The Bucket Foundry

[Flettner]

I started converting my cars to LPG in 1975. I never changed compression ratios, ignition timing, valves, valve seats, valve guides, etc. Spark plugs lasted 100.000 km.
Over the past 40 years I had 8 cars that together did about 800.000 kilometers and I have never had any LPG-related problems.
I think the main reason for LPG-related problems is greed. People tend to set the mixture too lean, although the stuff costs next to nothing.

Costs next to nothing? Here in NZ as the petrol prices increased so to did the LPG in price to a point were it's almost not worth converting.

[Grumph]

Costs next to nothing? Here in NZ as the petrol prices increased so to did the LPG in price to a point were it's almost not worth converting.

Correct - for NZ...I'm not sure we're comparing apples with apples when we hear about Europe. Here Frits, converting new cars is very, very rare. Often it's the older models which were converted which goes some way toward explaining the problems seen here. I'd say from observation - at least in the south island - that numbers have dropped since the peak interest period of the 70's and 80's. Locally, the one firm specialising in LPG conversions seems to have disappeared.

[husaberg]

Correct - for NZ...I'm not sure we're comparing apples with apples when we hear about Europe. Here Frits, converting new cars is very, very rare. Often it's the older models which were converted which goes some way toward explaining the problems seen here. I'd say from observation - at least in the south island - that numbers have dropped since the peak interest period of the 70's and 80's. Locally, the one firm specialising in LPG conversions seems to have disappeared.

You still see the odd taxi on them Ford was selling them New a while back in the Falcon not sure if they were set up in Aussie or done here.
They should =be able to make more power than STD as LPG has an higher effective Octane plus an intercooler effect.
Most of the original ones were hamstrung by being duel fuel.

Quite a few people with Turbo Diesel 4WD were using it a power booster it will not self ignite under the comp a diesel does until the diesel sets it off and it had more energy plus a Intercooling effect.
http://www.autospeed.com/cms/article.html?&A=112610

[Frits Overmars]

Costs next to nothing? Here in NZ as the petrol prices increased so to did the LPG in price to a point were it's almost not worth converting.

Here are the fuel prizes in Europe: http://www.fuel-prices-europe.info/ As you can see, LPG costs less than half the prize of petrol just about everywhere.

Here Frits, converting new cars is very, very rare. Often it's the older models which were converted which goes some way toward explaining the problems seen here.

New cars? I buy cars that have been run in for me (usually over 100.000 km) by their first proud, rich owners.

[husaberg]

New cars? I buy cars that have been run in for me (usually over 100.000 km) by their first proud, rich owners.

Smashing stereotypes

[Flettner]

There we go, running on a BBQ bottle.

Look mum, no crutches!

[WilDun]

Look mum, no crutches!

Been away again, see a lot of new stuff on the thread!
Neil, glad to see you properly back on your pins again and getting to grips with that new aero engine, should be a lot less weight to lift than the old Subaru, hope it takes off (ie the project!).

I didn't see the cost of LPG coming down when the petrol prices dropped though! - how did they manage to justify the price rise immediately petrol/diesel prices rose anyway, extra transport costs?

Last night I was trying some simple pattern making also moulding (greensand) - glad I did that first, not as easy as some would make it look!
I do need to learn a lot more and get a feel for it first, I've got to practise over and over,it definitely can't be learnt from a book (although that and video does help). At least it may save me some embarrassing and/or dangerous moments when I actually attempt a pour, so I think a few "dry runs" first would be the best way to go!
My tongs also need a little "fine tuning" for the sake of safety if nothing else.

Getting there slowly.

[Flettner]

Engine number two on it's way together.

[ken seeber]

Neil, just more brilliant stuff from yourself.
Question. Is there something going inside the driven gear, like a cush drive or similar?
Keep it up. You're a pretty hip sort of guy.

[WilDun]

Engine number two on it's way together.

Beautiful looking job! - Integral reduction box too! - that should be very well accepted.
Do you cut and grind your own gears? - What's the reduction? 2:1?

[Frits Overmars]

Beautiful looking job! - Integral reduction box too! - that should be very well accepted.
Do you cut and grind your own gears? - What's the reduction? 2:1?

I dunno WilDun; we'll have to wait for Neil to answer this one. But if you are free in the choice of a transmission ratio, you try to avoid integer numbers like 1, 2, 3, etc. Here's why:
http://everything2.com/title/hunting+tooth

[WilDun]

I dunno WilDun; we'll have to wait for Neil to answer this one. But if you are free in the choice of a transmission ratio, you try to avoid integer numbers like 1, 2, 3, etc. Here's why:
http://everything2.com/title/hunting+tooth

Yes Frits, I remember having an OHC KSS Velocette engine in an Ariel frame many years ago and that was when I found out about the "Hunting Tooth" thing.
Now that I'm getting on a bit, I guess I should have known better than to ask if it was 2:1 ratio! especially when I'm also interested in light aircraft and have never seen a reduction box with a 2:1 ratio etc.
Anyway, he's done a great job whatever the ratio!

