Porting an Echo 303t

[Nutball]

I started a rear transfer port, but realized in time the free port issue. It might still free port, but only a by negligible amount if any.

 

[Nutball]

Exhaust is now about 106, transfers are about 130 & 135 degrees. Squish is between .020-.010. While rinsing the cylinder, water showed excellent improvement in clinging to the cylinder after exiting the "intake side" transfers.

Muffler and gasket matched to the enlarged port.

 

[Nutball]

147psi warm, I can't remember if I checked it stock, but I want to say it was around 120psi warm or somewhere low as seems consistent with Echo top handles.

I'd like to think I got roughly 36.875% faster cut time, but with a change in log size and an iffy first cut, and imperfect second cut, it's hard to tell. It's not as strong as I hoped, but it exceeded my minimum gains to call it a success, but then again I was going to take .050 off the base, but stopped around .0275 when I ran into alignment issues on the lathe, and at the same time found that though the plating goes to the top of the cylinder, it tapers to a wider ID, so I stopped working on compression.

I also had to grind on the engine cover and oil pump to get it all lined back up.

Video to come.

 

[Nutball]

It's about 2 seconds slower in the triple cut in pine compared to my modified 355t, but the 355t was tested with .043 chain, and the log may have gained a slight bit of diameter.

 

[Nutball]

The air filter cover appears designed to let dust fall off the filter when the engine is off, so it can collect in the bottom, and get sucked out when restarted or at idle. I think the exhaust is big enough, just needs a different deflector to avoid the risk of melting the muffler cover.





If I can see through it, air can see through it.

 

[Nutball]

I've found the switch is easily operated with the third finger. Also found this thing cuts up to 10% faster in 14" Ash than a stock 201tcm (same b/c used in the test).

 

[NPKenny]

View attachment 193923

What material is this mesh and what adhesive did you use? I thought I had read it, but now can’t find the reference to it. Thank you!

 

[Nutball]

It's Nylon mesh (gasoline proof), glued on with super glue (also gas proof)

 

[Nutball]

Another Echo with oil pick up problems. They used a short stiff line that basically holds the orientation you see. So, it works best with the saw level, or clutch side down (only if lowish on oil). When hanging from a climbers belt and 1/3-1/2 full it will not pick up oil. A good thing if the saw is left idling, so the continuous shaft driven pump doesn't pour all the oil out, so maybe that's why they did it? But, why have a shaft driven pump anyway? Also, most climbers will make horizontal cuts with the clutch up (right handed). Horizontal cuts usually involve bigger wood, bigger wood is where you definitely want oil, but clutch up horizontal will give the worst oil pickup ability.

 

[Graf]

How did you get a 0.020 0.010 squish from that type of cylinder? What mod to cut the base?

Imho the reed valve has good potential but probably needs a larger carb/passage for a good petal opening

 

[Nutball]

I did cut the base, and lots of sanding and test fitting, and such. It's a lot of work just for compression. The reed has a travel limiter, which if it didn't, it could hit the crank. It has good high end power just not a lot of low end power.

 

[Sawpaw]

I have a 330T and found an older Echo muffler without the cat and bolted it on, makes it run a lot better than the cat version and cooler also...

I know this is an old thread but do you remember the not cat muffler you used as a replacement?

 

[FergusonTO35]

Are you looking for a muffler for a 303 or 330? If a 303, then any muffler from a 300/340/3000/3400 series saw will work. I want to say the 330 is new enough to have always had a cat, but I could be wrong.

 

[Nutball]

302 probably uses the same muffler, but may be old enough to not have a cat.