Echo cs 590,600,620 porting/mod/build thread

[Ronie]

Thread you asked in.
https://www.arboristsite.com/thread...s620pw-differences.257613/page-4#post-7589302

 

[Ronie]

After reading your post on AS I sent you a PM on this site with a link to Nutball's comparison of the 590 and 620, you can find the stock timing numbers on page two.

 

[Ronie]

https://opeforum.com/threads/echo-590-vs-620p.18203/page-2

 

[Nutball]

620 ignition doesn't have a rev limiter is all, or the rev limit is much higher than the 590. Really not something I personally worry about. You see lots of old threads about who can lean their saw to rev the highest out of wood, but 15,673rpm out of the wood means nothing to me when you are cutting 15-30" logs. It may help you see how well your ports flow, but will those flow characteristics have a noticeable effect at 8-11krpm in the cut? Probably not so much in my version of a work saw, but some people like them spicy.

 

[Cerberus]

After reading your post on AS I sent you a PM on this site with a link to Nutball's comparison of the 590 and 620, you can find the stock timing numbers on page two.

https://opeforum.com/threads/echo-590-vs-620p.18203/page-2

Thanks man, not just for linking it but for taking the time to do that!!!! Reallly makes me wish I had a better setup, my backyard is a squished bonsai-nursery I have to work on-top-of!

Your vids are great but that last one (620 ported #2), seems that wood may've been a bit tougher? Am clocking it as one of the slowest of the 5 cuts..

The muffler comparison is awesome it was:
Stock 620p: 22.5s, 19s averages to 20.75s,
Muff-modded 620p: 17.5s, 19.25s, avg to 18.375s That's 11% gain on muff-mod!

I think you'd done "the standard" IE a big, extra exit-hole in the top-plating (allowing exhaust escape from the rear-half of the baffle)? Would love to see how mine stacks-up, being it keeps the OEM "design intention" (am unsure if I've opened-up the exit holes, have two in the front-portion of the muffler that, together, are about 1/3rd larger than OEM but w/o relying on the straw they're far less restrictive, and of course baffles are significantly enlarged!)

Have yet to even "properly tune" mine, it got better through&after that first Oak (did another Oak right after that one) so haven't thought to do it, crap my tachometer broke yesterday I couldn't do it if I wanted to! Or am I getting that wrong....Because it's got a limiter, and a high-jet override, can't I just tune-by-ear and even go kinda lean when doing so? (lol am realllly hoping for a Yes here ;D Still need to order a new tach, a better one than the 2-readings/second one that just failed me after 20hrs use)

~~~~~~~~~~~~~~~
Comparison of OEM timing#'s, courtesy of Nutball (thanks!!)

Exhaust: 590= 111*; 620p= 105.6*
Transfers: 590=127*; 620p= 125*
Blowdown: 590= 16*; 620p= 19.4*
Squish: 590= 0.040"; 620p= 0.035"
same PSI, is my understanding.

^I can look at that for an hour and not understand it a fraction as much as you guys, gotta say I'm surprised seeing such low blowdown #'s I thought 20* was basically a minimum, this is eye-opening to me for sure!!

You see lots of old threads about who can lean their saw to rev the highest out of wood, but 15,673rpm out of the wood means nothing to me when you are cutting 15-30" logs.

It's unambiguously *bad* to do this anyways (no-load revving, or serious revving), right? I mean short bursts are unlikely to be damaging but they're a non-zero, non-friendly use of the powerhead...was my understanding. It's designed to go to peak-power under load, but - luckily - that's all that matters

~~~~~~~~~~~~~~~
Am astounded at how dirty this filter is getting, presumably this is the norm? Any tricks? If it's not the norm then I need to double-check the tightness because I've never seen a filter plug-up so quickly!

Seems the "automotive type" filters are best (like the 660, like the 7310, like so many 40+ cc echo's!), keep thinking one of the other echo models, of comparable displacement, may fit-up well enough to be McGuyver'd in!!

