Tomos forum

I'm just getting to grips with these 2 stroke engines, since i'm used to working on cars they make no sense to me! haha. It seems you can be very relaxed with tolerances compared with what i'm used to working on, although, I am TOTALLY lost with regards to more advanced tuning of the ports!

Anyway, of the few 1000000000000s of idea's that go through my head every moment i stare at my new (old rusty) Tomos, one of them was with regards to cooling the head and block.

Has anyone seen or used an oil or water cooled head / block on one of these A3 / A35 engines? I've seen swaps for things like Mallossi? but nothing modified so far.

I'm just wondering what the options are... currently i am considering making my own head / block using CNC, just for a bit of fun really!

Any ideas on the subject are welcome!

edit - The point of this is that I am looking at an all aluminium head and block running a liner with a cooling jacket, rather than the very heavy lump of Iron currently attached to the bike!

yup you can do that if it fits on your engine and the specs are the same but you will have to find/create a place for your (electric) water pump aswell as your radiator.
By the way usually there is some tweaking to do for your intake manifold/carburator and your exhaust but i do not think that's a problem for you as a professional.
When you search for a liquid cooled set look at how they operate because when they use a membrane this can make things slightly more difficult so be aware on those.
Sometimes the membrane is on the engine itself like in lawnmowers and there is no option to do that on the tomos engine so now you know you will have to design a solution if you decide to go with those types of set's.

Hey thanks for the reply man!

I have to say, I am far from professional! haha.I suffer from... IDEAS

I was thinking more of oil cooling the block or the possiblity of nitrogen cooling. Nitrogen is fairly self explanatory, although i'm not totally sure of the tempratures the block has to deal with. I believe a normal 2 stroke engine will have an EGT around 500-600*c whilst i am used to peaks of 950*c on my 4 cylinder turbo engine, but that running liners and much lower comp ratios!

I was thinking an oil jacket around the cylinder running a high grade motorsports oil (300*c + breakdown temp) litterally running through a series of copper pipes down the side of the frame to a mechanical pump driven by the drive chain. Using the length of the pipes to allow for sufficent cooling before the oil returns to the engine block. Or if need be, a small oil cooler.

I was looking at running an all alloy head and block with nikasil plating, which should allow very good heat exchange. I also like the idea of being able to run very close tolerances If the cooling system can provide a constant block temp, then i'd assume i can run a leaner mixture without suffering detonation.

So, based on my assumptions, I'd be able to maintain a stable block temp, without having a big ugly radiator hanging from below my gas tank.

I would like to base this on a 50cc bore, running slightly higher compression (via reduced quench) and normal inlet and exhaust ports. It goes without saying that all imperfections from the standard block would be corrected allowing for a more efficent flow.

Do you know where i could get a blueprint or possibly a CAD file with the exact dimensions of the A3 and A35 blocks / heads? That would save me a lot of time!

Thanks!

well i have no drawings but i have one question..
why would you do all that on a 50cc ?

I was asuming you were wanting to tune that engine to a sick level

Well, It's the same as anything, if i wanted crazy power, i would change the engine! I would like to increase power, i think a lot can be gained using the 50cc size. Even some basic tuning on a stock engine will create more power!

From my experience, the best engine is the most reliable engine. If i can increase power, but also make the engine more stable, then i have achieved the best result.

I don't think the 50cc is as efficient as possible, so first i would like to work with that. Later, i can look into bore size and stroke length. Once the head is designed in CAD, it's quite simple to make changes.

Once i have the measurements i can select meterials and begin