Oddball engines and prototypes

[tjbw]

This fracture splitting technology isn't new, in fact I think McCulloch may have used it in their chainsaws way back, but not sure on that. Haven't seen integral bolts though.
Here is a link describing the fracturing process well:-
http://www.dieselduck.info/machine/0...%20conrods.pdf

That's a very good paper Will.

Groove to initiate crack just 0.2mm wide, formed by electro discharge, I think that's what I'd call spark machining.
Thirty percent cost savings achieved, however I'd prefer to spend extra for something that isn't sintered, or doesn't fracture easily.

I'd like to see any problems with carbon fibre rods overcome.

Another thought on the "integral bolts", if any fastener is integral with the rod, wouldn't be a stud, since a bolt has a bead?

[husaberg]

That's a very good paper Will.

Groove to initiate crack just 0.2mm wide, formed by electro discharge, I think that's what I'd call spark machining.
Thirty percent cost savings achieved, however I'd prefer to spend extra for something that isn't sintered, or doesn't fracture easily.

I'd like to see any problems with carbon fibre rods overcome.

Another thought on the "integral bolts", if any fastener is integral with the rod, wouldn't be a stud, since a bolt has a bead?

On the ducati supermono they side stepped all this malarkey by making the rod one peice like a two stroke they then pressed in a 2 piece plan shell bearing.
They would have prefered to use a one piece like a bush but they are not available in the high spec they wanted to use.
I wonder if the could split the rod and then fuse it back together electrically.
Not like this though.

[WilDun]

They would have prefered to use a one piece like a bush but they are not available in the high spec they wanted to use.
I wonder if the could split the rod and then fuse it back together electrically.
Not like this though.

I always knew that guy MacGyver was a genius!
Didn't you notice that's exactly what he was doing - I think I must have missed the episode where he split it in the first place! - where'd he go by the way? I bet Harley had him round as a consultant later on - that's probably why they came out of the Doldrums!

That's a very good paper Will.
Another thought on the "integral bolts", if any fastener is integral with the rod, wouldn't be a stud .........

Well just for the purpose of clarity, (and I can never remember the word "integral" anyway) so I'll just call them "built in studs"

[husaberg]

I always knew that guy MacGyver was a genius!
Didn't you notice that's exactly what he was doing - I think I must have missed the episode where he split it in the first place! - where'd he go by the way? I bet Harley had him round as a consultant later on - that's probably why they came out of the Doldrums!



Well just for the purpose of clarity, (and I can never remember the word "integral" anyway) so I'll just call them "built in studs"

I think its the episode where he made a microlight out of a concrete mixer, bamboo, some plastic sheeting and duck tape.
As i recall he was welding with a battery and a nickel coin.
EDIT no its a pump in the jungle 2.44
http://www.dailymotion.com/video/xgk...2-3_shortfilms
He looks a little different now.

[Grumph]

I'd like to see any problems with carbon fibre rods overcome.

So would I - but I doubt if it will be in my lifetime. John Britten I believe played with a CF rod - I was told the end result was messy - in every sense.

I've played with CF pushrods - alloy ends bonded in. Worked for a short period, but again, messy end result.

It's not nice stuff to clean out of a motor.

[WilDun]

So would I - but I doubt if it will be in my lifetime. John Britten I believe played with a CF rod - I was told the end result was messy - in every sense.

I've played with CF pushrods - alloy ends bonded in. Worked for a short period, but again, messy end result.

It's not nice stuff to clean out of a motor.

Next thing you know, some clever guy will discover that Cast Iron is good for making cylinders, crankshafts and all sorts of things we never realized.
Power to weight ratio? well, unless you are trying to gain the last tenth of a horsepower to make the thing accelerate better or go faster by 1 kilometer an hour - who cares, a 50cc engine will be as powerful as a 500cc street bike was a few years ago anyway! The power to weight issue could after all be sorted by drinking a few less bottles of piss and by driving on past MacDonalds on the way home from a meeting! ( and no I didn't listen to that sort of advice ........ years ago)
Never mind, the triple bypass a few years back fixed that and I'm sure the surgeon found it just as messy as having to clean up the carbon fibre damage in an engine!!
BTW, the anaesthetist who was to be looking after me didn't turn up on the day because he had crashed his Ducati !!!

