I Ported my 346XP

[Gruff89]

Hi spud. Just wondering how you measured squish, and if you remember the reading before and after. I've just ported my 346 and wasn't going to bother with lowering the squish but seen as i have gone this far if i can get the info ill do it. Been on AS, loads of info on porting but could'nt find any on squish, Im sure its there tho, thought id ask you as you've done it

 

Cheers

[Megatron]

Hi spud. Just wondering how you measured squish, and if you remember the reading before and after. I've just ported my 346 and wasn't going to bother with lowering the squish but seen as i have gone this far if i can get the info ill do it. Been on AS, loads of info on porting but could'nt find any on squish, Im sure its there tho, thought id ask you as you've done it

 

Cheers

 

Use solder. Ensure piston is on "the way up" and near TDC. Put the solder in through the plug hole to one of the 4 "corners" of the cylinder. Turn the engine over slowly. Measure with calipers. Repeat for the other 3 corners.

 

To "tighten" the squish unless doing a pop-up piston you would usually just use a thinner base gasket. Ensure the material you make the gasket out of does not change dimension in time.

[spudulike]

Use solder. Ensure piston is on "the way up" and near TDC. Put the solder in through the plug hole to one of the 4 "corners" of the cylinder. Turn the engine over slowly. Measure with calipers. Repeat for the other 3 corners.

 

To "tighten" the squish unless doing a pop-up piston you would usually just use a thinner base gasket. Ensure the material you make the gasket out of does not change dimension in time.

 

Looks like we have two experts on this site - I couldn't have put it any better myself - I used a 0.15mm home cut gasket bringing the squish down to 0.65mm - you can go as low as 0.5mm and use sealent with no gasket but chose not to.

 

I raised the exhaust port by the same to retain the port timing but am told by one of the top saw tuners that this isn't necessary - the unlimited coil is a big improvement when tuning the carb with a tach.

 

Next step is to do a comparison cut - a standard 346XP against my tuned one - should be interesting - just wish I had more time, too busy fixing saws for others!

[Cut4fun]

Little hint, use grease or vaseline to hold all 4 pieces of solder on piston top and check all 4 at once when cylinder is put back on carefully.

I only check through sparkplug hole on a running saw that is not torn down yet.

[Gruff89]

Cheers guys, thats what ive read but i thought id check. Are callipers accurate enough or should i get a micrometer? Ye cant wait to have a race when its going. I seen a massive change after the MM but got hooked and wanted more! Its a working saw tho so i didnt go to overboard, could always go back and do more.

[spudulike]

Cheers guys, thats what ive read but i thought id check. Are callipers accurate enough or should i get a micrometer? Ye cant wait to have a race when its going. I seen a massive change after the MM but got hooked and wanted more! Its a working saw tho so i didnt go to overboard, could always go back and do more.

 

Vernier calipers would be fine - use a set of digital Mitutoyo ones myself - just asaccurate as micrometers - down to 0.01mm but 0.1mm is ample for this measurement.

[Gruff89]

Ye mine are mitutoyo but ain't digital so user error may occur! Cut some wood yet spud?

[spudulike]

Ye mine are mitutoyo but ain't digital so user error may occur! Cut some wood yet spud?

 

I wish:001_rolleyes: Got a guy in France needs an MS200T, one in Asia wanting a felling saw for his return, another two wanting top handles Stihls............not enough hours in the day, and I have a non Arb job as well!!

 

I may get the chance in a couple of weeks, one of the log stores is half empty!

 

I plan to compare another non modified 346xp with mine using the same bar/chain to cut the same piece of wood - think I am as interested as any in what it will do:thumbup:

[burrell_]

if u dont get a vid soon spud i will tip a big log out side ur house that u cant move so u will have to try that husq out im waiting for this vid :lol: ps the 024 took one step closer to the lathe

[spudulike]

Go ahead Martin - nothing like a bit of free firewood this time of year:thumbup: