18 Cylinders Isotta Fraschini (straight six-cylinder x3 )

[Peter Twissell]

Or we call it "Tufnol"

https://tufnol.com/sectors/electrical/
Tufnol Whale rod is available in brown (light tan colour) and in diameters ranging from 6mm up to 100mm.

https://www.directplastics.co.uk/tufnol-rod

Indeed, but I'd like to cast mine, so I need to mix the resin at the time of casting.
It's made with formaldehyde, which might be an issue for the home workshop.

 

[Foketry]

Not brilliant. The plastics used for extrusion are typically quite hygroscopic, which doesn't help.
I made the "test" distributor cap for my radial from 'water clear' acrylic resin, poured into a mould. It works ok so far, but it's only been used for bench testing with no compression on the plugs.
The ideal material is phenolic resin.

I know the problem, PLA is a hygroscopic material, the more time passes the more it absorbs humidity,
but I want to do a test, this distributor will be used on my engine in over 2 months, if it doesn't work, I'll make it again in Delrin like all those built up to now.
In reference to water absorption, I found these values on Internet: Delrin 1.5% - phenolic resin 1.15% - PLA 0.8%
I don't know if they are correct, but it would seem that PLA is better than phenolic resin ????
What do you think about it ?

Another solution could be to paint the distributor cap internally and externally , the paint does not allow moisture to enter

 

[Foketry]

Amazing work Foketry,
How was the mold for the flywheel removed from the sand?

I covered the model with Petrobond sand in the lower drag, pressed the sand, turned the flask 180 degrees , dug out the sand on the inclined planes, covered the sand with talc, put the upper flask, filled with sand (Petrobond), pressed and, removed the cope, removed the model, poured molten brass.

 

[Peter Twissell]

I know the problem, PLA is a hygroscopic material, the more time passes the more it absorbs humidity,
but I want to do a test, this distributor will be used on my engine in over 2 months, if it doesn't work, I'll make it again in Delrin like all those built up to now.
In reference to water absorption, I found these values on Internet: Delrin 1.5% - phenolic resin 1.15% - PLA 0.8%
I don't know if they are correct, but it would seem that PLA is better than phenolic resin ????
What do you think about it ?

Another solution could be to paint the distributor cap internally and externally , the paint does not allow moisture to enter

And now it gets complicated ...
Without getting into the detail of polar and non-polar resins, consider that automotive distributor caps are made from phenolic resin and are lacquered to protect them from water absorption.

 

[Foketry]

Rotation transmission from timing gears case to camshafts

Failing to guarantee perfect coaxiality between the 3 output shafts of the timing box and the bearings on which the bevel gears are mounted which transmit rotation to the camshafts , I had thought of using small joints used on RC toy cars, I bought 2 for testing, but I found a lot of backlash between the joints . discarded solution.

I took another solution

The balls and pins are hardened, almost zero backlash

 

[ajoeiam]

Rotation transmission from timing gears case to camshafts

Failing to guarantee perfect coaxiality between the 3 output shafts of the timing box and the bearings on which the bevel gears are mounted which transmit rotation to the camshafts , I had thought of using small joints used on RC toy cars, I bought 2 for testing, but I found a lot of backlash between the joints . discarded solution.



I took another solution

View attachment 144587




View attachment 144589


The balls and pins are hardened, almost zero backless

Interesting solution.
Questions on what I can't see - - -
1. in your socket do you have a bored (squared end) finish or are you doing a rounded end (internally)?
2. not clear but is the pin (cross pin whatever it may be called) actually a spring pin? ( Spring pin - Wikipedia )
3. have you measured - - - -what is the difference between the pin dia and the slot width?

Thank you so much for sharing!!!!!

​

 

[Foketry]

Interesting solution.
Questions on what I can't see - - -
1. in your socket do you have a bored (squared end) finish or are you doing a rounded end (internally)?
2. not clear but is the pin (cross pin whatever it may be called) actually a spring pin? ( Spring pin - Wikipedia )
3. have you measured - - - -what is the difference between the pin dia and the slot width?

Thank you so much for sharing!!!!!

​

The bottom of the socket is spherical made with a ball end mill , but it could also be conical made with a drill bit, maybe it works better
The pin is hardened, diameter 2.5 mm x 12 mm, it is commercial and can be easily purchased at any screw dealer , it is not a spring pin, not very resistant, I think it would break.
I drilled a 2.5mm hole, hardened the sphere and the hole narrowed, then pressed the pin inside.
Between pin and slot no backslah , I milled the slot with a 2.4mm disc , then I widened the slot with diamond file. It would also be necessary to harden the socket but probably due to the very small thicknesses it becomes too brittle.


To reduce the load that pushes on a very narrow point you can use this solution,. the load is distributed over a plane of the slot instead of a small point

 

[ddmckee54]

Foketry:

It looks like you got some U-joints that were designed for electric motors in boats/cars. If you look for dog-bone u-joints for nitro boat motors you might be able to save yourself some design headaches. They might be too big for your application though.

Don

 

[ajoeiam]

View attachment 144606
The bottom of the socket is spherical made with a ball end mill , but it could also be conical made with a drill bit, maybe it works better
The pin is hardened, diameter 2.5 mm x 12 mm, it is commercial and can be easily purchased at any screw dealer , it is not a spring pin, not very resistant, I think it would break.
I drilled a 2.5mm hole, hardened the sphere and the hole narrowed, then pressed the pin inside.
Between pin and slot no backslah , I milled the slot with a 2.4mm disc , then I widened the slot with diamond file. It would also be necessary to harden the socket but probably due to the very small thicknesses it becomes too brittle.

Thank you for your generous response!

You can tell that its a labor of love when someone is filing things to size - - - - grin!

 

[Foketry]

The three heads, each for 6 cylinders

I used a rectangular aluminum bar, each head has 103 holes, some holes like those of the valve guides required 3-4 drilling with drill bits of different diameters, particular precision is required for holes of the valve cages which are inserted using the press and Loctite 620 to avoid gas leakage .

some drawings ...

some workings

 

[Foketry]

The drive system from crankshaft to camshafts

 

[Steamchick]

I can't do as big a "WoW!" as your "W". Really, only you know how good you are. "We, mere mortals, can only gaze upon thy works in awe".
(Well done Sir!).
K2

 

[michelko]

a piece of art...

 

[CFLBob]

I second both Steamchick and michelko: WoW! and what a piece of art!

 

[Foketry]

Valve turning and valve cages

 

[Richard Hed]

Valve turning and valve cages

View attachment 145020

View attachment 145021


View attachment 145022View attachment 145023View attachment 145024

View attachment 145025View attachment 145026

Vivaldi?

 

[michelko]

Hi
What material did you use for the valves?. Chips Looks like free turning steel.
What tolerance are you aiming between stem and guide?

Michael

 

[ajoeiam]

Hmmmmmmmm - - - - given the level pictured here - - - - what might be your next challenge?
(LOL - - - maybe you'll have to design something new? - - - a turbine - - -for the engineering challenge - - - - this is an incredible build!!!)

 

[Nerd1000]

Hmmmmmmmm - - - - given the level pictured here - - - - what might be your next challenge?
(LOL - - - maybe you'll have to design something new? - - - a turbine - - -for the engineering challenge - - - - this is an incredible build!!!)

I recommend a Napier Sabre. With functioning sleeve valves of course, no cheating to hide sneaky poppets somewhere.

 

[Peter Twissell]

If I were to embark on a sleeve valve engine, it would have to be the Bristol Perseus...

But I think we should let Foketry complete this project before we start pushing him further.