Topsy Turvy

[fcheslop]

Hi All,
Just a couple of questions on building a Topsy Turvy will alloy be OK for the engine body/cyl head and will it be OK to lap the cylinder liner and piston so that it wont require piston rings.Iv built a couple if I.C engines but have never used other materials than the designers specified and have never had any luck making piston rings for some reason.
Many thanks
best wishes Frazer

 

[nemt]

Hi Frazer,

I have been building a Topsy Turvy from aluminium with a cast iron sleeve. Runs very well. I used normal pistonrings because in normal practice they are used too. I never use a lapped piston in the engines I build.
By the way I build Topsy a bit bigger. 32 mm to the inch.
Hope you will be successfully in building this nice engine.

Nemt

 

[fcheslop]

Hi Nemt, many thanks for the reply.Alloy it is ;D
best wishes Frazer

 

[Harold Lee]

Hi All,
Just a couple of questions on building a Topsy Turvy will alloy be OK for the engine body/cyl head and will it be OK to lap the cylinder liner and piston so that it wont require piston rings.Iv built a couple if I.C engines but have never used other materials than the designers specified and have never had any luck making piston rings for some reason.
Many thanks
best wishes Frazer

Frazer

I am currently building a Topsy Turvy and it is made from aluminum. I have built three of the Odds & Ends engines and made them all out of aluminum and have had no problems. The stresses put on these engine parts which are usually just running are well within the stress capabilities of materials other than steel. On the other engines I have made the valve bodies out of aluminum and brass and have had very good performance with them. I even made one of the cam gears out of black delrin and it probably has 200 - 300 hours on it without any problems. Regarding piston rings, I believe you could lap the piston and get by without any rings but I think you would have to make the piston out of cast iron as well due to the material thermal expansion coefficient and that could lead to balance problems with the much heavier piston material. I would recommend you consider using O rings. Many people (including me) will swear by them and they work real well and last a long time. They are very cheap and are easy to replace when they wear out. All three of my current engines use o rings and they all work very well.

I did purchase a set of cast iron rings from Coles for my Topsy Turvy but that was because they were cheap and I bought some silver solder from them and bought them at the same time. I am still trying to decide if I am going to use them since I have had so much success with the o rings.

 

[fcheslop]

Hi Harold,many thanks for taking the time to reply.I have been quietly watching you're fantastic build of this engine and kept wondering if you had used alloy.
The lapped piston/cylinder would both be made from cast iron Iv used this method on a couple of engines such as Bob Shores Little Angel but had not thought about balance.
The O rings are they Viton? Iv never used them and it just seems a little strange using an O ring in a I.C engine cylinder although i have seen many builders using them on the forum.
Its a future build as iv a few boats to finish off first and a replica Stuart Turner Henley I want to make so hopefully I will be starting on Topsy in the spring god willing.
Best wishes Frazer