ESE's works engine tuner

[Flettner]

If you were constructing say a 25cc cylinder, I would imagine you would use model engine cylinder technology?
ABC, aluminium, brass, chrome, do they still make small engines like this with a cast in brass sleeve that takes the hard chrome easily. Is the brass sleeve coated with anything before the alloy is cast on? I think with the model engine I had, the brass sleeve was only pushed in?
Cylinder is water cooled, or it would be if I was making some.

[jasonu]

_MG_6029 by sonscc, on Flickr

Notice anything about this photo of the front of the pack today at Mt Welly?

The flagger is asleep.
(and not an RM85 in sight thank goodness)

[TZ350]

TeeZee I think your bmep for the RGV Aircooled is a bit high, your numbers would translate into near on 40 RWHP. Pulling the proposed numbers back to around 12 Bar is still a tough ask, but more doable I think. Going too radical is just going to create transfers that will loose excessive velocity/stream control - even with a good powervalve setup it will drop the mid power too much.

Thanks for the heads up, I will have another look at it ....

[TZ350]

FUEL DROPLET SIZE REALITY CHECK

Some pages ago, there was some discussion on fuel droplets. Got me thinking as to what size a fuel droplet might be.

Great post, very interesting, thanks Ken.

[Frits Overmars]

If you were constructing say a 25cc cylinder, I would imagine you would use model engine cylinder technology? ABC, aluminium, brass, chrome, do they still make small engines like this with a cast in brass sleeve that takes the hard chrome easily. Is the brass sleeve coated with anything before the alloy is cast on? I think with the model engine I had, the brass sleeve was only pushed in? Cylinder is water cooled, or it would be if I was making some.

Model engines with Aluminium cooling fins, Brass sleeve and Chrome coating are still being made, Neil, but they are not winning any races anymore. There are also AAC engines (you can figure that out, can't you?) but those are not winning either. Sleeveless alu cylinders with a chrome bore are.
By the way, I never encountered ABC or AAC cylinders with cast-in sleeves. They were all a push fit, with the accompanying bad heat transfer. And I can't see why you would consider using these obsolete technologies for any size of cylinder (well, maybe I can see, considering the kind of engine you're working at. But I fear cooling is going to be a problem).

[WilDun]

If you were constructing say a 25cc cylinder, I would imagine you would use model engine cylinder technology?
ABC, aluminium, brass, chrome, do they still make small engines like this with a cast in brass sleeve that takes the hard chrome easily. Is the brass sleeve coated with anything before the alloy is cast on? I think with the model engine I had, the brass sleeve was only pushed in?
Cylinder is water cooled, or it would be if I was making some.

The ABC pistons/cylinders are still used in model glowplug engines, although they are normally ringless with a very minutely tapered bore and tapered piston to match. The brass/chrome liners are a 'push in' fit.
When you buy a new one and you turn it over by hand there should be a 'click' as it slips over TDC, this is the piston just about locking on the bore, however, when it starts up and the cylinder warms up then it seems to expand away from the piston. Quite hard to manufacture a one off "just right" I'd say!
I believe that companies like OS now use something like Nikasil instead of hard chrome, but I would say that the chrome is cheaper than Nikasil (ABN). There are ringed versions available also but I'm pretty sure they use parallel CI bores.(don't quote me!).
I do get the feeling that with the ABC motors (plated brass liners) the compression is dependent to a large extent on lots of oil, these things use plain bearings and therefore need heaps of oil! and I mean heaps !! - like about 6:1 - yes that's right, 6:1 not 60:1.
Then of course they don't need to worry about fancy ignition , they use glowplugs, which are disconnected when they warm up, they use methanol /nitro fuel.

As a matter of interest, MZ also tried ringless pistons way back, - without success.

There are petrol engines for the bigger model aircraft which normally range from around 15cc to up around 75cc and which are normal petrol engines as we know them but nothing near bucket specs. they are built so light with overhung cranks (like the old Scott motorcycles) which I think would probably disintegrate at bucket outputs! They are normally chrome plated bores which seem to be done directly on the aluminium (like chainsaws).
I've got a Chinese 30cc which weighs FA. and puts out a healthy 3HP. -
It cost about $320 I think. - nice little engine if it was properly sorted.

Sorry for the ramble but at least I can say something on this - can't keep up with all those tuning guys, they have left me trailing!

Will.

[WilDun]

FLETTNER,
The model boat guys are well up with the play on small water cooled two stroke racing engines I'm told, - I would think you could get some good info from those forums and sites.

[2T Institute]

Attachment 297338

I have just managed to get a set of three stage power valves.

Attachment 297337

It looks like the RGV250 three stage timings are:-

104 atdc
90 atdc
84 atdc

I am not sure how much these can be changed but I would like to have fully open at 80 atdc.

