Zenoah Glow fuel eng?

[Rod Fonda]

The boat can hold 32oz hard tank.
Only planning on using lower nitro amounts not going to try any thing above 15%.
Will make my own head for it.
I have to get a piston from CNC Piston for Tiger King 27 EVO RC Engines Rear exhaust
Will see when I get one what I will do with the head.

32oz seems ample..tank looked small in the pic,,but just noticed you already mentioned 32 oz previously,,yeah,,just the methanol would give it some kick,,should pull a fair bigger prop I'd imagine,,that cnc piston looks nice,,wonder if its a machined billet or machined from a forging ?

 

[dwilfong]

32oz seems ample..tank looked small in the pic,,but just noticed you already mentioned 32 oz previously,,yeah,,just the methanol would give it some kick,,should pull a fair bigger prop I'd imagine,,that cnc piston looks nice,,wonder if its a machined billet or machined from a forging ?

I am not sure about if it is a casting or not. Will see when I get my hands on one.
Don't think with this size eng it will need much nitro to make good power and RPM.
It is no heaver than a CMB 1.01 but much more CID. Over 50% more CID.
With all the new style ABC props it should be fun to see what it can pull at 20000+ RPM in a light boat.

 

[Rod Fonda]

I am not sure about if it is a casting or not. Will see when I get my hands on one.
Don't think with this size eng it will need much nitro to make good power and RPM.
It is no heaver than a CMB 1.01 but much more CID. Over 50% more CID.
With all the new style ABC props it should be fun to see what it can pull at 20000+ RPM in a light boat.

Hopefully its either billet or forged less chance of cracking, and have some silicon content or you'l need more expansion clearance,,I know with Chev forged pistons the race ones expand more but are stronger and the street ones more silicon less strenght but more than cast,,,although I suppose meth will keep it cooler than gas
Its looking good in the pics,,wow,,same weight as a 1.01 +the meth/nitro advantage over gas
I hope they make big enough props haha

 

[mercguy]

David
From the c/l of the crank to the top of the cylinder looks like a long stroke. What are you using for a rod etc?
Bill Hoch

 

[dwilfong]

David
From the c/l of the crank to the top of the cylinder looks like a long stroke. What are you using for a rod etc?
Bill Hoch

Bill
I am using the longest rod I can get 55mm that is 5mm longer than stock. I have a brass and chrome liner on order with a CNC piston. I will see where I am at when I get all the parts in hand to check the timings. Will start with a 130 transfer and 190 ex to start off.

 

[dwilfong]

I got the new sleeve and piston from HM. The ex port is very nice. More timed area in just the right place.

Also the front transfers are larger.

Has a nice thin wall pin that came with the Tiger King Tuned cylinder set.

The HM piston is very nice. is releave at the top with nice detail to the relief with oil groves.

Looks to be cast. But every inch has had a tool on it. The dome top is very shallow also.

Now to mock it up and run the numbers.

 

[Danny King]

I got the new sleeve and piston from HM. The ex port is very nice. More timed area in just the right place.
View attachment 291799
Also the front transfers are larger.
View attachment 291800
Has a nice thin wall pin that came with the Tiger King Tuned cylinder set.
View attachment 291801
The HM piston is very nice. is releave at the top with nice detail to the relief with oil groves.
View attachment 291803
Looks to be cast. But every inch has had a tool on it. The dome top is very shallow also.
View attachment 291804
Now to mock it up and run the numbers.

Very nice.

 

[Wasted wages]

What side and end gap are you going to run on the ring??
Do you know what type of material the ring is??
Have you thought about a two ring piston, or cutting a second groove?

 

[dwilfong]

What side and end gap are you going to run on the ring??
Do you know what type of material the ring is??
Have you thought about a two ring piston, or cutting a second groove?

It came with 2 rings.
One is a spare.
It is all part of the package with the piston.
Will run what he sent with it as it is.

 

[Wasted wages]

Just make sure the ring end gap is large enough so it won't butt together when it gets hot...

Reason I suggested a two ring piston is a single ring is going to be a heavier ring and that can cause ring flutter at the top of the stroke.

Plus a second ring will capture any blowby of the first ring due to flutter...

And lastly, all of the heat in the dome of the piston must transfer to the cylinder walls thru the ring, and having two rings doubles the pathway for heat removal...

All good reasons to run a two ring piston.

