McCulloch Chain Saws

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Special Pre-Season North East Tennessee MAC Report

Rainy day in North East Tennessee Saturday. Most of the day spent cleaning the garage, I am about 40% done.

Between rains - last two on the site as I see heavy equipment being staged next door. It is a relief to have no more chest high falling to do.

A nice little white oak.
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Trees are like fish. They look bigger until you reel them in. I had earlier guessed this beech to be 42"; it is actually just a tad over 28" at the cut. It was my final tree.
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It extracted a little revenge - but no harm done.
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It continued the fight - little Deere ran out of traction and fuel at the same time.
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Victory in the end. Five nice firewood logs ready to be loaded plus the white oak.
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We will be back to the shooting range for a while. I moved the equipment up the hill tonight. I hope it will dry out enough to get the truck up the hill. If not, then there is going to be a lot of shuttling with the crawler and trailer.
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Be safe.

Ron
 
I may have taken a little longer than I guessed, but I finally got pics of the 640 cylinder: Staring at the upper left port, reed bypass port, 3 transfer, 3 exhaust, and 3 intake ports

6 transfer ports.

Here is a regular 87cc port with the third port open:

 
6 transfer ports.

Here is a regular 87cc port with the third port open:


So are the three left hand ports all fed by the "slot" next to the reeds? I'd never realized how many port configurations Mac had, the 1-43 had less than the 640, the 640 had less than the 1-50's, and I think the 1-50's had less than a Super 250?
 
Yes, they are the 'third port' outlets which are fed by the port that bypasses the reeds. Most 87cc saws are this configuration, including Super 250s. The larger front tanks saws like 450, 550 and s550 models are also like this.

From memory, 1-40 to 1-46 only have two of the three exhaust ports and 4 of the 6 transfer ports drilled.

Other 80cc saws like the 1-50, 1-51 and others have all exhaust and transfer ports drilled, but no 3rd port.

Not having the third port drilled isn't a bad thing if you want to port, because you can more easily 9 port or boost port them. Having only two of the exhaust ports drilled also allows you to add MC91 style exhaust ports.

I think of the third port being a good feature if your carburetor is a little small, or if you are using stock reeds; otherwise, a boost port is better.
 
I recently acquired an all yellow RH start 10-10 and I'm looking to do some upgrades to it to get a little more power squeezed out of it? What's the best route to go for that? Depending on prices I wouldn't be against sending it to someone to get it ported. With that being said though, I'm quite mechanically confident and have rebuilt other two stroke motors before on fourwheelers, just never chainsaws. Just looking to have a fun old vintage saw that sounds good and cuts decent to mess around with on my buddy's farm.
 
I recently acquired an all yellow RH start 10-10 and I'm looking to do some upgrades to it to get a little more power squeezed out of it? What's the best route to go for that? Depending on prices I wouldn't be against sending it to someone to get it ported. With that being said though, I'm quite mechanically confident and have rebuilt other two stroke motors before on fourwheelers, just never chainsaws. Just looking to have a fun old vintage saw that sounds good and cuts decent to mess around with on my buddy's farm.
A sharp chain and a quality bar are the best upgrades for a vintage saw ( in my opinion) .
Some of the ten series saws had a smaller venturi carb , moving to the larger carb may help?
The 10 series are a clamshell design so dropping the cylinder for higher compression really isn't an option without a quality machinist doing the work. Which also changes the timing of the ports obviously.
A few porters will work them over , but I've never seen one afterwards that really made me think it was worth the cost.
I personally like an upgrade to the electric ignition chip , seems like I get alittle more snap of throttle.
 
A sharp chain and a quality bar are the best upgrades for a vintage saw ( in my opinion) .
Some of the ten series saws had a smaller venturi carb , moving to the larger carb may help?
The 10 series are a clamshell design so dropping the cylinder for higher compression really isn't an option without a quality machinist doing the work. Which also changes the timing of the ports obviously.
A few porters will work them over , but I've never seen one afterwards that really made me think it was worth the cost.
I personally like an upgrade to the electric ignition chip , seems like I get alittle more snap of throttle.
I second the above statement, and advice. If you want something stronger than the 10-10 use the money you would put in the 10-10 to get a 7-10 or 700, maybe even an 82cc.
 