They are 2 stage PV's the highest or eyebrow blade never moves. With the 2 stage valve be very very careful with the centre blade, it can wear enough to fallout. Check the grooves in the other 2 blades and the pin on the centre blade is tight. Also check the collars and the ends of the PV's where the hardened shaft connecting the 2 run through if that is egged out find another set. What I have always made is replacement bronze collars that the shaft rides on and PV problems disappear.

[TZ350]

Thanks for the tips, I will look at these two sliding element ones carefully. I also have some single element ones so not completely stuck for something to use. The initial part of this project is to see if I can successfully air cool what was a water cooled cylinder.

[F5 Dave]

Rob what might be interesting is to set up your air cooled bike. With best jetting for relatively cool and dyno measuring head temp and make a chart of how much it falls off power. Then can do asme with new barrel to see how effective it is

[Flettner]

Model engines with Aluminium cooling fins, Brass sleeve and Chrome coating are still being made, Neil, but they are not winning any races anymore. There are also AAC engines (you can figure that out, can't you?) but those are not winning either. Sleeveless alu cylinders with a chrome bore are.
By the way, I never encountered ABC or AAC cylinders with cast-in sleeves. They were all a push fit, with the accompanying bad heat transfer. And I can't see why you would consider using these obsolete technologies for any size of cylinder (well, maybe I can see, considering the kind of engine you're working at. But I fear cooling is going to be a problem).

Frits, thank you, yes I can see the sleeve would at least have to be cast in. The problem is NZ cylinders can not nickasil these small bores plus the cost will kill the project. No one in NZ can hard chrome straight onto aluminium, but brass no problem.
I do want my own cylinder, not someone elses compromise. Had to ask.

[Flettner]

The ABC pistons/cylinders are still used in model glowplug engines, although they are normally ringless with a very minutely tapered bore and tapered piston to match. The brass/chrome liners are a 'push in' fit.
When you buy a new one and you turn it over by hand there should be a 'click' as it slips over TDC, this is the piston just about locking on the bore, however, when it starts up and the cylinder warms up then it seems to expand away from the piston. Quite hard to manufacture a one off "just right" I'd say!
I believe that companies like OS now use something like Nikasil instead of hard chrome, but I would say that the chrome is cheaper than Nikasil (ABN). There are ringed versions available also but I'm pretty sure they use parallel CI bores.(don't quote me!).
I do get the feeling that with the ABC motors (plated brass liners) the compression is dependent to a large extent on lots of oil, these things use plain bearings and therefore need heaps of oil! and I mean heaps !! - like about 6:1 - yes that's right, 6:1 not 60:1.
Then of course they don't need to worry about fancy ignition , they use glowplugs, which are disconnected when they warm up, they use methanol /nitro fuel.

As a matter of interest, MZ also tried ringless pistons way back, - without success.

There are petrol engines for the bigger model aircraft which normally range from around 15cc to up around 75cc and which are normal petrol engines as we know them but nothing near bucket specs. they are built so light with overhung cranks (like the old Scott motorcycles) which I think would probably disintegrate at bucket outputs! They are normally chrome plated bores which seem to be done directly on the aluminium (like chainsaws).
I've got a Chinese 30cc which weighs FA. and puts out a healthy 3HP. -
It cost about $320 I think. - nice little engine if it was properly sorted.

Sorry for the ramble but at least I can say something on this - can't keep up with all those tuning guys, they have left me trailing!

Will.

Will, yes I could just buy something, but I did want to make my own version.
I just can't buy a chinese engine. I don't like to encourage them.

[senso]

Don't take this the wrong way, and I think I'm not forgetting anything, but there will be a lot of thermal interfaces from the inside of your cylinder to the outside fins, why don't you cut out the original water sleeve and directly weld some giant fins directly to the outside of the sleeve, a couple(more like 6-7) years ago in some pirate MX competitions there was a guy that took a water-cooled 100cc cylinder made for the yamaha lc 50 engine, cut out the water sleve and welded 10 or 12 30x20x4mm aluminium plates, got the cylinder re-plated and it could run for half an hour in front of everybody with a cylinder that was always "cold" to the touch.

[WilDun]

I just can't buy a chinese engine. I don't like to encourage them.

Too late to close the door, the horse has bolted!

[fixer]

Just a wee note about the performance of my Aprilia RS50 on Sunday. It's first official outing with the Team ESE inspired 13.6hp. I can confirm that 13.6 well-shaped horses are a lot nicer than 9.9 ugly ones (with Doppler kit but without raised barrel and machined head). It called for some minor mods to how I ride the bike (feathering the clutch rather than changing down made more sense than before at the hairpin), but even in the absence of any real pressure (the championship leader circulating with a broken collar bone - not bad for a 50-something-year-old!) I managed a 31.44. This is 0.3s better than anything I've done in a race before and at least half a second better than what I was generally managing with 11hp (from the ported original barrel). The bike was a pleasure to ride. Now if I can just hit a few more apexes (still learning F5 after years on an FXR), then I might be able to get somewhere near the 30s.

PS. Love Chris C's photo of the front of the F4 class!