Bugatti Typ 50 1/4 Scale model

[michelko]

I think that the difference when you carried out your test with the resistor plugs was that they were not grounded to the engine block but to the ignition modules, hence the possible requirement to have a good ground between the modules and the engine block.

Hm.... then i will hold the big plugs to the housing and test again. Lets see

[michelko]

Hello Michael

Thank you for your reply, The information is very helpful for my Mercedes engine project.

I mistakenly thought you made the discs with an interference press fit, It appears you have bonded (glued) them together with Loctite 648. Is this correct?

Am I correct to think you make the second disc with a 5/10 oversize bore to give some small clearance for the Loctite 648 ?.

I am sorry Michael, but I did not understand what you meant by "check runout and then turn the second disk to secs."

After your press the two discs together in the vise, do you return the parts to the lathe to check the runout of the two parts and twist the two parts to correct any misalignment. How much time do you have to correct any misalignment before the Loctite starts to harden?

What is the diameter and width of the Loctite joint? and how wide are the discs?

Sorry to have so many questions. You will understand,  it is important for me to correctly understand the process of assembling a straight crankshaft

Thank You

Mike

hi mike my english is a little rusty because of rare usage, sorry. So i try to describe it a bit better.
The hole for the crank pin is made 0,03mm smaler then the pin, so its a press fit. The loctite is used for my peace in mind.
As written above one disk is manufactured to specs, outside dia, bearing seat dia, etc. The second one all diameters left over 0,5mm bigger.
Since i have used the three jaw chuck you can see some runout if you put the piece again in. To achieve the least runout of the ready turned side i tried different positions.
After pressing i didn try to twist the parts but  i turned the oversiced part to spec. So i was able to keep the runout between left and right disk at 1 or 2 /100mm.
This loctite is some awesome stuff. When i glued the cams to shaft i noticed an error just after slip the cam on. 5 seconds later it was not moveable so i had to heat the stup to 200 celsius to loosen up the loctite.

Lets see maybe i can do some pics tomorow with some left over pieces  to show you the way i did it

Michael

[steamer]

Ahhhh    I get it Michael!    Good piece of sideways thinking there!

Dave

[Vixen]

Hello Michael

Thank you for your patience. I now understand how you did it.

Thanks again

Mike

[michelko]

I think that the difference when you carried out your test with the resistor plugs was that they were not grounded to the engine block but to the ignition modules, hence the possible requirement to have a good ground between the modules and the engine block.

Hm.... then i will hold the big plugs to the housing and test again. Lets see

So i did some quick and dirty experimentation.
Hold the plugs to the housing, no spikes in rpm signal,  all fine.
So i decided tu turn my wires so that the rsistor is at the plug side.
Seems that this did it. Because its late i didnt start it but the log looks nice.
Will try it tomorow.

Michael

[Admiral_dk]

I meant what I wrote earlier. Your ignition system does not need a ground connection between the sensor, box, ignition coil and the engine block for it to work if you use normal dual output ignition coils like the ones found on twin / 4 cylinder motorcycles - BUT it will need the grounding between the box and the engine block when you use a Hall-effect as the sensor, to make sure you don't get magnetic induced interference and the best way is to connect the screen on both ends of the sensor cable.

If you electric system contains more than the ignition - like Keiths V10 - you get a multi ground system (I know there in principal only is one, but for this to behave like you think, there can be no current flowing through it) and then you really need to do things right - in this case Keith is right about connecting the screen on one end only. This also applies to distributed ignition systems where the "switch" (MOSFET, IGBT, etc.) has it's own connection directly to the battery, not shared by the rest of the ignition box in almost all systems I had seen or as done today, with the ignition coil directly at the plug with the switch connected directly to the battery and a signal wire from the box (ECU).

This is also the reason I newer understood why anybody wants to use a Hall-Effect as the sensor in any motor vehicle 

The reluctor coils is much more stable, can endure much higher temperatures, withstand gasoline etc. and requires no power to work, the signal is balanced and therefore almost completely immune to interference from the rest of the electric system in the vehicle and cheaper too - and that's why I never saw a Hall-Effect sensor on a motorcycle but numerous reluctor coils over the years as the pick-up for ignition, fuel injection etc.

The ignition system can be a very complex system - or a simple one - but the moment you include Hall-Effect sensors, the simple disappears from the equation. In most cases this can still be simple if you follow the manufactures instruction to the letter (they have blown many of their own design and knows what not to do) - but if you design your own, you will have to learn and often the hard way.

Best wishes

Per

[keith5700]

Michael, bear in mind also that it's dead easy to fire plugs at atmospheric pressure.  It's when you get them under higher pressure that all the fun starts. That's why I made the small Perspex pressure chamber for my plugs, which was extremely enlightening. Trying to get the plugs to fire at 80 psi is a different ball game. All sorts of tracking and internal leaking starts going on.
Anyway, hopefully you've sorted it now?

[racinjason]

 Per,

"to make sure you don't get magnetic induced interference and the best way is to connect the screen on both ends of the sensor cable."

You should only ground the shield at one end, if its grounded at both ends it can act as a conductor and induce voltages into the conductors its protecting.
  Cheers Jason

[michelko]

Tried to start today but something went bad. Cant get any ignition. Searched a while and then i noticed one chanel isn't firing.
When i hook up im stimulater all coils are firing
Then i did a tooth log with tunerstudio and i could see that the missing tooth is missing. I want to say that all spikes are nearly the same hight. What could have caused this? I am realy frustrated at the moment.
When i retrofitted my clasic car with an megasquirt i had not near as much troble like here.

Michael

[Admiral_dk]

You should only ground the shield at one end, if its grounded at both ends it can act as a conductor and induce voltages into the conductors its protecting.

Sorry but, your statement is only true if you create a ground-loop by doing so, and I pointed out that the only ground connection between the box and the engine block would / should be the screen in the simple system as there is absolutely no ground connection on the high-tension side of the system + (almost) none of our systems use the battery for anything other than the box.

And I did point out that this only applies to the systems with waste fire.

You can use a separate ground wire and only connect the screen in one end, but you will lose between 10 and 20 dB noise reduction from what I recommend (depending on frequency).

[keith5700]

Michael, are you on tooth log or trigger log? What do you get when you're in trigger log?

[michelko]

Hello Michael

Thank you for your patience. I now understand how you did it.

Thanks again

Mike

I am happy if i can help thank you.
As promised  here are some pics how i adjustet the disks on the lathe.
One side in the chuck one sidein the tailstock. Crank pin complete pressed in in one side. after aligning slightly pressed the pieces together, only enough they hold till they are moved to the vise. Added some Loctite into the bore and pressed them together

One disk has thread and the other side has countersunk holes. The crankparts were then screwed together.

Michael

[Vixen]

Hello Michael

Thank you for posting the photos of the crankshaft assembly process.

They say a picture is better than a thousand words.

Thanks again

Mike

[michelko]

Hi guys,
i can Report some success 
since i had a other Problem with the triggering because an additional flywheel weight i was able to get the engine running and somewhat iddling. Have to hook up the coolant System now and rework the flywheel to get some more inertia.

<a href="https://www.youtube.com/watch?v=69ZlucqNCl8" target="_blank">http://www.youtube.com/watch?v=69ZlucqNCl8</a>

Thanks for all of your Input.

Michael

[Nick_G]

.
Yippeeee. Bravo. 

Nick