MCCULLOCH The official McCulloch thread

[Dream]

I'm about to take my part of history out and buck some cedar and red oak. I love history, especially when its loud and makes chips fly!

 

[WillG]

A bit more progress on the 1-50 tonight. Fuel tank flushed, new fuel lines and filter installed, and the carb went for a 2 hour swim in the ultrasonic cleaner. Will reassemble the carb tomorrow afternoon and then I will see if she's going to run!

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[heimannm]

There were both 10-10S and 10-10S Special Edition models.





Both models were 57 cc as opposed to the conventional 10-10 models at 54cc. The piston and cylinder were the same bore and stroke the PM55, PM555 and PM570; the PM55 was points ignition and the PM555 electronic ignition, and the PM570 was an anti-vibe electronic ignition version. The PM555 and the 10-10S/SE were essentially the same saw.

McCulloch had a very good marketing department.

Mark

 

[Al Smith]

Good looking macs Al.

Thank you .Actually I've been very lucky finding pristine examples that for various reasons didn't get much use . They all run great but although they get some exercise are mostly shelf queens .

 

[birdmeter]

man i would like to get a big
MCCULLOCH
one of these days.

 

[Frank bierce]

Got some of the Mac’s together today

 

[PogoInTheWoods]

Nice little herd right there.

 

[Bigmac]

Made a few cuts today to help break in the rings

 

[WillG]

The McCulloch 1-50 is ALIVE!! One loud mother!!

Just need to repair the fuel leaks (which I'm hoping will be simple fixes) put a bar and chain on it and get it tuned in some big wood!!

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[Heavy]

I have noticed that a system by points and condenser has the same maximum rpm as an electronic system if both are based on the same time

 

[Bigmac]

I have noticed that a system by points and condenser has the same maximum rpm as an electronic system if both are based on the same time

Yes, I don’t believe points ignition are a limiter for rpm, it was the engine design. Apparently the points will float at a certain rpm and it’s running Maverick, without a points trigger.

 

[H.B.]

There were both 10-10S and 10-10S Special Edition models.

View attachment 205944

View attachment 205945

Both models were 57 cc as opposed to the conventional 10-10 models at 54cc. The piston and cylinder were the same bore and stroke the PM55, PM555 and PM570; the PM55 was points ignition and the PM555 electronic ignition, and the PM570 was an anti-vibe electronic ignition version. The PM555 and the 10-10S/SE were essentially the same saw.

McCulloch had a very good marketing department.

Mark

Very nice saws! They look new!

 

[Al Smith]

I' m not sure exactly where the term "Maverick " came from .Duffy Livingstone mentioned the fact that on one time after a race they noticed the return spring on the points had became broken .The engine was running much faster than normal until he slacked off the gas and it died .Evidently at those RPMs it was firing much like an electronic ignition trigger by firing at the top or near top of the magnets passing at the top of the sine wave .The faster it turned until the saturation of the coil was exceeded the more it evidently self advanced .
I always used the term related to varying the timing by using the points setting rather than shifting the flywheel forward .

 

[Al Smith]

--more --I couldn't find where Duffy mentioned how much actual advance it was but remember most Kart engines were cranked with a long shaft Ford starter motor .With a high degree of advance and high compression on a kart engine the same on a saw you wouldn't be able to rope it over short of having arms like a gorilla .---unless the timing could be retarded on start up .

 

[Bigmac]

--more --I couldn't find where Duffy mentioned how much actual advance it was but remember most Kart engines were cranked with a long shaft Ford starter motor .With a high degree of advance and high compression on a kart engine the same on a saw you wouldn't be able to rope it over short of having arms like a gorilla .---unless the timing could be retarded on start up .

Al, I was doing some research a while back and found it in karting world magazine in the early 70s I believe, I guess some guys would tweet the points float sooner.I think the easiest way to do it would be to have your standard points set up and run the electronica module and have a switch that you could switch between the two ignitions, That way you could fire it up on the points timing, and then switch it over to fly wheel timing with the chip once it’s running, I guess back in the day they would just take a switch and turn off the points so that it would go Maverick, the problem would be is once the RPM’s dropped the ignition will go out like Duffy was experiencing.

 

[Al Smith]

FWIW those kart engines even in the 60's would rev higher than anybody gives them credit for over 50 years after .Of course the life of a race engine was rather short .Kenny Burden died several years ago so I can't ask him .Louie Boughan ,who I went to apprentice school with suffered a stroke this passed spring and if he recovers I might try to get in touch with him .Louie was number 2 nation wide in the 70's .

 

[Bigmac]

Here is a decent article on maverick spark, it was from 1964

http://rearenginekarts.com/phpbb3/viewtopic.php?t=1806
Steve O’Hara is a big kart guy, he explains some of the pros/cons of maverick. He was expanding that Mac’s like a fair amount of cylinder pressure to keep the rod bolts together and compression and timing can help, I think he is more of a fan of compression

 

[Bigmac]

Here is a short forum clip on maverick

http://vkakarting.com/phpbb/viewtopic.php?f=1&t=2842

Steve is basically saying that the stock mac timing is fine. Not huge gains with advance

 

[Al Smith]

As general conversation it's been said at higher compression it takes less advance .Macs are factory set at 26 and Stihls are 27 ahead .However one variation of design ,the lombard al-42 series was at around 35 more or less .Weather that engine has a lower CR I can't say .Although I have two I've never taken a reading on them .
Both my 125 are west coasters ,one from Oregon ,one from northern California and it has an offset key .I've never paid much attention but they both pull real good so weather that slight degree of advance helps or not I can't honestly say .
On the other hand a 6-10 ,70 cc version of a 10-10 I've advanced the timing by setting the points to open quicker and it has greatly improved it .So in that case it did work although I haven't taken a compression check on it either only to say it's up there .That saw came from Washington state ,not that that makes a difference .

 

[Heavy]

Hi to Smith could you make a video of your 6-10?