MCCULLOCH The official McCulloch thread

[Al Smith]

There's only about 3 classes I stand a chance in , 65- 75 and 90 plus .Two Stihl 038's followed by a west coast Husqvarna 2100CD .The Mac 805 is a good cutter but against Husky or Stihl it probably lacks some speed .

 

[farminkarman]

Good afternoon fellas. I have been doing machine work/ porting on non-clamshell saws for a while now, but now I'd like to venture into the mac world a bit. Any of you guys have or know who might have a scrap 10-10 cylinder? I am wanting to build a fixture for my lathe that will allow me to re-cut the bearing pockets and thus be able to do squish clearance modifications. I figured the 10-10 would be a good place to start since they were so plentiful, but am open to using something else.

 

[Steve]

Good afternoon fellas. I have been doing machine work/ porting on non-clamshell saws for a while now, but now I'd like to venture into the mac world a bit. Any of you guys have or know who might have a scrap 10-10 cylinder? I am wanting to build a fixture for my lathe that will allow me to re-cut the bearing pockets and thus be able to do squish clearance modifications. I figured the 10-10 would be a good place to start since they were so plentiful, but am open to using something else.

If no one here has one I think I have one. I'll check next week when I'm home.

 

[jacob j.]

Good afternoon fellas. I have been doing machine work/ porting on non-clamshell saws for a while now, but now I'd like to venture into the mac world a bit. Any of you guys have or know who might have a scrap 10-10 cylinder? I am wanting to build a fixture for my lathe that will allow me to re-cut the bearing pockets and thus be able to do squish clearance modifications. I figured the 10-10 would be a good place to start since they were so plentiful, but am open to using something else.

I've got some 10-10 stuff that I can look through too. I've also got some scrap 125 cylinders if you want to check some of those out along with other parts.

 

[farminkarman]

If no one here has one I think I have one. I'll check next week when I'm home.

I've got some 10-10 stuff that I can look through too. I've also got some scrap 125 cylinders if you want to check some of those out along with other parts.

I appreciate the offers guys. If I can prove out a concept for doing machine work on these things, I would love to be able to get setup to handle other sizes....which brings up a good point...I have no idea how many different cylinder base sizes Mcculloch used

 

[Steve]

I appreciate the offers guys. If I can prove out a concept for doing machine work on these things, I would love to be able to get setup to handle other sizes....which brings up a good point...I have no idea how many different cylinder base sizes Mcculloch used

As far as I know just two.

 

[heimannm]

In regards to the "clamshell" design McCulloch saws:

10 Series
600 Series
300 Series
Mini Mac
PM6
32/35/38cc mostly plastic Mac

The older large frame models (D-30/44 through the SP125) were not a clamshell design, more of a variation on the split crankcase.

The Titan/Italian McCulloch saws were removeable cylinders similar to most modern "professional" models.

The Jenn Feng era saws were a clamshell crankcase with removeable cylinders.

I don't have any experience with the current Husqvarna built McCulloch saws but I suspect they are a clamshell design like the modern Poulan saws since they're all coming from the same plant in Nashville, AR.

Mark

P.S. I could find a worn out 10 Series cylinder/crankcase for you if Steve and/or JJ are unable.

 

[heimannm]

Steve is correct in that the only two models probably worth the effort are the 10 Series and the large frame machines.

Mark

 

[heimannm]

On the other hand, Steve may have been referring to two size of the 10 Series crankcases, 54 and 57 cc versions with the smaller bore for the PTO side bearing, and the 60cc and up with the larger bore for the PTO bearing and insert (sleeve).

Mark

 

[farminkarman]

On the other hand, Steve may have been referring to two size of the 10 Series crankcases, 54 and 57 cc versions with the smaller bore for the PTO side bearing, and the 60cc and up with the larger bore for the PTO bearing and insert (sleeve).

Mark

Mark, do you think the recoil on the 10-series can handle a significant bump in compression without a decomp?

 

[Steve]

Steve is correct in that the only two models probably worth the effort are the 10 Series and the large frame machines.

Mark

On the other hand, Steve may have been referring to two size of the 10 Series crankcases, 54 and 57 cc versions with the smaller bore for the PTO side bearing, and the 60cc and up with the larger bore for the PTO bearing and insert (sleeve).

Mark

Yes, I was referring to the 10 series pto bearing pocket but you are correct in my opinion as there are really only two series of macs worth the trouble to move bearing pockets.

 

[Maintenance Chief]

Mark, do you think the recoil on the 10-series can handle a significant bump in compression without a decomp?

