Author Topic: 1/4 scale Porsche 917 180 degree V12 Build  (Read 20320 times)

Offline stevehuckss396

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Re: 1/4 scale Porsche 917 180 degree V12 Build
« Reply #45 on: September 20, 2021, 09:39:02 PM »
Right on! I guess once everything is assembled you will know if you are good?
Do not be like the cat who wanted a fish but was afraid to get his paws wet.

Offline steamer

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Re: 1/4 scale Porsche 917 180 degree V12 Build
« Reply #46 on: September 21, 2021, 03:56:19 AM »
Hey Bubba!    thanks for dropping by.

Right on! I guess once everything is assembled you will know if you are good?

Almost!!!   

In the first photo below....
the crank cheeks to the left are finished....

The crank cheeks to the right have the bearing diameters left large

Once the crank pins are hardened,  they will be installed in all the crank cheeks to the left..

THEN....all the right cheeks will be pressed on and oriented to match the left ones as close as possible.

See the second photo

Next...the semi finished crank is mounted in lathe fixture.    the fixture locates the left crank directly on center of the lathe.

Then....we finish turn the bearing diameter of the right hand crank disk  IN SITU, which results in two concentric diameters!

Then I'll bolt all these together and we have a crank!

Dave

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Offline crueby

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Re: 1/4 scale Porsche 917 180 degree V12 Build
« Reply #47 on: September 21, 2021, 03:59:24 AM »
Quote
Then I'll bolt all these together and we have a crank!


you make it sound so easy!

Offline steamer

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Re: 1/4 scale Porsche 917 180 degree V12 Build
« Reply #48 on: September 22, 2021, 12:07:08 AM »
Quote
Then I'll bolt all these together and we have a crank!


you make it sound so easy!

It's labor intensive    YES.   Particularly difficult?    NO  I don't think it is!!!!

All these parts could have been done on a Sherline manual lathe and mill.  Is there a lot of parts?   Sure!   But it spreads the risk out.    Imagine cutting a 6 throw 7 main bearing  crank with a gear in the middle in a home shop from the solid on a Sherline or any other lathe for that matter!    This solution really helps make building this engine feasible.   The crank pins are precision ground A2 round stock. Right out of McMaster!
I part to length, face the ends and drill a hole through them.     Harden and polish the ends and they're done.   you have 6 crank pins all within 8 microns of each other....Thank you Mcmaster Carr!


The crank disks are fussy in three dimensions.   But it's simple turning and boring, and the way the crank is built up, you get several chances to correct errors as you go.  Most of the crank dimensions are +/- .005" which most can hold without too much difficulty.   the rest can be jig positioned

The assembly will be about some assembly fixtures and an arbor press.   Most here have the press, and can make simple fixtures...which if you're going to be making engines, you better get used to it....you make lots of fixtures!!!!!

No I don't think it's that bad....

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

Offline steamer

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Re: 1/4 scale Porsche 917 180 degree V12 Build
« Reply #49 on: September 25, 2021, 02:05:09 PM »
Gear cutters and arbors are here!!! :whoohoo:

I'll post up what I get up to,    once I can cut the 3 primary gears, and get the pins hardened at Cletus's Heat treat Haven.....I can get on with the rods perhaps....

Gonna go where I see fun to do next.

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

Online Kim

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Re: 1/4 scale Porsche 917 180 degree V12 Build
« Reply #50 on: September 25, 2021, 05:32:56 PM »
Dave, it's always fun when new tools arrive!  :LickLips:

Can't wait to see what you do next!  :popcorn: :popcorn:

Kim

Offline steamer

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Re: 1/4 scale Porsche 917 180 degree V12 Build
« Reply #51 on: September 25, 2021, 07:05:49 PM »
Hey Kim

Thanks for following along.   Today's exercise will be mostly tool making and I may just post it to the tools section till I'm cutting-edge gears...

Thanks again for your interest..someone is reading it.     :ThumbsUp::ThumbsUp:
"Mister M'Andrew, don't you think steam spoils romance at sea?"
Damned ijjit!

Offline stevehuckss396

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Re: 1/4 scale Porsche 917 180 degree V12 Build
« Reply #52 on: September 25, 2021, 09:08:36 PM »
Were all reading it!
Do not be like the cat who wanted a fish but was afraid to get his paws wet.

Offline Craig DeShong

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Re: 1/4 scale Porsche 917 180 degree V12 Build
« Reply #53 on: September 26, 2021, 12:31:24 AM »
Hey :cartwheel: Iím here.  Just stepped out to refresh the popcorn. :popcorn:
Craig
The destination motivates us toward excellence, the journey entertains us, and along the way we meet so many interesting people.

Offline RReid

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Re: 1/4 scale Porsche 917 180 degree V12 Build
« Reply #54 on: September 26, 2021, 02:05:44 AM »
I never miss an episode.
Regards,
Ron

Offline steamer

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Re: 1/4 scale Porsche 917 180 degree V12 Build
« Reply #55 on: September 26, 2021, 03:15:54 AM »
Ok   I really wanted to cut some gears for the 917 model  Got a Tormach arbor blank, got the gear cutters..   made the arbor from the blank.  Needed  1/2-20 tap..my two taps are dull, ok I'll single point them on the lathe.   Don't have a bolt with that tread..ok I'll go to the hardware store in the morning...let's get the gear blanks ready!    I'm out of material!!!!....sigh    :zap: :hammerbash: :Doh:....I'll get on the conrods tomorrow, and send the crank pins out to Cletus for heat treat...... :facepalm2: :wine1:
I may salvage something from this weekend.....
"Mister M'Andrew, don't you think steam spoils romance at sea?"
Damned ijjit!

Offline steamer

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Re: 1/4 scale Porsche 917 180 degree V12 Build
« Reply #56 on: September 26, 2021, 03:39:08 AM »
OK  conrods.    The conrods on the prototype had nuts on the opposite face... ( see pictures one)

I'm going to try and duplicate that ....

It turns normal conrod build process on it's head a little...but shouldn't be too bad..   and yes    I DO have the material for the rods.!!! :facepalm:

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

Online Roger B

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Re: 1/4 scale Porsche 917 180 degree V12 Build
« Reply #57 on: September 26, 2021, 04:55:06 PM »
Looking good  :ThumbsUp:  :ThumbsUp:  :wine1:

I've made some conrods that way round. It's the easier way (the only way??) to assemble and engine with a tunnel crankcase.
Best regards

Roger

Offline steamer

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Re: 1/4 scale Porsche 917 180 degree V12 Build
« Reply #58 on: September 26, 2021, 08:46:14 PM »
Looking good  :ThumbsUp:  :ThumbsUp:  :wine1:

I've made some conrods that way round. It's the easier way (the only way??) to assemble and engine with a tunnel crankcase.

If you put all the rods on first, you can do it conventional
"Mister M'Andrew, don't you think steam spoils romance at sea?"
Damned ijjit!

Offline crueby

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Re: 1/4 scale Porsche 917 180 degree V12 Build
« Reply #59 on: September 26, 2021, 09:49:16 PM »
 :popcorn: :popcorn: :popcorn: