Author Topic: 1/4 scale Porsche 917 180 degree V12 Build  (Read 57533 times)

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Re: 1/4 scale Porsche 917 180 degree V12 Build
« Reply #240 on: January 18, 2022, 12:13:31 AM »
That crankshaft is deeeeeeeeeelux Dave.   Just superb!

Thanks Craig,  its starting to fill in nice....

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Offline Art K

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Re: 1/4 scale Porsche 917 180 degree V12 Build
« Reply #241 on: January 18, 2022, 02:56:14 PM »
Dave,
Things are looking very good!  Great that you can just swap out the center bearings and have thrust under control.
Art
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Offline Roger B

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Re: 1/4 scale Porsche 917 180 degree V12 Build
« Reply #242 on: January 22, 2022, 08:16:21 AM »
Excellent  :praise2:  :praise2: That's a neat solution for the thrust bearings  :ThumbsUp:
Best regards

Roger

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Re: 1/4 scale Porsche 917 180 degree V12 Build
« Reply #243 on: January 31, 2022, 12:09:14 AM »
OK so full design intent  installed.     Everything but the scavenge side on the right side block with strainers....But not tonight
The pump is iin  as is the drive for it, and the pressure feed passages to the spray bar above.  I also have the scavenge delivery passages in the left block

What remains is the fan drive items, which I'll get into, and the aforementioned scavenge ports and strainers  ect on the left block.

I'll build the output shaft and the oil/scavenge pump system next and debug on the bench.   Then the fan drive.   THEN  the blocks...that will give me a chance to develop everything that goes in the block before I cut metal on the block ...

Oil and scavenge pumps were sized by copying Ron Colonna's pump dimensions from his Offy, which is only slightly smaller than this engine, and had a pressure lubed/plain bearing main and rods...so this should be more than enough to feed this girl..

I have distributors designed and modeled, but before i finalize, I need to get my cross helical gears from across the pond....its on the list

Work has been crazy.....67 hours last week,,,,and they want more....I played hooky today.....

Dave

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Online Vixen

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Re: 1/4 scale Porsche 917 180 degree V12 Build
« Reply #244 on: January 31, 2022, 11:33:05 AM »
Hello Dave,

That's a neat little pump and installation with all the pressure and delivery passages machined into the blocks. I see you have gone away from the idea of an externally located pump. You said the external location was to give access to the pump during development. You are obviously more comfortable with this version of the design, because when the two sides of the crankcase are eventually bolted together, it's in there for keeps.

67 hours last week...... you can  :censored: that

Mike
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Offline Admiral_dk

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Re: 1/4 scale Porsche 917 180 degree V12 Build
« Reply #245 on: January 31, 2022, 11:38:26 AM »
Looks like a very neat and easy installation of the pumps  :ThumbsUp:

I must admit that I'm not sure I got all the detail right in my head. I presume that the two lower holes are the oil entry points for the two of tree pumps - but what is the the input to the one closest to the pumps input shaft ?

The recesses on the pumps outputs, are they for the o-rings  :thinking:

Great that you got a good income after some hard times, but I understand if you would have liked it, to be more even workload over time ....

Per

Offline JonC

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Re: 1/4 scale Porsche 917 180 degree V12 Build
« Reply #246 on: January 31, 2022, 12:59:15 PM »
Hi Dave,

Incredible build so far and love it every time there's a bit more progress to be admired. The thrust bearing idea is excellent, are you using 25x32x4 bearings? I'm using these on the DFV crank but cannot find a flanged version of it.

Thanks

Jon
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Re: 1/4 scale Porsche 917 180 degree V12 Build
« Reply #247 on: February 01, 2022, 04:13:02 AM »
Hello Dave,

That's a neat little pump and installation with all the pressure and delivery passages machined into the blocks. I see you have gone away from the idea of an externally located pump. You said the external location was to give access to the pump during development. You are obviously more comfortable with this version of the design, because when the two sides of the crankcase are eventually bolted together, it's in there for keeps.

67 hours last week...... you can  :censored: that

Mike

14 hour day today too.....but they gave me a nice raise.....

Mike, You sir are correct on all counts.....here's the scoop....no matter how I tried to do it, that external pump looked like Q(*E(*Q .    It is NOT how the 917 engine looks...  My previous comments about fiddly bits inside the engine is still accurate.    To get around that, instead of running the pump with a gear train at about 1/2 engine speed, I'll be running this one at engine speed.   Pump speed is well within limits for a gear pump ( pitch line velocity below 20 m/s.    In this application it's under 3 m/s at 8000 rpm)    But this pump needs to be reliable....so I'll be following a theme that has already saved my bacon on thius project....work from the inside out.     SO   to develop this pump and make it reliable, it will be the next thing on the list to build, followed by the power layshaft and the fan/distributor layshaft.    And I'm very happy I'm taking this path as it's like the REAL one......

