MCCULLOCH The official McCulloch thread

[Sloa]

Outside doing bar maintenance and really looking at it outside of the basement. Looking at bar down groove you notice a thickness to the rails at a point. Further inspection shows a wallow. Will turning over bar correct or reverse the forces playing on it.
Rail and grooves look good all considering. Except for 3 inches 10 inches from the tail .Never played with a bar this long any thoughts on the wallow. Runs smooth by hand. So my brain says just mount bar wallow side up. As long as chain is not pinched. Widen if is.

 

[heimannm]

That frequently happens when someone does a lot of cutting in the same area of the bar. While it is possible to grind the rails and true it up, it isn't really necessary for an infrequently used bar.

If there is no hardfacing on the nose, just keep regrinding the groove and let the bar get shorter.



Mark

 

[JIMG]

Clean low hour 800 I just picked up.
Not necessarily the fastest but a pretty smooth old machine.
A little bulkier and WAY quieter than the 80.

 

[Squareground3691]

Clean low hour 800 I just picked up.
Not necessarily the fastest but a pretty smooth old machine.
A little bulkier and WAY quieter than the 80.

Get rid of that awful exhaust, and find a 850 exhaust if you can, to put on it , those 800 exhaust were a terrible design,

 

[heimannm]

It is ugly under the covers.







Mark

 

[heimannm]

I believe the bearings were made this way and I am pretty sure I have seen it before but would like some independent confirmation that those outer races are supposed to have that slit.





Mark

 

[Bigmac]

View attachment 426546

View attachment 426547

I believe the bearings were made this way and I am pretty sure I have seen it before but would like some independent confirmation that those outer races are supposed to have that slit.

View attachment 426551

View attachment 426552

Mark

Yes mark, those are factory bearings.

 

[jacob j.]

View attachment 426546

View attachment 426547

I believe the bearings were made this way and I am pretty sure I have seen it before but would like some independent confirmation that those outer races are supposed to have that slit.

View attachment 426551

View attachment 426552

Mark

Yes mark, those are factory bearings.

Yep and a great design too - low drag and made for high RPM...

 

[Bigmac]

Yep and a great design too - low drag and made for high RPM...

I agree it’s a good design in general, lots of support, with all the balls( make fun of that as you wish) but good load support!

It seems that the Outer races wear against the block surfaces at a higher rate than regular bearings!, Or these are just starting to get pretty old! Lol

 

[jacob j.]

I agree it’s a good design in general, lots of support, with all the balls( make fun of that as you wish) but good load support!

It seems that the Outer races wear against the block surfaces at a higher rate than regular bearings!, Or these are just starting to get pretty old! Lol

That's the downside - Because that race is split, at high speeds it actually spreads a tiny bit and puts more load on the pocket.

I've wondered if there's a way to get a similar designed bearing with a solid outer race. Of course, chainsaws aren't a target market
for higher-end materials science...

 

[heimannm]

"Full Compliment" bearing, no carrier or cage for the rolling elements.



Looks like I need to clean off the lens of my camera...getting a little hazy.

Mark

 

[JIMG]

Here's the 80.

Thanks, Mark, for all the bits and pieces. It's a fun ride.

 

[heimannm]

Bad news on the SP125C project...



...I'll put the pieces in a tote for now and see what comes down the road.

So, I have decided to go another route for a big saw and pulled these down from the attic of the garage. Two blocks are stamped 66251 which is consistent with the 797, one is stamped 940, and one 55581 (if I remember correctly). I will start with trying to get one complete, running 797 and see what develops after that.



Mark

 

[Shane¹]

Anyone know what model this is I think it might be a promac 650

 

[Shane¹]

Bad news on the SP125C project...

View attachment 426738

...I'll put the pieces in a tote for now and see what comes down the road.

So, I have decided to go another route for a big saw and pulled these down from the attic of the garage. Two blocks are stamped 66251 which is consistent with the 797, one is stamped 940, and one 55581 (if I remember correctly). I will start with trying to get one complete, running 797 and see what develops after that.

View attachment 426736

Mark

Maybe someone has a cylinder kicking around?

 

[heimannm]

600046 is a PM 650.

Mark

 

[jacob j.]

Maybe someone has a cylinder kicking around?

I've bought around 14 125C projects over the years and only one of them had a good cylinder in it.

The plating that Mac used for those just didn't stand up as well as more modern saw cylinders. It was
a great design and the "C" cylinders make good runners though.

 

[Bigmac]

I've bought around 14 125C projects over the years and only one of them had a good cylinder in it.

The plating that Mac used for those just didn't stand up as well as more modern saw cylinders. It was
a great design and the "C" cylinders make good runners though.

125c’s barnfinds make great kartsaw donners! My only decent 125c has a little corrosion around the exhaust port, but runs well..I dread the day the platting peals! I have heard the early c blocks had good plating and the later ones were more prone to peal. I haven’t seen a factory yellow painted 125c block. Do they exist?

 

[jacob j.]

125c’s barnfinds make great kartsaw donners! My only decent 125c has a little corrosion around the exhaust port, but runs well..I dread the day the platting peals! I have heard the early c blocks had good plating and the later ones were more prone to peal. I haven’t seen a factory yellow painted 125c block. Do they exist?

I've never seen a factory yellow "C" block but I've seen many factory yellow 105 blocks and I have one here. I have a freshly replated C block here that I'm thinking about painting flat black just to keep crud from building up on it. There was a company years ago that did Nitride coating in steel-sleeve blocks and I thought about trying that to get a sleeved bore to run like a chrome-bore. I never got around to it and the company went out of business. It would be sweet if we could get one of those early blocks with the good timing to run with a plated bore and a larger carburetor.

 

[JIMG]

Here is the initial result from replacing the 800 muffler with a simple square tubing L. It seems to have a little more go. A little sheet metal might end up necessary for replacing the directing of cooling air flow.