Advice: building 268/272 from parts

[Keaton85]

My father-in-law has lots of chainsaw carcasses in the basement, which of those, I found a couple 268s and I think a 61.

There are a few cylinders laying around but I would like to go with a 272 top end, which I did order a farmertec P&C with caber rings. I know, not great, but I already had an order in for other parts and they were cheap to try out.

My thoughts:
272 top end
new crank seals (are hyway lip seals ok? or is genuine the only way to go?)
Port and derestrict exhaust
.020 squash setting

Anything else that should be inspected on these saws?
What are some other mods that can be done? and are there difference carbs to "look out for"
Are there any Jonsered parts that interchange with these?

 

[Redstar409]

I just finished converting a 61 to a 272 with a Farmertec P/C that I ordered 6 months ago to see what a Huztl P/C was like. All of my other saws are OEM, so this was a first. The good news was that the cylinder, for some reason, looked like it was made by Tecomec. It had black finish, made in Italy and the Tecomec logo were cast into it. The exhaust port was at a weird angle and required a fair amount of porting to correct. The rest of the cylinder looked good. Either a Tecomec "second" or who knows.
The piston had about a quarter of an inch of "float" for the connecting rod and is not usable IMHO. The circlips were also unacceptable - a paper clip would have more spring tension. A Meteor piston corrected these two problems. Squish, sans gasket, with the Meteor piston was .025.
I tried some NWP AM seals on a 288 and they bulged excessively after installation. It could have been a fluke, but I went back to OEM seals only.
The 268 carb and intake should be the same as the 272. The 61 carb and intake are for the smaller displacement model.
Use the 268 case for the 272 conversion. The 61 has different iterations (i.e. tops, bolt spacing, ignitions, muffler clearance) that can really complicate this upgrade. The 268 should be plug and play with the 272 P/C. If you have a good 268xp OEM cylinder, I would use that over any AM P/C.

 

[Cantdog]

My father-in-law has lots of chainsaw carcasses in the basement, which of those, I found a couple 268s and I think a 61.

There are a few cylinders laying around but I would like to go with a 272 top end, which I did order a farmertec P&C with caber rings. I know, not great, but I already had an order in for other parts and they were cheap to try out.

My thoughts:
272 top end
new crank seals (are hyway lip seals ok? or is genuine the only way to go?)
Port and derestrict exhaust
.020 squash setting

Anything else that should be inspected on these saws?
What are some other mods that can be done? and are there difference carbs to "look out for"
Are there any Jonsered parts that interchange with these?

I always go with OEM seals when available which these are. The pto side seal is installed in the oil pump housing....this is o-ringed to the case so you also need to replace this o-ring... these are special and must be had from OEM as well.

260 A is the best carb to use....

Jonsered is very interchangeable depending on what you need and what you have...

 

[Stihlmar]

https://www.arboristsite.com/community/threads/61-to-272-parts-kit.313942/

A lot of info and helpful people on this one. I did it and am happy with results. I have been trying my hand at alittle port work so I would ignore that but the rest was all dead on.

 

[Keaton85]

Thanks guys! I will note the above info and take a look at the builds.

cantdog: I just bought land in Camden, thus collecting a few saws for clearing and possibly milling later down the road.

 

[Cantdog]

Thanks guys! I will note the above info and take a look at the builds.

cantdog: I just bought land in Camden, thus collecting a few saws for clearing and possibly milling later down the road.

Sweet!!......Was down there Saturday Xmas shopping with the bride.

 

[svk]

There are a couple more threads by spike60 and briantutt that go over this in detail. You need a 272 cover and if your donor case is older there will be two top cover mounting screws that do not line up. You can drill and tap new holes which is what we did on mine.

If you go the route of the 272, I'd suggest an OEM jug. The China jug I had didn't make as much power.

Great saws and parts are relatively easy to find and are normally reasonably priced.

 

[Keaton85]

Thanks, if I find the Farmertec cylinder to be poor I will go with a genuine 268 or Jonsered cylinder with new piston and rings. I wont be using it all that much, just building it for fun and to have a little larger saw over an 026.

 

[svk]

I think Farmertec may be the exception to the rule when it comes to cheap parts. The one on my 350 runs great.

 

[Griffdog1]

I cannot see why you would not use a genuine Mahle cylinder against the farmertec if you had the choice. Hold the two side by side and the difference is pretty clear. If all you can get your hands on is the farmertec then they are fine but 272 kit will not run as nicely as a 268xp with a meteor piston. If you have the parts a good combo is the closed port 268 cylinder with the later style airbox air filter (uses the same filter as the 262 in its own "airbox"). As has been said, matching the carb up is important as there were a number of options available over the life of this series of saw. Also use a set of cases that take the single piece ignition and the later top cover if you have a choice.

 

[Keaton85]

I will go for the 268 cylinder if there are any usable ones in the stash, or see if a jonsered P&C will work with the parts available.

 

[Keaton85]

Update:
Stripped down the parts saws and one is actually a 272 cut off saw. All crank bearings were pretty shot but cranks look good. What’s the lifespan of these cranks?

I am replacing the main bearings, seals and top end with the stock 272 or a very nice made in Italy farmtec.

What else should be added to the list for common parts to go bad? I have a lot of carbs that are known.

 

[svk]

I think you pretty much have it. Maybe throw in a carb kit?

Cranks are usually good unless there’s excessive up and down play on the rod bearing. Side to side doesn’t matter.

 

[Keaton85]

All good with up and down play on both cranks. I will post a few photos when I get a chance.

There are a few Jonsered cylinders laying around that look identical to the huskys, just with a different carb mount, can those be used by chance?

 

[svk]

All good with up and down play on both cranks. I will post a few photos when I get a chance.

There are a few Jonsered cylinders laying around that look identical to the huskys, just with a different carb mount, can those be used by chance?

They will work. I think plug angle may be different. Spike and HTSS have a very good YouTube on the different cylinders.

 

[Cantdog]

The plug angle will only be an issue putting a Husky cyl under Jred top covers. The plug angle is steeper/taller on the Husky cyls and the Jred is flatter/lower. However this too can be over come buy using a later 670 Super II or Champ air filter cover as it allows more room for the plug than the 625 or 630 covers.

This pic is shows the various plug angles you might find......left is a 52MM 272XP middle is 48MM 630 (same height and angle as 670) and the far right is a 268 XP Cyl.

Now a thing of particular interest is the transfer bulges.......note that the 272 and 630 cyls are just cast......but the 268XP cyl has had clearance machining done to clear the flywheel....the 670 has the same machining done.......this is factory and leads me to believe the 268XP and 670 cyls are the best flowing cyls before porting. Likely the 272 makes it's power more from displacement than advanced transfer porting.