MAC Question

[coveredinsap]

Are you not aking how to simply measure the stroke here?

My reply to this was to clarify that "just" a piston swap, as in your post, will not give you the stroke increase you desire.

Jeez Louise

Relax Sap, we're just tryin to help.

Thanks for the reply. But I think my point (and the ensuing confusion) was that the stroke had already been measured, and the fact established that the longer stroke assembly wouldn't fit into this saw, well before your post showed up.

Your posting of a 'diagram' (and Lake's comments) only appeared to be smart-ass in nature. If I'm wrong here then I stand corrected.

 

[Lakeside53]

Your posting of a 'diagram' (and Lake's comments) only appeared to be smart-ass in nature. If I'm wrong here then I stand corrected.

You should stand corrected... and since when did you start getting a thin skin?

Ultra was just showing you a picture of the internals of a 2 stroke. If you'd have known how one worked you never would have asked the question about increasing your stroke anyhow... Do you ever admit you don't know everything?

And in this case my comment about just getting another if you wanted the bigger version wasn't as you describe. I have exactly that saw, and I tracked them on ebay for several months..

 

[sawinredneck]

And what does that method get me exactly ...that the wire thru the spark plug port trick couldn't? The stroke is now 1 3/8". What more do you need to know?

You mentioned that the plug was at an angle and you might not be able to do it that way, another sugestion was given!And for futere reference, if you wan t to do this to another saw you can!
Sorry I go into this!!!!!!!!!!!!!!!

 

[Lakeside53]

I missed that.. yes, angled plug, good luck with the wire method...

 

[Paul61]

Thanks for the reply. But I think my point (and the ensuing confusion) was that the stroke had already been measured, and the fact established that the longer stroke assembly wouldn't fit into this saw, well before your post showed up.

Your posting of a 'diagram' (and Lake's comments) only appeared to be smart-ass in nature. If I'm wrong here then I stand corrected.

Hey, no prob on my end Sap but, it was Ultra who make the informative post with the diagrams. Someone readin this with a lesser knowledge of internal comb. engines may have benefited from the info?

 

[THALL10326]

Thanks again Mc Bob for the wire thru the spark plug hole trick to measure the piston's stroke.

Not only was it a neat trick, it was evidently a new one on the johnny-come-latelys posting pictograms to this thread also. 'Machinists scale' indeed! LOL!

Thanks

(By the way, wtf was up with the after-the-fact pictogram post and comments? I said I wasn't an engine specialist, not that I didn't know anything about engines. Jeez Louise already.)

Durn Sap its nothing to get your feathers ruffled over. I think they were just showing you another way to measure the stroke as well as what McBob pointed out. Nothing wrong with suggesting other ways to do it. Calm down man, no one was trying to upset you but instead merely help you with your saw, thats all. Sap I gotta tell you, that Jeez Louise thing there, I'm going to try that at work on a few customers and see what they say, thats a neat line, I like it.....................

 

[THALL10326]

Thall, do you mean a 3-25??

Nope, I mean 35. Thats what it says on the right side of the engine housing. It a odd looking saw, real tall but thin. I looked it up in Acres site once and it said it was last made in 1949 I think. Don't hold me to that , that was a while back but I'm almost thats what it said.....................

 

[coveredinsap]

You should stand corrected... and since when did you start getting a thin skin?

Ultra was just showing you a picture of the internals of a 2 stroke. If you'd have known how one worked you never would have asked the question about increasing your stroke anyhow... Do you ever admit you don't know everything?

And in this case my comment about just getting another if you wanted the bigger version wasn't as you describe. I have exactly that saw, and I tracked them on ebay for several months..

Uh, not true. I'm familiar with how they work. The fact is, some manufacturers use the same crankcase/piston size and simply use a longer throw on the piston to increase the cc's. This doesn't appear to be the case with this particular saw, however. That was the reasoning behind the question.....not ignorance of how 2 cycles operate. (Ignorance of how McCulloch operates, maybe LOL!)

