660 clone port timing numbers for milling (torque)

[Lightning Performance]

I do not believe the stroke on either motor is relevant. However which engine revs higher. I believe more than once there is no substitute for displacement. an 090 will produce a substantial amount of torque period. It is not up to me what saw you use or build. My experience by far found the the slower revving engine produced a longer lasting chain and just plain lived longer. I love my 660 for limbing and all around use but only minor use for milling. Thanks

We were discussing 070 and you jumped to the 090 right quick.


Try a real built 660 not a stock one. Even in stock form with muffler mod it will pull like an 070 up to about 42" bars. I ran side by side stock for stock cylinder, muffler mod with stock off the real chain on both. The 660 was the same cut speed. The 070 is a vibration prone anchor that drops screws like a 181 does. The cylinders potential is just an old turd.
Enjoy those dinosaurs.

Oh btw It won't matter what you believe about engine stroke. Longer arms make more grunt. Ask Stihl why they keep making it shorter and the bore bigger. It's not for torque but weight savings nothing more.

 

[Ted Jenkins]

We were discussing 070 and you jumped to the 090 right quick.


Try a real built 660 not a stock one. Even in stock form with muffler mod it will pull like an 070 up to about 42" bars. I ran side by side stock for stock cylinder, muffler mod with stock off the real chain on both. The 660 was the same cut speed. The 070 is a vibration prone anchor that drops screws like a 181 does. The cylinders potential is just an old turd.
Enjoy those dinosaurs.

Oh btw It won't matter what you believe about engine stroke. Longer arms make more grunt. Ask Stihl why they keep making it shorter and the bore bigger. It's not for torque but weight savings nothing more.

I agree that the 070 is an older design with all around slower revving motor which is more likely to produce less HP per CC. Because of slower operational speeds the older design it has some detrimental aspects and some some positive also. If you do some milling with it is quite remarkable. The 660 has some great qualities also and it is a lighter all around configuration. The 070 has more displacement to start with and with the 090 cylinder available an easy update it makes an attractive option to accomplish much milling with out much trouble. I also have an 075 and 076 which I think are not as good all around as the 070 for milling. Thanks

 

[Lightning Performance]

I agree that the 070 is an older design with all around slower revving motor which is more likely to produce less HP per CC. Because of slower operational speeds the older design it has some detrimental aspects and some some positive also. If you do some milling with it is quite remarkable. The 660 has some great qualities also and it is a lighter all around configuration. The 070 has more displacement to start with and with the 090 cylinder available an easy update it makes an attractive option to accomplish much milling with out much trouble. I also have an 075 and 076 which I think are not as good all around as the 070 for milling. Thanks

I could never stand the vibes on any 090. That is a personal preference and a huge turn off as a user.

I'm stuffing a bigger crank in the 660 to see if anything can be had from more arm. A simple task, not. The 076 was the one most of us would choose besides the 1124. Sometimes is too be said for pulling chip verse dust with the old grunt hogs as they are. The fact always remained they pull bigger chip at lower rpm. My 084 only needs to have a very very aggressive chain in 404 to pull chip milling. You have to back off quite a bit but still be on the high speed circuit to keep the fuel flow up. Much easier to do with less overall rpm on a unit that has a smaller carb. The carb plays a very import part of running off WOT. You know this with a trained hand. Your chains are exposed to less heat and less impact on the cutting edge. This does not equate to faster milling in my experience. Overall equiment wear remains about the same over the long run. The chain will stay sharp longer but why make a 25 minute cut that requires you to refuel when I'm doing it on one tank in 15 minutes?

Please explain the advantages?

One thing of curiosity to me is do you run a ten pin milling?
404 or 3/8?

 

[thompsoncustom]

I'm stuffing a bigger crank in the 660 to see if anything can be had from more arm.

you'll have to let us know how this turns out, I've been thinking about making a 106cc ms660 which would be a good comparison for the 070 CC wise at least.

 

[Ted Jenkins]

My experience

I could never stand the vibes on any 090. That is a personal preference and a huge turn off as a user.

