husqvarna 268 open port cyl vs 266xp cyl...

[SawTroll]

I have a January 1993 Husqvarna Forest and Garden catalogue with models 266xp and 268 non xp specs. Both saws have a cylinder displacement of 67cc and 4.1 cu. in. The engine horsepower on the 266xp is 4.5 HP and the 268 is 4.6HP. The 266xp max rpm's are 12,500 and the 268 max is 13,300. The 266xp weighs 13.5 pounds and the 268 weighs 13.6 pounds. The 266xp power to weight ratio is .54 and the 268 is .55.
The 272xp is 5.2HP and the power to weight ratio is .60

Look like there is a misprint there - the non-xp 268 was rated at 4.4 hp (3.2 kW), as was the earlier model 66 (same top end, like Spike said).

 

[tbarnhart]

Jonsered versions as well

Spike's pictures got me curious enough to go and take a look at my '88 model 670 Super. My cyl looks exactly like the larger transfer 268xp cylinder except for the intake differences. I know the J'red models were listed at 4.9 hp and mine surely runs well. Until I get something larger, it often ends up with the 30" and does quite well with it. If I can convince my friend to sell me his roasted 281xp, maybe the 670 could go back to 20" duty.

 

[SawTroll]

Spike's pictures got me curious enough to go and take a look at my '88 model 670 Super. My cyl looks exactly like the larger transfer 268xp cylinder except for the intake differences. I know the J'red models were listed at 4.9 hp and mine surely runs well. Until I get something larger, it often ends up with the 30" and does quite well with it. If I can convince my friend to sell me his roasted 281xp, maybe the 670 could go back to 20" duty.

The early 670s were listed at 3.3 kw/ 4.5 hp, the Super II/Champ at 3.6 kW/4.9 hp. I don't really know about the original Super.

 

[kmcinms]

My 266xp jug is a little different than that one in spike60s picture. Here is the 266 next to a 272xp jug.
266 has the manifold bolted to it.
View attachment 281278View attachment 281279View attachment 281280View attachment 281281

 

[husky01]

Yes, and both are 67cc btw!

What does ''btw'' mean, thanks

 

[SawTroll]

What does ''btw'' mean, thanks

By the way.

 

[almondgt]

Look like there is a misprint there - the non-xp 268 was rated at 4.4 hp (3.2 kW), as was the earlier model 66 (same top end, like Spike said).

The 268K power cutter/chop saw is rated at 4.4 HP in the 1993 reference I have on hand. Would make sense since the 268K wouldn't rev as high to create the HP of the 268 model chainsaw. On the other hand the 272K is rated at 5.2 HP which is the same specs as the 272xp chainsaw. Who's to say which specs are correct when Husqvarna prints their specs so recklessly.

 

[eat a peach]

Another question.............

If you were to do modding of an open port cylinder. Would it do anything to performance if you thinned the middle divider of the open port?
What exactly is the purpose of this divider? I assume it has to do with making the gas flow the best way.Could you mod it enough to make up for the power difference? Just trying to learn here fellas.otstir:

 

[eat a peach]

bump for knowledge :msp_thumbup:

 

[SawTroll]

If you were to do modding of an open port cylinder. Would it do anything to performance if you thinned the middle divider of the open port?
What exactly is the purpose of this divider? I assume it has to do with making the gas flow the best way.Could you mod it enough to make up for the power difference? Just trying to learn here fellas.otstir:

I am far from an expert, but thinning the divider will help some - it just isn't a full porting job. Keep in mind that there usually is little help in just thinning it at the ends, do it all the way. Also keep in mind that you want to direct the output at the top to the rear of the cylinder bore, when possible.

 

[Cantdog]

If you were to do modding of an open port cylinder. Would it do anything to performance if you thinned the middle divider of the open port?
What exactly is the purpose of this divider? I assume it has to do with making the gas flow the best way.Could you mod it enough to make up for the power difference? Just trying to learn here fellas.otstir:

It won't hurt but very little gains to be had in the transfers on the Gilardoni cyl....widening the exhaust and intake and setting the squish does make a difference. On the 61/268xp in my sig...I started out with the Gilardoni ported and it was a dramatic increase in power over the 61.....when I changed it out to a ported 268XP cyl there was another dramatic increase!! This is my go to saw with a 20" bar fully buried in hardwood it pulls very well.....

I am far from an expert, but thinning the divider will help some - it just isn't a full porting job. Keep in mind that there usually is little help in just thinning it at the ends, do it all the way. Also keep in mind that you want to direct the output at the top to the rear of the cylinder bore, when possible.

Good info Niko......

 

[eat a peach]

thanks guys