Baking muffler clamshells for lunch

Started tearing this down.

Looking good!

Excellent

Found my minor fuel leak, pretty obvious

flippy caps

I use Stihl MS 170s in my business.

This is the first I have read about modifying them.

What suggestions does anyone have for modding the MS170 that is used for cutting pilings and 2x8s around marine construction sites?

Took 3 silver maples and a mulberry down last week. Started cutting it up yesterday.

I put a bigger bar\chain on mine.  Muffler mod and an adjustable carb to tune it better would be next\easiest.  

Do a muffler mod. A muffler mod is where you open up the muffler some to allow it to have a better throttle response and more power. It works by allowing the exhaust gas to exit faster. You only want to open it up some, going overboard messes with the very specific flow range needed to run well. Another smart and relatively easy mod to increase power is to remove the base gasket for the cylinder. You use a sealant that allows it to change the tolerance of travel of the piston to travel up to .020”(can’t remember the exact number)….   .020” clearance between the top of the piston and the ceiling of the cylinder. That will increase your compression, and thus increases power. You could also change your drive sprocket for more torque or more speed. More teeth in the drive sprocket for the chain increases chain rpm, less increases pull and torque. Between the two I prefer torque. Imagine it like if you could push a car slow, but steadily or push a baby stroller fast. That’s what it’s like for a chain. Chain speed has a place, but for such a small engine you’ll want a torque preference. You can also remove any safety chain and use straight up non ramped depth gauges and a chisel chain profile tooth.



Remove the spark arrestor too, that impedes airflow. If you want to get ass deep into it you can do porting, change the ignition timing, remove the base gasket for the cylinder, dome the top of the piston, turbo the crank, but I think we’re getting way ahead of ourselves, haha.

Disston!

Attached File


Attached File


Attached File

Whoa, neat!

Doubletap

Factory squish on my 361 was .035
Its now at .019 with gasket delete.
We shall see when I get it all back together how it runs.

Picked up a new MS661C today

Finally fell the red pine that's been dropping sap on our vehicles and anything else under it. Gonna use the logs for practice with the chainsaw mill.

Ran the 372xp OE (24" with 3/8) and ported 254xp today (20" with 3/8).

Bear with me as I make a long story short;

My Dad sold Disston saws in the early 50's.  In NE Ohio they were a big saw and the area was developing fast.  He had a power equipment business and also a Mercury (outboard motors) dealership.  The Disston was a natural since he already stocked many of the parts since the Disston saw used Mercury engines.

Decades later he said to me "I'd like to have one of those saws again.  Just to hear it run."  I tucked that nugget of information away and began the search for a saw.  It took some time, but found one and restored it.  I brought it to him and delivered a surprise gift.  One tug of the rope and two cylinder two stroke music was playing!

He proudly displayed it in his shop until he passed.  

My venture into these saws was not over.  A nearby Amish shop had several.  I restored a saw for the owner and payment was yet another saw!  Later on I ended up with more parts and now have all of the saws I restored back.

Two are Disstons, and two are the more rare Keikaffer saws.  

In the 50's, I'll call it "the chainsaw wars" were on.  You had Maul, Homelite, McCulloc, Disston, Remington, and others all pumping out faster, lighter, more useful, efficient saws.  Disston was counting on Mercury to engineer and deliver a lighter saw, and they did.  The DA101.  It was quickly outsold by more competitive products.  The relationship between Mercury and Disston fell apart and that was the end of Disston saws.  Not so fast said the Mercury people.  They changed the color and attached a new nameplate to sell a Keikaffer chain saw.  Again, the market did not respond to the heavy, two man saws and in a year of so they were in the history books.  Well, with one exception.

With this nicely tooled engine package, there must be someone that could use it.  That someone was the Watson-Jackson Pump Company.  Mostly known as Wajax pumps.  They made a four stage centrifugal water pump head that attached to the engine.  With a lightweight base, this was sold as a portable firefighting water pump.  I believe that they are still in business.

I only ran across one of these pumps and I own it.  It is hard to prime, but when it does you had better be hanging on to the nozzle. It really moves the water.  Here are two pictures of the Wajax pump in action with my friend Doug.  RIP Doug.  You were a good man and are missed.

Bob


Attached File


Attached File

MyMan.gif

Which models are those?

That bit of history was worth the read.
Thanks

445, 455, 371xp

What are the cheap no-brainers to replace while I have this thing apart?

I am already am planning on new ignition module, fuel lines, air filter, spark plug and vibration dampers ( they are spongey).

