McCulloch Chain Saws

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Whith that being said. Which one will move the most air? Would too many fins block it from having enough space between the fins to efficiently move air? Would a larger space between the fins give more room for air to flow, or would it have turbulence between the fins and case less air to flow? We may need a wind tunnel.

Brian
 
Some updates from the land that time forgot. My 1-62 is disassembled and awaiting my fixing the crack in the tank cover and buying a tank gasket before it should be a runner. My 10-10 has been returned to the bench and has received a RH start full wrap from @heimannm and is waiting for me to rustle up some hardware and drill out the clutch cover to install a new spike from @Goinwheelin. I'll try to get it installed tomorrow, but no promises. In the meantime, I'll give a report on the full wrap fitment and installation. The handle is tighter near the (not a) recoil housing, as was mentioned in Heimann's post, but I could still easily fit my hand in the space. The handle fit pretty well, but I had to use a screwdriver as a drift pin for the bottom holes. I didn't realize it hadn't fully sunk in the wrap cutout, but when it did it fit perfectly. The handle diameter seems a little small, but I'd have to use it to make a final judgment. Worst come to worst, I'd pull it off and put some wrap tubing on it. All in all, I love my West Coast-erized 10-10 and I highly recommend both the dog and the wrap and if I get another 10-series I'd definitely get a second of each for it.
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Come on NOW! YOU KNOW I WORK FOR THE STATE! No union in SC .
Anyway I waited for the yard to dry up for my other responsibilities and modified my muffler. 20200802_103253.jpg20200802_104740.jpg20200802_105855.jpg20200802_111356.jpg20200802_111428.jpg
A process of foldind and brazing will hopefully seal.20200802_120046.jpg20200802_123824.jpg
Quite a bit of difference in size now.
 

Ok so it doesn't sound too much different, but its a hell of alot cooler. When I was cutting yesterday in the same heat it was almost impossible to touch that starter housing. After modifying the muffler the saw feels cooler then my other macs ! I imagine an early style muffler as Ron suggested would have a similar effect.
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I can slip my hand underneath in there and feel it pushing alot air now.
Im still running it alittle rich on 40:1 for a while after the rebuild with used parts.
 
MS, good job.

They say great minds think alike. Do you think they sometimes think in reverse? Last night and today, I was mulling over sawing the backside off the muffler versus cutting off both front and back. Either way would require a fan shroud. I was bemoaning the fact that I can't weld or braze - shoot I can't even solder - so I just check in here and what do I find -your handy work!

I am also mentally exploring a different route altogether. Have you followed the flow in the 800 muffler? Some of the exhaust is directed to the side given the shape of the exhaust port. It is then bounced around in the can only to flow 90* straight up just to hit a flat surface to be directed 90* back where it hits a divider to disperse it around the screen. My thoughts were to outlet out the front or front clutch side. I fell back to the front as a first try - but alas without nuts and bolts I can't put two pieces of metal together.

Ron
 
MS, good job.

They say great minds think alike. Do you think they sometimes think in reverse? Last night and today, I was mulling over sawing the backside off the muffler versus cutting off both front and back. Either way would require a fan shroud. I was bemoaning the fact that I can't weld or braze - shoot I can't even solder - so I just check in here and what do I find -your handy work!

I am also mentally exploring a different route altogether. Have you followed the flow in the 800 muffler? Some of the exhaust is directed to the side given the shape of the exhaust port. It is then bounced around in the can only to flow 90* straight up just to hit a flat surface to be directed 90* back where it hits a divider to disperse it around the screen. My thoughts were to outlet out the front or front clutch side. I fell back to the front as a first try - but alas without nuts and bolts I can't put two pieces of metal together.

Ron
Well honestly I don't know if brazing is anything more than melting a stick on a crack? I know from soldiering that you want to draw material to the joint with heat but brass doesn't flow like that when your in a woodshed with a map gas torch.
I'm an idiot's idiot should have seen me, 90° had the fan turned off using a blow torch this morning! The "Real" supervisor came around the corner and she gently asked if I was drinking enough water?
The flow of exhaust through just about any of the Mac mufflers is pretty bad with all the close bends , if I was gonna start from scratch with this I'd put two pipes with long sweeping bends .
 
I am debating two sweeping pipes versus a sweeping wide duct that terminates with one or two pipes, but I come back to my lack of skills to make it a reality. You should have seen me today just tinning wire ends to repair my jig saw. Sad sad sad.

Ron
 
I am debating two sweeping pipes versus a sweeping wide duct that terminates with one or two pipes, but I come back to my lack of skills to make it a reality. You should have seen me today just tinning wire ends to repair my jig saw. Sad sad sad.

Ron
Hows Brian at that stuff? Maybe you could bribe him with something?
Well theoretically any configuration of " mandrel" bends are better for flow then sharp angles. The length of pipe would probably effect power curve.
McCulloch did get the exhaust outlet placement correct though, opposite the intake .
The only benefit of the huge muffler I could think of is that it's volume is close to the volume of the cylinder so the cylinder could dump exhuast equivalent of the engine into the muffler and recharge the cylinder but having the sharp angles kind of negates the efficiency of it.
 
I bought some low temperature brazing rod from McMaster Carr, works well on thin material like the bar plates or inner shields on the 10 Series SP and 600 Series with the yellow Mapp cylinders. Anything much thicker would likely require oxy-acetylene.

I added some things to the displays in the museum.

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I have a few more H&S spikes but I've misplaced a couple including one that fits the large frame gear drive saws. If I accidentally sold it to one of you please remind me so I don't myself batty trying to find it.

Mark
 
Well, the dog is installed and it looks great! The hardest part was finding and shortening the required 3/8 mounting bolts.
P.S. I included a pic of the gap between a Husky 61’s handle and recoil side by side with the Mac to show how similar the gap is. I know the 61 is kicked a little to one side but the gap is pretty much the same.
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SP 40 is all back together, just have to try to starting it. I would hope it runs, spark is hot and carb was completely gone through, 150psi compression.

Next project is most likely fixing the carb on my Mini Mac 25.
 

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