18 Cylinders Isotta Fraschini (straight six-cylinder x3 )

[Foketry]

Intake manifolds and exhaust manifolds

I built the manifolds with brass tube brazed on brass supports to be screwed to the heads.
The intake manifolds are split three by three to obtain the length of the pipes similar to each other to have equal fuel distribution for each cylinder.

Intake manifold finished , after sandblasting

Exhaust manifold

welding with 40% silver rods and equipment to hold the pipes in place

after welding all the manifolds were tested with compressed air , silicone caps, immersed in a bucket of water

 

[ddmckee54]

Foketry:

That's an interesting torch, what is it and who makes it?

How many of those itty-bitty caps did you have to make to close off the ends of the tubes? With one each for intake and exhaust, times 18 cylinders, plus all the other end caps, I'm guessing it had to be close to 50 of the little buggers.

Don

 

[Foketry]

Foketry:

That's an interesting torch, what is it and who makes it?

How many of those itty-bitty caps did you have to make to close off the ends of the tubes? With one each for intake and exhaust, times 18 cylinders, plus all the other end caps, I'm guessing it had to be close to 50 of the little buggers.

Don

The torch is an old torch that a friend of mine gave me for free ,it is completely in aluminum and brass, produced in Italy by FRO, more than 10 years ago.
Today the brass has probably been replaced by plastic or aluminum or zamak.

 

[Foketry]

The engine is taking shape, I mounted the heads with the exhaust and intake manifolds, all with Viton ORings , resistant up to 180 degrees.
Between the cylinders and the heads I put Teflon gaskets (the photos of the gaskets in the previous posts) .The 3 carburetors are fixed in the manifolds with a nylon bushing which insulates them from the heat to avoid the vaporization of the petrol, they are very close to the exhaust manifolds .
Now I have to do the timing of the cams, 36 cams, an operation to be carried out with extreme care, if the piston goes towards top dead center with a valve still open, this bends and I will have to redo everything .
After this cam timing I will have to check the compression of each cylinder, I hope to find everything ok

 

[Mechanicboy]

To syncronize the carburettors: Put the 2 mm rod in each carburettors and shut the drums and adjust all linkages. Then remove the rods and check all drums are moving in same time. Main needle in same counts of turns, same with idling mixture screw. Hope we are to see your engine is started up and running. Let the Pope in Rome bless your engine since you are Italian and all will be well.

 

[lechataignier]

Superb work!
Will it burn petrol or methanol?

 

[Steamchick]

WoW! - I think that must be the best expletive to describe this "W" engine!
Amazed at every step - I wouldn't even attempt a single bank 6-cylinder!
I take my hat off to you, Sir!
Keep up the good work Foketry.
K2

 

[ajoeiam]

I'm thinking that this engine should run with incredible smoothness.
Straight 6s already are quite smooth and if - - - don't know if its part of the design - - - the banks are at 120 degrees timing to each other - - - - it should run like the proverbial Rolls-Royce - - - - you know with the shilling on edge balanced on the running motor's radiator.
How very very impressive - - - something like this build!!!!!

 

[Foketry]

Superb work!
Will it burn petrol or methanol?

Petrol

 

[Foketry]

To syncronize the carburettors: Put the 2 mm rod in each carburettors and shut the drums and adjust all linkages. Then remove the rods and check all drums are moving in same time. Main needle in same counts of turns, same with idling mixture screw. Hope we are to see your engine is started up and running. Let the Pope in Rome bless your engine since you are Italian and all will be well.

It will take a lot of setup work to make it work, maybe a few months, but I hope I don't have to go to Rome to the Vatican City for the Pope's blessing, from experience I know that when an engine is finished, the real work begins, at least 1/3 of the time that was used to build it will be necessary to make it functional .All the flaws emerge now .
Thanks for suggestion for the carburetors, I will use this method of yours .

 

[Foketry]

The 3-level distributor cap, each level for 6 cylinders

I copied from an old Ferrari 12-cylinder distributor, 2 levels, each for 6 cylinders, I added a level for another 6 cylinders, total 18 cylinders

my project : The lower disk contains 18 magnets (3mm diameter) which drive a Hall sensor.
Hall sensor is glued into a small sled that you can remove to replace the sensor when it burns out , the high voltage cable coming from the electronic ignition transmits through a charcoal with spring to the central brass pin of the rotor .Rotor has 3 lateral pins which discharge the high voltage towards the first pin they meet on the distributor cap , this pin with a cable reaches the spark plug of the cylinder in the compression stroke. Timing is the most complicated part of this engine.

the first 3D printed prototype

the assembled prototype, I redid the distributor cap

the first functional tests, everything seems ok, all sparks arrive in the correct place

 

[mole42]

Very impressive!

