Duce's 390xp!

[Miller Mod Saws]

Ok guys here we go! You know me and build threads. I'm gonna tease @Duce a little as I had to order a couple more parts but we'll get the discussion rolling! Here's what we started with! A toasted 390xp that the intake boot was ripped. I bought this saw as a builder and a nice one it will be!

 

[Miller Mod Saws]

So I we started off with a brand new oem p@c for this build!
Numbers takin with flashlight!
Exhaust-96°
Trans-121°
Intake-74°
Squish-.035"

 

[Deets066]

Drop the jug .020, raise the trans back up and call it a day

 

[Miller Mod Saws]

Now for this build I really like to talk the saw over with my customers and try and figure out what's best for them. He will be using this as a tree service saw running anywhere from a 24-36" bar. O ya!!!! Let's see if we can being a smile to his face! So for this saw it's throttled back just a hair and I will try to show ya as we go threw the build what I mean.

 

[Miller Mod Saws]

Drop the jug .020, raise the trans back up and call it a day

Psshhhh that's no fun!

 

[Deets066]

Psshhhh that's no fun!

Ok.... Might as well make it snort then

 

[Miller Mod Saws]

Almost stock pics of the jug!

 

[Miller Mod Saws]

First things first. I just tapered the transfer divider a little to help flow. Nothing major just helping flow! As the pics come you will also see I cut .050" from the base and .037" from the squish to achieve a .022" squish. That should help with torque a little.

 

[Miller Mod Saws]

And this is a little bit if my throttling back a little. On a wood cutter saw I would be a little more aggressive and add some more comp. But this will do very nicely! It drops my exhaust to exactly 100°.

 

[Miller Mod Saws]

Next let's open the exhaust outlet up to match the heat shield!

 

[Miller Mod Saws]

Next the exhaust! Thought I'd show ya this pic before I cleaned it up. I widened it up to 70% of the bore. However you can see its gentle. So its easy on the rings. As you see I didn't touch the roof and I rounded the corners very nicely where I did grind to produce a nice arch on the exhaust. Again I want to keep it very nice to the rings!

 

[Miller Mod Saws]

Next let's play with the transfers. On these I tried to retain the stock shape and approach angles the best I could but I raised them to 120° for 20° blowdown!

 

[Miller Mod Saws]

Next the intake. I forgot to take one pic but I matched the inlet to the boot. Now for the rest. I did not lower it at all other than clean up. And retained the factory curve on the bottom. Much like the exhaust roof. I didn't touch the floor. I widened it to 65% but tried to follow the factory curve. Squared the sides just a tad and them I raised the roof back up. Roughly a ring width!

 

[t4driller]

^^ very clean looking. Always like reading your build threads!!
(Clap)

Sent from my SM-G925V using Tapatalk

 

[Miller Mod Saws]

^^ very clean looking. Always like reading your build threads!!
(Clap)

Sent from my SM-G925V using Tapatalk

Thank you!

 

[Miller Mod Saws]

Let's talk the intake. While a square intake offers a lot more flow. I believe it comes with some sacrifices as well.

And this maybe all in my mind. But it seems as the wider and flatter the intake floor gets the faster it wears the bottom of the pistion skirt. So my theroy is here to try to take the pistion rock out of it the best I can but sacrifice as little performance as I can. So hince the leaving the curve in the floor and rounding the corners just a bit more. I think that closes the port smoother with less wear to the piston.

 

[ft. churchill]

Sweet lookin' port work.

 

[Deets066]

Well damn is it runnin yet

 

[Miller Mod Saws]

Well damn is it runnin yet

Well Dammit I'm hoping others will join in here. I like group build threads and discussions. I always learn from them!

 

[Miller Mod Saws]

I do have the saw this far back together but here's where it gets sketchy! I had a jack up! Lol. Ya'll are gonna laugh at me!