Does anyone know some good materials too use in making of racing cylinders for two strokes?
The problem is that alcohol and nitro mixes create unusual high temperatures. It must altso tolerate punishing high revs' (20,000 rpm )
And the piston?
Titanium perhaps?
I would think a beryllium alloy could do something here, but I guess it's just too feared and expensive to try. Maybe a lithium aluminum alloy...
Tim
-- "California is the breakfast state: fruits, nuts and flakes." Website:
Try here;
There are lots of other companies that do similar work.
Don't know if it's useful, but model airplane engines burning alcohol & nitro typically use an aluminum piston running in a chrome plated brass cylinder liner (typically in an aluminum block). No rings - it's a tight fit cold, and works out via the thermal expansion.
The usual stock cylinder material on sachs two stroke is cast iron. Kreidler uses crome plated.
skrev i meld> > Does anyone know some good materials too use in making of racing > cylinders
I made a pair of sleeves from DuraBar . Runs great and no wear on a two stroke outboard.
Pete
If you want information from professional engineers who research this subject with the aid of serious money and well-equipped labs, it's a subject that has come up from time to time in SAE white papers. You have to pay for them, but it's cheap if you're serious about building something.
Go to the SAE site and you'll find the publications.
-- Ed Huntress
You didn't indicate a displacement size. Assuming you are interested in something up to about 10cc displacement, but most likely in the 1cc -
2.5 cc displacement range:4032 AL for the cylinder with chrome plating on the bore
A high silicon (>20%) AL sintered piston (not quite, but almost unobtainium)
2024 AL for the rod with the lower end bushed or perhaps 7068 AL without a bushing2024 AL T3 or T4 for the case if you machine it from a block
390 AL aged to T6 if you cast itStay away from 6061 and 7075 for model airplane engines. 6061 moves too much under pressure and heat. 7075 loses a lot of its desirable properties when heated much over 125 to 150 degrees C
Titanium has a lot of nice properties except it has a tendency to gall when there is a moving interface. It's temperature expansion ratio is very different that the normal bushing materials, AL, and steels used in model engines which bring a whole new set of problems.
Ed is right, the SAE has some very good materials. Send them lots of money and brush up on your math. Those reports have a wealth of information but are not written for the non-engineering type.
Dave Rolley
Ed Huntress wrote:
"Dave Rolley" skrev i melding news: snipped-for-privacy@comcast.com...
about 60-70cc
unobtainium)
Most hi-performance two-stroke cylinders we use are aluminum with a NiCom plated bore.
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