MS660 stock to big bore conversion...

[MCW]

Hi peoples.
I was talking to Andrew (stihlman441) a while back and asked if he'd like to be an 066/660 big bore test mule. He said yes so I decided to donate a big bore kit to play around with and fit it to his immaculate Aussie spec MS660. He has commented a number of times about how strong his 660 is compared to other guy's 066's and MS660's that he's run.
Anyway the saw arrived nicely packed a few weeks back but hadn't had the opportunity to run it until last weekend. I had planned on getting a few larger (36 odd inch) pine logs here to play with but unfortunately time didn't allow it.
I ended up testing the saw stock in a hardwood log about 12-14" in diameter. I used a 20" Tsumura with 8 pin rim and Carlton semi chisel. The chain was setup "semi" aggressive but was a walk in the park for a saw like this. It ran way better than I thought it would with really good throttle response for a stock saw. After the first run and video I did the top end change and a muffler mod.
Firstly like most pro saws getting the lid off was easy and within about 15 minutes the top end was off (if that). The P&C on this saw was a Stihl branded one, not Mahle. On closer inspection it actually wasn't bad quality and not as bad as the two previous 660's I've owned. Prior to porting they had more dag's than a sheep's bum (maybe the Aussies will understand this one?). It was pulling 155psi warm. Andrew had measured it at 150psi.

Stock P&C...

(by the way Andrew, I actually found a bit of DIRT on your saw!!!)

 

[MCW]

Plus a piston comparison (the stock piston was longer)...

And BB kit photos. These kits are very nicely finished. I whacked a set of Caber rings on too as I still have trouble trusting supplied rings on some of these aftermarket kits...

I also fitted a Work's Connection tacho as requested by Andrew. I was originally a bit sceptical about these after a fellow AS member fitted one a while ago and started a thread on it but thought the hour meter would be handy. Just so happens both the hour and tacho feature provide some interesting entertainment. I have a few for my own saws and had one fitted to my last MS660. Where it has been mounted does not get in the way at all - you just have to ensure you route the wires correctly to avoid getting them pinched in the handle's antivibe.

 

[Slamm]

I'll be interested in what you find. I had a Big Bore 660 and an OEM both were modded by the same guy, and I couldn't stand the Big Bore. It had torque out the rear, but was slow, it was like a diesel. I like the OEM much, much better.

That Tach thing looks pretty neat, can we get them in the US?

Sam

 

[JDNicol]

The cylinder is a Kolbenshmidt one (Signified by the K and S overlayed). They always used to do good work (IMO), haven't seen much of them on Stihls recently though.
I know in the past they did piston and cylinders for the Husky 3120XP and Stihl 075/076 along with many smaller saws.

 

[MCW]

I also performed a muffler mod while I had it apart and simply removed the end of the cage. I didn't change anything else. It only increased exhaust noise slightly.
The video is below and although the times of the stock kit compared to the BB kit look disappointing, the BB kit felt every bit as strong as the stock kit. I am still running it quite rich and it seemed to have oodles of torque. I will say this - when I ran through the videos and worked out the times I was shocked as I messaged Andrew the second after I'd run it and said it didn't get slower. Despite the times I don't actually think it did - hard to explain.
The log got a little bit wider for the BB test plus I was digging into the lump of wood I had the log sitting on. I did actually try my hardest to compensate for this in the times. The chains were the same for both kits and fresh. I also stuck my modded 7900 in the mix as well with a very similarly setup Carlton Semi Chisel chain.
As another Aussie member mentioned port timings may have contributed to the difference in cut times but I feel with longer bars the BB kit will easily match the stock kit - time will tell.
The other thing to take into account is that "maybe" the Aussie dual port mufflers are also quite free flowing, meaning removing the cage did very little to performance? Another factor I considered was the "perceived' performance gains from a louder and tougher exhaust note.
Anyway here's the video

<iframe width="560" height="315" src="http://www.youtube.com/embed/NgMxiDxgpZY" frameborder="0" allowfullscreen></iframe>

I haven't publicly listed this video on Youtube as videos like this seem to attract nothing but dic*heads. I'm also sick of endlessly explaining to guys that yes my chains are new/sharp and dead Aussie hardwood does create dust with a sharp chain. I have then had to explain that no, properly filed square chisel won't cut better in wood like this etc etc.
I blocked my first guy ever the other day because he said the video I did of my fully modded 660 compared to my stock BB kitted Makita 6401 was meaningless, that Youtube chainsaw comparos were full of liars, nobody can be trusted with comparisons like this etc etc. If he'd have carried on like that to my face I'd just plain have to beechslap him. Ubér cyberlegends, they're everywhere...

 

[MCW]

I'll be interested in what you find. I had a Big Bore 660 and an OEM both were modded by the same guy, and I couldn't stand the Big Bore. It had torque out the rear, but was slow, it was like a diesel. I like the OEM much, much better.

That Tach thing looks pretty neat, can we get them in the US?

Sam

Hi Sam.
My thoughts are similar on the BB kit regarding truck like torque but no real speed - despite not checking revs in the wood with the stock kit the BB kit was holding between 10,500-11,000 rpm in the cut in that video. Andrew is intending to mill with it and I think in that case it will be suitable. The Work's Connection tachos were actually sourced from the US itself I can't remember where though - I know I have a confirmation email somewhere in my inbox but can't remember who to search for.

