MS 310 versus MS260

[Diesel Pro]

A while back my Brother in law ate a piston in his MS260. I procured a new P&C from a member here and put it together for him. As I recall I did very little porting work, bringing the ports out to near the edge of the very generous factory bevel. No base gasket and a good muffler mod.

He has a neighbor with a MS310 that he's been cutting with. Well the 260 just stomps all over it. I'm waiting to hear back about filing the chains fresh and then comparing, but it sounds doubtful. His neighbor wants me to make his saw run better. The 260 is running .325 and the 310 should be running 3/8 if I follow specs correctly.

So my question is, does the 310 have as much potential as the 260? Being a larger displacement saw it sure should. Just want to be sure I am not setting myself up to try to polish a turd.

 

[nmurph]

Here's my take- A 310 with a good MM will out-cut the (friends) modded 260 easily. Your port work didn't do much to significantly improve power. The MM does help, but the 260 is already starting at a .6hp deficit. I have a MM 310 and it will cut with a stock 361 all day long...

To answer your question, there are gains to be made by porting a clammy, but the outcome is limited by the inability to adjust squish. That limits increasing compression. That limit can be overcome by welding the piston, but that gets pretty involved. Widening the ports and cleaning things up will improve the performance significantly.

 

[Diesel Pro]

I was not aware that the 310 is a clamshell. Good thing I asked.

I'm not going to split it so I'm thinking MM and pop the carb limiters, tune and go.

 

[cheeves]

Here's my take- A 310 with a good MM will out-cut the (friends) modded 260 easily. Your port work didn't do much to significantly improve power. The MM does help, but the 260 is already starting at a .6hp deficit. I have a MM 310 and it will cut with a stock 361 all day long...

To answer your question, there are gains to be made by porting a clammy, but the outcome is limited by the inability to adjust squish. That limits increasing compression. That limit can be overcome by welding the piston, but that gets pretty involved. Widening the ports and cleaning things up will improve the performance significantly.

I fully agree. I think the 310 is underestimated. I ran a 260 for three weeks when I bought my 310. The gas tank had a crack in it so the dealer gave me a 260 to use while I waited for a new tank. I MM my 310 and it would out cut that 260 I used with a dull chain. I don't like to cast aspersions on the 260. I think it's a great little saw. Feels great and ported would love one. But the 310 MM can cut.