McCulloch SE2012s (MAC3200) A/V Conversion

[Chris-PA]

I picked up this SE2012s (MAC3200) a few years ago as a lark, because it was cheap and matched my SE3420 McCinderblock:


It was in great shape and after some fuel line work I found it ran great. It was made in 1994, and I liked the way it was designed. It has a horizontal engine, which is essentially a clamshell, but the bar studs mount to the lower cap (not my picture):

I like the way the tab cast into the housing fits into the bar slot:

I was impressed enough to do a muffler mod - the baffles got extra holes:

There were only two of these holes to start with:


A bunch of extra outlet holes:

Then it ran so well I bought a spike for it:

With 32cc and a 12" bar it's got plenty of grunt and it's nice and light - but without A/V I never used it. I ran two tanks through it in a row once, and cut a lot of wood too, but my hands were numb for hours.

So I've kept my eyes open for an A/V version of this saw, but they always went for more than I was willing to pay, and I was always involved in other projects. However, I finally got a powerhead for $22 shipped, and all my other saws are working. It's actually a 38cc, and for all I know the engine is fine, but I have plenty of 38-42cc saws and I plan to keep this one at 32cc. Now I just have to wait for it to arrive!

 

[Chris-PA]

So while I was waiting I figured I'd tear it down. I had no intention of opening the engine up, but I found it was carboned up so bad I though the cylinder would not last long - so apart it came!

No weenie con rod here!

In the pictures above you can see the intake is located 90deg from the exhaust, so the porting is rotated in the cylinder. However, note the quad transfers:

Intake port (the bore is chromed):

Exhaust port:

That exhaust port looked pretty big to me, so I measured it - it's at 60% of the bore, and the top edge is quite flat! Now I was curious, so after cleaning it up and putting it back together (I didn't intend this to be a porting job), I checked the timing:

The squish is at 0.040", but that seems to be pretty typical for homeowner saws. The combustion chamber is compact, and the step around the outside is pretty shallow.

So overall, it's got quad transfers, even if they are open ones, a big exhaust port with good duration, a blowdown angle that's spot on - and a completely pathetic intake duration?

I'm not sure what they were after there! The intake port is wide enough, and the carb is a 28/64" WT (I replaced the stock ZAMA C1Q which was the same size). The saw does run pretty well this way, so I'm now debating if I want to pull it apart and cut the edge of the piston a little bit. There is a bit more case volume than in some of my Poulan clamshells, so a longer case compression angle is OK - but that seems extreme.

I've got a few days to decide!

 

[.404]

I must say your grammar, spelling and punctuation is swell.

*

No weenie con rod here!

Well one fragment is acceptable.

 

[Chris-PA]

Well clearly there's not much interest in a tiny old McCulloch, but I'll finish documenting this project anyway as it will be my last for a while. This was the last of my saws that needed attention to be useful, and I don't actually want more of them.

Anyway, the parts saw arrived yesterday and both the chassis parts and the engine were in good shape. So since I have a good spare 38cc engine I decided to modify the intake timing on this one. I pulled it apart and cut a notch in the piston skirt at the intake:

Here is a shot down the intake with the modified piston installed:

Here's the stock exhaust port:

The timing worked out just as I wanted:


I'm hoping to put it together tomorrow, but I have to do rear wheel bearings on my Daughter's car first. Hopefully that will go quickly and I'll have time to work on the saw.

There's not much to these:

 

[Chris-PA]

New fuel lines:

New A/V case parts:

This attachment on the top of the cylinder is not used on the A/V case:







It fired up and ran nice, but I did not have time to cut with it. Hopefully tomorrow. It certainly felt smoother!

 

[Chris-PA]

Here it is cutting some very hard white ash that has been dead for at least 3 years. It sounds like bowling pins when you split it.

The A/V system worked well. I'm sure it's gained a bit of weight, but the saw is useable now.



And that's going to be it for saws mods for a while, as I'm happy with the way my saws work now. I need to spend more time using them rather than modifying them!

 

[sawfun]

Good job, some of those little homeowner saws are more that a lot of folks give them credit for.

 

[heimannm]

One day I will have to get an SE2012 to go with my SE3420. Might as well have the full set. Thanks for the photos.

Mark

 

[sawfun]

I would like a Mac 5020 and to get it ported. It would be fun to run against a healthy 10-10.

 

[Chris-PA]

I would like a Mac 5020 and to get it ported. It would be fun to run against a healthy 10-10.

OK, I have to admit I'm unfamiliar with that model. Can you point me to some info on it?

 

[sawfun]

Maybe its a 2050, but they no longer manufacture them. I believe they had issues and stopped a year ago or so.

 

[Chris-PA]

Maybe its a 2050, but they no longer manufacture them. I believe they had issues and stopped a year ago or so.

Oh, I know which ones you mean now! Based on the styling cues I believe they were designed around the same time as these saws, although they are totally different mechanically. I was interested in a 55cc version at one time, as I suspect the engines can put out quite good power - it is a 3-piece clamshell.

 

[Chris-PA]

BTW, I checked the timing of the 38cc engine before I put it away - the intake on it is also 136deg duration. They run pretty well that way, and taking it out to 151 did not make all that big of an improvement (it was noticeable, but not incredible). I tend to think the engineers who designed these engines knew what they were doing, and it just goes to show that each engine is unique. You cannot just apply set port timing number and have the same results.

 

[walterg]

I still have my MAC3200. Ive had mine sense new. Fired it up last year. Looks like it will need a carb kit.
Did you see the NOS MAC3216 on eBay.

 

[Chris-PA]

I still have my MAC3200. Ive had mine sense new. Fired it up last year. Looks like it will need a carb kit.
Did you see the NOS MAC3216 on eBay.

LOL - $500!!!! It's cool, but it's a common non-A/V saw that simply not worth much no matter what. I'd like to have the case though!

I ran mine today a bit, and I'm happy with the performance given it's 32cc. I may have to weigh it though - it's not really much different than the GZ4000 I had out today too. I don't care though, I like running it. Contrary to what some seem to think it's a sturdy and well made saw, and not hard to work on either. Just too much vibration without A/V.

 

[Chris-PA]

I've noticed that the later saws had an extra shroud that deflects the air down along the outside of the cylinder and towards the ground (like the exhaust outlet). Neither of my engines had that (1994 & 1995), nor the boss to mount one.

I wonder if they were to improve cooling or to try to prevent problems with the exhaust outlet so close to the ground?

 

[walterg]

I believe the 3200 is listed at 10.1 lbs pho.
I liked using mine back in the day.
Thought it was a decent saw .
I haven't used a non AV saw in awhile tho.

 

[Chris-PA]

I haven't used a non AV saw in awhile tho.

It didn't bother me back when I used my Craftsman/Poulan (basically a Wild Thing in gray), but now I just can't tolerate the vibrations for any length of time.

 

[walterg]

Didn't bother me back then either.
After I get my 3200 done.
Don't have a Wild Thing. But,
Next on the list is my Poulan Wood Shark.

 

[walterg]

Found my owners manual to my 3200. Its got 1995 printed on it.