McLuvin’

[huskihl]

Back in September at my gtg, my buddy Cole leaves this saw http://opeforum.com/threads/mcculloch-10-10s-special-edition-no-sn-tag.14212/
here and says “Make it better”. It’s a pretty sweet Pro Mac 10-10s. Fast forward a few months and here we are. I thought I’d post a few pics along the way. This is the first Mac I’ve ever worked on, let alone tried to add horsepower to, so I thought it would’ve cool to get some thoughts and ideas flowing.

As received

 

[huskihl]

Took a few pics upon disassembly

Pretty good sized clutch for 54cc



Next is the spitback baffle. Seems a little restrictive. May be some gains to be had there




And finally with the carb removed. Just a normal clamshell type piston ported saw



Hands got oily and dirty real quick, so I didn’t get more pics of the disassembly process.
Here’s the exhaust side of the cylinder, along with the oil tank/crankcase assembly still attached

 

[huskihl]

Here’s the intake port with the impulse passage in the cylinder. On the oil tank, you can see the manual oiler bolted to the tank




Removable rod cap and rod bearings

Looks like it was sealed really well. No signs of a leak

 

[huskihl]

Open ports with decent swoop out and direction back toward the intake



Long oval intake is pretty wide already





Exhaust port with a bridge to keep the rings tucked in

 

[huskihl]

I ran it earlier and it’s kinda like a tractor. Not a pulling tractor, more like a Farmall Cub lol.

I was surprised at the stock port opening timing numbers. I expected a lower exhaust and transfers

E 100
T 120
I 60

Not much room to widen the exhaust, maybe a mm on one side and a half mm on the other. The intake is already quite wide. Can’t cut the cylinder for more compression.

After some thinking, I widened the exhaust to within 1.5mm of the skirt edge and thinned the bridge,





and lowered the intake floor opening to 68*. The carb is a walbro sdc and is quite huge for this size saw by today’s standards. I’m guessing that’s why it had such low intake duration

 

[huskihl]

.

 

[Backtroller]

You might need to get a sticker version of this

 

[heimannm]

Nice thing about Dirko HT is it cleans off pretty easily...

Mark

 

[Duane(Pa)]

What is the displacement of a Mac 10-10?

 

[Steve Billak]

54cc

 

[heimannm]

10-10S is 57 cc like the PM55, 555, and 570.

Mark

 

[beaglebriar]

Nice old saw. What's the game plan??

 

[huskyboy]

Nice thing about Dirko HT is it cleans off pretty easily...

Mark

I love dirko. Even used it to seal the rear diff of my truck. Lol

 

[huskihl]

Nice thing about Dirko HT is it cleans off pretty easily...

Mark

I wiped most of it off with my fingers. It had a really consistent thin coat over all the right surfaces

 

[huskihl]

Nice old saw. What's the game plan??

Originally, we just wanted to speed it up a little. But unless it really likes more intake duration and a timing advance, we might have to find a 4 barrel for it. There’s just not much meat left on the table. It’s really nice and smooth inside, but the muffler takes off on a 90* angle through a 3/4” square tube 3” long. That may well be the limiting factor

 

[Wolverine]

You get good with Macs and I might have to box up:

 

[beaglebriar]

Originally, we just wanted to speed it up a little. But unless it really likes more intake duration and a timing advance, we might have to find a 4 barrel for it. There’s just not much meat left on the table. It’s really nice and smooth inside, but the muffler takes off on a 90* angle through a 3/4” square tube 3” long. That may well be the limiting factor

Welded pop up or you could poke some holes where they don't belong and make the intake look like it has meth mouth.[emoji38]

 

[huskihl]

You get good with Macs and I might have to box up:
View attachment 211841

Send it out west. CJSaws

 

[fossil]

Took a few pics upon disassembly

Pretty good sized clutch for 54cc

Those clutches were used on most of the 10 series all the way up to the 82cc versions. Great units.

 

[Stump Shot]

Originally, we just wanted to speed it up a little. But unless it really likes more intake duration and a timing advance, we might have to find a 4 barrel for it. There’s just not much meat left on the table. It’s really nice and smooth inside, but the muffler takes off on a 90* angle through a 3/4” square tube 3” long. That may well be the limiting factor

Remember what we talked about last time...