McCulloch Chain Saws

[PogoInTheWoods]

BTW, thanks to everyone for their contributions. Anyone have some 6-10 cylinder pics handy?

 

[mogulmasher]

Thanks for doing this research pogo!

At some point....maybe sooner than later now that I'm curious....I'll pull apart that cp70 cylinder so we can see piston and better look at cylinder for comparison.

 

[vinnywv]

BTW, thanks to everyone for their contributions. Anyone have some 6-10 cylinder pics handy?

I just went to look. I could not get a picture but i tried. It has the three finger transfer. Looking through the spark plug hole. I could see the tops of them. Fyi

 

[vinnywv]

Speaking of more 70cc saw...my friend just sent me a video of the cp70 he just got running. It needed a boot i asked about last weekend. Installed and sounds really good. Thanls for the part number.

 

[vinnywv]

Speaking of more 70cc saw...my friend just sent me a video of the cp70 he just got running. It needed a boot i asked about last weekend. Installed and sounds really good. Thanls for the part number.

 

[Jethro 2t sniffer]

So that 3 finger port is that an iron liner port design? The 3 finger 54s I have here are iron. That 6-10 vinny is iron?

I remember 2brokes was the early type 7-10 with the lever dsp. Is his iron too?

 

[Jethro 2t sniffer]

Oh and thanks for putting all the photos together poge this is good stuff finally something to really chew on. And thanks to everyone for taking photos.

This troubled 7-10 of kevin's still keeps a few of us awake at night and probably will until it finally runs.

I'm wondering if the iron cylinders need the full skirt piston

 

[Jethro 2t sniffer]

Goes back to another question at the start of it all. Is kevin's 7-10 really a 6-10? Were all early 7-10s just left hand start 6-10s?

 

[PogoInTheWoods]

Lifted from a similar conversation over on OPIE. I don't think Steve would mind.

85239 fits all 70cc 2in bore saws. It has thin steel rings and a windowed skirt. The only other option is the 85240 piston that was used in the early 10 series like the 4, 5, and 6-10. It was a full skirt thick iron ring piston. 85240 pistons are not very common and if you do find one you have to match the rings to the cylinder as iron bore and chrome bore rings are different.

I should point out that the table I posted earlier lists 3 different ring sets for the 85329 piston..., presumably for different cylinder lining applications for two of them and maybe a typo for the third in the case of the 87166 listed for the early 7-10 which should probably also have the full skirt 69412 piston listed instead of the 85239. I'm certainly not sure about that, but it sorta seems like it leans that way.

 

[Jethro 2t sniffer]

Well hopefully kevin the 1st (two Kevin's now) runs out and checks what cylinder it has.

Maybe it is just the wrong piston all along.

Was hoping Mark would chime in with his memory if chrome or cast.

Perhaps it was rebuilt by someone ran like a dog for ages and gave up. The notch in the piston was him or the next guy or 3 later attempting to get the clutch off or flywheel saw what he had done and called It quits. Perhaps those 3 hypothetical guys are all still laying in bed at night wondering what the hell was wrong with that dam saw hahaha.

Ya just never know

 

[2broke2ride]

Well hopefully kevin the 1st (two Kevin's now) runs out and checks what cylinder it has.

Maybe it is just the wrong piston all along.

Was hoping Mark would chime in with his memory if chrome or cast.

Perhaps it was rebuilt by someone ran like a dog for ages and gave up. The notch in the piston was him or the next guy or 3 later attempting to get the clutch off or flywheel saw what he had done and called It quits. Perhaps those 3 hypothetical guys are all still laying in bed at night wondering what the hell was wrong with that dam saw hahaha.

Ya just never know

I just looked, curiosity got the better of me. Mine has the 3 finger ports. I can see them through the spark plug hole. I tried to get a picture but was unable to. It is an iron liner. This is the piston that came in the saw which is obviously the windowed design but I never had the saw run with this piston so I dont know if it ran right or not. Also a pic of the tag from the saw.

