Novarossi .28 conrod length
#3
Thread Starter
Tech Initiate
Joined: Nov 2009
Posts: 38
This is for an engine project that im working on and not to just replace a rod in the Nova .28 motor. I think the rod is possibly longer than the 28.5mm c to c on the .21 rods. Reason being a completely different part number, If Novarossi use a common part in any of their motors irrespective of size of motor they use the same part number. Also with the longer stroke of 17.6 mm and longer piston the piston would be to far into the bottom of the case and backplate at bdc. I really need for some one to measure one. Best regards Martin.
#6
Thread Starter
Tech Initiate
Joined: Nov 2009
Posts: 38
Thats correct, There are longer rods ie OS Speed rod is 30mm c to c. I need to know if the Nova .28 rod is even longer than 30mm. Also you have to be very carefull useing rods from other motors regarding big end size, Common size in most motors is 5mm.But different manufacturers size the pin and rod bush different ways so their not all the same size. Take Novarossi and Axe Rossi their pin is 4.99mm and rod is 5.01mm. The OS pin is 4.96mm and rod is4.99. An OS rod is to tight on a Nova and Axe and the Nova and Axe is to loose on an OS pin. This is comparing new components and not part worn out rods and pins, Nova tolerance up from pin size for clearance where as OS go the other way, they tolerance down from their bush size for clearance. Alot of these rods may go on to other pins but their not the correct tolerance. unless you check carefully what your doing, There just not 5mm accross the board. best regards Martin
#7
Tech Regular
Joined: Apr 2009
Posts: 380
The 29.5mm novarossi rod works on the 17.6mm stroke, that's what the toro nero has stock. RB rods are 5mm main journal bore. NR are 4.95 on the main journal. Sirios/OS use 30mm c/c. MAC and CMB new 21 engines are 31mm c/c, but I haven't measured the journals. piccos I think are also longer than the most common 29.5 but I dont remember...
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#10
Thread Starter
Tech Initiate
Joined: Nov 2009
Posts: 38
We are refering to so called 5mm pins, 4.75 and 4.5 are distintively different size pins that have been tried. The Nova that i measured was a slightly older model that was 4.99mm pin , Just taken apart an 09 Nova that i got 2weeks and that pin is 4.97. Got a CMB shaft in front of me and thats 5.09mm pin. I still need some one that has the .28 rod to measure for sure, might be or should be the same is not really telling me what i need to know. best regards Martin
#15
The last Novarossi engine that I spec'd was the N528XR, so it's not the current engine, but all the .28 engines use the same conrod. The crank journal is 5.38mm and the wrist pin is 4.38mm with a center distance of 32mm. Most .21 engines run a 30mm rod, but this one is supposed to be 32mm by my measurements, and by what Jim from Fusion confirmed when I bought a 528 rod for another application. Just passing it along, but it appears to be in conflict with other measurements that have been posted.