It would be cool to see if different types of ring materials and profiles would make a difference in power and longer life/ piston siezure issues..

Just more food for thought...

 

[dwilfong]

Just make sure the ring end gap is large enough so it won't butt together when it gets hot...

Reason I suggested a two ring piston is a single ring is going to be a heavier ring and that can cause ring flutter at the top of the stroke.

Plus a second ring will capture any blowby of the first ring due to flutter...

And lastly, all of the heat in the dome of the piston must transfer to the cylinder walls thru the ring, and having two rings doubles the pathway for heat removal...

All good reasons to run a two ring piston.

It would be cool to see if different types of ring materials and profiles would make a difference in power and longer life/ piston siezure issues..

Just more food for thought...

Not looking to reinvent what already works good.
Keeping it as simple as I can.

 

[Daniel's Racing]

If you cut another groove for another ring you would cut the crown right off the piston. Look up in it. That thick section around the top is just enough for the groove that is already cut for single ring.

 

[dwilfong]

If you cut another groove for another ring you would cut the crown right off the piston. Look up in it. That thick section around the top is just enough for the groove that is already cut for single ring.

Yes there is no extra material in this piston that is for sure.........

 

[Wasted wages]

No, obviously couldn't use that piston, was thinking about possibly sourcing a two ring piston to start with..

 

[Daniel's Racing]

No, obviously couldn't use that piston, was thinking about possibly sourcing a two ring piston to start with..

Have you thought about a two ring piston, or cutting a second groove?

 

[dwilfong]

You can't get any other piston that is 35mm for a rear ex eng It has to be custom made.
It all comes down to friction at high RPM's.
Thy pull the second ring out of the two ring pistons when thy want to rev the eng.
The holes in the side of the piston are there to get air and fuel circulation under the piston crown to keep it cool.
Do not need to get every nano bit if power from every little thing. Nitro will make up for it 100 fold.
Nitro is a great crutch.

 

[bermudadude]

digging up old news. single ring is IT ,,,2 stroke tech is at its apex ,all the experiments where done before some of us where born. problem was the metals and manufacturing processes where too expensive. fast forward 40 odd years now we can buy ,at regular retail,,all the tricks. its in there. maybe not in every engine but just get a few italian pocket bike or scooter or go-cart engines n yup its done .
it used to fascinate me when id get some cylinder or piston or later a model engine that had the stuff my dad used to "try" and describe to me . i havnt seen anything that surprises me in bout 15 years .
if u really want to get fancy about cutting ring flutter and blow-by try a ***** ring .
i first heard about dual plug heads when i was in my teens . hmm yes lets somebody try that with 1 of these engines

 

[dwilfong]

digging up old news. single ring is IT ,,,2 stroke tech is at its apex ,all the experiments where done before some of us where born. problem was the metals and manufacturing processes where too expensive. fast forward 40 odd years now we can buy ,at regular retail,,all the tricks. its in there. maybe not in every engine but just get a few italian pocket bike or scooter or go-cart engines n yup its done .
it used to fascinate me when id get some cylinder or piston or later a model engine that had the stuff my dad used to "try" and describe to me . i havnt seen anything that surprises me in bout 15 years .
if u really want to get fancy about cutting ring flutter and blow-by try a ***** ring .
i first heard about dual plug heads when i was in my teens . hmm yes lets somebody try that with 1 of these engines

***** rings would be nice But I don't think thy make one this size?
That would be a easy cut on the piston to try.

 

[LohringMiller]

All modern, high performance small two strokes I know about run one ring pistons. The most recent experiments with a ***** style ring involves a piston without a wrist pin hole. This video doesn't show the ***** ring, but a reverse ***** ring has been used with that type piston.

Lohring Miller

 

[dwilfong]

All modern, high performance small two strokes I know about run one ring pistons. The most recent experiments with a ***** style ring involves a piston without a wrist pin hole. This video doesn't show the ***** ring, but a reverse ***** ring has been used with that type piston.

Lohring Miller

This eng layout has the wrist pin front to back not side to side.
The wrist pin is blind on one end to keep the ex from pulsing back to the case.
Have you see any 35mm ***** rings that are available ?
One more question if you could help me understand the crank end play.
The crank set up as is has no way to clamp one of the inner bearing races to the crank like on a nitro eng.
So do you just let it float?
If so how much end play is needed?