262XP Day

[Landmark]

I'm still hoping for a updated video of previous saws, but using the same bar and chain. I havn't slept good since the 262 fell to the 562 in an unfair fight.

 

[M&Rtree]

I'm still hoping for a updated video of previous saws, but using the same bar and chain. I havn't slept good since the 262 fell to the 562 in an unfair fight.

262 was faster. I timed all the cuts and posted the numbers. Randy was joking about it losing.

 

[Landmark]

I got 12.5 seconds 262 and 12.6 562. 18 vs 20 bars?

16" on the 562......20" on the 262.

262 was faster. I timed all the cuts and posted the numbers. Randy was joking about it losing.

if the 262 won by .1 with a 20" b/c vs 562 16" b/c I still want to see a video of same b/c combo head to head. The 262 should obliterate it's younger competitor.

 

[M&Rtree]

I agree on the same bar video. 361 in the mix would be nice.

 

[skippysphins]

If this beats my 562 it will have to go . the 562 that is

 

[KenJax Tree]

I'll keep my 562's[emoji6]

 

[bryanr2]

 

[skippysphins]

Anyone have videos of there freshly worked saws

 

[Mattyo]

I'm taking video of my rebuild process ... I've got enough parts to put together 3 of them I think... eventually i'll have a bolt for bolt vid like my other vids.

I'm not cutting squish band on these, just cutting the chassis down to optimize squish while retaining a gasket. Anyone have some timing numbers I should be shooting for? I think MM said somewhere in the 103 deg for exhaust, but what about blowdown and intake? around 78 sound ok for intake? I may not touch the transfers at all. who knows

-Mattyo

 

[SawTroll]

if the 262 won by .1 with a 20" b/c vs 562 16" b/c I still want to see a video of same b/c combo head to head. The 262 should obliterate it's younger competitor.

It might still be misleading to an extent, as we don't know how close to optimal the work on the different saws are - and only one combination of gearing, bar, chain and wood won't tell the full truth anyway. Results will be different with other combinations....

Actually, there are no way at all to find the "final truth" - although it is very easy to get closer than was done here.

 

[Mattyo]

FINALLY am getting around to this saw. I cut the chassis down a bit so I can run a tighter squish and retain a gasket. I'm at .019 right now... timing numbers are 103, 125 and 68. Seems like I'd wanna tighten the blowdown a touch and take the intake to 78 or so... no? I'm not planning on touching the exhaust timing... maybe just do a little widening and shaping. thoughts?

 

[Mastermind]

Don't add too much intake........72 seems to work well on these saws. I'd take the uppers way up......to 118.

 

[Mattyo]

welcome back, hope the vaca was nice....

15 blowdown...gotcha... i'm surprised a little on the intake... okaly dokaley.... thats why I come here... pics to follow and eventually a bolt for bolt vid

 

[Mastermind]

Think of it like this......

The intake is a valve. Once it closes......pressure builds up. Until the transfers open. Keeping the intake short.....like the designers did, allows you to raise the transfers higher without losing case pressure. The early jugs only have about 12° of blowdown.

 

[Mattyo]

there are at least seven chainsaws in this pile

 

[Mattyo]

but doesn't a longer intake duration mean that there's more air fuel mix added

 

[Mastermind]

You can only fill the case.......you can't overfill it.

It's really about trapping what is inside.......so you can transfer it.

 

[redfin]

Don't add too much intake........72 seems to work well on these saws. I'd take the uppers way up......to 118.

Randy, I remember reading in another thread about raising the roof of the intake instead of the floor to gain duration. What's your take on this?

 

[Mattyo]

Ok...so let's say you fingerported it...does that mean you could have more intake duration or does that mean that you need more intake duration?

 

[Mastermind]

Randy, I remember reading in another thread about raising the roof of the intake instead of the floor to gain duration. What's your take on this?

I use that, and width to gain area. Remember, the porting on these engines is measured in Time/Area. If you keep the time short.....you need more area. You'll still be able to fill the case, but you can trap, and transfer more. Really what we are seeing is a more efficient engine. Less spitback, less fuel usage, same power, if not more.

Ok...so let's say you fingerported it...does that mean you could have more intake duration or does that mean that you need more intake duration?

I still use 72° on this saw. With or without fingers.

The more pressure you can build in the case.....the more aggressively the charge will be forced thru the transfers.