262xp R&D

[trooney]

I started out my MM 262 at 14,200. I'm now running it at 13,900. It seems to be happier there.

 

[David Young]

Take a looks at the tunnels in the decomp vs. non decomp jug Dan.

Also, if the uppers are equal on both sides with a ring.

Most of the 262's I've seen do NOT have equal upper timing. Very odd. I wonder why they did that and I doubt it's a mistake. IIRC, the flywheel side has the indent on it and I believe that they set that transfer higher because it flowed slightly less.

Jug design is simply excellent for performance. The lowers are right up against the piston skirts. Huge tunnels compared to an 036 Stihl.

The intake tract sucks balls though. Even with the 87 carb, it ain't enough to feed this beast. We need to find another way. @Chainsaw Jim, any ideas on this?

At least for me, the 262 doesn't want to Rev. the fastest I've done so far was happy at 13,800 to be safe. A comparable Stihl 036 will piss rev 4 stroking 1000 rpm higher. I blame the intake tract fo this, I believe it's the limiting step.

The 242 has the same difference between transfers. Why would they go with the indent when they could have changed the contour of the flywheel. I love the reverse engineering of saws.

 

[malk315]

I started out my MM 262 at 14,200. I'm now running it at 13,900. It seems to be happier there.

Mine seems similar. I'd like to try 14200 and 13800 on the dyno and then stare at the graphs.

I gotta get together with Bill to try the new dyno setup. Too many things going on.

Sent from my XT1585 using Tapatalk

 

[Frank bierce]

Steppin in here to attempt to learn something
Looks like this will be a great thread!!

 

[trooney]

My stock 262 is better at 12,900 than at anything above that. The specs say 13.5k is the unloaded limit, but I agree, that really doesn't mean a thing in the real world, just a mark you shouldn't go over stock.

 

[Duane(Pa)]

I think everyone is always trying to get more unloaded Rpm, but it's really irrelevant unless it can maintain good rpm under load.
I'm beginning to find that tuned a little fat actually performs better working. And its better for the saw.

I tune fat a lot. I can find rpm in the cut with rakers and dog pressure. I come from the airplane world and power settings are largely based on fuel flow. My bottom ends are juicy and that keeps them from blowing up, so I can run the snot out of them. I get real chicken about a saw tuned lean. Too close to the edge for me. Did I mention airplanes?

 

[Mastermind]

I've never played with lean tunes more lately....and I've come to the same conclusion that I did several years ago. It takes fuel to make power.

 

[dustinwilt68]

I've never played with lean tunes more lately....and I've come to the same conclusion that I did several years ago. It takes fuel to make power.

My dad always told me"Son you have to pay to play", course we were talking about big block 440 motors but same rules aply I imagine, you have to feed the beast. Takes fuel to make power. That's why a Prius just isn't that sexy.

 

[Mark71gtx]

Ahhh, 440...

 

[dustinwilt68]

Yep got 8 of them in my barn, pm coming

 

[awol]

The 242 has the same difference between transfers. Why would they go with the indent when they could have changed the contour of the flywheel. I love the reverse engineering of saws.

I think the staggered trans opening has more to do with exciting a swirl scavenge than flow restiction. If you've ever noticed a 372/390 exhaust, its skewed to one side, and transfers are also staggered. It works pretty good to port with that in mind sometimes.

 

[jmssaws]

Take a looks at the tunnels in the decomp vs. non decomp jug Dan.

Also, if the uppers are equal on both sides with a ring.

Most of the 262's I've seen do NOT have equal upper timing. Very odd. I wonder why they did that and I doubt it's a mistake. IIRC, the flywheel side has the indent on it and I believe that they set that transfer higher because it flowed slightly less.

Jug design is simply excellent for performance. The lowers are right up against the piston skirts. Huge tunnels compared to an 036 Stihl.

The intake tract sucks balls though. Even with the 87 carb, it ain't enough to feed this beast. We need to find another way. @Chainsaw Jim, any ideas on this?

At least for me, the 262 doesn't want to Rev. the fastest I've done so far was happy at 13,800 to be safe. A comparable Stihl 036 will piss rev 4 stroking 1000 rpm higher. I blame the intake tract fo this, I believe it's the limiting step.

I stagger the uppers all the time.
There's something to it,maybe helps scavenging

 

[jmssaws]

I think everyone is always trying to get more unloaded Rpm, but it's really irrelevant unless it can maintain good rpm under load.
I'm beginning to find that tuned a little fat actually performs better working. And its better for the saw.

The farther away from optimum rpm the easier it is to bog back to optimum rpm
A saw that tunes over 15 but hold 10.5k in the wood is a slow saw.
It has to have fuel to make power,most every 1122 I port seems to be strongest around 14k they will go faster but not gain much more especially if the bar is very long.

 

[jmssaws]

I think the staggered trans opening has more to do with exciting a swirl scavenge than flow restiction. If you've ever noticed a 372/390 exhaust, its skewed to one side, and transfers are also staggered. It works pretty good to port with that in mind sometimes.

If you want to see some skewed ports put a 056 mag 11 cylinder on a 1122.
Every port is out of wack.

 

[exSW]

Yep got 8 of them in my barn, pm coming

Three,I feel so inadequate

 

[dustinwilt68]

Been saving them for years, looking at set of 440 source stealth heads, for my truck

 

[Mastermind]

I was most impressed with the 340......and a set of X heads.........yeah baby.

 

[dustinwilt68]

Yes the short stroke of the 340 is tough to beat. And the 2.02 valves in the x head is what makes the power for sure. I going with a 360 in my 68 cuda, maybe a stroker kit making it a 408. Glad there are some Mopar guys on here.

 

[Mastermind]

Yes the short stroke of the 340 is tough to beat. And the 2.02 valves in the x head is what makes the power for sure. I going with a 360 in my 68 cuda, maybe a stroker kit making it a 408. Glad there are some Mopar guys on here.

A friend of mine once told me that I was the reason 340s were so rare these days.

I campaigned one in a 69 Dart for several years.

Then I discovered the Fox body Mustang.......and stuffed it full of SBC. lol

 

[dustinwilt68]

Can't blame you there, much cheaper build for sure, you say mopar just double the budget compared to a sbc. And people think saw are expensive,lol. V8 motors cost way more.