem to me pretty tough to maintain He pressurized in a chassis for very long. I've done a lot of He leak testing on welded SS and Ti devices for hermeticity, but never anything with welded alum. Anyone have experience with it?

Andy

QUOTE (Sammy @ Feb 8 2005, 11:56 AM)

Oh great, we get a wild-ass discussion going and cloudbuster tries to screw it up by using logic.

Sorry. How about this for a mea culpa?

I heard that after a race, the crew would fill the chassis with oxy-acetylene at 100psi. Then they'd check every joint with a lighter. Any crack would become a mini blowtorch and weld the crack closed from the inside.

the good thing about using helium is that you dont need fancy equpment to detect a leak... if your voice sound funny, there is a leak! mouhaha
nevermind..

i like the creativity in that

I personally like how in the pictures of the 917 engine, they take a picture of Carl and his helper putting the heads/cam towers on... but its going on up-side down

QUOTE (URY914 @ Feb 8 2005, 03:10 PM)

QUOTE (davep @ Feb 8 2005, 12:08 PM) The real reason that helium was used in the frame is that helium is the smallest molecule. That means that the smallest of leaks or cracks could be detected. Helium is often used for leak detection due to the small molecule size. Why not hydrogen? Well, hydrogen molecule is H2 whereas helium is He. That is helium is a single atom, and hydrogen is two atoms and hence much larger. I knew that.