Getting started on a 917K - Page 2

John M · 28th November 2007, 12:08 PM

Quote:

Originally Posted by Conquest351

WOW!!!

$20,900.00

That's a lotta scratch for that aircraft engine! Of course you may spend that much on a Porsche Twin Turbo 3.6L 6-cyl anyways building it up to monstrous proportions. But that's a ton of money for 180HP.

Yeah, probably not that practical. I bet you could get some more power if you turned it over 3000rpm, but the engine looks like it has pushrods and is not designed for high rpm use. High cost is probably from aircraft certifications.

Mike Christian · 28th November 2007, 12:52 PM

20K is cheap for an airplane engine. I bought a non-certified 125HP four banger COntinental IO240 cubic inch for 18,900 plus delivery two years ago. A certified USA aircraft engine can easily double that for 300HP. Sad fact due to liability reserves I think...

OhioMark · 28th November 2007, 04:10 PM

SpyderMike:

My father had to replace the motor in his TC Bonanza and it was close
to $50k for the priviledge. Needless to say, he was less than happy and
didn't get much sympathy from Beechcraft nor the engine MFG....

Thanks!

Mark

Jac Mac · 28th November 2007, 08:23 PM

Quote:

Originally Posted by gt40fran

Two 911 engines joined together will be too long...by sharing a crank pin the original 912 engine(its original designation) can be shorter(also less torsionals in the crank) the trans shaft and also the fan motor are driven from a bevel gear at the center of the length of the crankshaft..again to reduce "wind up" of the crank.. ..the 917 does have a large tail section but eventually you run out of space.....

Dont loose sight of the fact we are paying homage and building replicas.....even spending 350-400k for an original engine wont help as you need the bespoke transaxle also....

If the primary drive was taken out in the middle as per original then the harmonics can be dealt with and the two 6cyl engines left alone- yes it will be longer & that would require a rethink in the TA dept, but the whole lot could still be contained within the original dimensions re wheelbase & engine bay.

Where do you draw the line in regard to replica vs dead nuts original copy, really depends on the builders wants doesnt it- in your case it might be front mono grafted to a rear tube sub frame with proper porsche motor & TA, whereas I might want the double 911 & one of TA copyto suit and a full tube frame. Anyone who wants a full original everything just has to pay mega $$$ for the honour , others simply get what they can afford to pay for!

Jac Mac · 28th November 2007, 08:23 PM

Double Post.

Fran Hall RCR · 28th November 2007, 09:38 PM

Jac,
you may be able to package in a longer 917/30 chassis but you could not get it into a 917k ...you would not get the axle cl and transaxle packaging to work...and as you say still trying to spin the transaxle from the end of one crank will create a more than little whip .

I agree ...deeper pockets allows more accurate replication....

Howard Jones · 29th November 2007, 07:16 PM

Fran, Those of us with less than very deep pockets would really like to see some pictures of this car as it goes together. If it is anything like your other products then I think getting a on going look at it as it is built will sell them like hotcakes after church on Sunday morning.

Great concept by the way. Our favorite cars from the past built to today's standards.

Fran Hall RCR · 29th November 2007, 07:34 PM

Howard,

thanks for the praise.

I agree...I only build the cars that I like and then it does not feel so much like work.

There will be many pictures of the 917's as they go together...just like our other cars.
I have to be careful to not upset the balance of the forum though with too much gratuitous RCR product....

johng · 29th November 2007, 09:04 PM

Mike & Mark,
We just ingested some debris into one of the motors on our Regional Jets. The motors complete are 3.4 million. This debris just damaged each of the 28 fan blades, 248,000 in damage! Crazy,,,,sorry to side track.

Howard Jones · 29th November 2007, 10:08 PM

Fran, These old mid engine sport cars are like our previous girl friends from the past. We still love em all but we settled down with our true love. GT40's. I for one am torn between a new super-light and the 917 mono. Now before you say build them both I must tell you that if I can do another car it will be only one more. Thus my delima. So for now its keep working on a buget and beginning to save my duckets. The research part of this hobby is really nearly as much fun as the rest of it. So I await a closer look at both cars. Hopefully by the end of 08 I can move forward one way or the other.

The 917 really calls out to be used as a track only car which is what I am after. BUT the SLC will work very well with a SBC. Again buget constraints hindering decisions. Anyway I wish I could build them both but alas it's not going to be that way.

Betty (my GT40) does need a stable mate however. How about Heidi for the 917 and maybe Lucy for the SLC.

Jac Mac · 29th November 2007, 10:23 PM

Quote:

Originally Posted by gt40fran

Howard,

thanks for the praise.

I agree...I only build the cars that I like and then it does not feel so much like work.

There will be many pictures of the 917's as they go together...just like our other cars.
I have to be careful to not upset the balance of the forum though with too much gratuitous RCR product....

Dont worry Fran ol buddy, I'll keep an eye on Yah, give you a complimentary short back n sides if you need it!!!!!

Jac Mac

craigdillon · 29th November 2007, 10:41 PM

Regarding the posts on how "replica" does a replica need to be, I agree that it just depends on the pocket-book. For me, the mono chassis and a modern air-cooled Porsche engine is about right.

