ESE's works engine tuner

[wobbly]

Significant DeSaxe gives exaggerated piston port asymmetry, problem is ALL the ports become asymmetric in open/close timing.
Mock it up in SolidWorks or write a spreadsheet exported to a graph to see if its what ( you ) is really needed.

Re the 10mm plug issue, I have done,solved this once before.
Bore thru the plug hole and then press in a tophat insert with some small fins around the OD to suit a "normal " 19mm plug length with 14mm thread.
Then weld the insert in around the bottom and the top.
No plug issues and no heat transfer issues.

[lodgernz]

Re the 10mm plug issue, I have done,solved this once before.
Bore thru the plug hole and then press in a tophat insert with some small fins around the OD to suit a "normal " 19mm plug length with 14mm thread.
Then weld the insert in around the bottom and the top.
No plug issues and no heat transfer issues.

Tim (Cotswold) and I have deliberately made our head inserts with 10mm thread (x 19mm length) for our 50s for reasons of combustion chamber space, but it sounds like you're saying dump them and go back to 14mm.

[cotswold]

Tim (Cotswold) and I have deliberately made our head inserts with 10mm thread (x 19mm length) for our 50s for reasons of combustion chamber space, but it sounds like you're saying dump them and go back to 14mm.

No Roger certainly not, I'm after a plug that wont fall to bits and wreck my nice new head with it's 10mm thread, the last thing I want to do is go back to a 14mm plug. I bought a couple of Iridium plugs (NGK) but Wobbly reckons they will fall to bits, so I am after a suitable race plug in 10mm that costs less than $80 each as I have a wife that will make her feelings very plain if I go buy a box of them.

[ken seeber]

Significant DeSaxe gives exaggerated piston port asymmetry, problem is ALL the ports become asymmetric in open/close timing.
Mock it up in SolidWorks or write a spreadsheet exported to a graph to see if its what ( you ) is really needed.

Thanks Wob, yeah I did have a spreadsheet coming on feeling, but I just wondered if anyone had actually given it a go, despite the potential benefits/disbenefits of the resultant asymmetric timing.

[lodgernz]

No Roger certainly not, I'm after a plug that wont fall to bits and wreck my nice new head with it's 10mm thread, the last thing I want to do is go back to a 14mm plug. I bought a couple of Iridium plugs (NGK) but Wobbly reckons they will fall to bits, so I am after a suitable race plug in 10mm that costs less than $80 each as I have a wife that will make her feelings very plain if I go buy a box of them.

My response was to Wobbly, not you Tim.
I totally share your feelings. I used a CR9EIX at Tokoroa, and previously at Taumarunui and Kaitoke, with no problems, but I don't trust those plugs.

[cotswold]

My response was to Wobbly, not you Tim.
I totally share your feelings. I used a CR9EIX at Tokoroa, and previously at Taumarunui and Kaitoke, with no problems, but I don't trust those plugs.

sorry Roger I read that without my brain in gear

[sispeed]

The number for the R7376-8 or R7376-10 does not mean the gap. This number means the heat range.
TZ is right there might be a number at the end that specifies the gap but this is the heat range
http://www.ngk.com/product.aspx?zpid=26333

[Frits Overmars]

Is anyone aware of using a significant cylinder offset relative to the crank centreline, sometimes called deSaxe(?). I know that this is used in some current 4 strokes, but I am thinking obviously of modern high performance 2 strokes. I do remember that someone (Jan Thiel I think) said that they tried pistons and found that any offset, either way, was better than no offset. But this is just piddly stuff, say +/- 0.5 mm, I am thinking of a lot more, say 5 to 10 mm.
The potential advantage being a shorter duration compression stroke and a longer power stroke with more crank leverage.

Jan tried it a long time ago, at Bultaco I think it was, so it must have been around 1976, and he did find what you remembered.
Aprilia RSA pistons have 1 mm offset in the direction of the exhaust port, which is in the direction of rotation for the RSA and against the direction of rotation for the RSW: as far as I know, the same type piston was used in the RSA with rear rotary inlet and forward-facing exhaust, and in the RSW with side rotary inlet and rearward-facing exhaust.
Advantages? I am not aware of any.

Thanks Wob, yeah I did have a spreadsheet coming on feeling, but I just wondered if anyone had actually given it a go, despite the potential benefits/disbenefits of the resultant asymmetric timing.

I gave it a go before there were spreadsheets, so it's a real program (the things they call apps nowadays). Hope you can get it to run. It should work in Win-98, maybe Win-XP as well.
CRANK.zip

If you play with the program, you will notice that enlarging the offset also enlarges the stroke of the piston. So don't overdo it, or you may find yourself with an illegal cylinder capacity .

[peewee]

What are you going to use that tank for, Peewee? A motor home ?

frits I never knew there was a motorhome with just 2cylinders running on methanol . the fuel tank wasn't as easy as I figured it would be and probly the last one I ever do

[Flettner]

frits I never knew there was a motorhome with just 2cylinders running on methanol . the fuel tank wasn't as easy as I figured it would be and probly the last one I ever do

Peewee, how hard is it to get those tyres? I have a plan for one.

Don't ask about the thermostat housings, I'll get on to them this week. Ish.

[Frits Overmars]

Peewee, how hard is it to get those tyres? I have a plan for one.

I can't imagine it flying, so maybe it will have to float. Are you planning a paddle steamer Neil?

[peewee]

there not hard to get but what are you using it for? theres alot of different sizes and scoop configurations and carcass thickness

[Flettner]

I can't imagine it flying, so maybe it will have to float. Are you planning a paddle steamer Neil?

Every year we go to the Aria two day trail ride, and every year they hold what's called the mud run, mostly standard fourstrokes enter. Ususally funny but no one has a real go at it. I was thinking a light twostroke with lots of power and a paddle wheel one for the driven front wheel as well
And a decient belly pan.
Look it up on youtube, Aria mud run.

[TZ350]

Aria mud run .....

[peewee]

skatrak is what I always use but theres a few other brands. chengshin has some motorcycle sized paddle tires that are fairly inexpensive. ebay might have some used ones, otherwise this is probly the cheapest http://www.chaparral-racing.com/prod.../368-1360.aspx