McCulloch Chain Saws

[northwest saws]

That would be great but not if it means giving up on the saw.
I have a good friend up here that builds 2 stroke race bikes. There are pistons available to him in pretty much any size.
If you send me the factory dimensions of the piston and an actual measurement of your cylinder, I'll ask him what he thinks.
If he thinks he may have some luck we can get better measurements.
Some of the aftermarket companies, like Meteor, actually make pistons for bikes but happen to market a few for chainsaws.

It's an extra filter I got from a 4-30 so it's no problemo. I'll see if I can dig it out later today. I had contacted wiseco awhile back about making custom pistons and it would cost a fortune for a minimum run of 12 units. I contacted a couple other folks who used to make custom pistons and that's also a no go. I never got in touch with Meteor so that may be an option. I'll get back to you with dimensions sometime later. Always willing to explore an option. The good thing about this piston is the flat top and no ring landing pins which may make it easier for folks making custom pistons.

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[Camperspecial]

It's an extra filter I got from a 4-30 so it's no problemo. I'll see if I can dig it out later today. I had contacted wiseco awhile back about making custom pistons and it would cost a fortune for a minimum run of 12 units. I contacted a couple other folks who used to make custom pistons and that's also a no go. I never got in touch with Meteor so that may be an option. I'll get back to you with dimensions sometime later. Always willing to explore an option. The good thing about this piston is the flat top and no ring landing pins which may make it easier for folks making custom pistons.

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Thanks. No hurry.
I had a brief conversation with my buddy, Jim, he has a place the does one-off pistons for him. Didn’t have time to talk about cost.
I’ll look into it.


Rob.

 

[Maintenance supervisor]

Someone else built a 73 using a British automobile piston last year but I can't remember who. It's in the annals of this thread.

 

[edju1958]

It's an extra filter I got from a 4-30 so it's no problemo. I'll see if I can dig it out later today. I had contacted wiseco awhile back about making custom pistons and it would cost a fortune for a minimum run of 12 units. I contacted a couple other folks who used to make custom pistons and that's also a no go. I never got in touch with Meteor so that may be an option. I'll get back to you with dimensions sometime later. Always willing to explore an option. The good thing about this piston is the flat top and no ring landing pins which may make it easier for folks making custom pistons.

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I contacted Lee from LRB back a couiple yrs.ago about making cylinders for either Mac or Homelite (I can't remember which one),& his reply to me was "In order to make a casting for a piston it costs me $10,000,I can afford that.In order to make a casting for a cylinder it costs $100,000,I can't afford that."
I've noticed that since I contacted him he is now having aftermarket cylinders made.Either the price came down on castings,or he suddenly got rich.

 

[edju1958]

I need a part for my SP125 recoil & it's not listed on the IPL,at least the illustrated part.On the top rear of the recoil where it attaches to the saw there's a clip with a nut in it that the screw goes into.Does anyone know what the part # is?I talked with Bob J.& he doesn't have a clue as to what I'm talking about.It has the same clip on the bottom too.

 

[vinnywv]

I think i understand the question ed. Top rear of the recoil housing is a hole for a mounting screw. Almost under the fuel tank, not quite but close. So on the rear shroud, theres a nut for that screw thats actually stamped in place. Theres also one on the bottom of the saw. Those are part of the rear shroud. Its like a nut with a collar that is stamped into the recess. Attached are pictures of what i think you mean. If it is there is no part number. They are just part of the rear shroud. If its not then sorry.

Its like it was "flared" into place. This is on my 105. Same parts though.

 

[vinnywv]

Im sure mcculloch had a part number for it but it is not a ipl listed part in any of mine.

 

[edju1958]

You're exactly right Vinny.The "nut" is stamped into a "clip",& the "clip" fits onto the rear of the saw.I have the bottom one in place,but the top one is missing.I took some pics,the bottom pic sucks,hard to discern anything,but the top is clear as can be with the "clip" missing.I was wondering if these were available at a hardware store?If ol;d Bob would move into the 21st century we could send pics & life would be so much more easier.

 

[vinnywv]

Ok, thats a tough one. Id have to go pic thru a hardware store to find something. Those nuts with the starred washer attached come to mind but there could be something else available

 

[Woodslasher]

Per @heimannm ’s advice I pulled down my 5-10 for a ring job and a semi-thorough decarboning. Aside from the highly worn rings everything looks A+ in there, all I need to do now is pick up a suitable case sealer (I kinda doubt permatex red would suffice) and I can put her back together!

 

[vinnywv]

I personally use red high temp rtv if i have it. If all i have is clear rtv then i use it. Ive not used anything else and have had great success. Others use dirko with good results as well as other sealants with success. Its almost like asking the best oil. Lots of opinions. Mcculloch used clear silicone sealant. The ones that have never been apart in 50 years are still running strong with silicone. Hard to argue with success.

 

[mogulmasher]

I think more important than what you use is how flat surfaces are. I always take a long flat file and run it across cylinder halves. You'd be surprised sometimes the high spots that get smoothed out.

 

[Woodslasher]

Well, guess I’d better get busy then!

 

[vinnywv]

Youve got a great start.

 

[PogoInTheWoods]

I do a vac/pressure test before installing the muffler and carb. If the case and seals are tight, that eliminates a whole bunch of guessing if there are running problems after the saw is together. Not much left to chase down if your case integrity has already been established.

 

[Woodslasher]

I do a vac/pressure test before installing the muffler and carb. If the case and seals are tight, that eliminates a whole bunch of guessing if there are running problems after the saw is together. Not much left to chase down if your case integrity has already been established.

I’m impatient, I’ll do the test later when I fix the issue that causes my tank to sit too high. @heimannm does a later sdc tank on a 70cc block require a thinner tank/cylinder intake block than if it were on a 54cc block? I’m not gonna run the 36 on it, I just mocked it up for an east coast/west coast debate.

 

[heimannm]

The 70cc saws require the thinner insulator due to the larger diameter of the cylinder.

Mark

 

[edju1958]

Ok, thats a tough one. Id have to go pic thru a hardware store to find something. Those nuts with the starred washer attached come to mind but there could be something else available

I found out what they're actually called - barrel nuts or U clip nuts.I'll check with my local hardware store.The thing is Mac,as all the other saw makers of the day,used a 12-24 thread,whioch is not very common nowadays.

 

[Woodslasher]

The 70cc saws require the thinner insulator due to the larger diameter of the cylinder.

Mark

Thank you, I thought as much but it's nice to have someone confirm it. You wouldn't know the p/n for the thinner block, would you?

 

[PogoInTheWoods]

I see two part numbers for the insulator -- 63258A for no prefix or 1 prefix, and 66661 for a 10 prefix (if you still have a tag). This IPL seems to cover from early on until '71.