XP 268 - 272 practical differences

[Wombat Ranger]

I've read a bunch of old threads addressing this. Mostly I get the same picture from them, don't tear down a good 268XP for a 272XP top end. Understood.

I am rebuilding an all original and very worn out 268XP-W, bottom end split, might need a crank, yadda yadda. The cylinder is in usable shape, and I also have a good used 272 top end available. And my main bucking/all-purpose saw that I usually grab for most anything around the homestead is a 300th Anniversary 61 that is in pretty nice shape, which of course could use a quick & dirty top swap. I also have a strong engine'd but beat to death 268XP (SE, non-W) for parts, meaning donor carb intake etc to do up the 61.

Between the 268XP & 272XP top ends, which is a better choice for a falling saw with 24-28" bar, and which is a better choice for a mainly bucking saw wearing a 20" bar? I've never run a 272xp to know how they run. I tend to think of an ideal bucking saw as a high rpm screamer, where a falling saw needs to be happy being loaded pulling down to some lower rpms. In all honesty either cylinder would probably make me real happy in the 61, so lets focus on making a mean middleweight falling saw out of the 268XPW? Moderate/woods porting would be the dream on either/both cylinders but I don't really want to ship the whole saw/s somewhere. One last little detail is I refuse to cut up the top on either saw, yes that means the small 61/266 style filter on the grey top.




Thanks!

 

[HumBurner]

I tend to think of an ideal bucking saw as a high rpm screamer, where a falling saw needs to be happy being loaded pulling down to some lower rpms.

View attachment 993994


Thanks!

I think of it slightly differently. When falling, especially if doing stuff on the more dangerous side, you would want RPMs. The faster the chain can sever wood the safer you are.

That's not to say chain speed can't be useful when bucking smaller sized wood. But when you get into wood over 16-18", power takes over for how quickly you can get through a round. Especially in bigger wood or fully buried. Then there's changing sprocket tooth count. Chain type. Other factors.

 

[Cantdog]

Chain speed for either the 268Xp and 272Xp will be for all intents and purposes will be identical until you get over 24" bar length using the same type of chain. The 272 simply has more grunt to run a bit more bar but is not any faster than the 268XP rpm wise....

 

[Wombat Ranger]

272 is all around stronger then, not just peaky? I seem to have read that somewhere.

 

[Sepia]

Will a 268XP cylinder fit under a gray top? I'm thinking it won't, but my memory is fuzzy on that. A 266SE cylinder is the same bore and would fit.

 

[Wombat Ranger]

Grey top is same as 266 top, far as I understand. If it won't fit - I won't do it. I was under the impression it's the earlier 61 tops with not enough space.

 

[Cantdog]

Yes the 268 or 272 cyl will fit under a 61 gray top. In the first pic on the left is a 272 cyl, middle is a 630 Jonsered cyl and on the right 268XP cyl. As you can see the 272 and 268 cyls are axactly the same size and hieght. The 630 is also but note the plug angle difference....this is why the Husky clys don't fitt under the Jonsered covers even though they bolt to the cases fine.

Second pic is of one of my gray top 61s with a 268XP cyl installed.

 

[Cantdog]

One other thing to notice between the 272XP cyl and the 268XP cyl is the transfer bulges. Notice on the 268 cyl (on the right) that the transfres are milled out to allow the flywheel to pass by......also the cooling fin at the top of the transfer on the 272 cyl extends all the way to the back of the transfer bulge but on the 268 it peters out mid way through the bulge. The 268 actually has larger interior (and exterior) transfers than the 272Xp cyl.....all three of these cyls are OEM Mahle clys.

 

[briantutt]

You might read through this. I think I like the 372 but really only because it looks a little meaner. They are very similar. Form memory the bolt pattern on the top covers has two variants (which means the top of the two case halves has a different bolt pattern). Other than that I think you can interchange almost every part once outside the cylinder.

https://www.arboristsite.com/threads/husqvarna-162-2x-266-268-frankensaw-project.286153/

 

[Cantdog]

That was a good thread Brian......took me a bit of reading to remember most of it!!

On more thing I will advise concerning these saws is that when putting a 268 or 272 topp end on a gray top 61 you will need to stick with the original 61 or a late 266 muffler as after the case change to the single piece ign the cover got taller as did the mufflers. Running a late style 268/272 muffler on a gray top 61 or 266 will soon melt the top cover as there is not enough clearance for the necessary air flow between the top of the muffler and bottom of the cover.......though it will all bolt up fine.

 

[briantutt]

light bulb dings! Yes the mufflers are definitely different, I actually melted one cover because I didn't notice it being too close. Great point. They will interchange but the gap is basically zero if you match the wrong combo.

 

[Wombat Ranger]

Thanks for the muffler tidbit. I had intended on using the good condition 61 muffler. My parts 268 has a dented muffler which deflected the side/top enough to melt the top cover a bit. So I am familiar with exactly what you are talking about.

I'll read that thread. Thanks for the info fellas.

 

[briantutt]

Side note the 3 saws from the Frankensaw project are my favorites to run! Cool to have saws so old run so great.