sorry if i am asking an old question but i plan on putting an extra o-ring on my secondary 850's in order to have them safely fit in the stock primary fuel rail.

does anyone know what size o-ring i will need to add on?
also is it just a second stock o-ring that needs to be put on?
if so, what is the size of the stock o-rings on 850 secondary injectors.

sorry, im a newbie
any help would be greatly appreciated

 

you may want to call rc engineering. unless some one has some injectors o-rings handy and can post their findings. I called them once and they read some measurements to me of 2.3mm thick, 22mm od, 118mm id. the other one was 3.5mm thick, 14mm od, 8mm id. I dont know which one is which, the numbers dont make precise sense and I don't know which is for the 850 or 550.

I had them measure them because they said they switched from viton to n-buna because they had trouble acquiring viton from their source. You can buy the viton ones at mcmaster.com. Or you can pm me the exact size and I can check those against the ones my brother bought for me, he was making an order from them, I have 25 of each. but before I open the package I wanted to make sure they were the right size. I dont know if the sizes were different when you switch rails either.

Else, you can have rc engineering clean, test, and rebuild yours.