Is improving the muffler a viable option for these Macs? 🤔
Depends on the Mac. The chubby 82 mufflers yes. The 850 reed type cover isn't amazing. Needs bent open a bit or a 81 louvered style or homebred. The pancake 54cc mufflers are not fabulous but can open up the exit. It's still a big wall after the exhaust port.

There is subtle improvements to be had but basically a ducted muffler and the most open cover you can deal with is the best for power

The possibly loudest Mac I have is someone's homebrew 7-10 muffler. I'm reasonably sure the duct part is Mac but the box on the outside is homemade. It's slightly on the piss which I couldn't deal with if I made it and is a bugger to get a new chain on. All it has is some holes in it and I promptly put more holes in when I got it. Extremely loud and not sure but seems to make decent balls for a fixed jet saw.

I'm not against fixed jet but in smaller wood they are looseing a fair bit of speed. Once that 20 or 24 is buried there's sod all in it

20220916_200446.jpg
Pancake on the 57cc S thing 20220916_200539.jpg
Just what I had and seems to have plenty. I did remake the outer flap thingy a fair bit wider but yeah good sound level not atrocious.


Long story short no not really like a modern saw
 
Depends on the Mac. The chubby 82 mufflers yes. The 850 reed type cover isn't amazing. Needs bent open a bit or a 81 louvered style or homebred. The pancake 54cc mufflers are not fabulous but can open up the exit. It's still a big wall after the exhaust port.

There is subtle improvements to be had but basically a ducted muffler and the most open cover you can deal with is the best for power

The possibly loudest Mac I have is someone's homebrew 7-10 muffler. I'm reasonably sure the duct part is Mac but the box on the outside is homemade. It's slightly on the piss which I couldn't deal with if I made it and is a bugger to get a new chain on. All it has is some holes in it and I promptly put more holes in when I got it. Extremely loud and not sure but seems to make decent balls for a fixed jet saw.

I'm not against fixed jet but in smaller wood they are looseing a fair bit of speed. Once that 20 or 24 is buried there's sod all in it

View attachment 1017426
Pancake on the 57cc S thing View attachment 1017427
Just what I had and seems to have plenty. I did remake the outer flap thingy a fair bit wider but yeah good sound level not atrocious.


Long story short no not really like a modern saw
Funny thing my loudest saw is a 7-10 also. It however sports a NOS complete muffler I got off of Bob J a few years back. The muffler is stock, the seal at the exhaust port is leak free, and it will hurt your ears. Its an MMS for sure (Mandatory Muff Saw) lol.
 
The only mufflers on the 10 series i feel like need some work are the reed on the 700 and the reduction in size of the 800.
The reed type muffler has a tendency for the reed to shatter , being that its covering a hole that leads to the cylinder, I remove it to eliminate the possibility of a peice getting into the cylinder. Yes they are loud!
The 800 seemed to be a giant heat sink under the saw motor, I reduced the extension of the muffler under the saw.
 
I've told this story before, but just to add to the confusion...I have an SP70 that was rebuilt with NOS cylinder & piston and added a NOS reed type muffler to make it complete. I was rather disappointed in the performance of the saw, just did not sound like it was running hard. Then I ran is side by side with AWOL's 7-10 and Hedgerow's 372 (?) and it soundly spanked them both. Don't let the attenuated sound from the reed muffler make you believe the saw is working well.

Mark
 
There are a few universal truths among MACs, but the performance of every saw varies. Brian’s 800 in its original stock state was the strongest 82cc MAC, I have run. Note the unfortunate past tense. Rechromed and rebuilt it is every bit as strong as my best, but no longer noticeably stronger. Maybe a more conservative tune than before, IDK.

I can’t say that my duct muffler 800 will greatly outperform my stock muffler ones, but it sure sounds more powerful.

I’m in the displacement and sharp chain camps when it comes to MAC performance. McCulloch didn’t leave much improvement room on the table.

Ron
 
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