The cylinder is a Kolbenshmidt one (Signified by the K and S overlayed). They always used to do good work (IMO), haven't seen much of them on Stihls recently though.
I know in the past they did piston and cylinders for the Husky 3120XP and Stihl 075/076 along with many smaller saws.

Thanks and good to know. The recent 660's I've owned, ported by Brad Snelling, were the same as these and were very poorly finished.

 

[Stihlman441]

I'll be interested in what you find. I had a Big Bore 660 and an OEM both were modded by the same guy, and I couldn't stand the Big Bore. It had torque out the rear, but was slow, it was like a diesel. I like the OEM much, much better.

That Tach thing looks pretty neat, can we get them in the US?

Sam

Ya Sam they come from the US and have found them very usefull,interesting to see the hrs ya put on ya saws and for tuning,ya can see rpm in the cut,when ya turn ya saw off it shows max rpm.
I get them from
Works Connection 2 & 4 Stroke Engine Tach Tachometer & Hour Meter 37-100: 37-100 Seismic Cycles

 

[Slamm]

LOL, a mill, thats where my BB660 went. I sold it to a guy that is going to use it in a chainsaw mill, milling some hard South African wood, it should be perfect for that setup.

I honestly thought the thing was weird, had torque out the rear, but no speed. I hated limbing with the thing, LOL, you had to hit the trigger about .5 second before hitting the limb, just to get the revs up high enough, but in a big cut you could just pull on it hard and it would just cut right along very nicely.

Sam

 

[Slamm]

Ya Sam they come from the US and have found them very usefull,interesting to see the hrs ya put on ya saws and for tuning,ya can see rpm in the cut,when ya turn ya saw off it shows max rpm.
I get them from
Works Connection 2 & 4 Stroke Engine Tach Tachometer & Hour Meter 37-100: 37-100 Seismic Cycles

Perfect, thank you, I am going to get some. I like things like that for checking things like trees cut per hour, or how many hours my saw ran in order to get X amount of wood on the ground. Thanks,

Sam

 

[MCW]

Oh and forgot this photo. I installed the kit without a base gasket - squish was a very nice .0195" Haven't checked compression yet as it only has half a tank on it - I'm sure Andrew will check that when he gets his saw back, if I can't sell it in the meantime

 

[MCW]

Perfect, thank you, I am going to get some. I like things like that for checking things like trees cut per hour, or how many hours my saw ran in order to get X amount of wood on the ground. Thanks,

Sam

You're probably well aware of this already with the work you do Sam but you'll be putting way more hours on your saws than you think. I was really surprised on my 660 as I only fitted the tacho late and when I thought I'd done two hours it was actually more like 3-4.

 

[Stihlman441]

Nice work there Matt.

(by the way Andrew, I actually found a bit of DIRT on your saw!!!)

That bit of dirt is my most liked stuff in the world, Redgum dust.:msp_angry:

This will be interesting to see the differance the BB kit makes,i have done vids in Cypress with a .040'' raker chain when it was stock so i still have the same log and chain to put it back into when she gets home.The torque is what im looking for and the milling will sort that out.
Thanks again Matt for your efferts and time.

 

[Slamm]

I think you will be quite happy if you are wanting torque, as it will be like a diesel through the wood, just very steady.

Sam

 

[w8ye]

Seismic Cycles has no phone number, mobile or land line, nor brick and mortar address listed on their web site.

If there is any problem with your order - there is nothing you can do about it!

I would hesitate to do business with them or trust them with my CC #?

 

[Stihlman441]

I have got two lots of tachs from them and had no probs.:msp_thumbsup:

 

[MCW]

Nice work there Matt.

(by the way Andrew, I actually found a bit of DIRT on your saw!!!)

That bit of dirt is my most liked stuff in the world, Redgum dust.:msp_angry:

This will be interesting to see the differance the BB kit makes,i have done vids in Cypress with a .040'' raker chain when it was stock so i still have the same log and chain to put it back into when she gets home.The torque is what im looking for and the milling will sort that out.
Thanks again Matt for your efferts and time.

No problemo mate. Easy stuff I've got a MS650 and an 066 to do for a guy this weekend.

Seismic Cycles has no phone number, mobile or land line, nor brick and mortar address listed on their web site.

If there is any problem with your order - there is nothing you can do about it!

I would hesitate to do business with them or trust them with my CC #?

I haven't had any issues with them either. I did have a charge come up on my credit card to www.fatchicksandbabyoil.com but then remembered that was legit and my annual subscription...

Their address was on their invoice (not brick and mortar) but email was [email protected]

Seismic Cycles, LLC
PO Box 483
Cotati, CA 94931

 

[MCW]

I wonder how may people will click on my fatties link before realising I was joking?

 

[openloop]

That is a neat little tach isnt it? I have found that you can make it work with inductance also. Just bunch up the wire near the plug and it will pick up the signal.

edit: Oh and IBTOGTAPPOTT (in before the "old growth" take a poo poo on the tach)

 

[mtngun]

Thanks for the excellent pics and information, MCW.

Maybe it's just the pic, but looks like the chinese jug has the usual black ring of death at the top of the bore.

 

[Stihlman441]

Perfect, thank you, I am going to get some. I like things like that for checking things like trees cut per hour, or how many hours my saw ran in order to get X amount of wood on the ground. Thanks,

Sam

It would be interesting to see if ya put a tach on the older ported 441 and one on the new ported 441 C M-Tronic and see fuel use and hrs between them.