I bet this is what I am seeing. Thanks Tim. I think this explains a lot.
Brian
Brian
McCulloch Chain Saws
- Thread starter Bruce Hopf
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Walter Glover
ArboristSite Guru
Mounted a b&c from my 670 Jred onto my CP70L. Way better balance with a 20" bar and man does it rotate that chain! Will make little sleeves forbar studs to tighten up the up n down play. Drilled a new hole for tensioning then using dremel cut a slot down into original tensioner hole for oil flow. Bar plate covers the original oil hole so all goid now. Bit of sharpening and final tuning then find some more trees to buck up. Great saw with weird starting requirements. I get a kick out of tgat lever operated decomp. The thing is rock solid impossible to turn over if one forgets to set it every time. I dont think i am strong enough to do a compression check on this ole girl. Having fun for sure
Ya, Let me see that done. Brian Is not right.
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Lee, it would be, of coursre, possible but would require welding and serious different size line hone/bores so why. Welding a pop up would make more sense. Still, why?
Shout out to Joey. I ran the 805 today to cut a 24" black walnut for an anvil base. With muffs on, it reminded me of the DE80 - didn't sound wound up when revving but in the wood it zipped through without losing any speed. Any chance the 805 carb is governed like the DE80? Maybe I am just losing my hearing.
Nice cutting saw. Both powerful and straight cutting. Thanks again for putting it in my hands.
Note to Brian: I'm a little slow but I noticed your avatar with my 101b sitting next to that cotton picking Bultaco. Even subliminal messages isn't going to get me back on a bike.
Ron
Nice cutting saw. Both powerful and straight cutting. Thanks again for putting it in my hands.
Note to Brian: I'm a little slow but I noticed your avatar with my 101b sitting next to that cotton picking Bultaco. Even subliminal messages isn't going to get me back on a bike.
Ron
Mac&Homelite
Addicted to ArboristSite
Send it over to me for a compression test. I'm a young buck with some grunt.
Mac&Homelite
Addicted to ArboristSite
Say, does anyone have a chart on how to read the 10 series serial numbers. I recently purchased one last month, and would obviously like to learn more about it because I have CAD.
sawfun, most here have forgotten more than I know. But I do know that sometimes if we ask why then we won't. Other than the fun of trying something different, economics would usually dictate that we leave things factory.
I don't know enough about squish to debate "why" much less engage in the running debate of pop-up versus shaving/shortening the cylinder to crank centerline length. But like said above with enough work one can tighten the squish on a one piece block from either end.
Despite the distain shown by many ASers for clam shells, I believe a tool maker could easily make a tool and jig to shave the bottom of the cylinder side of a ten series to tighten the squish. Before investing in that venture, I hestitated and asked myself, why when a different approach may result in more gains with no tool making. Thus my new project. If it works as well as I hope, I am sure some folks will still ask why. If it doesn't, I may wish I had asked - and regret that I hadn't devoted my time and resources to my first idea.
Ron
I don't know enough about squish to debate "why" much less engage in the running debate of pop-up versus shaving/shortening the cylinder to crank centerline length. But like said above with enough work one can tighten the squish on a one piece block from either end.
Despite the distain shown by many ASers for clam shells, I believe a tool maker could easily make a tool and jig to shave the bottom of the cylinder side of a ten series to tighten the squish. Before investing in that venture, I hestitated and asked myself, why when a different approach may result in more gains with no tool making. Thus my new project. If it works as well as I hope, I am sure some folks will still ask why. If it doesn't, I may wish I had asked - and regret that I hadn't devoted my time and resources to my first idea.
Ron
Walter Glover
ArboristSite Guru
Mac&Cheese, wish you were closer and you could help me out on that compression test! Haha
Gonna haff todoit. Hmm mmmm
BTW what 10 series sawdid you get?
Gonna haff todoit. Hmm mmmm
BTW what 10 series sawdid you get?
