High or Low RPM Power Heads???

[zzrjohn]

We all agree a large capacity power head is required, I have read that the high rpm saws need slowing down by retuning the carb (066/084/088/880), does this mean that the older high torque low rpm saw are preferable for milling (070/090)........

Which type do you prefer and why?

 

[aggiewoodbutchr]

We all agree a large capacity power head is required, I have read that the high rpm saws need slowing down by retuning the carb (066/084/088/880), does this mean that the older high torque low rpm saw are preferable for milling (070/090)........

Which type do you prefer and why?

I have not milled with any of the 070/090 etc. saws so I can't help you with that one.

What I have learned through my experience with testing different sprockets on my 084 is finding the right ballance between available torque and chain speed is the a key factor to efficient milling, especially with long bars. For example, while keeping all other variables as equal as possible, I ran a series of test cuts with 3/8" chain changing only the sprocket size from 7, 8, 9 and 10 pin sprockets. Cut speed improved substantially from 7 to 8 and again from 8 to 9, but no gains were seen with the 10 pin. Chip clearance seemed to be a major factor in these tests and the faster they were removed from the kerf, the faster the saw cut to a point where torque suffered.

I guess how this applies to your question is it illustrates how low RPM/ high torque doesn't always translate to faster cuts when it comes to milling.

As far a detuning is concerned, I reduce the WOT RPM's by about 500 for milling to be on the safe side. This practice seems to keep the saw cooler.

 

[Adkpk]

Low rpm, more torque. If I could go back in time, my choice for milling would be a 395. Just as many horses but lower rpms and geared for more torque. The 066 is to fast for milling. Does the job for sure but my opinion is the saw suffers. I've tuned it down and that works fine but the 395 seems to me a better saw to mill with. Never used an 090 but sure would like to see one do it's dirty work.

 

[aggiewoodbutchr]

I guess I should qualify my above statement a bit...

I'm running a modified 084 and it has power to spare. I wish I could get my hands on an 090 as well to compare the two in the cut.

 

[Railomatic]

I would like to add the following information.

I have also messed about with sprokets etc and come out with the same findings as Haggy.

Where the real benefits are gained is by reducing the chain sizes, 3/8 is good on the big saws of the 880 etc, but where the real advantage lies is a combination of saw and bar,see below

Makita 9010, = 90cc which are a very good saw and can be bought for half the price of an 880 or 3120, using a Cannon or similar bar, which can be conveted down to a 325 chain, the result is a much faster cut with a much better finish.

In some cases you wil have to re-drills the oil ways, but the Dolmar will take the big Stihl bar.

There is no real need to go for a 325 on the really big saw, unless you are cutting over 50 - 60 inches wide,

 

[aggiewoodbutchr]

I would like to add the following information.

I have also messed about with sprokets etc and come out with the same findings as Haggy.

Where the real benefits are gained is by reducing the chain sizes, 3/8 is good on the big saws of the 880 etc, but where the real advantage lies is a combination of saw and bar,see below

Makita 9010, = 90cc which are a very good saw and can be bought for half the price of an 880 or 3120, using a Cannon or similar bar, which can be conveted down to a 325 chain, the result is a much faster cut with a much better finish.

In some cases you wil have to re-drills the oil ways, but the Dolmar will take the big Stihl bar.

There is no real need to go for a 325 on the really big saw, unless you are cutting over 50 - 60 inches wide,

After Rail mentioned using 325 a few months ago, I had to try it for myself. The results were impressive on a 44" bar. I tried both 9 and 11 pin sprockets and while the 11 pin cut somewhat faster on the first cut, it dulled more quickly and vibrated badly.

Thanks for the tip, Rail.

 

[Railomatic]

I guess I should qualify my above statement a bit...

I'm running a modified 084 and it has power to spare. I wish I could get my hands on an 090 as well to compare the two in the cut.