(I should mention that I am using that carb-spitback-plate inside the air filter, and still the entire filter, front/back top/bottom, just fully covered after each use..)

~~~~~~~~~~~~~~~~

Dogs....
I'd only learned how useful dogs were a couple weeks ago, using the 660 factory-spec dogs and holy-crap with a longbar....they're almost *necessary* if you wanna control the bar's tip!
So I remembered "XL custom dogs" on ebay, ordered a pair and jeeebus what a difference!!! Loved them so much - and was feeling generous - so gave first pair to a local who has (2) 590's, and have a new pair (in orange ) landing today or monday, can't recommend them enough am sure google will yield them they're by "customchainsawparts" on ebay, just under $30 shipped and take ~just under a week for FL shipments at least!

~~~~~~~~~~~~~~~~

Love this saw, wish I had been setup like @Ronie with OEM baselines, especially would've liked to compare "just the standard muff-mod" to my style with the full port-matching (which was just such a beast the muff's rear wall is so strong/thick, and tolerances need to be so precise if your exhaust-flange was ported aggressively like mine!

 

[Ronie]

Your vids are great but that last one (620 ported #2), seems that wood may've been a bit tougher? Am clocking it as one of the slowest of the 5 cuts..

The first two that was stock and with a muffler mod was in pine. The second two was in oak, 26 seconds on the first one and 25 on the second one, on the second one I was cutting through the rounds I was using to support the bigger one so it may have been a little quicker if I had pulled the bar back a little like I did in the first one.

 

[9050lx]

https://www.sawagain.com/chainsaw-d...0vkXsof79G1sMZexrE_Uw5bE7lRamy9gaAmSeEALw_wcB

Decomp threads (Echo 590) are 10mm x 1.25, I believe Husky threads are 10mmx 1.5 pitch.

 

[K-techcowboy]

Thank you for the reply.

Seems these saw would get a rather healthy bump in compression with minimal off the base.

Didn't realize the stroke was that long... that piston is really moving. That explains some things I've seen in my older jug.

I plan on getting the unlimited 620 coil, may not help much, but it does have a different ignition curve than the 590,600 coil.

Now how do you know that?

 

[Red97]

Now how do you know that?

Looking up the technical service data at the time. 620 has 8* more total advance and a different curve.

 

[Thesandman]

Brother Red97; Can you summarize where we are in cs590 porting and mods to make a wicked timberwolf? What worked and what didn't? How did it compare to your 357(9)? Thanks

 

[Red97]

Brother Red97; Can you summarize where we are in cs590 porting and mods to make a wicked timberwolf? What worked and what didn't? How did it compare to your 357(9)? Thanks

Cut base/set squish .025~

Raise ex to 105 ~ widen a bit
20* be
Intake 78~ widen a bit

Nozzle swap in the carb to allow leaning out enough.

6-8* timing advance

Healthy muffler mod.

Makes a whole new creature out of the timberwolf

Honestly don't even Remember the 359/7 at all, sorry.

 

[Mastermind]

Cut base/set squish .025~

Raise ex to 105 ~ widen a bit
20* be
Intake 78~ widen a bit

Nozzle swap in the carb to allow leaning out enough.

6-8* timing advance

Healthy muffler mod.

Makes a whole new creature out of the timberwolf

Honestly don't even Remember the 359/7 at all, sorry.

What nozzle are you using Joe? I just fill the hole in it with epoxy.

 

[Red97]

Husky had, 153,191,etc or I think stihl 361 works as well.

 

[farminkarman]

Husky had, 153,191,etc or I think stihl 361 works as well.

Joe, was that supposed to be HDA 153 & 191?

 

[kentuckyguy]

Also curious about the nozzle change out. Do you feel the timing advance is 100% necessary?

 

[farminkarman]

What nozzle are you using Joe? I just fill the hole in it with epoxy.

Randy, have you ever posted about the mod you do with epoxy?

 

[Red97]

Joe, was that supposed to be HDA 153 & 191?

Yes hda

 

[Red97]

Also curious about the nozzle change out. Do you feel the timing advance is 100% necessary?

Not if you don't want to. They run fine without it. Just add a bit of snap.

 

[Mastermind]

Randy, have you ever posted about the mod you do with epoxy?

I'm not sure. I hate posting about chainsaws. LOL

 

[Ronie]

Here's how I did my 600p.