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Bugatti straight 8 cylinder with blower, design, 3D printed molds, castings , machining, assembly

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michelko

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Hi Jules,
those 3d prints looks awesome. I think i also need a printer soon.
Your pump makes some good flow (maybee to much?) , what rpm is it in the photo?
Here is my pump impeller, with idle aprox 1500 rpm it makes just enough flow that i can see the coolant slightly flow out of the returnpipe.
With an pc fan on the radiator i can keep the engine temp at 60-70 degree.
When will we hear it running?

Regards Michael

P.S: Just started machining the holt castings you gave me.
 

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Foketry

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Hi Jules,
those 3d prints looks awesome. I think i also need a printer soon.
Your pump makes some good flow (maybee to much?) , what rpm is it in the photo?
Here is my pump impeller, with idle aprox 1500 rpm it makes just enough flow that i can see the coolant slightly flow out of the returnpipe.
With an pc fan on the radiator i can keep the engine temp at 60-70 degree.
When will we hear it running?

Regards Michael

P.S: Just started machining the holt castings you gave me.
Hi Michael
My cordless drill rotates approx at 1100 rpm without load, I think 950-1000 rpm during the test, if the flow of water is too much, I can reduce it, but I assure you it is never too much.
Running? I hope by the end of the year (2020)
 

Foketry

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That is beautiful work, absolutely superb! I've been using a resin 3d printer for mechanical parts (gears, brackets, mounting frames etc). One thing to bear in mind is that most of the resins are very brittle, very much like acrylic. I've used purpose made engineering resins have much better mechanical properties, although they aren't cheap. Here's one supplier that I've used:
Formfutura Engineering Resins

The clear type is less brittle, the grey type is very very strong, and heat resistant.

Cheers,

Oliver
Thanks for your suggestion, I have read the mechanical characteristics, they are great, but what does it mean ? :
Test method on post cured objects through 10 minutes high power mercury curing
Is mercury curing the same as UV curing?
The manufacturer is Dutch, maybe I find this resin also in Italy, the price is at least 50% higher than the standard resin, but I want to try it.
Regards
 

cds4byu

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Mercury discharge lamps have spectral lines at 405 and 385 nm. 405 is a standard wavelength for photosensitive resins an home printers. 385 is a standard wavelength for laser-based sla printers.

Carl
 

OllyM

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Yes, they just mean UV curing after printing and clean up. All the resins need something like that, although I've yet to see any that have a datasheet specifying exactly how much UV they need (intensity / mm^2 or whatever). Also helps to warm the part up.

They are very expensive compared to regular resins. I usually use a cheap resin for proving the design before using the good stuff for the final part. The "heavy duty" is recommended for printing moulds for plastic injection moulding, to give an idea of it's strength. The print settings need expose quite a bit longer per layer as well.

Cheers,

Oliver
 

ALEX1952

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Another method of engine turning which I have used to good effect on scale mode aircraft is a wood dowel of a size to suit scale and lapping paste, used at a modest rpm & pressure, speed and grit is varied to achieve desired appearance. Apologies if I'm teaching you to suck eggs
 

bruski

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Doesn't any body but my area have sunshine to cure the resin parts?

bruski
 

Jennifer Edwards

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Your post has reminded me of my youth when I helped my father build a Buick straight eight with eight little Webber carb. We mounted it in an old “rail” dragster frame he had and took it to the track.
I remember well the roar it made as he drove it.

good luck with your model
 

Foketry

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Your post has reminded me of my youth when I helped my father build a Buick straight eight with eight little Webber carb. We mounted it in an old “rail” dragster frame he had and took it to the track.
I remember well the roar it made as he drove it.

good luck with your model
Very interesting, can you share some photos of the Buick 8 ?

Jules
 

Jennifer Edwards

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Hi Jules,

at the time I was about 12 years old, I’m noW 64, and unfortunately if there are any surviving photographs they ar3 not in my possession.

to describe it a bit more:

it was a flathead motor. I’m not sure what year the motor was, most likely early 50’s if I had to guess. I do know that a lot of Buick flathead seights were converted into marine engines.

Dad fit eight little Webber carburettors to it. I can recall him constantly fiddling with them, watching the exhaust pipe for that cylinder as he did.

He had welded up eight separate exhaust pipes. Swept down and to the rear, perhaps 18” long.

it was hooked up to a three speed transmission and the shifter came right out the top of it. In fact it is how he decided where to place the seat, roll cage, and other controls.

it was basically a 1960’s front engine dragster.

He ran it as a “Class ‘C’ Econo Rail”. The NHRA has since done away with the “Econo” class, which if I recall correctly was: home built, naturally aspirated, gasoline & carburettors for fuel class. The class was designed to allow the backyard mechanic with limited resources a way to compete.

it has since been replaced with the “Sportsman’s Class”. You would need a good $150,000 to compete in that class. When it superseded the “Econo” class, drag racing for

the car was not very competitive as small block V-8’s were also lumped into class “C”.

Dad had built other cars and did ok for a weekend warrior. That thing I think was just his way of trying to make a point. A point that I have no clue about:)

Being Daddy’s Girl, tinkering with my father in his shop, is how I learned to appreciate things mechanical.

Hope this helped you visualise it a bit more
 

ddmckee54

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In the mid 70's my Auto Mechanics instructor was running a Javelin in the local stock car races.. What was special about this car was that he was using a Hudson straight 8 flathead engine, and winning.

My instructor, who flew B-24's in WW2, said that his father had been the local Nash/Hudson dealer and he would never forgive him if he ran any other engine.

Don
 

Foketry

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The original Bugatti radiator consisted of an outer frame and thousands of small tin-welded brass tubes, air passes inside the pipes and the water flows outside the pipes from top to bottom
Between one pipe and the other there is a small space where the water flows, the pipes are welded at the 2 ends and do not allow the water to escape

IMG_0173.JPG
 

Foketry

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I printed an external plastic shape with a 3D printer and then cast it in aluminum
I wasn't sure I could bend a brass U-profile around the shape without heating it, so to avoid problems I made the external shape with aluminum casting

IMG_1030.JPG
 

Foketry

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To simulate the grid of the front and rear tubes I used 2 commercial perforated aluminum sheet, enlarging the holes from 2mm to 3.7mm
This activity cost me hours and hours of drilling, and several recharges of batteries

IMG_1141.JPG
 

Peter Twissell

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I would have thought the 'scale' brass tube structure could have been soldered using paste.
Your solution avoids potential issues in the future, using a commercial PC radiator.
 

Foketry

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Exhaust pipes, as shown in the photo of the original engine, the exhaust pipes are grouped 4 in 1, I tried to replicate them, designing the 4 in 1 manifold.

%23BC139_TC2008-4.jpg


the manifold project , from this project I made a plastic mold and then a brass casting

collettore scarichi.jpg


the plastic mold, still attached to the 3D resin printer plate

IMG_1080.JPG
 
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