He looks a little different now.

Good clip (Kiwi one) thanks - I missed that!

[pete376403]

That's a very good paper Will.

Groove to initiate crack just 0.2mm wide, formed by electro discharge, I think that's what I'd call spark machining.
Thirty percent cost savings achieved, however I'd prefer to spend extra for something that isn't sintered, or doesn't fracture easily.

BMW have sintered, fracture split rods in some of their car engines, and are as far as I know are not known for rod breakage.

Good Yamaha article on fracture splitting on this page https://global.yamaha-motor.com/about/technical_review/

[tjbw]

BMW have sintered, fracture split rods in some of their car engines, and are as far as I know are not known for rod breakage.

Good Yamaha article on fracture splitting on this page https://global.yamaha-motor.com/about/technical_review/

Lots of interesting pdfs on that page, but the fracture split pdf is the same one I was commenting on, Will posted it already.

Good to know that BMW and others are getting good results with their rods, as breakages can be very expensive.

Lamborghini are developing various carbon fiber parts, including conrods:

https://arstechnica.co.uk/cars/2016/...-21st-century/

[guyhockley]

http://proceedings.asmedigitalcollec...icleid=1750750

[WilDun]

Very exciting, very interesting stuff of course but (as I see it,) it would appear that resin is still resin and not good with high temperatures and metal and resin living together being so diametrically opposed (like cats and dogs) will be a disaster which will take huge amounts of cash to get round and maintain...........and being done just to catch and kill some "baddies" - instead of spending that cash on social engineering, understanding people and promoting commonsense to produce more "goodies"! - sorry, there I go digressing again!
Is there a reason why carbon fibre can't be incorporated in a metal casting (eg. carbon fibres in aluminium) and making it possible to have very thin castings? or impregnating the fibres with metal for use in the "forging" process described somewhere in the previous links.

Oh and I see that my spellcheck is telling me that fibre and aluminium are spelt wrong - funny, it didn't tell me that "spelt" is wrong too- have we got a New Zealand spellcheck?

[Frits Overmars]

If your spellcheck doesn't like aluminium, throw it out. The spellcheck, I mean.

[WilDun]

If your spellcheck doesn't like aluminium, throw it out. The spellcheck, I mean.

Stuff the spellcheck, they don't know when to shut up (like me) - But ....... Do I detect then that you are thinking aluminium could possibly be an alternative to resin?

[tjbw]

For high temperature CF applications:

http://www.high-temperature-composit...c-pyrokarb.htm

Hope it's cost effective.

Another thoughts for CF conrod:

Use a thermal barrier in the piston crown and/or at gudgeon pin.
Run engine at lower temperature, e.g. with HCCI.

[WilDun]

For high temperature CF applications:

http://www.high-temperature-composit...c-pyrokarb.htm

Hope it's cost effective.

Another thoughts for CF conrod:

Use a thermal barrier in the piston crown and/or at gudgeon pin.
Run engine at lower temperature, e.g. with HCCI.

I seem to remember someone trying Titanium (alloy) for rods, but no doubt at astronomical cost - who was it and what happened to that experiment?
I also remember when the Kiwi boat in the "round the world" boat race tried CF masts, they tended to snap like carrots but probably that has all been cured by now.

[tjbw]

I seem to remember someone trying Titanium (alloy) for rods, but no doubt at astronomical cost - who was it and what happened to that experiment?
I also remember when the Kiwi boat in the "round the world" boat race tried CF masts, they tended to snap like carrots but probably that has all been cured by now.

Titanium is quite popular for conrods. Honda, Yamaha, Renault and others have used them. I'm not sure if any alloying elements help.

I just saw a price of about US $2500 for an aftermarket titanium conrod!