372xp/385xp transfer port work

[hellomyles]

I have been looking and searching and cannot seem to find what I am looking for. So I figured I would post up and see if anyone has some light to shed.

I just ported my first saw a few weeks ago (385xp) and last night I did my 372xp. Both are 2008 models. I did the 385xp first since my dad had my 372. I was super impressed with how he saw turned out. She's a beast!

All I did on both saws was widened the ports on the intake and exhaust and made the ports better flowing. I also removed the base gaskets to bump the squish and then I lowered the intake port timing a bit. Both saws have similar timing. Which I was actually surprised. I felt like the 372 I didn't do much to actually. Lol. Anyways everything I read basically said if it's your first go, to leave the transfers alone. Which I did. But I am wondering if there is much more to gain by working on the transfers some or is it not worth the time? If it is worth the time, what's the best approach to porting them out?

I didn't do any machining on the jug at this time. I figured baby steps and I am super happy with the 385. The 372 I am waiting on a new Dominant piston to try and a new light weight Sugi bar to show up. Just wondering if I left much on the table or if I should just leave well enough alone?

Anyways let me know if you have any input! Thanks!

 

[mdavlee]

Depends where the numbers are

 

[hellomyles]

Depends where the numbers are

372 numbers are:
Squish-.23
Exhaust-102 degrees
Intake-80 degrees
Transfers- 122 degrees

385 numbers
Squish- .22
Exhaust- 97 degrees
Intake- 82 degrees
Transfers-121 degrees

 

[mdavlee]

I like those numbers. If you did a little machine work I'd go back to those numbers after dropping it .035" in the 385. 372 wit the dominant pop up piston would be fine with .025" off both and go to 100-120

 

[paragonbuilder]

Welcome to Ope!
And nice grinding!!
I think Mike is spot on. What do you have for porting tools?
That will make a difference.

 

[hellomyles]

I like those numbers. If you did a little machine work I'd go back to those numbers after dropping it .035" in the 385. 372 wit the dominant pop up piston would be fine with .025" off both and go to 100-120

You take off .035 off the bottom of the 385 and fine tune the port timing after words? And take off .025 off the 372 and go for between 100-120 on the transfers?

Also I am wondering if and what to do to the bottom area of the ports and some guys do work around the dividers. Is this not worth it? Or what should I do?

 

[mdavlee]

You take off .035 off the bottom of the 385 and fine tune the port timing after words? And take off .025 off the 372 and go for between 100-120 on the transfers?

Also I am wondering if and what to do to the bottom area of the ports and some guys do work around the dividers. Is this not worth it? Or what should I do?

Yes off the base and chamber. 100 exhaust and 120 transfers. I blend to match the case. You don't want to dead head or short circuit the flow

 

[hellomyles]

Welcome to Ope!
And nice grinding!!
I think Mike is spot on. What do you have for porting tools?
That will make a difference.

Thanks! I used to lurk around AS but seems that's not the same as it used to be there. Lol.

I have just a 90 degree air die grinder and a bunch of carbide burs. I need to get some other ones before I go about the transfers but just seeing if I should really do it or not.