For somenoe to go truly original in a replica would be on the extreme end. The original car really got close to the ideal race car, which falls apart the second it crosses the finish line. The chassis cracked sometimes. They used to pressurize it and put a schraeder valve on one of the rear chassis elements. They would periodically check the air pressure in the chassis - if it dropped, they knew they had a crack somewhere! The bodywork was so thin that if the car was raced over 12 hours on a track that had some grit or sand on it the wear was enough that it would eventually wear holes in the front. The average thickness of the fiberglass body was 1.2mm, or 50 thousandths of an inch. They even diluted the paint with paint thinner so it would add less weight. The bolts on the suspension were titanium and they drilled the centers out to reduce weight. Even the requisite ignition key was drilled out!

Back to my question, though, anyone heard of horizontal fans for 6-cylinder Porsche engines? Or anyone have suggestions as who to call about such things?

Thierry · 30th November 2007, 04:34 AM

Quote:

Originally Posted by craigdillon

Back to my question, though, anyone heard of horizontal fans for 6-cylinder Porsche engines? Or anyone have suggestions as who to call about such things?

Craig I've made some search....
here is an example....

LA Performance - Welcome

Rick S. · 30th November 2007, 12:59 PM

craig,
In the US, I would probably contact someone like Supertec Porsche Engine Rebuilder regarding fan conversions.

jacky morel · 30th November 2007, 01:40 PM

Hi, I can see that we, owners of GT40, also love 917 !! I was looking to buy one from Kraftwerkz when they decided to stop exporting it. I only have the DVD ! Regarding the engine, why do you need a 12 cylinders ? To be close to the original ? But you'll never be. It will be a replica and I suppose that you are not going to drive it at 200mph on the highways. So a good reliable Porsche 6 cylinders will be perfect if you have the flat fan like the Kraftwerkz has...And you will get the real Porsche sound (who remembers the real 12 sound ?). I will be happy to see pics of the RCR car in progress and will love to buy one , one day, to complete my collection...(Gulf GTD40 and 64 Sebring 289 ERA FIA).

John M · 30th November 2007, 05:46 PM

Quote:

Originally Posted by craigdillon

Regarding the posts on how "replica" does a replica need to be, I agree that it just depends on the pocket-book. For me, the mono chassis and a modern air-cooled Porsche engine is about right.

For somenoe to go truly original in a replica would be on the extreme end. The original car really got close to the ideal race car, which falls apart the second it crosses the finish line. The chassis cracked sometimes. They used to pressurize it and put a schraeder valve on one of the rear chassis elements. They would periodically check the air pressure in the chassis - if it dropped, they knew they had a crack somewhere! The bodywork was so thin that if the car was raced over 12 hours on a track that had some grit or sand on it the wear was enough that it would eventually wear holes in the front. The average thickness of the fiberglass body was 1.2mm, or 50 thousandths of an inch. They even diluted the paint with paint thinner so it would add less weight. The bolts on the suspension were titanium and they drilled the centers out to reduce weight. Even the requisite ignition key was drilled out!

Back to my question, though, anyone heard of horizontal fans for 6-cylinder Porsche engines? Or anyone have suggestions as who to call about such things?

It makes me wonder how some of these cars are still driven today. Doesn't David Piper make quite a few historic races in his original?

John M · 30th November 2007, 06:20 PM

Quote:

Originally Posted by jackymorel

Hi, I can see that we, owners of GT40, also love 917 !! I was looking to buy one from Kraftwerkz when they decided to stop exporting it. I only have the DVD ! Regarding the engine, why do you need a 12 cylinders ? To be close to the original ? But you'll never be. It will be a replica and I suppose that you are not going to drive it at 200mph on the highways. So a good reliable Porsche 6 cylinders will be perfect if you have the flat fan like the Kraftwerkz has...And you will get the real Porsche sound (who remembers the real 12 sound ?). I will be happy to see pics of the RCR car in progress and will love to buy one , one day, to complete my collection...(Gulf GTD40 and 64 Sebring 289 ERA FIA).

I do agree that 12 cylinders is not necessary, and the cost of doing such would be absurd. I also think that trying to duplicate the sound of the original flat 12 2-valve engine is pretty hopeless as well. I would be more interested to see if it would be possible to fit a liquid cooled engine and all its cooling in a 917, be it a porsche engine or otherwise.

Fran Hall RCR · 30th November 2007, 06:53 PM

John,

you can fit anything you want into anything you want given enough time and money.

There is no frontal area to mount a heat exchanger so you would be carrying all the weight and complexity under the tail.....

I could not sell you one if you were going to bolt in a Chevy though.....

Jac Mac · 30th November 2007, 11:08 PM

Water Cooled - Flat 12 - 31" wide - 36" long - 6+ litres - Yep, that should do it!

John M · 1st December 2007, 12:52 PM

Quote:

Originally Posted by gt40fran

John,

you can fit anything you want into anything you want given enough time and money.

There is no frontal area to mount a heat exchanger so you would be carrying all the weight and complexity under the tail.....

I could not sell you one if you were going to bolt in a Chevy though.....

I always wondered about putting a radiator up in front, looks like its not possible. Seems like a liquid cooled engine is going to be difficult... Well, didn't they put a falconer v12 in a 962? Wasn't that a air cooled car? Wonder how the cooling went with that!