Feels like it has good compression, but have a compression gauge coming and will pull some ohm readings off the coil before I go overboard with parts.

Learning as I go with this.

Nice

Gonna pressure and vac test it ?

Honestly hadn't planned on it, but looks like I can get a pump for $50 or so... so yeah, I will do that.

What else? Don't want to go overboard an a 40+ year old saw, but am interested in the knowledge and basic toolkit.

Appreciate the input.

Honestly hadn't planned on it, but looks like I can get a pump for $50 or so... so yeah, I will do that.

What else? Don't want to go overboard an a 40+ year old saw, but am interested in the knowledge and basic toolkit.

Appreciate the input.

I think testing a saw that old is worth it if it has some value to ya.
It would suck to do all that you mentioned only to find out you had a gasket leak or bad crank seals.
I’d pull the exhaust and rotate piston to check for bad scoring, hopefully compression checks out good !

Decided to be different, helps that orange is my favorite color.

Painted in Husqvarna orange?

I *really* want to learn how to do a little mild porting work (as well as opening up mufflers).  I have the equipment, and actually a few donor saws to practice on, just haven't taken the time....yet.

Damn you, I see it now
Gonna have to add some pinstripes.
High temp paint is expnsive.

Nothing to write home about, but enough to hold my own cutting firewood, and occasionally feeding my dad’s woodmizer.   I do miss my 346xp ??.  

Attached File

Homemade exhaust port blocker for air leak testing.
Made from scrap aluminum and some scrap silicone membrane.

7.5lbs pressure held solid at 7 minutes, no leakdown.
This makes me very happy.

Edit to add:
Vac'd to 15inHg for 10 minutes, rotated crank several times, held vacuum fine.

Stihl looks good though!

---------
Maybe do the lower half white?



Can't go wrong with that setup!

@rtlm
Do you do any side work? I've got a 044 with a leaky crankcase.  It runs good, under throttle. But dies when you let off.  I took it to my local Stihl shop and they told me it had a crankcase leak.

No sir, I just like to tinker, modify, and hot rod everything, strictly a hobbyist.
I have not personally split a case...yet.
With a pressure tester and spray bottle of soapy water, it shouldn't be hard to pinpoint your leak.
044 is a good saw, fix er up.
If you want to verify their diagnosis, the tester I bought was only $70
pressure/vac tester

I made something similar for a Stihl 066 years ago, chasing a clutch side crank seal.

Diy works.
Used membrane and tiny hose clamp to seal intake port.

Did a "stealth" muffler mod on my Echo 7310p. Hard to get good pics.  But stock, it is a wide open can with a fairly decent exhaust opening, but it has a half-pipe tube welded under the outlet that's pretty small compared to the outlet port.
It makes the gas have to bounce off the front of the muffler and then come back through the small tube to get out.
So I reached up inside and drilled a bunch of small holes around the edges of the tube,  then kept enlarging the holes and grinding with a dremel until I was able to connect the dots to sever the tube.
Them I enlarged the exhaust opening slightly by drilling up from the inside.
Can't tell anything is going on by looking at it, but it has a straight shot through the port now.  Gotta get the limiter caps off the carb and hopefully give it a try later.
Crappy pics to follow (didnt get a before of the half pipe tube)...
Attached File


Attached File


Attached File

Nice.
Let us know how it screams after tuning.

Quick tune and tryout after I figured out how to remove the limiters (these are different than the normal plastic ones),  Thank goodness for YouTube "how to" videos,  it was easy, (just had to drill out the plastic stop in the metal limiter) and I thankfully didn't break anything

Edit to add picture
Attached File

Very nice.

Stiffened up the suspension a bit with some cut down bushings from donor saws, and put a taller 500i bushing to replace a worn shorter one that sets against fuel tank.
Compression test was a fail, my gauge wouldn’t read past 60lbs and saw was easy to pull, no idea as I tested it against my air compressor and gauge worked and tested didn’t leak, no idea.

Put spark plug in and trust me, it has a shitload of compression, more effort required to pull it than before.
Deleting the base gasket definitely boosted compression.
Fueled it up just to hear it crank and let it idle and warm up, and it sounds sweet.
Looking forward to putting bar on and tuning it.

Still gotta figure out what I’m gonna do about air filter system.
Might use an aluminum spacer and aftermarket system for more air flow or even a bigger or bored carb.

Thanks, not super loud but definitely feels like it has more "pull".  
Wasn't forcing it when I dogged in on the cut, just letting the saw work and it just kept pulling itself through.
Before it seemed to want to bog down when I dogged the 28" in bigger wood

Looking great!