Hi all,

I know this topic has been cover in great detail but here is a new angle (i think). I broke a connecting rod in my '360' . After I pulled it appart I discovered 390 stamped on the side of the piston. Has someone converted this '360' to a 390?. I know I could tell for sure by measuring the bore or comparing the connecting rod to 390 or 360 but is a 390 piston marked?.

Thanks for any replies
Cies

 

The 360 and 390 have the same bore so therefore they use the same pistons.(I went through the same question several years ago)

 

You can tell by the casting on the crank; what is it?

 

Thanks for the replies guys, but the question is solved. Its a 390 ... the reason I know is that it broke a connecting rod. I took it apart and discovered that it had fully floating pistons; therefore it’s a 390. Lucky for me it broke the rod close to the crank and did little real damage before I shut it down. The 390 is now temporarily repaired and I will replace it with a rebuilt one after the winter.

Cies

 

By "fully floating pistons", do you mean that the piston pin freely slides into the piston rather than being pressed on? All FE's used a free floating piston pin that was retained by clips in the pistons. The only way to determine the difference from a 360 and a 390 is to find the crankshaft casting number, or measure the stroke.

 

Hi 390fe


Yes, I did mean "the piston pin freely slides into the piston rather than being pressed on". Guess I have learned more about FE's. Always thought this was one difference between the 360 and 390.
I did replace the connecting rod with one from a 390, after comparing lengths (best I could with the broken one). I hope there is a big enough difference to tell by eyeballing. However the beast runs, but like I said it is tired and due for some replacement.

Cies

 

The rod lengths are different and visible to the eye.

"Guess I have learned more about FE's"

I learn stuff about these old dinosaurs every week. That's why I love FE's so much! Now go git another 390 to rebuild while you drive this one. :-)