MCCULLOCH The official McCulloch thread

[Al Smith]

I have no idea about the actual porting on these things .For the time by the design it was nearly perfect .My only thought was one more ,actually a double boost port up above the transfers but I've never done it .Nearly center above the intake port .A finger so to speak and not the middle one .

 

[Dream]

Not much. It's a solid state ignition for one not as easy to bump the timing as an older points type .Start from the exhaust and work backwards .If it can't get out it can't get in is all I can say .

Timing advamce would be easy. Just file off some of the key, set it, and rattle the flywheel nut tight. Maybe 5 or 6 ugga-duggas.
Works on orange ones.

 

[Dream]

I'd be afraid of chipping the plating. Not the most robust of quality. I'm sure gains can be had but without an easy way to boost compression it may not be worth the time?

Now that you mention it, that might be an issue. Friend and I are trying to figure out whether that or bearings would let go first.
Maybe a 1010A would be a better candidate.
Cast iron bore. Plating wouldnt be a problem.

 

[Al Smith]

You can bump the timing a little bit with an offset key .Fact one of my Mac 125's came with one from northern California .Old redwood cutter I'd imagine .That one had an "Atom Arc " unit which failed but the points were still intact just not used . As far as setting the points wide you might get 3-4 degrees advance I figured the 6-10 to be near 30 advance but it's enough to make a difference .To gain much more you'd have to file the cam notch in the crankshaft because they won't close .No close no fire .I'm done with everything I'm ever going to do with that saw because it does good enough considering the age and design

 

[Maintenance Chief]

I have yet to see a ported pro mac 10-10 A with any verifiable proff that it would even come close to cutting faster or stronger then aleast 2 of the factory ones I have, I'm patiently waiting for someone to video a 10-10 that really impressed me after grinding on it.
Bellhopper does a very good job of making them cut , and he's still very conservative because no one wants to sacrifice the torque of a great saw.

 

[Al Smith]

Now as I've said I have a 10-10 S I think is the last year of production and it's cream puff because it didn't have much use .Complete except no brake handle which in the the first thing a tree trimmer did omit the brake .However spiffy it looks I have an earlier 10-10 that will out gun it .

 

[Dream]

I have yet to see a ported pro mac 10-10 A with any verifiable proff that it would even come close to cutting faster or stronger then aleast 2 of the factory ones I have, I'm patiently waiting for someone to video a 10-10 that really impressed me after grinding on it.
Bellhopper does a very good job of making them cut , and he's still very conservative because no one wants to sacrifice the torque of a great saw.

Thats the thing for me too.
I'd be pretty disappointed if it gained some speed but lost that grunt I'm used to.
The 1010A I have is pretty weak compared to my 1010S, but that could be worn out rings.
I literally brought that 1010A home from Dads, where he had it in the barn for a parts saw, cleaned and set the points, fueled it, and started it up.
The shop he got it from said it was a bad coil. They apparently didnt know or didnt want to pop the flywheel off.

 

[Maintenance Chief]

Thats the thing for me too.
I'd be pretty disappointed if it gained some speed but lost that grunt I'm used to.
The 1010A I have is pretty weak compared to my 1010S, but that could be worn out rings.
I literally brought that 1010A home from Dads, where he had it in the barn for a parts saw, cleaned and set the points, fueled it, and started it up.
The shop he got it from said it was a bad coil. They apparently didnt know or didnt want to pop the flywheel off.

I have found for me that switching from points to electric chip does give it a little more pep and I've done the same thing in my mopars for years.
Probably the biggest problem with porting a McCulloch 10 series is you can't adjust the squish, once you figure out how to get more fuel and air into the cylinder and speed it up you have to get it compressed enough for a really good charge, or else your wasting the heat energy.
If one of the major manufacturers like meteor would put out a pop up piston I'd buy half a dozen of them immediately.

