ESE's works engine tuner

[peewee]

frits is that a piece of alloy with small bolts holding it to the exh floor ? i wouldnt mind doing something like the picture to a old sleeved honda cylinder i have

[senso]

If I recall correctly its an experimental exhaust damn made by TZ.

[breezy]

Words for today nonsmoking 125cc 2t 70HP @ 17-18k rpm

Here's picture Attachment 312083

Frits could shed some light on it , but like he said other place he have a confidentiality clause.

Muciek, after starting this bomb shell, have you been able to find out any more about this engine

[Muciek]

Not much more , there is their "official" FB I think, https://www.facebook.com/mcd.twist.9...1/?pnref=story here is video of running but you can't see much and hear too...

[nick gill]

So?
Attachment 313423

Hi Frits.
Yes I have been thinking along these lines for a couple of years actually but I'm a bit too chicken to try it to date.
In fact I was thinking of attempting my own method: plugging the cylinder bore with copper billet bar, then pouring a molten aluminium floor into the cast iron exh port, then retain with high tensile screws as per your image. The cylinder would be rebored and the aluminium dressed away from the rings. I figure that unless its a fantastic fit, eventually a floor plate/stuffer would work loose and 'fukushima' the cylinder.

[F5 Dave]

If it were cast iron could you not fill it with brazing rod? That's probably more of a question I have no real experience in that area and aren't about to take on iron barrels any time soon.

[Grumph]

If it were cast iron could you not fill it with brazing rod? That's probably more of a question I have no real experience in that area and aren't about to take on iron barrels any time soon.

Yep, just a case of using the right flux. Some very good nickel bronze rods about now too though historically the original non nickel rods work well on iron.

[nick gill]

If it were cast iron could you not fill it with brazing rod? ...

In the past my cylinder welding guy said to braze cast iron you'd have to get it cherry red, so the metal has a phase change and the bronze can link interstitialy. He thought this amount of pre-heating could crack the cylinder. I've had iron exhaust ports metal sprayed before, but you can only build up a about 1-2 mm this way and it's more of a crust than parent material.

[Frits Overmars]

TZ350 did it without any welding or casting. It won't hurt to go back to his descriptions.

[peewee]

i found the brazing process isnt all that permanent, not much more than epoxy. brazing does have the advantage of being more resistant to chemicals than epoxy but your still not melting the parent underlying material so your bond is relying on surface grip strength.

maybe tz can chime in with how he holds the dam in place. appears to be some screws or something fastening it to the exh floor ?

[Grumph]

In the past my cylinder welding guy said to braze cast iron you'd have to get it cherry red, so the metal has a phase change and the bronze can link interstitialy. He thought this amount of pre-heating could crack the cylinder. I've had iron exhaust ports metal sprayed before, but you can only build up a about 1-2 mm this way and it's more of a crust than parent material.

Because iron doesn't conduct heat well, it's usually only a local hot spot which gets that hot. I've repaired a lot of fins in my time, successfully too.
As I said, it's finding the right flux to get a good bond on clean metal.
But as Frits says, if you don't want to bronze, fix it in place mechanically.

[peewee]

wob what you think. should be able to put some nice tea cups in now. lost count of how much filler was used but i think it was somewhere around 7 or 8 rods at 3' x 3.15mm. also took some molds of another cylinder so i have a 3D visual guide on how to make the radius twist on the front side of A as ill do a similar window shape with this other cylinder

[wobbly]

The brazing I do when building say a Post Classic chassis in chrome molly tube is stronger than the base material when using gas flux
thru the torch.
Any brazing process when done properly becomes a molecular bond - hugely stronger than any epoxys surface grip.
And the dozens of KT100 cylinders that I have seen metal sprayed first on the cast liner, then on the alloy top face to change the deck height
dont have any issues with it "not sticking " either - again if the process is done properly.

Peewee, the cylinder is looking better every post.
I want to see the Engmod results of course before you even think about doing any grinding on it.

[Flettner]

Not much more , there is their "official" FB I think, https://www.facebook.com/mcd.twist.9...1/?pnref=story here is video of running but you can't see much and hear too...

Yes it's all gone a bit quiet. But lets recap, for charge to flow from the crank case to the cylinder at speeds that would normally stall the transfer charge (not enough blow down time) there must be a method of "super" charging the crank case (I don't suggest mechanical) crank case pressure must be increased before transfer takes place. How is this done? That is the key, suggestions anyone.

[wobbly]

A bottle of Nitrous with a T,one line into the carb the other into Frits helmet.
Thats where all the perceived performance enhancement comes from - easy.