Woods Porting The MS660......Tricks And Tips

[Mastermind]

In this thread I will try to dispel some common myths and rumors about the late model MS660. I've Done more than a couple of these saws.....and have made a few mistakes. I learned a couple of tricks in the process and figured I would share them.

Here's the victim....a nearly new MS660....a tank or so has been put through it.

The HD2 filter is a performance enhancer all by itself. I've seen a 500rpm increase by just replacing the old filter with one of these.

Nice huh? I love working on new saws.

Here's another place we will find gains in cut speed. I cut .020 from the edge of the flywheel key and advance to ignition about 8°. The flywheel must be moved counterclockwise.

Here we open this tiny outlet up to 3/4". If more outlet is needed a dual port cover is a great idea.

In order to keep the bracing effect of this baffle, we cut off the end and about an additional 1/4" or so. I forgot to take a pic of that.

Inside the carb there is normally some casting flash at the venturi....this one was very smooth though. Most of the time we clean that up to enhance flow thru the carb.

The machine work has been done in this shot. Without a base gasket this engine only had .007 squish clearance. We cut .063 from the squish band and removed .045 from the base to end up with a .025 squish clearance.

 

[pioneerguy600]

Awesome Randy,..I am currently building one so I will follow this thread closely.

 

[mtrees]

Me too!!

 

[Tzed250]

Thanks for another great thread Randy.

 

[saxman]

Randy,
I too will follow closely, I have a 660 I purchased new in 2009 and I am thinking seriously about sending it to you for woods porting this winter. My dealer installed a dual port cover before I picked it up and I have installed the high output piston and bolt in the oil pump as I keep a 36" on it all the time. I have lots of other saws to play with but the 660 is the big daddy and I would like to take it to the next level. I will PM you when I am ready, thanks

Steve

 

[Mastermind]

Here's a couple of shots of the stock ports. After the machine work the height of the exhaust port is 4° lower......that's a good thing on the MS660. Care must be taken not to raise it any during the porting process. It's at 98° now.

In this picture notice the bevel on the bottom edge of the bore......it helps to let the ring into the jug without damage.

This is an area that can cause grief if not taken proper care of. Lowering the jug causes the transfer bulges to come in contact with the case. I find it ends up nicer to clearance the case rather than the jug.

Here the cylinder after the port work and polish. Notice the plating at the top center of the exhaust port. I'm careful not the raise it at all.......it's all but impossible to blend the plating in completely smooth.

The lowers are dropped to the base and blended in. On the uppers I've raised them to 122° and widened them slightly. The ring end locations only leave a little room for widening them toward the intake, I also take them toward the exhaust a bit......the angle of entry must be maintained when doing this though, so a right angle handpiece is a must.

On the intake I don't lower it at all, it's already got plenty of intake duration. I just widen and reshape the port. Notice the finish......60 grit is as fine as I go on this port.

 

[Mastermind]

I like a slick exhaust port.......hell, if nothing else it looks good.

Here's the kicker.......this saw had 148psi before I tore it down......

It was dark when I finished her up. There will be before and after videos tomorrow. I also try to put at least a tank of fuel thru every saw I build.....that takes time with some saws but I figure this one won't take too long.

 

[Nardoo]

Nice work Randy. Your pictures are so good even an old dolt like me can follow. Not necessarily understand, of course, but follow.

Al.

 

[Mastermind]

Awesome Randy,..I am currently building one so I will follow this thread closely

Heck Jerry it was your thread on the 046 that lit a fire under my ass to start porting saws in the first place.

Me too!!

I hope......it's your damn saw!!!!

Thanks for another great thread Randy.

You're welcome John. I've been able to get good gains on this model and figured I should share.

Randy,
I too will follow closely, I have a 660 I purchased new in 2009 and I am thinking seriously about sending it to you for woods porting this winter. My dealer installed a dual port cover before I picked it up and I have installed the high output piston and bolt in the oil pump as I keep a 36" on it all the time. I have lots of other saws to play with but the 660 is the big daddy and I would like to take it to the next level. I will PM you when I am ready, thanks

Steve

I'll be here.

 

[NPKenny]

This is easily my favorite thread of the day. I've got to get my jug dropped and squish band cut!!

Thanks for sharing, Randy.

 

[blsnelling]

Very nice Randy

 

[parrisw]

Nice work Randy as usual.

One thing, you say you don't lower the intake port, but it does get lowered with the machine work in-case someone doesn't realize that.

 

[pioneerguy600]

Heck Jerry it was your thread on the 046 that lit a fire under my ass to start porting saws in the first place.



I hope......it's your damn saw!!!!



You're welcome John. I've been able to get good gains on this model and figured I should share.




I'll be here.

You have come a long way, Grasshopper,..keep up the great work and threads that make being a active member of this forum worthwhile.....

 

[parrisw]

You have come a long way, Grasshopper,..keep up the great work and threads that make being a active member of this forum worthwhile.....

Yes!! Its what I like to read on the forum.

 

[Mastermind]

Nice work Randy as usual.

One thing, you say you don't lower the intake port, but it does get lowered with the machine work in-case someone doesn't realize that.

Good point Will. I should have stated that the intake should not be lowered any further. Any more doesn't seem to do anything but cause it to use more fuel.

 

[josh1981]

Nice write up thanks for sharing

 

[parrisw]

Good point Will. I should have stated that the intake should not be lowered any further. Any more doesn't seem to do anything but cause it to use more fuel.

Ya, it'll drink enough as is!! I know the last 395 I built could of used a fuel truck behind it.

 

[Stihlman441]

Nice work Randy again and again
There is not many builders that have the b_lls to show there work to the world.

 

[Primoburrito]

so sorry to bud in

Hey Guys,
I'm sorry, I cant seem to figure out how to start a new post.
I have a 066 Magnum that I want to discuss and I have forgotten how to post a new thread.
A little guidance would be much appreciated..

 

[Mastermind]

Hey Guys,
I'm sorry, I cant seem to figure out how to start a new post.
I have a 066 Magnum that I want to discuss and I have forgotten how to post a new thread.
A little guidance would be much appreciated..

Near the top of the chainsaw forum main page.......click on "start new thread".