I'm stuffing a bigger crank in the 660 to see if anything can be had from more arm. A simple task, not. The 076 was the one most of us would choose besides the 1124. Sometimes is too be said for pulling chip verse dust with the old grunt hogs as they are. The fact always remained they pull bigger chip at lower rpm. My 084 only needs to have a very very aggressive chain in 404 to pull chip milling. You have to back off quite a bit but still be on the high speed circuit to keep the fuel flow up. Much easier to do with less overall rpm on a unit that has a smaller carb. The carb plays a very import part of running off WOT. You know this with a trained hand. Your chains are exposed to less heat and less impact on the cutting edge. This does not equate to faster milling in my experience. Overall equiment wear remains about the same over the long run. The chain will stay sharp longer but why make a 25 minute cut that requires you to refuel when I'm doing it on one tank in 15 minutes?

Please explain the advantages?

One thing of curiosity to me is do you run a ten pin milling?
404 or 3/8?

My experience went like this. I had been using the 070 for awhile going from a 056 driving a 3/8 chain which was not too bad. One thing was obvious was the the 404 chain needed much less attention than I thought it would. Then I got the 660 and thought it would be unstoppable but it devoured chains. It did cut well and could be used for limbing which was a big plus. Then I thought to set up the 660 with a 404 chain and a smaller drive sprocket which did work but was quite a bit of effort to get to that point. Then I wanted to use the 660 in the field and not mill with it. Overall the effort to change back and forth did not seem like worth while effort. So I was happy just using the 070 to free hand the beams that I want out in the field then bring them back to my shop to true them them up and lightly plane them as needed. I suppose the bottom line would be how much lumber a OP want to go through and whether they plan to mill out in the field or mill strictly from the shop. There are many advantages to be able to mill out in the field then bring lumber to a shop for fine tuning. Not bringing waste to your shop and the ease of transporting seems worth while. Using the 660 as a platform I am sure is doable but at what amount of effort to do so seems like the question. Thanks

 

[Lightning Performance]

you'll have to let us know how this turns out, I've been thinking about making a 106cc ms660 which would be a good comparison for the 070 CC wise at least.

The problem as you know is losing the oil pump because the real-estate is gone with a bigger everything on the pto side. An alternative pump has to be fitted. If not the whole build is a fail as useful tool. Have a bad case to chop up was the easy part. Getting the case to sustain the larger works will be the chore.

 

[Lightning Performance]

My experience

My experience went like this. I had been using the 070 for awhile going from a 056 driving a 3/8 chain which was not too bad. One thing was obvious was the the 404 chain needed much less attention than I thought it would. Then I got the 660 and thought it would be unstoppable but it devoured chains. It did cut well and could be used for limbing which was a big plus. Then I thought to set up the 660 with a 404 chain and a smaller drive sprocket which did work but was quite a bit of effort to get to that point. Then I wanted to use the 660 in the field and not mill with it. Overall the effort to change back and forth did not seem like worth while effort. So I was happy just using the 070 to free hand the beams that I want out in the field then bring them back to my shop to true them them up and lightly plane them as needed. I suppose the bottom line would be how much lumber a OP want to go through and whether they plan to mill out in the field or mill strictly from the shop. There are many advantages to be able to mill out in the field then bring lumber to a shop for fine tuning. Not bringing waste to your shop and the ease of transporting seems worth while. Using the 660 as a platform I am sure is doable but at what amount of effort to do so seems like the question. Thanks

The 660 has no problem taking a 58mm bore if the case is enlarged a bit. The problems are all downstairs adding 2mm and the bearing.

