917 180 degree V 12

[steamer]

Some more sections

[steamer]

Going a bit smaller, to fit the mill better, so 1/4 scale instead of 1/3.   This also allows for a full ball bearing crank.....progress!

Working on the timing gear towers ...then the cylinder head

Block is 7.55" long now

Dave

[stevehuckss396]

Thats still pretty long. This will be an awesome thread once the chips start flying.

[steamer]

Thats still pretty long. This will be an awesome thread once the chips start flying.

Yes it will!    I start a new job tomorrow.   It's contract for 4 months.   But it's work!   and it will bring some money in, 90 percent of which will be putting back to replenish the bank account.    But soon.     I'll be creating a plan set for this engine that I can supply to others   That way others can go down the road I did, kinda like your little demon Steve.    I'm trying to make a good looking and prototypical engine, that will be a "runnah".    I'm trying to keep the machining simple, so that others can do it without a lot of 3D carving, or forcing CNC.   

I'll share the rest of the development on this engine here.   When the build starts I'll start a build thread.

Current specification
1/4 scale Porsche 912 engine of 4.9 liter displacement  ( this engine and a couple of variants were used in the Porsche 917K at Lemans in the early 70's)
0.85 bore
0.69  stroke
12 cylinder with a 120 degree crank but dispositioned 180 degrees.
Air cooled via engine driven fan ( like the prototype)
Ball bearing crank and connecting rod bearings
Ball bearing cam bearings
Electronic spark ignition with dual distributors,   Layout TBD.
Modular cam shaft, which makes long cams a lot easier to make.
7.5 to 1 compression with 2 compression rings.   No oil control rings.
True center gear drive to a separate drive shaft out rear of the engine which is keeping with the prototype.
I'll be using DP gears   ( 32 DP and 48 DP).    IF that is a problem, I'll offer an alternative design using MOD gears.
I'll probably detail the parts with dual dimensions  ( English and metric).

Stay tuned.....


Dave

[Vixen]

..........
I'll share the rest of the development on this engine here.   When the build starts I'll start a build thread.
..........

Stay tuned.....

Dave

Dave

You cannot believe how much I am waiting for you to start making chips.

Good luck for tomorrow and again when the build starts

All tuned in and waiting

Mike

[steamer]

Lol   Well Mike     me too   for the last couple of years.    Priorities are a changing all the time with my daughter and now recovery, for her and US.     Things will come together....

[fumopuc]

Hi Dave,
a very interesting project.
Just looking into the catalog of my favorite piston ring supplier, 22x2 mm are available of the shelf.
Looking into you first draft, it look´s like another project for the fast coming time after retirement end of this year.
It is good to know, that you have in mind already, that metric guys like me are able to modify bearings, shaft, bolts and may be the gear train.
On the other side, I have learned with the Snow Engine and Bruce Macbeth Engine also, that to redraw a design in Fusion 360 and to modify there all necessary metric design it not a big issue too.
Gear train will not be a big issue also, because 32 DP and 48 DP should be available in the UK of the shelf and standard Boston Gears gears are available for low freight rate by Amazon.
So I am waiting for your new thread.

[Johnmcc69]

 
 Pretty cool Dave! Looking forward to seeing this develop.

 Congrats on the new job!!

 John

[b.lindsey]

Dave, congrats on the new job as well. Maybe it will turn into more than just a contract, who knows.

Bill

[steamer]

Fumopuc

I'm trying to use simple design where ever possible.   The gears are primarily spur, though there are some small bevel and crossed helical like the prototype.

I'm still working the lubrication system.  It doesn't need the 5 scavenge pumps that the original had, as the crank will need very little lubrication.   However the cams will need some lubrication, so I'm keeping that in mind as I go.    I think grease packing the cam will be just fine.  Trying to keep it simple.... 

Keeping the prototypical cam drive boxes is proving to not be that hard, and they will be split down the middle like the original.   

Stay tuned!    And thanks for the support!   I start my new contract job today, and my consulting efforts are starting to pay off with more work!!!    Things are going to get crazy...but that's alright.

Dave
 

[Art K]

Dave,
It is great to see movement on this project. Good luck with the new job!
Art

[steamer]

Thanks Art!

Good progress tonight!!    Got the cam gears in and sorted out, and I've got the distributor holes sorted out relative to the drive shaft.   Need to source some gears for the distributors.     48DP or so I think will do just fine....

Fine tune both of these features, and then rods and pistons....from there I'll have everything I need to do the cylinder heads and valves, and then oil pump drive...won't be long now I hope....We'll see how crazy work gets.

Dave

[steamer]

Honing in on it.

[crueby]

Wow.  That sums it up!   

[sco]

Wow.  That sums it up!   

Agreed!  Keep at it Dave - enjoying seeing the design come together.

Simon