Matching Bar Length to Powerhead - What's Too Much? Too Little?

[Old Mac Guy]

I just watched a chainsaw auction in which the seller hyped the saw as "A real Man's Saw!! Not For Week-End Warriors!!" and a bunch of other BS about Whattasaw!!, which would require Whattaman!! to operate. His clever shilling worked -- many bidders elbowed their earlobes against each other to an end price with I thought was, while not totally out of line, probably $50 over what the saw is worth (and add over-priced $45 shipping). The main hype the seller emphasized was the 28" bar on this "monster".

The "He-Man Only!!" saw was a Pro Mac 650. McCulloch started the Pro Mac and Power Mac 600-series back around 1978 and produced the series well into the 1990's, including the 605's, 610's and 650, and, finally, Timber Bear. Each of the models came out in a couple of variations, but they all are very closely similar in design, with many interchangeable parts amongst them. The 605 has a 3.5 cui engine, all the others a 3.7 cui. Mac issued all of them with a minimum bar length of 16" and maximum bar length of 20".

I hafta assume that the r&d guys at McCulloch did their homework back in the 70's and 80's and through the 90's.... and that there was a reason for not offering the saw with a 24-28-30-36" bar..... {Despite that seller's hype about this, really, "consumer" saw, McCulloch DID make some serious professional saws which pulled some loo-o-o-ng bar and chains.... back in the days when Mac was a serious chainsaw maker.}

While I've put a shorter bar than the manufacturer's specs called for on some of my saws (Hey! - a 12" Carlton b&c on a Homelite 240 makes a light and handy little limbing saw for up to about 7" limbs...), I've never put a bar and chain which were significantly longer than specs called for on a saw. {We don't have many big-diameter trees here in New Mexico -- except cottonwoods -- and a 16" b&c will take very good care of about 99% of whatever felling needs we have around here.} So.... I got to wonderin'.... what happens when ya put too long a bar on a saw for the powerhead...??

And, as far as this line of alleged thought goes, what happens when ya put too SHORT a bar and chain on a powerhead??

Are there some dynamics involved which will make a saw more likely to kick-back-an'-bitecha?? Will such a saw bog in tha cut a lot more often?? Willya be wearin' out yer sprockets and clutch more often?? What about other parts of tha saw??

Maybe some of you guys might have some experience(s) along these lines, or know some things about bar and chain and powerhead combos that ye'll share midt der rest ob us jerkline skidder's waterboys??

Tell us, please....

 

[ozflea]

Yep that big bar would kill it somewhat, bar sizes offered out here in Aussie land were 16" and 20" and this helped in keeping the power were it was needed.

Mc Bob.

 

[Old Mac Guy]

Plain common sense tells us that too big a bar on too small an engine will lag in the cut. Assuming that bar-mount patterns match up well, what happens if you put, say, a 14-inch bar on a Mac SP125? or a Homelite 2100S?

What would the saw act like in an undercut? ....or when you first set it into a 14-inch hardwood log? How does a longer or shorter bar affect chain speed in one given place along the bar? ....Or does it remain the same?

Obviously, the shape and spacing of the cutting links would be a factor in how the over-all saw would behave....

I guess my thoughts and questions in this area eventually lead to this:

Do hot-saw racers use custom-made bars and especially designed chains?

 

[ozflea]

As dumb as some people think they are saw manfacturers off a selection of bar sizes to suit a particular powerhead take the SP 125 out here in Australia it started at 18" and seldom exceeded 36" with the most popular size being 24" as a good all round size for Aussie hardwoods but since we are mainly a hardwood country thats all that is needed and utilizes the power of the SP125.

Now some people have big ego's and think that a bigger bar is better when it is not. With the amount of old growth forests locked up the supply of big timber is not there for falling and the industry moving into plantation timber and sizes are down.

Anyway a well matched bar and chain on the right size saw is whats important.

Mc Bob

 

[Justsaws]

I saw that ad. It made me laugh! I am a big fan of that series of McCullough saws, but I would never run over a 20" bar on them. I generally stick to a 3 to 1 ratio of cc's to inches. I am happier with 4/1 or 5/1. If I am running my older saws with 404 chain than almost always 4/1. I only run 3/8 chain on my newer models so sometimes 3/1. My 066 or 2095 with a 20" 3/8 semi-chisel set-up is a pure delight to use. My Mac 300 with a 20" 404 is a different kind of delight.

 

[NWCS]

i have seen a 24" bar on an 084 that was cutting black walnut. big saws with short bars do have good use for hard stuff like that. in softwood your just burning a ton of fuel for a cut that an 044 could be doing

 

[Justsaws]

That is true, I should say that I mostly cut locust and other hard wood. Usually downed and "seasoned" as the locals would say. For me, I did not feel enough of a weight difference between the 046 and 066 to not run the 066. Now that I think about it I do not have many 70-80cc saws. I think I have found a new niche to collect.

 

[havvey]

bar length

:yoyo: too long a bar would over load the engine and could damage the bar mounts casting. to short just wouldn't make any use of the power as speed would be the issue. (ie a 346 husky vs mac 125 with 12 inch bar) I feel you can strech it a little like a 24 on a 610 with a good operator and right conditions. the oil tank and its ability wold come into question.:biggrinbounce2:

 

[havvey]

mac's

mac doing its home work inthe 1990's I saw the auction but what did it bring?

