McCulloch Chain Saws
- Thread starter Bruce Hopf
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All I can say is try Bob Johnson in Maryland,N.Y.607-638-9297.He might be in the shop tomorrow a.m.
Good chat with pistons dudes. Scrap bin find today
good compression too 
And then the 800 doing what it was made for. Nasty dry blue gum 
good compression too And then the 800 doing what it was made for. Nasty dry blue gum I'd be happy to find a cross cut saw in the garbage bin.Lol
Chainsawr pistons are problematic, rings are too wide to fit in the bore, wrist pin is too small to achieve a press fit in the rod, you have to press the bearings in for the wrist pin...but they are cheaper than OEM unless you need a "C" piston ($50 from Randy Duncan.
Mark
Mark
Haha yea was pritty lucky was my mate who found it and handed it over haha. Good afternoon with the 800 though the chain is way too hungry for this another few files to go yet and get a chain on the 24inch bar. 20 is way to small cos far out the grunt of the thing is incredible I see why you guys say there fun.
Blown away how tidy this is will find out the spark question tomorrow and flog some parts from the 10 10 hopefully mite have a nice free pm700. Imagine just tossing that in the scrap bin so far it seems the top handle has broke and the throttle link has popped off the trigger.
It has a really nice starter and sawdust screen also good air cleaner but best of all nice compression. Hopefully after being saved it will give many years of happy service in return
It has a really nice starter and sawdust screen also good air cleaner but best of all nice compression. Hopefully after being saved it will give many years of happy service in returnThat's the problem with today's society - if it doesn't work,throw it away.Also,it seems there are fewer younger people who are willing to take something apart to find out what went wrong,then add that to the misconception that you can't get parts for McCulloch anymore.....& presto,you have a garbage bin find.
BigBlue
ArboristSite Operative
Not taking up for the piston because it seams like a poor fit for the PM800 but many after market piston manufactures purposely manufacture the rings a little longer than stock. This is so if your bore is a little worn you can still achieve the proper ring end gap. You file the ends of the ring to achieve that proper ring end gap. This used to be normal in the motorcycle world when dealing with a steal or cast cylinder bore. But these days everything is nikasil and the cylinders cannot be honed just a little bit to clean them up and then file the ring down to achieve the proper ring end gap.
Brian
I find it hard to believe there is more than one manufacturer making replacement pistons for the 82 cc McCulloch saws.
Originals have thin steel rings but these replacements have thicker cast rings with offset locating pins so filing the ends is not an easy option. In any case, that is not the problem, the rings are actually too wide to seat fully in the groove and cutting the groove deeper is compliated by the pins so reducing the width of the ring is the best option. Doable but should not be required if the parts actually matched.
Mark
Originals have thin steel rings but these replacements have thicker cast rings with offset locating pins so filing the ends is not an easy option. In any case, that is not the problem, the rings are actually too wide to seat fully in the groove and cutting the groove deeper is compliated by the pins so reducing the width of the ring is the best option. Doable but should not be required if the parts actually matched.
Mark
Pretty sure Chainsawr and LRB Mac piston kits would be from the same source. Same with quite a few of the kits that aren't available from the typical Asian repop houses.
Walter Glover
ArboristSite Guru
Chainswr pistons and rings are nicely made and fit the cylinder well. They allow an inexpensive repair option and now that i understand the ring issue there is no problem fitting them. Better a piston than none
Edit:
As pistons of any sort seem unobtanium for the SP60, I bought the Chainsaw Mac 610 piston as the cylinder will be sleeved to fit anyways. Doubt the Ole girl will miss a cc or two lol
Edit:
As pistons of any sort seem unobtanium for the SP60, I bought the Chainsaw Mac 610 piston as the cylinder will be sleeved to fit anyways. Doubt the Ole girl will miss a cc or two lol
Yea its sort of good for us guys cos we find stuff but not good for society. My young 18 year old workmates couldnt give two flying f**S about any thing unless face book told them or if it directly affects them im only 30 but it seems a generation away from an 18 year old. Yea the parts thing pisses me off the saw n mower shops are adding to that they let me surf there junk pile for stuff and the hole time there sayin why bother you cant get parts or its old junk throw it away buy a new 1. People throw out a nice 7hp victa 2 stroke mower cos it wouldnt start and go buy china junk from big box that will last a few years meanwhile I take the victa from the bin clean the season old gas out new plug and... ting ting ting it go's mint as. I get 50 to 100 bux for them lol so yea pluses and minuses of these silly times.
More questions about the 82cc mac pistons. Do the old nos rings fit the new pistons? Do the aftermarket rings fit the oem pistons? or do these new rings need fiddling to fit any thing. Is it better to keep running an older warn piston and re ring than bother with this new stuff. I want to have this 800 running in 20 years but dont want to go wrecking a good barrel with aftermarket stuff when left alone would of been fine. Compression feels very good when turning it over just stops dead and really gota fight it to push it up past tdc no hissing noise no nothing.
Well the pm700 had a lovely spark so thought bugger it filled her up the airbox was filling up with gas leaking from the seem so gave her a cuple pulls any way and.... woof up she went like a bonfire so run like hell to the tap getting burnt hands and managed to get it out fewff shacking n trembling put it down for another day. Stuped me I new better I even said to myself before the 1st pull that it may catch fire. Allways listen to your instincts they know better than your brain sumtimes.
Believe this is what you need (check you IPL to make sure). https://www.ebay.com/itm/Vintage-OE...823065&hash=item33c94d31d3:g:cGQAAOSw4A5Ypiz4
More expensive but another three: https://www.ebay.com/itm/New-McCull...700542?hash=item28360fdabe:g:vDYAAOSwWKtUxSNv
Ron
BigBlue
ArboristSite Operative
I can't say anything with certainty but the OEM piston in the PM800 I'm rebuilding had two thin rings and the LRB replacement piston has two thick rings. So they definitely aren't interchangeable. But that's far from being a standard statement.
Rob
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