Porting a saw without cutting squish

[junkman]

They used to do porting this way ,anyone ever get a strong saw without doing the squish band on a lathe ? I have one done this way and it seems to be a good work saw ,seems like it would save some time if did not want a lot of compression on some models .

 

[Deets066]

It all depends on the cylinder and what you have to work with for stock ports.

 

[Four Paws]

Many strong saws have been built without cutting the chamber.

Some saws benefit from it, often to counteract factory de-tuning and/or undesirable exhaust height.

Chamber volume plays an important role in the overall performance of a saw...you can have too much, too little and just right.

 

[jmssaws]

No but I got a good running stock one

 

[jmssaws]

That's with a stock muffler
Other than a ignition advance it's 100% stock

 

[Four Paws]

No but I got a good running stock one

Did you really say no? As in not possible?

 

[junkman]

Saw sounds happy

 

[jmssaws]

I said no I have not ported one without cutting squish.
I've built a few popup saws so I guess that's not cutting squish

 

[jmssaws]

Some saws could run good without it
Ms460 comes to mind

 

[sawmikaze]

I have a 361 with no popup or squish cut thats nuked a few ported 60cc saws..just has the base cut

 

[junkman]

Some saws could run good without it
Ms460 comes to mind

I was told once keep the air in longer ,and fuel consumption will be less ,plus increase power .Does this theory make any sense ?
One i have was built with no squish cut will run out of bar oil before fuel , all my other saws still have some oil in them when run out of fuel ,even stock ones .it is a 460

 

[sawfun]

I was told once keep the air in longer ,and fuel consumption will be less ,plus increase power .Does this theory make any sense ?
One i have was built with no squish cut will run out of bar oil before fuel , all my other saws still have some oil in them when run out of fuel ,even stock ones .it is a 460

A longer rod will do that as well through dwell. While maybe not an option in most saws, if the sweet spot is found there can be benefits.

 

[jmssaws]

Intake duration and shape has a lot to do with gas mileage

 

[sawfun]

The more air and fuel you can get, keep, and burn in a cylinder, the more power made. But the speed of that is different matter. A smaller port make keep speed of gasses up, but may limit volume. Volume vs speed would seem to be a big contender.

 

[Deets066]

The more air and fuel you can get, keep, and burn in a cylinder, the more power made. But the speed of that is different matter. A smaller port make keep speed of gasses up, but may limit volume. Volume vs speed would seem to be a big contender.

This same thing applies to the transfers as well.

Well said

 

[mdavlee]

I have made a few but it's a lot different than just taking it apart and porting to go along with that.

 

[CR888]

I think Snelling used to build saws like this.

 

[Jughead]

I think Snelling used to build saws like this.

 

[Stihlbro]

There are a lot of good running saws out there with no squish band work. The gain depended on the model of saw. Chain saw porting has evolved tremendously over the last 4 years. Pop up pistons were the forgizzle my dizzle!
Welded pistons were a thing too. Then there was the epoxy.

Depending on the saw, and what it take to make the owner happy is what drives the fad now days.

 

[drf256]

If the saw has enough stock compression, I'm sure that you can.

A lot of times the band cut is to change the timing more than increase compression.

I recently redid @Jchin 044 so he would be able to still start it. The saw started out at .030 squish with a .020 base gasket. I took only 10 from the band, just enough to clean it up. I could have just replaced the base gasket with one .010 thick and left it there. I took 20 from the base to maintain stock gasket use.

No ports were touched on the saw. It came in at 175-180 psi and is one of the best running/revving 044's I've ever built. It has all the other mods of course-timing and muff mod.

Not sure if this saw would be considered "Ported", as no ports were touched at all.