 

[NSEric]

I'd just like to throw my timing numbers in here for my big bore 56mm 660 clone.
I tried two different 56mm cylinders(the dirt cheap matalo from amazon), both have jb weld in the intake to get it right, small finger ports, stock width intake and exhaust ports and flipped pistons. Both have .022-.025 squish with a gasket and so much compression they are hard to start, a good decomp is a must.
First I tried 100 ex, 120 transfers/fingers and 80 intake. It sucked, not enough blow down/case compression, it wouldnt four stroke above 12000rpm and lacked power.
Next I tried 97 ex, 125 transfers/fingers and 82 intake(was shooting for 80 but didnt add enough jb weld) This ones a runner, still four strokes at 14000rpm and cuts plenty fast.
Out of the box these cylinders had 100 ex, 128 transfers and 88 intake, they free port a hair but not enough to cause issues. If you want 100 ex dont raise the transfers and just add jb weld to the intake to get close to 80.

 

[Lightning Performance]

I'd just like to throw my timing numbers in here for my big bore 56mm 660 clone.
I tried two different 56mm cylinders(the dirt cheap matalo from amazon), both have jb weld in the intake to get it right, small finger ports, stock width intake and exhaust ports and flipped pistons. Both have .022-.025 squish with a gasket and so much compression they are hard to start, a good decomp is a must.
First I tried 100 ex, 120 transfers/fingers and 80 intake. It sucked, not enough blow down/case compression, it wouldnt four stroke above 12000rpm and lacked power.
Next I tried 97 ex, 125 transfers/fingers and 82 intake(was shooting for 80 but didnt add enough jb weld) This ones a runner, still four strokes at 14000rpm and cuts plenty fast.
Out of the box these cylinders had 100 ex, 128 transfers and 88 intake, they free port a hair but not enough to cause issues. If you want 100 ex dont raise the transfers and just add jb weld to the intake to get close to 80.

Um, first off why do you even care where the top end is? Four-stroke? Or falls off?

I see no point is using that as reference point when milling.

I have 22° blowdown it was 24 and also tested at 20.

Your intake is done at 82 unless you address air inlet issues. I now run an 87 intake and yes it's a bit too long for milling under 10k. The next six jugs get a major compression bump by filling in the chamber area. One needs a sparkplug relocation just to see how that goes. 0.035 is bit tight near the plug strap. It will likely be moved 0.040 and run a gapless type.

Did you taper the exhaust port window at all or hog out the port area?
What radius did you use on the port windows?

I'm always looking for something different from my stuff.

 

[NSEric]

It's not a milling saw for me, I'll never use a chainsaw for milling, my neighbor has a nice portable band saw mill.
The big bore with 100ex, 120t , 80in was low revving and slower cutting than an out of the box 660 clone cylinder, it was total dud.
I dont recommend those numbers in a 56mm 660, they maybe fine in the better 54mm cylinder.
The blow down is less important then the case compression to me, you need over 40 degrees difference between the intake and transfers. IE 80 intake 122 transfers or 82 intake 125 transfers. 82 intake and stock height 128 transfers would be fine too.
I rounded the edges of the intake and exhaust ports but didnt change much at all shape wise. I added finger ports so I left the exhaust narrow so I could flip the piston without worry.

On the other forum, they recommend 95-96 on the exhaust of a 660 as the port is very narrow for a 90cc saw.
I have stock squish/compression, it's really high and a bear to start, I wouldnt want more.

 

[Lightning Performance]

40°case time is quite common. Getting something to pull well below that takes even more work. 38 is pushing it. 42 is better.
Fix the intake so it's wide and bring it back to 78° or 156°D to get your 42 case time back. You'll see the change.

Your AM jugs will never have the right shot coming out of the transfer ports unless you fill and fix them. You got what you paid for.

 

[Bjorn T]

Blowdown and case compression is two different things.

 

[NSEric]

40°BD is quite common. Getting something to pull well below that takes even more work. 38 is pushing it. 42 is better.
Fix the intake so it's wide and bring it back to 78° or 156°D to get your 42° back. You'll see the change.

Your AM jugs will never have the right shot coming out of the transfer ports unless you fill and fix them. You got what you paid for.

The 56mm cheap matalo cylinder on it now runs great.
IMO those cheap jugs need finger ports, the transfers are so bad they're almost like open ports.
The whole point of my posting on here was someone claimed 100 exhaust, 120 transfers and 80 intake were good numbers for a 660 clone for milling, they are not good timing numbers for these saws.

