ESE's works engine tuner

[jamathi]

Widening the Aux ports to bore center does two things , increases Blowdown STA and increases port linking to the A Transfer.
You can reduce the effect of linking by making the Aux duct very shallow in depth at its rear wall next to bore center , and also grinding the port shape with alot of taper upwards from front to back.
This gives alot of area just as the port opens , with the max pressure differential , but reduces the linking time.
With capped pins the duct can have much less of a tangential exit angle on the rear , top , corner wall , with a nice sweeping pocket that improves flow and power.

Be carefull with using Frits idea of using Torlon inserts , that effectively blanks off the pin bore in the piston.
In the TM kart engines this reduced the access of lubrication from transfer flow into the piston bearing surface , and the pin ends turned blue.
Jan said that the Aprilia did the same , but I never wanted to find out if the pin bore became unreliable.
Making tophat CNC steel plugs and having them laser welded into stock pins is cheap , and relaible and just as effective power wise.
Maybe drilling a hole upward in the bottom of the piston pin boss would fix the issue , again I wasnt keen on destroying a motor if this was unreliable.

The pin ENDS turned blue, but the pin itself not...
There NEVER was a lubrication problem!!!

[TZ350]

Thailand, Drag Racing Motorcycles. 150cc 9 sec pass's on Nitrous and the Motorcycle enthusiasts who come to watch.

[F5 Dave]

Where do they get those helmets?!.

[Frits Overmars]

Where do they get those helmets?!.

It looks like a car helmet to me. These have a lower visor opening than motorcycle helmets because the driver leans back.

[F5 Dave]

You learn something new every day.

[pete376403]

I have a Bell Star 120 like that from about 40 years ago. Was made in response to the complaint that a regular Bell Star was limited peripheral vision, so this one has 120 degrees peripheral

[wobbly]

Here is a pic of the small end pin after around 10 dyno sessions in the TM engine with full cover Torlon caps.
I was way too scared of destroying a customers engine to go any further with that setup.
Now I can get enough caps CNC'd and have them laser welded into 5 pins for under $200NZD , cheap for the performance gain , and reliable.

[flyonly]

Here is a pic of the small end pin after around 10 dyno sessions in the TM engine with full cover Torlon caps.
I was way too scared of destroying a customers engine to go any further with that setup.
Now I can get enough caps CNC'd and have them laser welded into 5 pins for under $200NZD , cheap for the performance gain , and reliable.

Who can do the laser welding in NZ?


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[dtenney]

Here is a pic of the small end pin after around 10 dyno sessions in the TM engine with full cover Torlon caps.
I was way too scared of destroying a customers engine to go any further with that setup.
Now I can get enough caps CNC'd and have them laser welded into 5 pins for under $200NZD , cheap for the performance gain , and reliable.

We have made torlon caps in the same shape as your welded end cap. We see similar signs of heat at the ends of the wrist pin but have not had any failures. Why does the welded cap not show the same signs of heat as a similarly shaped Torlon cap?

[jonny quest]

Foul stroke Ex valves have sodium? Filled hollow stems in some applications for heat dissipation.

May be a good wristpin solution?

[wobbly]

DT , the torlon caps I made ( Kentastic actually ) were held in by the clip and covered the pin hole completely.
But yours colour up , and dont fail ?
The tophat welded pins allow lube into the piston pin bearing surface - and show no heat issues at all , plus identical power.
No other difference , so I can only assume for some reason the TM Vertex piston does not have sufficient rear lube entry ( sounds rude , sorry ).
As I said I aborted the Torlon tests as destroying a customer engine isnt really an option - giant blouse I know.

[wobbly]

Fly - Laser Welding NZ Ltd in Auckland , not hard to remember.

[Condyn]

I have a few photos saved of what appears to be a pin failure possibly propagated by the plugs. Also an interesting method to secure them. Looks almost like a pin holding them in.

[SwePatrick]

I was thinking about torlon, but had an 'way out there' thought.
In modern brakecalipers in often american cars, the pistons are made from some sort of plastic material
Wouldn´t it be able to take the heat as wristpin plugs?

[Frits Overmars]

I was thinking about torlon, but had an 'way out there' thought. In modern brakecalipers in often american cars, the pistons are made from some sort of plastic material. Wouldn´t it be able to take the heat as wristpin plugs?

I suppose brake caliper pistons will get hotter than piston pins, so they should be able to take the heat, but taking the heat is no problem for Torlon either;
the problem seems to be with the pins themselves, and using a different synthetic plug material won't change that.