ML12
ArboristSite Guru
I tore down a 1-72 that I had sitting around. It appears to have been run with a lot of oil in the mix, judging by the completely closed off exhaust port (carbon)
What I did find interesting is that it has "thin" rings. The saw had been apart before, but did someone put in a different piston? The piston obviously has been scuffed quite badly, but just on the one corner. Should I polish it out and just run it? I might have a spare thick ring piston available that I could use instead.
It also has quite a bit of transfer on the bore. and the piston is quite scuffed. What is the best way to clean up the bore? same as the chrome ones?
Thanks in advance!
What I did find interesting is that it has "thin" rings. The saw had been apart before, but did someone put in a different piston? The piston obviously has been scuffed quite badly, but just on the one corner. Should I polish it out and just run it? I might have a spare thick ring piston available that I could use instead.
It also has quite a bit of transfer on the bore. and the piston is quite scuffed. What is the best way to clean up the bore? same as the chrome ones?
Thanks in advance!
The 1-72 has a cast iron bore with oversize pistons available (.020" oversize piston is 48685, rings are 48693). Judging by the part number, thin rings were originally supplied in the early top tank saws. The front tank saws as the same time were thick rings.
If you can clean up the bore with a ball hone and the size is still acceptable, no reason not to run it like that. You can't use acid since the cylinder does not have the chrome plating to protect is. Since it has a removable head and over 2" bore, there should be sources to bore it oversize if you can find a piston. I believe you can use the thick ring piston from the front tank saws as well.
Looking a but further I see 0.010" oversize piston & rings (48684/48692) and 0.030" oversize piston & rings as well (48686/48694) for thin ring versions. The front tank/thick ring models also had 0.010", 0.020", and 0.030" oversize pistons and rings available.
Mark
If you can clean up the bore with a ball hone and the size is still acceptable, no reason not to run it like that. You can't use acid since the cylinder does not have the chrome plating to protect is. Since it has a removable head and over 2" bore, there should be sources to bore it oversize if you can find a piston. I believe you can use the thick ring piston from the front tank saws as well.
Looking a but further I see 0.010" oversize piston & rings (48684/48692) and 0.030" oversize piston & rings as well (48686/48694) for thin ring versions. The front tank/thick ring models also had 0.010", 0.020", and 0.030" oversize pistons and rings available.
Mark
Mac&Homelite
Addicted to ArboristSite
Just a PM 10-10 good runner so far, although I haven't had any chance to take any covers off.
Walter Glover
ArboristSite Guru
Well pulled my guts out on that CP70L and best it reads on my automotive comp tester is 140psi dead cold.
That number to me is soso accurate
Anyways got a number
That number to me is soso accurate
Anyways got a number
It may be more accurate than you think. My PM 700 reads around 130 psi. It too is pretty tough to pull over without the decomp. Ron
Walter Glover
ArboristSite Guru
Thanks Ron
This is the highest compression saw I own bar none
Tore the shroud off for a complete cleaning and to sort out the oiler.
Found the screw used for starter cover so long it was restrictions plunger movement.
Sorted that out and made sleeves to reduce slop in the jred bar. Couple strokes with a file and gonna go at some trees tomorrow.
Is there a preferred methodto starting these macs? Seems to only want to run if I use the throttle lock. Left on idle does not want to stay running.
Snow is melting so hope it all falls clear soon haha
Cheers
This is the highest compression saw I own bar none
Tore the shroud off for a complete cleaning and to sort out the oiler.
Found the screw used for starter cover so long it was restrictions plunger movement.
Sorted that out and made sleeves to reduce slop in the jred bar. Couple strokes with a file and gonna go at some trees tomorrow.
Is there a preferred methodto starting these macs? Seems to only want to run if I use the throttle lock. Left on idle does not want to stay running.
Snow is melting so hope it all falls clear soon haha
Cheers
brandonstc6
Addicted to ArboristSite
Mine read 175 psi but my gauge has the needle at 30 before use.
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BigBlue
ArboristSite Operative
Just a small update on my PM 800 cylinder issue:
I brought the cylinder to a shop that specializes in cylinder head work (not really small engine stuff, but still...). He took a look and felt it wasn't too bad. He did a little work on it and was able to get much of the aluminum transfer off the walls. He still can't get all the way to the top but he had something else he was going to try. He thinks it will be salvageable and fine when done.
