Eurokit 43 mm 8 port repair.

[12VTopic starterBerichten: 27]

Hi

I bought an engine that came with an Eurokit 43 mm 8 port, the one with a threaded exhaust stud. I guess it’s chrome coated and not nicasil? Looks like someone has put chrome rings in it, it has light-medium scratches all the way round where the piston has moved. Either that, or no ring end gap.

Anyway, is it such a great kit that it’s worth saving? New piston and nicasil would probably cost ~150€. You can buy many nice kits for that amount. What is your opinion?

Some pictures:
https://www.dropbox.com/sh/6c21mmzvkl7hc1j/AAAjuzb2XOsY_kKInDbCklVOa?dl=0

regards, Carsten

[MartinoModeratorBerichten: 7384]

Unfortunately Eurocilindro is known for bad quality. Yes these are all chrome coated and not in a good way. I have several of these Eurocilindros, many of them have bad spots, scratches or even chipped of chrome. This isn’t due to the use of chrome rings, but even with normal cast iron rings this problem can occur.

Still these kits are rare to find and have a lot of potential. OK the port-layout is not that symetric, but this you can work with and make some preperations before use. Indeed you better get rid of that chrome cylinder wall and change it into nicasyl or something more durable. I think it’s worth saving although prices may be high.

Link naar Mijn collectie / Projecten.

[12VTopic starterBerichten: 27]

Thanks for your answer. I think i will repair this cylinder in the future, with a good thick Nicasil layer.

But what piston can i use? Now that i have studied some of the pictures here in this forum, it looks like i don’t have the original piston. The pictures from Jockoballa show a small “lubrication/cooling window” next to the wristpin.

http://postimg.org/image/91unkl3jz/

The one i have is just like the normal Athena 43 mm, but the pistonring seams all clear the ports.
Do you think the Athena piston from the newer kit will fit?

Like this one:
http://www.jmpbdele.dk/vespa-ciao-si/engine-parts/pistons/zuiger-athena-43mm-p10-vespa.html

Another option from Polini, it has the small groove like the original piston. But it looks like the pistonring stop could be right in a transfer window:

http://www.jmpbdele.dk/vespa-ciao-si/engine-parts/pistons/zuiger-polini-43mm-p10-vespa.html

And what about piston to cylinder clearence? I’m used to 2-3/100 for aluminium and 4-5/100 on cast iron cylinders. But in the Malossi Big Deps manual i read that they use 5-10/100. Should i make it 4-5/100 to be on the safe side, or what are your experiences?

regards, Carsten

[MartinoModeratorBerichten: 7384]

A well the Eurocilindro pistons… The thing is there are many different pistons beeing used by Eurocilindro and the most common pistons i’ve seen with 43mm cylinders is the Athena style piston. The piston from jockabolla is just another Polini/AssoWerke piston, but it can be used in the Eurocilindro. Indeed you have to check if the pistonringstops are not going through some ports, but even then I’ve known speedbuxy was using a piston for years this way.

Link naar Mijn collectie / Projecten.

[12VTopic starterBerichten: 27]

I have ordered a new piston now and i’m sending this for re-plating.

Any comments on the piston to bore clearence?

regards, Carsten

[eidosDonateurBerichten: 823]

You should improve the ports (edges) in the cylinder a bit before sending it out for a new nycasil layer. Like Martino is mentioning the quality and finish is not that great from Eurocilindro. I think its best if you measure the bore after the new coating/layer of nycasil is applied. Chances are the measurements now and after are different. I dont know the best tolerance for cylinders/pistons.

Can you post some pictures from the Eurolindro after its been retouched?

[12VTopic starterBerichten: 27]

I will make sure that all ports are cleaned up and chamfered before plating, but i actually think it looks very good right now. I must have been lucky, the build quality looks good on mine. Just the old plating is totally scratched up, i still think it’s due to chrome rings. It looks just like an old hard chromed Kreidler cylinder i’ve seen, that was run with chromed rings. It has no marks from heat seizure.

I’m sending the piston to the plating company, they will measure the largest/correct piston diameter and diamond hone the newly plated cylinder to that measurement + 0,04 mm (that’s what i think i’ll go for). I’ll be using Airsal for the plating, they have good prices and a thick coating. It should be able to fill all scratches without having to weld and rebore the cylinder. At least i hope so, it’s not going to be easy to find a oversize piston for this.

Yes i will share pictures 🙂

regards, Carsten

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