Looking over this thread again and I have forgot to mention, I have tried an older 090 one from the late seventies, I must agree it had a lot of power but the only area where it shone was in the low torque field,
modern saws tend to be reving more where as the older saws like the 090 and my freinds old 111s Jonsered have a long stroke engine, which are very good for really tough felling jobs.
My MS880 has the same power as an 090 but works much better using less fuel per board, so I wouldn't go for the 090.

 

[BobL]

How much of what has been said so far in this thread depends on what you are cutting? For example Aussie hardwood? I asked my local stihl agent about moving from a 404 to a 3/8 chain (for an 076) and he advised against this when using such a big/powerful saw in Aussie hardwood. He said he sees too many snapped 3/8 chains because the aussie hardwoods put so much resistance against the chain. Does that make sense, or is he maybe just trying to sell me his excess 404 chain?

 

[oakman]

well you don't ''detune'' a saw for less rpms for milling. thats silly. you want to richen up the H for more fuel to keep the motor from frying. more fuel means more cooling effect on the piston. and if anybody thinks a 40 year old saw will mill as fast as a modern one of the same cc's, go ahead and give it a try. i have, and there's no way. i mill with a d/p 066. and i went from a 8 pin to a 7 for more torque, but it was slower. so my opinion is you want speed and torque, i.e., modern saw.

 

[Railomatic]

How much of what has been said so far in this thread depends on what you are cutting? For example Aussie hardwood? I asked my local stihl agent about moving from a 404 to a 3/8 chain (for an 076) and he advised against this when using such a big/powerful saw in Aussie hardwood. He said he sees too many snapped 3/8 chains because the aussie hardwoods put so much resistance against the chain. Does that make sense, or is he maybe just trying to sell me his excess 404 chain?

If you are using 325 chain you don't need to use the biggest saws, a good combination is a mid range saw like the 385 husky dolmar 9010, then the power to weight ratio is better and you won't get broken or badly stretched chains.
What you loose in power you gain in less curf and less fuel, the equipment is also cheaper than running the bigger saws, in the long term you are a winner.

 

[aggiewoodbutchr]

How much of what has been said so far in this thread depends on what you are cutting? For example Aussie hardwood? I asked my local stihl agent about moving from a 404 to a 3/8 chain (for an 076) and he advised against this when using such a big/powerful saw in Aussie hardwood. He said he sees too many snapped 3/8 chains because the aussie hardwoods put so much resistance against the chain. Does that make sense, or is he maybe just trying to sell me his excess 404 chain?

The only time I have broken a 3/8" chain is when I found a 6" nail in the log. Other than that they have lasted just fine for me. In my tests where I ran several different types of chain back to back in the same log, I found that 3/8 actually cut slightly slower than 404 on my setup but did produce a narrower kerf and slightly smoother finish. This was in six month old water oak which has a dry specific gravity of .63. For comparison, Australian red gum is .46 green and .62 dry.

 

[Railomatic]

well you don't ''detune'' a saw for less rpms for milling. thats silly. you want to richen up the H for more fuel to keep the motor from frying. more fuel means more cooling effect on the piston. and if anybody thinks a 40 year old saw will mill as fast as a modern one of the same cc's, go ahead and give it a try. i have, and there's no way. i mill with a d/p 066. and i went from a 8 pin to a 7 for more torque, but it was slower. so my opinion is you want speed and torque, i.e., modern saw.

I second this, my friend has an older Jonsered 111s, she is about 30 years old and can mill ok but very slowly, she uses huge amounts of fuel compared to my 088 and has oiling problems which only makes the problem worse, you can't beat a modern saw for power reliability and speed, n, ease of use.

 

[brian660]

090G is hands down the best saw i`ve ever used for milling, my first was a junker that took me a while to find parts for because I refused to have 2 grand in a chainsaw, but it seems like after I got that one running I could damn near go out and trip over a fairly cheap 090 every few months.

 

[stonykill]

I'll go for lower rpm, hi torque old school saws all day long