ORIGINAL: mig3
OPS are some of the best Italian RC engines ever made,
BUT like the gent says below = lots of connection rod blows in them, especially in the .40 AERO and boat / water cooled versions. These rods do have the oiler holes in them and they are brass bushed like the better RC engines.........the BRUTE power makes them blow.
NOTE: Rossi uses a much thicker crank / rod assembly and they do NOT blow up. But LIKE the mighty Rossi = JUST AS FAST,.....
The OPS uses a 1 piece hemispherical head ( dome like ) with the seperate ''donut'' that fastens the head to the case. Norvel also uses this design which makes for the fastest engines in this hobby.
PORTING is the 5 way style; and not the 3 like most. I have a Italian Rossi here with 7 intake ports and it is a .65 in a .60 case. Stamped ''65'' on the mounting lug from the factory.
The racing / slide carb versions are among some of the fastest RC engines.
I have MANY OPS boat engines here, some are in bags taken apart because I can not find a connection rod. ( piston to crank rod ) But I do know of a guy who makes the rods for any engines. I can ship these to anyone who wants them FREE = less shipping of course + YOU CAN HAVE THE PARTS! = pay the shipping only!
I did not know of the factory burning down,; but that may explain why all of a sudden; parts were almost impossible to get!
MIG3
OPS 40 aero engines blow because they used a poor quality brass for the conrod bushings. I have 2 that have blown and are just sitting in a box. What you are talking about is a head button, only some Norvel engines use the head button. Norvel is now owned by ASP, and ASP stopped producing the Norvel style motor shortly after the buyout. Have any Norvel engines you want to sell?