18 Cylinders Isotta Fraschini (straight six-cylinder x3 )

[Foketry]

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

Hi Michael, for the last engines I built (Porsche 917 and Bugatti T50) and also for this engine I used high speed steel turning , 36SMnPb14 , this steel, despite the lead, is hardenable with good hardness. This engine doesn't have to fly in an airplane, so no quenching is needed.
Valves have a 3mm stem, the bore is 3.00 mm, my stem is 2.98-2.96.
Some of my friends reduce the stem up to 2.95-2.93 and their motors work fine.
Their theory is that in case of small coaxiality errors between the head and the stem or errors between the cages hole and the 45 degree chamfer ,there are no leakage problems and everything is simpler and faster, maybe they are right.

 

[Foketry]

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!!!)

My next project? A much simpler engine I'm thinking Fairbanks Morse 2-3 cylinder.
Does anyone have drawings or photos or dimensions of this 2-stroke engine?

 

[anday1]

2nd WOW do you ever sleep lol

 

[ajoeiam]

My next project? A much simpler engine I'm thinking Fairbanks Morse 2-3 cylinder.
Does anyone have drawings or photos or dimensions of this 2-stroke engine?

View attachment 145046

I am thinking you will find this also a fascinating project!!!

Spending a wee bit of time - - - - I'm not seeing too much information out there on this particular model.
Lots on the smaller engines and then on the the much bigger ones.

It will be interesting to follow your journey - - - even to where you can find information!

Wishing you well on your new journey!!!!

 

[Foketry]

Heads, valve cages and valves are assembled , after the assembly I made the inlet and outlet holes, both with housing for orings

 

[anday1]

ART..so much work

 

[Foketry]

Valve lapping and control with vacuum pump, 36 valves, real boring work.
A first rough lapping was done with valves and cages not yet assembled on the heads, I pressed the cages into the holes of the heads with Loctite 620, I drilled the exhaust and inlet holes and then I did a finishing lapping ( grade 1000) and checking.
I closed the inlet and exhaust holes with conical silicone plugs, I sucked in with the vacuum pump through the hole for the valve stem .
The target to reach is from 25 to zero in one minute , otherwise repeat the lapping...

 

[Foketry]

The heads assembled with rocker arms, camshaft , camshaft supports and 1:1 ratio gears

rocker arms left and right