I did fix the crappy running cylinder but havent tried it yet, it's my spare top end now, I think it'll be fine.
I went with 78 intake, 120 transfers( I cant lower them) and 95 on the exhaust.

 

[Lightning Performance]

Blowdown and case compression is two different things.

Edited.
Better?
Busy morning online today and early afternoon. Mistakes happen

 

[Lightning Performance]

The 56mm cheap matalo cylinder on it now runs great.
IMO those cheap jugs need finger ports, the transfers are so bad they're almost like open ports.
The whole point of my posting on here was someone claimed 100 exhaust, 120 transfers and 80 intake were good numbers for a 660 clone for milling, they are not good timing numbers for these saws.

I did fix the crappy running cylinder but havent tried it yet, it's my spare top end now, I think it'll be fine.
I went with 78 intake, 120 transfers( I cant lower them) and 95 on the exhaust.

Cut out the port and try an open one.

Plenty of people run 100 120 80 on 460s and 660s. Might be better for short bars. The 460 I did years ago is still doing well with those numbers and a 28 bar. Most people are likely running a 25 bar but might be milling with it also. A 42 bar on the mill is only a few more cutters in the wood with a heavier chain. Chain will mean a bunch if the torque is there. Many are not. The intake starts at the air filter. That is sorley missed or a Vstack. The lengths change everything about the longer intake duration. Stock type filters and box will not run it's best with more than 80 intake.

 

[Lightning Performance]

The 56mm cheap matalo cylinder on it now runs great.
IMO those cheap jugs need finger ports, the transfers are so bad they're almost like open ports.
The whole point of my posting on here was someone claimed 100 exhaust, 120 transfers and 80 intake were good numbers for a 660 clone for milling, they are not good timing numbers for these saws.

I did fix the crappy running cylinder but havent tried it yet, it's my spare top end now, I think it'll be fine.
I went with 78 intake, 120 transfers( I cant lower them) and 95 on the exhaust.

They can be lowered.

 

[NSEric]

Cut out the port and try an open one.

Plenty of people run 100 120 80 on 460s and 660s. Might be better for short bars. The 460 I did years ago is still doing well with those numbers and a 28 bar. Most people are likely running a 25 bar but might be milling with it also. A 42 bar on the mill is only a few more cutters in the wood with a heavier chain. Chain will mean a bunch if the torque is there. Many are not. The intake starts at the air filter. That is sorley missed or a Vstack. The lengths change everything about the longer intake duration. Stock type filters and box will not run it's best with more than 80 intake.

The chinese 660 big bores are different then the normal 460's and 660's.
Those numbers are fine in an OEM cylinder or some of the 54mm 660 after market ones with decent transfers.
If I spend any more time or money on the 660 clone, it will be on a 54mm cylinder, the 56mm with a bunch of work is only a little better than the 54mm was out of the box. I slipped making finger ports and wrecked the 54mm cylinder the saw came with.

I also know I could machine the cylinder to lower the transfers but wouldnt bother on a 30 dollar cylinder, I'd just buy another and start over.

 

[Lightning Performance]

The chinese 660 big bores are different then the normal 460's and 660's.
Those numbers are fine in an OEM cylinder or some of the 54mm 660 after market ones with decent transfers.
If I spend any more time or money on the 660 clone, it will be on a 54mm cylinder, the 56mm with a bunch of work is only a little better than the 54mm was out of the box. I slipped making finger ports and wrecked the 54mm cylinder the saw came with.

I also know I could machine the cylinder to lower the transfers but wouldnt bother on a 30 dollar cylinder, I'd just buy another and start over.

Money
You've spent nothing on parts. You admit it is a thirty dollar pos and expect a miracle. Just stop buying junk and spend the money to get a good cylinder. I hear complaints constantly but people won't spend good money on good parts.

Cut open the port if you want more flow with garbage transfer ports. It's just that simple.