 

[Foketry]

Spark plug boots


I often use these little elbows, DORMAN ELP 47410, but they are not available in Italy, I should have placed the order in the USA at least 20 days ago, so I thought of making them with a 3D printer , TPU material, like black rubber
I don't know if they are resistant to high temperatures, TPU is printed at 230 degrees C, but the spark plugs should reach around 140 degrees C.

My drawing

My printed boot whit 1/4 32 spark plug

 

[CFLBob]

I don't know if they are resistant to high temperatures, TPU is printed at 230 degrees C, but the spark plugs should reach around 140 degrees C.

Seems like plenty of margin - 90 degrees. Do you have a way to test them before you build everything up?


Bob

 

[petertha]

Coming along nicely!
1) What brand of spark plugs are those?
2) I don't quite understand how electric contact is made if there is a small running gap between rotor, a spring behind one of them maybe?
3) with so many cylinders to fire in a crankshaft rotation, does this push the capability of the ignition module to deliver spark & recharge itself? (Sorry I'm electrically challenged).

 

[Foketry]

Seems like plenty of margin - 90 degrees. Do you have a way to test them before you build everything up?


Bob

Do the test by simply placing the spark plug and the boot in an oven at 140 degrees, it does not reproduce the same conditions as the hot engine, when the engine is running, the boot surface is not subjected to heat, whereas in the oven it is
I therefore tried to heat only the spark plug thread with a contact thermometer and the boot had no problems for a few minutes at 140 degrees

 

[Foketry]

Coming along nicely!
1) What brand of spark plugs are those?
2) I don't quite understand how electric contact is made if there is a small running gap between rotor, a spring behind one of them maybe?
3) with so many cylinders to fire in a crankshaft rotation, does this push the capability of the ignition module to deliver spark & recharge itself? (Sorry I'm electrically challenged).

View attachment 146914View attachment 146915

the spark plugs are Rcexl

there must be a small gap between the rotor and the distributor cap , the high voltage voltage jumps between a conductive zone and another , this must be perfectly controlled otherwise it jumps in the wrong place or does not jump and then damages the Hall sensor , frying it
For this 18-cylinder engine, therefore 9 ignitions each revolution of the crankshaft, an ignition is required that can deliver over 25,000 sparks each revolution.
Example, if my engine rotates from 700 to 2500 rpm (I hope), 2500 x 9=22500 sparks each revolution
The ignition that I will use is handcrafted by an electronic friend of mine, the tests done with an oscilloscope show that up to 30,000 rpm the electronic ignition works.
This friend of mine is producing 20 of these ignitions, cheap, less than 40 euros each , and is willing to sell them

 

[ddmckee54]

Doesn't that leave you with 22500 sparks per minute? You only need 9 sparks per revolution no matter what the rpm is. (9 sparks / rev) * (2500 rev / minute) The rev units drop out and that leaves you with sparks per minute. You had the right number, just your units were wrong. Sorry, my 1st year Physics instructors harped on having the units right - old habits die hard. Still, as you said, it should be easily within the capability of that ignition module.

 

[Foketry]

Doesn't that leave you with 22500 sparks per minute? You only need 9 sparks per revolution no matter what the rpm is. (9 sparks / rev) * (2500 rev / minute) The rev units drop out and that leaves you with sparks per minute. You had the right number, just your units were wrong. Sorry, my 1st year Physics instructors harped on having the units right - old habits die hard. Still, as you said, it should be easily within the capability of that ignition module.

Yes certainly, revolutions per minute, but here in Modena in the valley of engines (Ferrari , Lamborghini , Ducati ), when we talk about revolutions, they are always rpm ,as in my previous message, 30,000 rpm I wrote

 

[Foketry]

Distributor improvements
The distributor needed some modifications to keep the spark from jumping from one level to another.
The first tests I had done by turning the distributor by hand did not highlight a major defect, the spark jumps from one level to another in an uncontrolled way.
This defect emerged with the spark plugs installed in the cylinders and with rotation by a cordless drill ,I modified the rotor by making the diameter of the 3 levels more distant. Consequently I also had to redo the distributor cap.

to see what happens inside the distributor while it turns and distributes the sparks, I tried to build it in plexiglass, gluing overlapping sheets of plexiglass, but without success, I made mistakes several times, the 2 mm drill bit deviates due to the deep hole .
Then 3D printed a new cap distributor with semi-transparent PLA wire and redid all the cable connections.
The rotor is also redone

some attempts, all failures