I told him not to hone it, so I'm sure he's using something less aggressive. He said he may "ball hone" it which as he described is more like what they use to put crosshatching on the cylinder walls, not actually taking off material. I'm not sure though.
Assuming it comes back in good condition I'll need to get that new piston & rings and see what can be done. What other parts will I need to get everything back together happily? New seals for both sides of the crank, I believe. How about any new bearings? Other seals/gaskets/hoses/etc. that might be good to do since I have the saw all the way apart?
Thanks,
Rob
I brought the cylinder to a shop that specializes in cylinder head work (not really small engine stuff, but still...). He took a look and felt it wasn't too bad. He did a little work on it and was able to get much of the aluminum transfer off the walls. He still can't get all the way to the top but he had something else he was going to try. He thinks it will be salvageable and fine when done.
I told him not to hone it, so I'm sure he's using something less aggressive. He said he may "ball hone" it which as he described is more like what they use to put crosshatching on the cylinder walls, not actually taking off material. I'm not sure though.
Assuming it comes back in good condition I'll need to get that new piston & rings and see what can be done. What other parts will I need to get everything back together happily? New seals for both sides of the crank, I believe. How about any new bearings? Other seals/gaskets/hoses/etc. that might be good to do since I have the saw all the way apart?
Thanks,
Rob
Rob - Replacing the seals is generally a good idea, also check the intake boot very thoroughly and replace it if there is any question. PTO side seal is SKF 6119, the flywheel side should be McCulloch 61618 but many were assembled with a different bearing that has a wider outer race and the seal presses into the I.D. of the bearing race rather than the bore of the crankcase. In that case the seal is McCulloch 65746. I can get some dimensions tonight if I remember.
The bearings are normally good to reuse, but check them carefully for any signs of corrosion and replace if they are at all questionable. The PTO side needle bearing is a standard size:
This is the flywheel side bearing with the wide inner race, the 65746 seal would press in the outer race of the bearing in this case.
Like this:
Many IPL's show the narrow bearing and larger 61618 seal but I have only found that combination on the older -10 models. Everything else seems to have the combination shown above.
The oil tank gasket is normally good to use again, any of the gaskets in the intake that are torn or otherwise damaged should be replaced.
If the cylinder does not have an "A" or a "C" stamped in the top of the cylinder head it is a "B", customchainsawparts on E-Bay had the piston with rings for $49.95 + shipping. Looks like Little Red Barn has an aftermarket piston kit for them if you are willing to gamble a bit. Piston kits (piston, rings, bearings) as follows:
"A" 92518
"B" 92519
"C" 92520
Mark
The bearings are normally good to reuse, but check them carefully for any signs of corrosion and replace if they are at all questionable. The PTO side needle bearing is a standard size:
This is the flywheel side bearing with the wide inner race, the 65746 seal would press in the outer race of the bearing in this case.
Like this:
Many IPL's show the narrow bearing and larger 61618 seal but I have only found that combination on the older -10 models. Everything else seems to have the combination shown above.
The oil tank gasket is normally good to use again, any of the gaskets in the intake that are torn or otherwise damaged should be replaced.
If the cylinder does not have an "A" or a "C" stamped in the top of the cylinder head it is a "B", customchainsawparts on E-Bay had the piston with rings for $49.95 + shipping. Looks like Little Red Barn has an aftermarket piston kit for them if you are willing to gamble a bit. Piston kits (piston, rings, bearings) as follows:
"A" 92518
"B" 92519
"C" 92520
Mark
BigBlue
ArboristSite Operative
Great info! Thanks!
I bought one of the Little Red Barn pistons. It looked like a really well made piston but it had the wide rings instead of the thin rings and opted not to use it thinking it may damage the chrome in the bore. Just my thinking. It also did not have A, B or C and that kind of made me not comfortable with it. I have had others tell me that an after market piston did not have these markings and you could use them on all cylinders but I felt better using the OEM piston.
Brian
Brian