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

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Re: 1/4 scale Porsche 917 180 degree V12 Build
« Reply #248 on: February 01, 2022, 04:21:55 AM »
Looks like a very neat and easy installation of the pumps  :ThumbsUp:

I must admit that I'm not sure I got all the detail right in my head. I presume that the two lower holes are the oil entry points for the two of tree pumps - but what is the the input to the one closest to the pumps input shaft ?

The recesses on the pumps outputs, are they for the o-rings  :thinking:

Great that you got a good income after some hard times, but I understand if you would have liked it, to be more even workload over time ....

Per
What you see there Per is 3 pumps stacked on top of each other.    From the left to right....the first is the pressure pump,   The second and third are scavenging pumps.  They each have 1.5 x the capacity of the pressure pump.     the round recesses on the side are for seals that seal the pump agianst each half of the engine block.   All passages are drilled passages leading to the top of the block and down a stand pipe with 7 nozzles.   1 for each crank bay and 1 for the gear bay in the middle.   The scavenge pumps will draw from the two bottom sump wells with strainers down low.   All that will be on the RIGHT side engine block half.   Not shown..    JUST like the real one.   there will be 1 hose into the right block feeding the pressure pump from the scavenge oil tank, and the two scavenge pumps down to a hose on the left side of the block up front.

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

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Re: 1/4 scale Porsche 917 180 degree V12 Build
« Reply #249 on: February 01, 2022, 04:28:01 AM »
Hi Dave,

Incredible build so far and love it every time there's a bit more progress to be admired. The thrust bearing idea is excellent, are you using 25x32x4 bearings? I'm using these on the DFV crank but cannot find a flanged version of it.

Thanks

Jon

Thanks Jon,   The McMaster Carr part number is in the top left of the corner of the picture below. 
https://www.mcmaster.com/4390N142/

Dave



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Offline fumopuc

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Re: 1/4 scale Porsche 917 180 degree V12 Build
« Reply #250 on: February 01, 2022, 07:11:11 AM »
Hi Dave, I am following along quietly all time.
Impressive to watch the progress.
There is an always upcoming desire to ask you for the plans/drawings if it is coming closer to the final stage.
Kind Regards
Achim

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Re: 1/4 scale Porsche 917 180 degree V12 Build
« Reply #251 on: February 01, 2022, 11:39:03 AM »
Hi Dave, I am following along quietly all time.
Impressive to watch the progress.
There is an always upcoming desire to ask you for the plans/drawings if it is coming closer to the final stage.

That will be a ways off sir.   But I think it doable....not sure which decade... :lolb:at this rate

"Mister M'Andrew, don't you think steam spoils romance at sea?"
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Re: 1/4 scale Porsche 917 180 degree V12 Build
« Reply #252 on: February 01, 2022, 11:46:21 AM »
The other place to look for all kinds of small bearings is Fast Eddy's


https://www.fasteddybearings.com/

They provide specialty bearings to the RC industry.  Good stuff

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

Offline Craig DeShong

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Re: 1/4 scale Porsche 917 180 degree V12 Build
« Reply #253 on: February 01, 2022, 01:47:30 PM »
67 hours is insane.  Many years ago, a group of us ‘hot shots’ started our own company.  We put in hours like that for around two years… but then we were working for ourselves so that is different.  We learned a valuable lesson on marketing; much better to have a crappy product and great marketing.  Unfortunately we were the opposite. After two years we realized we were getting nowhere and probably would continue to go no where.  It was time to move on.
Craig
The destination motivates us toward excellence, the journey entertains us, and along the way we meet so many interesting people.

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Re: 1/4 scale Porsche 917 180 degree V12 Build
« Reply #254 on: February 07, 2022, 12:33:31 AM »
Made some progress today!!

Here are all the major parts for the pressure and 2 scavenge pumps for the engine.   First operation on all is complete.   I designed the pump so that all critical dimensions could go in with 1 set up and 1 tool...minimizing the errors as much as I can.   Now  they get chopped off the bar, and mounted, finished face down, on a fixture so the back side of each part is finish machined.    This will maximize the chance that the parts are parallel.   Next each part will get its oil ports put in, and then cleaned up and deburred.

Productive afternoon!

Maybe with CNC   I can keep up with Chris! :insane: :Doh:

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

 

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