Its BEASTLY, overbuilt in my opinion. But Mark probably has seen any weaknesses if they exist.

 

[Dream]

Its BEASTLY, overbuilt in my opinion. But Mark probably has seen any weaknesses if they exist.

I'm agreeing with chief on this.
The recoil pulley shafts like a good cleaning and a little dry graphite to work smoothly, but they seem to be well built and VERY durable.

 

[Dream]

Yes, I was referring to the 10 series pto bearing pocket but you are correct in my opinion as there are really only two series of macs worth the trouble to move bearing pockets.

So someone correct me if needed, but ive been wondering this for a while now...
The 10 series that ive been in to all have a removeable rod.
ie, a two piece rod cap with rollers on the crank end.
If someone has access to a machine shop, why couldnt they mill out a billet connecting rod to correct the "squish" and get the compression up?
I realise port timing would be affected, but it is on "modern" saws when the cylinder is shortened and port timing is "ported" to compensate for this.
I guess my question is, are there more gains to be had from a shorter stroke or longer?

 

[farminkarman]

So someone correct me if needed, but ive been wondering this for a while now...
The 10 series that ive been in to all have a removeable rod.
ie, a two piece rod cap with rollers on the crank end.
If someone has access to a machine shop, why couldnt they mill out a billet connecting rod to correct the "squish" and get the compression up?
I realise port timing would be affected, but it is on "modern" saws when the cylinder is shortened and port timing is "ported" to compensate for this.
I guess my question is, are there more gains to be had from a shorter stroke or longer?

I think a custom billet rod for one of these things could get real expensive in a hurry, but probably not outside the realm of possible.

 

[Steve]

So someone correct me if needed, but ive been wondering this for a while now...
The 10 series that ive been in to all have a removeable rod.
ie, a two piece rod cap with rollers on the crank end.
If someone has access to a machine shop, why couldnt they mill out a billet connecting rod to correct the "squish" and get the compression up?
I realise port timing would be affected, but it is on "modern" saws when the cylinder is shortened and port timing is "ported" to compensate for this.
I guess my question is, are there more gains to be had from a shorter stroke or longer?

Like @farminkarman said, cost of a custom rod is a major drawback. Plus you still wouldn't get the full benefits of having the band in the cylinder cut parallel to the piston crown. Unless you cut the band, took your measurements, and then had the custom rod made. I feel there is a lot more room for error in the custom rod and way more work than needs to be to get the same result as cutting the base, squish band, and bearing pockets.

 

[Maintenance Chief]

1.375 -1.500
10-10 / 800
Rod length, I'm not sure if the bigger series rod would work for the 50cc motor?

 

[Al Smith]

I had thought at one time a reworked bearing pocket could be used although it would be a challenge to do it .There's a lot you could do to a 10 series to improve it but you have to think outside of the box .Firstly the muffler, bottom exit .Find the type with a curved bottom and a straight out the side . Not the square bottomed type with a turn up on the end with a screen .
The early models with a points ignition can have the timing advanced by opening up the points gap to maybe an additional 3 degrees but if you go too far they get hard to start .Fact they try to tear your arm off .
On the carb my fastest 10 series is a right hand start model 6-10 not a cinder block but an early 70 cc model the fore runner of the 7-10 and later 700 .The carb on that thing I threw together from parts of two or three carbs that quite frankly I did it so long ago I forgot weather it was a Walbro or a Tilley .At at any rate the choke assembly is much larger than the throttle so in effect at high rpm's it acts some what like a vee stack .Not bragging just fact this one will run at RPM's almost only those who had seen it would believe it .At several GTG's back in the day it would run neck and neck with a Husqvarna 372 .So yes it can be done but it takes a lot of tweeking .BTW it's a shelf queen these days because first it will blow your ears out and if I used it sooner or later it would fly apart like dollar watch .In other words it's just a big kids toy .

 

[Al Smith]

To the actual question of finding a 10-10 depending on where you are located there might be a bunch of them that have sat on a shelf for decades or in the dead pile of saws at a chainsaw dealer . I might have half a dozen they were all freebies .From real early models to one of the last ever made that looks brand new .Some are willing to pay top dollar for them or the parts to repair them however I am not one of them .I've played this game long enough I know some day they will just show up like stray cats .What others do is their business .

 

[heimannm]

I have seen several flywheel covers with the recoil start pillars broken off, JoeyMT has one from his PM850 that broke when trying to start it without the compression release. I'm sure a lot of that comes from technique (drop starting and jerking on the starter for example) but there are limits to what the recoil starter/flywheel housing can handle.

Mark