 

[Dream]

I have found for me that switching from points to electric chip does give it a little more pep and I've done the same thing in my mopars for years.
Probably the biggest problem with porting a McCulloch 10 series is you can't adjust the squish, once you figure out how to get more fuel and air into the cylinder and speed it up you have to get it compressed enough for a really good charge, or else your wasting the heat energy.
If one of the major manufacturers like meteor would put out a pop up piston I'd buy half a dozen of them immediately.

Just wondering if anyone has had any success with swapping a different crank, rod, or piston to achieve better squish? The machine work could be done to cut bearing pockets deeper and then the clamshell base to follow.
Would the gains be worth the work, and would the risk of a bearing not taking the extra speed and pressure be too great?
Wish there was a way to get a stouter PTO side bearing and get the bearings out of the piston pin bores and into the little end of the rod.
I would feel better about giving one some juice if that last problem alone could be solved.

 

[Al Smith]

I've never done this but thought about it .From my perspective about the only thing I can see to do on a 10-10 is another small finger coming off the back segment of the transfer ports . It might act like a boost port or maybe not .The scheme of staggered multiple ports with a windowed piston was well thought out especially considering the time period .Bearings in the piston was not well thought out . I don't think McCulloch thought removable cylinders would be the design they wanted when designing this series of saws .So they are what they are and that's what you have to work with . Great thoughts ,many of them but until proven nothing but pipe dreams .Until then until such they remain a fairly reliable firewood saw that runs almost forever .

 

[PogoInTheWoods]

Would the gains be worth the work, and would the risk of a bearing not taking the extra speed and pressure be too great?

The easiest gains are made by just going to a larger displacement version of the same saw. The same basic crank and bearings don't seem to mind.

 

[Dream]

The easiest gains are made by just going to a larger displacement version of the same saw. The same basic crank and bearings don't seem to mind.

True. I think a PM700 crank is basically the same isnt it?

 

[Steve]

True. I think a PM700 crank is basically the same isnt it?

The bearings from 54cc all the way up to 82cc are the same from my experience. I'm sure you IPL Nazi's can prove me wrong though!


The pm700 crank is the same for any of the 10 series that use electronic ignition all except the 82cc. The 82cc is a different animal. The electronic crank does not have a points cam.

 

[Al Smith]

I've never done it but I'd imagine a points ignition crankshaft would work on a solid state ignition ..Some of the saw engines had a larger bearing on one side but I think the crankshaft would work ..I can't be saying it's Gospel if I haven't done it you know ..

 

[PogoInTheWoods]

The bearings from 54cc all the way up to 82cc are the same from my experience.

Others will have experienced two distinctly different bearings (and seals) being used on the flywheel side of 10 series saws.

I'm sure you IPL Nazi's can prove me wrong though!

No IPL's required in this particular case.

 

[Steve]

Others will have experienced two distinctly different bearings (and seals) being used on the flywheel side of 10 series saws.




No IPL's required in this particular case.

Yes, as have I and Brent, but as far as interchangeablity, they are the same load bearing. Obviously you have to use the correct seal with the correct bearing.

 

[PogoInTheWoods]

Just keepin' it real, bro.

 

[Maintenance Chief]

Doesn't one seal use a locating ring and one a clip? I'm not sure, but I think there was something about this.

 

[Steve]

Doesn't one seal use a locating ring and one a clip? I'm not sure, but I think there was something about this.

The flywheel bearing uses the clip on both styles. The groove locates the crank in the same spot with either bearing. The seal is press fit either in the crankcase bore or the extended race inner bore. Depending on the bearing/seal style used. The pto bearing and seal in the 54cc engines is just sandwiched by press fit in the crankcase bore. On the 57cc and up saws the pto bearing and seal is pressed into a sleeve that is sandwiched into the crankcase. The early sleeve uses a ring like the flywheel bearing to key it. The later uses a pin in the oil tank half and a hole in the bearing sleeve to key it.

 

[heimannm]

What he said ۩

67905 is the same bearing uses on the 600 Series saws and most of the 10-10 models. 63429 has the wider outer race that the seal presses in to.

Mark