Bugatti Typ 50 1/4 Scale model

[michelko]

Hi Mike,
i am using an arduino based ecu called speeduino. Its already controling the spark. www.speeduino.com
I am using a megasquirt on an other Project : Porsche 914/6 with Triumph Speed tripple ITBS on EFI. And yes,  will fabricate two carb dummys that will act as Throttles.

Michael

[Vixen]

Michael,

Wow, speeduino, so many variables to mess up. Do you start with a basic set-up, or map, that is known to work?
What do you use for the physical fuel injection hardware. Is this something you make, or is it based on automotive hardware? And the same question for the ignition system.

Mike

[michelko]

Hi Mike,i am using automotive parts.
There are some small injector called pico. I think they are first build by magnetti marelli.
here is a pic from one that i had already chopped. Ground away the plug and shortend the injector a Little bit.

The Coils are also from automotive. These ones came from a VW golf.

[Vixen]

Michael,
Thank you for sharing this information.
Someone must take the first steps and other will follow.
One day, when you have time,  you could do the full story about installing and setting up a speeduino system.

Mike

[steamer]

Michael,
Thank you for sharing this information.
Someone must take the first steps and other will follow.
One day, when you have time,  you could do the full story about installing and setting up a speeduino system.

Mike

Following along as well!

[michelko]

Hi guys,
have some Problems running the Bugatti. The engine pushed oil out of the crankcase vents while running.
I made some baffles to Keep away the oil splash from the breathers.
After that i couldnīt get the engine running mor than a pair minutes and then the plugs where fouled.
It pumped so much oil that it came unburned out of the exhaust.

I decided to Change out the spraybar with a solid pipe.
Hope that cures the oil Problem.
Since the crank is equiped with roller bearings it should not Need much oil.

Michael

[michelko]

i also thought about using some 2 stroke oil in the fuel to lubricate the Piston/cylinder.

Michael

[Vixen]

Hi Michael,

Could the plug fouling and excessive crankcase venting be due to a piston ring problem? If some  rings are no longer sealing properly, they can cause these sorts of problem.

You can check the compression of each cylinder to see if one or more cylinders has become low on compression. Or you can remove each piston and inspect each of the piston rings. Perhaps a ring has broken or become trapped and unable to move. You will also be able to see if each ring has even wear all round the circumference or if it is localised to three contact points.

Good luck with the problem solving

Mike

 

[Vixen]

Hi Michael

Can you remind us, do you have oil rings in addition to the compression rings?

Mike

[michelko]

Hi Mike,
at this Point i do not want to dismantle the Pistons because this means take of the head etc.
I can feel strong compression while turning the crank, so i think (and hope) the rings are o.k.
I planned two compression rings an one oil Control ring.
Unfortunatly i was not able to Mount the oil ring beause they broke while i am trying this.
This oil pumping was an issue from the beginning, but not so bad as after Fitting the baffles

Michael

[Vixen]

Hi Michael

I can completely understand why you do not want to pull down the complete engine to examine the piston rings. Having only the compression rings and no oil control rings does not help.

You must assume that here is blow-by past the rings and it is increasing the pressure in the crankcase. The excess pressure is trying to escape through the breather and also upwards into the cylinder head. You could try and enlarge the size of the crankcase breather to reduce the pressure. It may help.

Perhaps you could stop using the crankshaft oil pump and use two-stroke oil/ fuel instead. That is the way most flying model engines are lubricated. The blow-by past the piston rings now works to your advantage and oil is blown into the crankcase to lubricate the bearings.

I have a Siedel 5 cylinder radial engine which is lubricated  by a 5 to 10% fuel/oil mixture. You only need a small quantity oil in the fuel. If the engine makes smoke, you are using too much oil.

It should work well for your Bugatti, you have the advantage of roller bearings

Mike

[michelko]

Hello,
here is a Little update on the Bugatti build.
The changes on the oil spray bar went well. Ran the engine 30 minutes with no plug fouling. i also Used two stroke oil with the fuel, just to be safe.

An old Problem with the ignition/ECU turned on again. I changed the Position of the Coils and had again Problems with the triggering.

I purchased some shielded coax cable to connect the sparks to the Coils.
Will Keep you informed.

Michael

[Vixen]

Hello Michael

Good to hear that the oil spray bar changes have helped with the plug fouling. Is it still blowing oil out of the breather with the new crankcase baffles? Can you reduce the pumped crankcase oil supply now that you are using oil mixed with the fuel?

They say that shielded cable should only be connected to earth at one end only, to avoid earth loop problems. Do you have shielding around the trigger wires?

Keep us posted about progress

Mike

[Roger B]

Hello Michael,

Shielded HT wires are generally not a good idea. The capacitance of the cable tends to slow the rise time of the spark and cause burning of the sparkplug electrodes. Sometimes it has to be done to avoid radio interference, such as in aircraft engines.
Looking at your picture of the coils above it would be better to bolt them both to an aluminium plate and then bolt that to the engine body. You need to consider the complete spark circuit and how the current returns to the ground end of the coil.

[michelko]

Hi guys,
i gave the shielded wires a try and ... same as before.
But i think i found the Problem. It is maybe a faulty sparkplug that produces These heavy Spikes in the rpm pickup.
Have to fabricate some more plugs.


Michael