I just watched a chainsaw auction in which the seller hyped the saw as "A real Man's Saw!! Not For Week-End Warriors!!" and a bunch of other BS about Whattasaw!!, which would require Whattaman!! to operate. His clever shilling worked -- many bidders elbowed their earlobes against each other to an end price with I thought was, while not totally out of line, probably $50 over what the saw is worth (and add over-priced $45 shipping). The main hype the seller emphasized was the 28" bar on this "monster".

The "He-Man Only!!" saw was a Pro Mac 650. McCulloch started the Pro Mac and Power Mac 600-series back around 1978 and produced the series well into the 1990's, including the 605's, 610's and 650, and, finally, Timber Bear. Each of the models came out in a couple of variations, but they all are very closely similar in design, with many interchangeable parts amongst them. The 605 has a 3.5 cui engine, all the others a 3.7 cui. Mac issued all of them with a minimum bar length of 16" and maximum bar length of 20".

I hafta assume that the r&d guys at McCulloch did their homework back in the 70's and 80's and through the 90's.... and that there was a reason for not offering the saw with a 24-28-30-36" bar..... {Despite that seller's hype about this, really, "consumer" saw, McCulloch DID make some serious professional saws which pulled some loo-o-o-ng bar and chains.... back in the days when Mac was a serious chainsaw maker.}

While I've put a shorter bar than the manufacturer's specs called for on some of my saws (Hey! - a 12" Carlton b&c on a Homelite 240 makes a light and handy little limbing saw for up to about 7" limbs...), I've never put a bar and chain which were significantly longer than specs called for on a saw. {We don't have many big-diameter trees here in New Mexico -- except cottonwoods -- and a 16" b&c will take very good care of about 99% of whatever felling needs we have around here.} So.... I got to wonderin'.... what happens when ya put too long a bar on a saw for the powerhead...??

And, as far as this line of alleged thought goes, what happens when ya put too SHORT a bar and chain on a powerhead??

Are there some dynamics involved which will make a saw more likely to kick-back-an'-bitecha?? Will such a saw bog in tha cut a lot more often?? Willya be wearin' out yer sprockets and clutch more often?? What about other parts of tha saw??

Maybe some of you guys might have some experience(s) along these lines, or know some things about bar and chain and powerhead combos that ye'll share midt der rest ob us jerkline skidder's waterboys??

Tell us, please....

 

[Old Mac Guy]

$197.50, with the shipping.....

Good point about the oiling....

 

[PhilKawasakiuser]

This guy I know who isn't anyone close has what looks like a 24 McCulloch bar inch on his McCulloch PM650. The chain needs replacing before it can be used but neither of us know which chain is the correct one for this either. Does this make sense as a saw to be used occasionally and only for a couple minutes worth of mostly mesquite. The guy is pretty short on money for upgrading equipment and can't pay many of the shop fees many people would be happy to. I got his hedge trimmer back to usable condition as well as his polesaw. He seems to be hopelessly lost when trying to work on his tools. That trimmers tank to carb line didn't go in the tank an had a breather on the end to. One of his chainsaws had no bar an chain tension adjuster either. I am also curious if there is a way to rethread a cylinder head for another spark plug then the original threads are no good anymore.

 

[svk]

This guy I know who isn't anyone close has what looks like a 24 McCulloch bar inch on his McCulloch PM650. The chain needs replacing before it can be used but neither of us know which chain is the correct one for this either. Does this make sense as a saw to be used occasionally and only for a couple minutes worth of mostly mesquite. The guy is pretty short on money for upgrading equipment and can't pay many of the shop fees many people would be happy to. I got his hedge trimmer back to usable condition as well as his polesaw. He seems to be hopelessly lost when trying to work on his tools. That trimmers tank to carb line didn't go in the tank an had a breather on the end to. One of his chainsaws had no bar an chain tension adjuster either. I am also curious if there is a way to rethread a cylinder head for another spark plug then the original threads are no good anymore.

The cheapest way would be to count the drive links and order the same chain online where the prices are much cheaper. If you have questions post up a picture of the chain and be sure to let us know of any numbers on the bar and chain.

 

[Sepia]

This guy I know who isn't anyone close has what looks like a 24 McCulloch bar inch on his McCulloch PM650. The chain needs replacing before it can be used but neither of us know which chain is the correct one for this either. Does this make sense as a saw to be used occasionally and only for a couple minutes worth of mostly mesquite. The guy is pretty short on money for upgrading equipment and can't pay many of the shop fees many people would be happy to. I got his hedge trimmer back to usable condition as well as his polesaw. He seems to be hopelessly lost when trying to work on his tools. That trimmers tank to carb line didn't go in the tank an had a breather on the end to. One of his chainsaws had no bar an chain tension adjuster either. I am also curious if there is a way to rethread a cylinder head for another spark plug then the original threads are no good anymore.

I have put heli-coil inserts into spark plug holes in aluminum heads on small engines with success, but I have never tried it on a chain saw. Perhaps if you start a new thread you will get a bit more exposure and some of the old hands will chime in with advice.