Athena New Cylinders

[broyager]

Just building a case to buy one of these pretty much...

Here's some interesting info found on a 2stroke development group on facebook

As far as I have read the port patterns on this Athena are similar to the mekratik

www.facebook.com/photo.php?fbid=360347156507879&set=a.182388914303705&type=3



Would love to hear anyone's experience with this cylinder

[billwill]

Nov 20, 2023 0:57:15 GMT -5 broyager said:

Just building a case to buy one of these pretty much...

Here's some interesting info found on a 2stroke development group on facebook

As far as I have read the port patterns on this Athena are similar to the mekratik

www.facebook.com/photo.php?fbid=360347156507879&set=a.182388914303705&type=3



Would love to hear anyone's experience with this cylinder

I've been seeing this image get posted around on facebook in multiple groups and its very interesting. 

I was very close to getting one of these newer Athena cylinders for my prebug but opted for the stage6 mk2 instead. Really curious to see how these compare and perform.

[broyager]

This is the result of a transcribe and translate of this www.youtube.com/watch?v=OGYiifWu8B4, re port timings.

tldr;

Stock is 196 and 125 for transfers.

His mods are to open out the boost exhaust ports, but not too much, lower the cylinder with thinner gaskets, I think, to get 192 and raising the transfers to 130. He also sets squish at 0.8, and talks about opening up the squish band, which I assume he means, put a slight angle on it toward the chamber. Also opens the exhaust port exit slightly to match whatever exhaust he is using.

So you see, I made some big boosters, so I made some big boosters here, I didn't converge too much because you can imagine, once I saw there was no room, I didn't go very far and above all I lowered the cylinder because originally there's 196 and a half on the exhaust and 125 on the sides. For me, it's too much. For a booster, you really need to lower the diag because, as you can see, it already doesn't have much power. So if you start looking for power beyond the operating speed, that's not good. Plus, it doesn't require a diet. Boosting them on something like this, I don't think we'll get anywhere. We're going to be at 12,008 maybe, I don't know, 13,000 is already a lot for a booster. So there I went again, down to 192 and a half and up the sides to 130. So now I'm dead center, low nickel. And here I've redone the clean passage a little, you see, because here there was a bump, but so I redirected it well and then I aligned the exhaust pipe with the flange, so just at the outlet really so that it's clean.

Well, now I'm going back up and I'm going to mount this with 0.8 of scotch and ten zero six is the same, it still looks pretty low to me. So I'm going to put zero eight of tape and then we're going to set it at thirteen of max rate. So now I'm going to install it, and then I'm going to make my cylinder head. So this is a full piston, so we're not talking about squish tape, but I'll see what I can do, maybe open up the tape a little more than the flat piston, to evacuate the calories a little more, so that it doesn't heat up so much. I've already done that in. The same has happened in the past with boosters, and it works relatively well

[broyager]

In my hands!

First observation is that the ports are not very straight etc.. or the chamfers put on are quite inconsistent.

The nikasil seems to have lips in quite a few places, ie the casting is lower than the liner on the transfer port roofs, aux exhaust ports top and bottom and top and bottom of the main exhaust port. The nikasil is chamferred on the exhaust port roof, but the lip is still present.

Plannning to make some adjustments anyway, so shouldn't be too much of an issue, as long as I don't chip the nikasil.... I have some diamond bits.

Transfer passages look clean, but a fair few casting flaws in the exhaust ports.

Also the boost port sides don't quite line up, like there were definitely 2x halves here, they pretty much line up...

Going to have to shape the entries to the transfer ports too, my cases have all been enlargened a fair bit

[wallzip]

May 16, 2023 19:49:33 GMT -5 chadbullet said:

The youtube ad claims up to 19hp. Not bad for AC kit I think.

There was a guy that benchedmarked 22hp with a 70cc Polini EVO 1 AC. Very close to a MHR Speed 7t LC which benchmarked around 26hp.