 

[Jethro 2t sniffer]

I just looked, curiosity got the better of me. Mine has the 3 finger ports. I can see them through the spark plug hole. I tried to get a picture but was unable to. It is an iron liner. This is the piston that came in the saw which is obviously the windowed design but I never had the saw run with this piston so I dont know if it ran right or not. Also a pic of the tag from the saw.

Boom goes the dynamite lol. Is it worth trying the other piston?

This is really interesting stuff just need to see a piston from an iron cylinder.

Poge are the thick and thin ring versions of the full skirt actually a thing or is just mac playing with numbers.

Edit.. I just realized that's a thick ring in the picture. I was thinking thick and thin had something to do with bore type and ring type but no just getting muddled.

Are there four pistons? Thick and thin of both styles

 

[2broke2ride]

Boom goes the dynamite lol. Is it worth trying the other piston?

This is really interesting stuff just need to see a piston from an iron cylinder.

Poge are the thick and thin ring versions of the full skirt actually a thing or is just mac playing with numbers.

Edit.. I just realized that's a thick ring in the picture. I was thinking thick and thin had something to do with bore type and ring type but no just getting muddled.

Are there four pistons? Thick and thin of both styles

I am not sure that the other style piston is readily available. I would certainly be willing to give it a shot at this point lol.

 

[PogoInTheWoods]

I think I may have seen one on the bay earlier..., with yet a different part number, of course. LOL

That's a very early tag number you have for sure. The 1970 IPL says it should have had a 69030 piston / 63290 ring set (same as a CP70) and 84105 cylinder which evidently had the CP70 style transfers but a different part number than either of the cylinders used on the CP70 (at least according to the CP70 1970 IPL).

The ring types do correspond to the liner type..., or at least originally did and the piston number seemed to correspond accordingly, too. With the introduction of the 85239 piston number there were evidently both thin and thick ring versions of that same part number according to the ring set numbers associated with the 85239 piston number.
That, of course, is the later style windowed piston which evidently superseded (combined?) what appears to be two previous cylinder part numbers with one also evidently being a full skirt piston typically found in the divided transfer design. That's where it gets weird for me considering what we now know are at least three different transfer port designs among the 70cc saws with the 85239 ending up being the default 2" piston for all of them according to the later IPL's. I just can't see anything but performance anomalies among all the different possible combinations.

Continuing to scratch head...

 

[PogoInTheWoods]

There are two other piston part numbers for the 70cc saws that I believe correspond to the full skirt pistons. Pretty sure there's an 85240 that corresponds to an earlier 69412? Would need to do some cross reffing to determine which ring set for which piston may correspond to an iron liner / divided transfer cylinder if those pistons are indeed full skirt versions.

The other confusing aspect of all this is the cylinder itself not having its own specific part number, but rather being listed as part of the whole crankcase assembly. Would be a whole lot easier to sort out if we had the actual cylinder numbers handy. They gotta be out there somewhere.

 

[2broke2ride]

I think an important part of the puzzle is to see what style piston Mike's @mogulmasher s CP70 has in it

 

[Jethro 2t sniffer]

I think an important part of the puzzle is to see what style piston Mike's @mogulmasher s CP70 has in it

Yup I'm betting the full skirt.

Real interesting stuff poge I feel as though we have answered some questions and have made some more questions too

 

[heimannm]

I don't know...

Mark

 

[PogoInTheWoods]

LOL Me either!

And agreed on both Kevin's and Jethro's points.

We certainly now know that the 7-10 came with both open and divided transfers with two types of cylinder liners and possibly four different pistons..., provided Kevin's
7-10 has the original cylinder assembly for a 10 serial prefix 600052 tag number..., which appears to use the same cylinder as a 1970 CP70.

 

[Jethro 2t sniffer]

Agreed. LOL Me either!

We certainly now know that the 7-10 came with both open and divided transfers with two types of cylinder liners and possibly four different pistons..., provided Kevin's
7-10 has the original cylinder assembly for a 10 serial prefix 600052 tag number..., which appears to be the same as a 1970 CP70 cylinder.

And vinny's 6-10 too