[husaberg]

I dunno WilDun; we'll have to wait for Neil to answer this one. But if you are free in the choice of a transmission ratio, you try to avoid integer numbers like 1, 2, 3, etc. Here's why:
http://everything2.com/title/hunting+tooth

The way around this is to use an idler gear as the actual number of teeth on the idler is irrelevant. This does however also change the direction of rotation.
Sometimes there is no other option but to use a non hunting tooth design like in the instance of the Contra rotating tandem crank designs.

One thing I only ever noticed (I guess I never thought to wonder about them at all)the other day was that most gear boxes individual gears pairs add up to the same number.



As that is the Meshing point distance of the chosen profile.
Of course some manufacturers modify the gear modus and sometimes profiles to fit in other different ratios.
I would assume the multiple gear ratios available for the GP bikes have a fair bit of this occurring.
Some seem to do this from the factory and have multiple different gear profiles or patterns in the same gearbox.
Bradley Gives an example of the KR1 Kawasaki which used 1.75, 2.0 2.25 and 2.5 Module in the same gearbox.

Example
Moto 80cc Honda CR80 Gearbox Ratios (Primary: 17/70) 4.117

1st Gear: 15/35 =50 4th Gear: 23/27 =50
2nd Gear: 18/31 =49 5th Gear: 25/25 =50
3rd Gear: 20/28 =48 6th Gear: 26/23 =49

So I assume with the gear profile the centre difference for the shaft centres and unmodified tooth profile Meshing point is 50 and they modified the Addendum for ratios 2nd 3rd and 6th from the factory to accommodate the ratios they wanted to use.
Most gear boxes also have wider teeth for the lower gears and thinner for the higher ratios.

Most of the Modern 250 Four Stroke MX bikes are based on 125 Two strokes gearbox's and the 450's were designed around the 2 stroke 250 boxes. For Honda at least if not the others.
The Honda CR250 gearbox is also pretty much the same as the CR500.
I have likely used a few improper terms but the Bradley book The racing Motorcycle is a good read.
The NOVA transmission site also likely covers it.

[ken seeber]

As that is the Meshing point distance of the chosen profile.
Of course some manufacturers modify the gear modus and sometimes profiles to fit in other different ratios.
.

Ages ago, Suzuki made a race kit for their A100, a rotary valve 100 cc inclined 4 speed engine. New cylinder, carb, valve and pipe and whatever else. Also though, was a new 4th gear , maybe separate or maybe integral with the shaft. This was designed to bring 3rd and 4th closer, with a one tooth difference. However, it was a single gear only, the new gear meshing with the previous existing gear. I can't remember which way it went though. So, the PCD of the old gear was altered, either by changing the addendum or dedendum to suit. Seemed a bit crude to a non gear type person, but it worked. These might have also been around in Kiwiland as well.
The following gives a bit more info:

http://www.ozebook.com/compendium/suzi/jones2.htm

[husaberg]

Ages ago, Suzuki made a race kit for their A100, a rotary valve 100 cc inclined 4 speed engine. New cylinder, carb, valve and pipe and whatever else. Also though, was a new 4th gear , maybe separate or maybe integral with the shaft. This was designed to bring 3rd and 4th closer, with a one tooth difference. However, it was a single gear only, the new gear meshing with the previous existing gear. I can't remember which way it went though. So, the PCD of the old gear was altered, either by changing the addendum or dedendum to suit. Seemed a bit crude to a non gear type person, but it worked. These might have also been around in Kiwiland as well.
The following gives a bit more info:

http://www.ozebook.com/compendium/suzi/jones2.htm

Yes Nova or Dyson what ever they are called does it extensively. (Edit used too)
They sell a individual gear that meshs with the STD T20 first and from memory the CB350 fifth and likely many more. To alter the ratios.
I googled and it doesn't look like he does them anymore (but pretty sure he used to do the ones eddie crooks sold for t20's)
http://www.novaracing.co.uk/index.html
Yes The Term as Bradley describes it (he opens a book) is called addendum modification thus they can have a different number of teeth with the same diameter and still mesh.
There of course never something for nothing and the modification can weaken the root and the tip. But save a lot of money.
Yes I am definitely a non gear person.

edit this guy does them even for it seems buckets....shhhhhhhhh

Plus individual gears for RGVs
the scoll down is a little hard to find. but plenty of engines
http://www.mpe07.co.uk/mpeprevcoms.html