And the reason I was asking was because if I wanted to replace the rings, I would have maybe tried this too. I'm certainly not going to get another saw just for 7cc though.

 

[spike60]

What's familiar about the direction that this thread is taking?

 

[THALL10326]

What's familiar about the direction that this thread is taking?

Hey there ole Spike. How ya been? Does seem the thread was getting abit shall we said touchy but looking at Saps last post I think everything is cleared up. Sometimes these ole saw questions and answers can get confusng and taken the wrong way and I think thats all that happened. Looks like all is back on course now. Beings Lake and Sap both have the exact same saw I'm sure they can work together on any questions that may arise.....
Spike I'm getting closer to your Dolmars ole feller, the store is now open and hopefully we can get them babies in there..............

 

[trimmmed]

Your posting of a 'diagram' (and Lake's comments) only appeared to be smart-ass in nature. If I'm wrong here then I stand corrected.

It seemed like genuine help to me, IMO, you should stand corrected. Lighten up, this is a good thread, lets not drag it down.

 

[coveredinsap]

Nice avatar BTW.

LOL! Yeah, you too!


Anywho.....here's a few more photos for the Mac fans out there. (Team Stihl....you can all close your eyes now.):

 

[coveredinsap]

 

[Paul61]

Uh, not true. I'm familiar with how they work. The fact is, some manufacturers use the same crankcase/piston size and simply use a longer throw on the piston to increase the cc's. This doesn't appear to be the case with this particular saw, however. That was the reasoning behind the question.....not ignorance of how 2 cycles operate. (Ignorance of how McCulloch operates, maybe LOL!)

Sap, this is exactly what I was tryin to straighten you out on (& for the benefit of others) .

A piston has no throw, only the crank. It is impossible to increase engine size by replacing a piston only, regardless of design or make. This applies to all internal combustion engines.
If you replace a piston with one from a larger saw with the same bore size, you'll not have ANY compression as the piston's pin placement will be higher,(thus the piston top will be lower in the bore @ top dead centre) allowing for the longer stroke in the saw it was designed for.
Due to the higher pin placement, you have now increased the volume in the combustion chamber.

Here's an idea........if you used this piston from the big saw and extended (replaced) the con. rod by the .125" difference, you would have more power due to the encreased rod ratio...............the piston remains @ bottom dead centre longer thus allowing a larger fuel/air charge to enter the chamber.

BTW, you can't have a saw that's too big!

Paul

 

[RaisedByWolves]

I think you may need to adjust your chain there sap.

 

[chowdozer]

LOL! Yeah, you too!


Anywho.....here's a few more photos for the Mac fans out there. (Team Stihl....you can all close your eyes now.):

No problemo! The yellow saw poses no threat to Team Stihl.

 

[coveredinsap]

No problemo! The yellow saw poses no threat to Team Stihl.

Cool. Then you won't mind the new paint job on my bar.

 

[spike60]

Sap;

Your pictures are so good that it's almost like I have the saw on MY bench. Good Job. Except maybe for the last pic.

You know, I went by a yard sale a week ago and the guy had an old Mac on the ground that looked an awful lot like yours. Had at least a 2 ft. bar on it.Now I'm thinking that I should have stopped. I might have to look into that and see if it's still there.

 

[coveredinsap]

Sap;

Your pictures are so good that it's almost like I have the saw on MY bench. Good Job. Except maybe for the last pic.

You know, I went by a yard sale a week ago and the guy had an old Mac on the ground that looked an awful lot like yours. Had at least a 2 ft. bar on it.Now I'm thinking that I should have stopped. I might have to look into that and see if it's still there.

LOL!

Pssst, don't worry...the paint job is just 'photoshopped' on (actually...'Gimped' using Linux).

 

[THALL10326]

Cool. Then you won't mind the new paint job on my bar.

lolol, Sap that last pic is almost provoking to Stihl guys like me however I do think its funny. Since you have sorta brought Stihl into your Mac thread now would you mind if I replied with a pic to answer your pic???