Low Profile on a 24 or 28" Bar?? Newly Ported Husky 55 Saw.

[777funk]

I just finished up work on a Husqvarna 55 Open Port. It came to me with a china cylinder and piston and when I measured squish, it was bigger than 0.062" solder. I think it was probably 70 or 80 thou. The saw could be stalled easily with the 20" 3/8 (regular) that it came with. I decided to try to get it closer to Husky specs and brought squish down to 0.020", widened the exhaust 0.040" on each side. I gave it a little more intake (78 degrees) by removing about 0.040" off the intake side of the piston skirt (matched the intake port). I beveled the piston slightly at the exhaust to get (104) and raised the transfers up. That was the one area I missed slightly. I was going for 122 transfer and ended up at 118 or 119.

The end result is a saw that I can't stop unless I really muscle it while dogged in. It's so much better than how it came. I decided to muffler mod it also (gutted the baffles inside) which improved it even a hair more and advanced the timing 5 or 6 degrees. I'm not sure I noticed much difference on spark timing. Need to tweak a little more back and forth. I'm thinking the biggest difference was sqish and getting the port timing more normal.

That got me to wondering, can I throw LP 3/8" chain on it and go to a bigger bar size for the occasional bigger work? 20" regular 3/8 0.050" is no problem for this saw. I figure I can go a little bigger with the Low Pro. Am I thinking correctly or would this just break something? Lets assume the bar and sprocket are rigged to work with the LP.

 

[singinwoodwackr]

LP is pretty weak for the added power and may be prone to breakage. But, folks, including chainsaw mill guys use it, so
Make up a couple loops and try it. The chain does usually need specific rims/sprockets and bar tips. I’ve thrown on on a regular 3/8 bar to see how it worked and it seems to. But…just be aware it may not work

 

[J D]

If you go longer than 20" you'll need to do something to get enough oil for the longer bar.
Breaking chains shouldn't be a concern if they're decent, sufficiently oiled, & run on the correct sprockets/spur.
The additional stress a longer bar will put on the bar mounts is also something to consider.

 

[Franny K]

The Stihl 63 picco version of 3/8lp has larger diameter bushings and more massive tie straps I would use that, Oregon stuff says 42cc tops if I recall correctly.

What is wrong with just skip in the larger 3/8. I would expect chip kind of clogging up in the low space under the cutting top plate.

Longer than 20 inches/ 72 drive links in 3/8 hard nose bars seem to be 0,063" and large nose radius and large mount so if you do it post back how you rigged up the bar and sprocket. As mentioned above milling guys do it somehow.

 

[NSEric]

I'd go with skip tooth full size 3/8 if you want to run a 24.
You can mod a large mount husky bar to fit, if you have one. Slot the oiler and tensioner holes until they line up, then make little rings around the bar studs to get rid of the up/down slop. Do the oiler hole on a 45 degree angle towards the back.
You could also buy a small mount 24 inch bar for a 460 rancher.
3/8 lp bars over 18 inch are expensive and hard to get.