Huztl MS660

[jakemce89]

I found some more info, thoughts?

Stihl 066 660 54mm
Piston Pin 12mm x 8mm x 33mm
Pin top to top of Piston 17mm
Height 43mm


Stihl 046 460 Big Bore 54mm
Piston Pin 12mm x 7mm x 35mm
Pin to top of Piston 15.5mm
Height 36.5mm

 

[blsnelling]

That's a significant crown height and skirt length difference.

 

[Johnnybar]

I order my 660 kit and it turns out huztl shipped me a piston for a 54 mm ms 460. I realize the skirt is shorter than the ms 660 piston but I have a parts 660 saw I'm putting together, can I run a 54mm ms 460 piston in the 660 cylinder?

I wouldn't but are you certain you did receive a 660 cylinder? Mount the piston (no rings installed) to the rod and drop the cylinder on. What does it look like at TDC and can you rotate the crank freely? 660's have 40mm strokes and i think 460 strokes were in the mid 30's.

 

[jakemce89]

Yes, the cylinder is off of a parts 660.I threw the piston and cylinder on. Everything seemed to rotate and move freely so I just entertained myself and fired it up, it seems to run good...like I said this is a parts/cyclops saw so I don't have much in it.

 

[Johnnybar]

Yes, the cylinder is off of a parts 660.I threw the piston and cylinder on. Everything seemed to rotate and move freely so I just entertained myself and fired it up, it seems to run good...like I said this is a parts/cyclops saw so I don't have much in it.

If your measurements are accurate, the 460 piston skirt sits 5mm higher in relation to the piston pin than a 660 piston would. That's 5mm / 0.200" more contribution toward potential freebore but it sounds like it's handling it OK.

 

[jakemce89]

Since there is a difference in center of wristpin to top of piston would that change the combustion, what would a larger combustion space do? More compression? Less compression? The saw seems to run as normal, not saying that I will keep it like this when the 660 piston comes in

 

[emanaresi]

You have a lower compression ratio if the space above the piston at TDC is larger. That is why people worry about the "squish" or space between the piston and squish band in the cylinder. The goal is to minimize it within reason to get the compression ratio as high as is practical.

Your saw may be running, and it may pull a chain through wood just fine, after all, it is still a big saw, but here is no way it is running "normal".

 

[jakemce89]

A simple compression test will confirm lowered compression. Is that why guys aren't putting in base gaskets? It gets them less space between the piston and cylinder resulting in more compression?

 

[emanaresi]

Yeah, thats right. A compression will not tell you the compression ratio. If everything is perfect between 2 engines, the one with a higher cr will have a higher reading on the compression gauge. But there are a lot of factors that go into what your compression gauge reads. The compression ratio is the ratio of the max and minimum size of the combustion chamber.

 

[emanaresi]

Most guys set squish around .020 (.508mm) when setting up a saw.

Your 046 piston is has .059 (1.5mm) more squish clearance than an 066 piston.

I am not surprised the saw runs. I am surprised you can't tell the difference between it and a proper 066. I would expect it to be down on power, significantly.

 

[jakemce89]

So obviously a base gasket isn't required when assembling the saws? I've ran other 660's before but I can't seem to tell a significant difference in power?!?

 

[emanaresi]

I certainly wouldn't use a base gasket with that 046 piston. On my huztl, I made a base gasket from soda can because it was too tight with no gasket.

 

[emanaresi]

I just received all the bits and pieces from huztl that were missing/damaged in my kit. I was able to get them to ship me the shutter for the air box and the bushings for the top cover! Just wanted everyone to know that Huztl does have access to them.

 

[Johnnybar]

I just received all the bits and pieces from huztl that were missing/damaged in my kit. I was able to get them to ship me the shutter for the air box and the bushings for the top cover! Just wanted everyone to know that Huztl does have access to them.

So what was the final word from Huztl as to items they cannot provide? Heat foil comes to mind as one possibility?

 

[Wood Chopper]

Instead of sending 2 pounds of extra rubber pieces it would be nice to start getting those in the kits. Wonder if they have always had access or they finally heard us and started making them or getting them????


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[Johnnybar]

So obviously a base gasket isn't required when assembling the saws? I've ran other 660's before but I can't seem to tell a significant difference in power?!?

Yes and no depending on how you look at it. A "base gasket" is required to seal cylinder to deck...it's just a matter of how thick it is and what material it is made of. My "gasket" is Threebond 1184 applied to both surfaces and well skinned over before assembly.

 

[RoverRebellion]

Yes and no depending on how you look at it. A "base gasket" is required to seal cylinder to deck...it's just a matter of how thick it is and what material it is made of. My "gasket" is Threebond 1184 applied to both surfaces and well skinned over before assembly.

This is what I'm going to do with my build when I receive it. Considering I ordered my kit about a week ago, what is the likelyhood of it having the shutters, etc.?

I also wanted to take a moment and recommend Wolf Creek Saw Shop... got my big bore kit from them and they treated me like a king when I had an issue with the cylinder. They didn't even bother with a bunch of back and forth email - they called me immediately and worked with me to come up with a great solution for all involved. They have an eBay store as well as a website. I'm not involved with them in any way, I just wanted to pass along a great source for 660 big bore kits.

Lastly I've looked at NWP, Hyway cylinders and I can tell you the Nikasil plating on the Hyway cylinders is amazingly thick. This will be my cylinder of choice for this build and future builds.


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[emanaresi]

Instead of sending 2 pounds of extra rubber pieces it would be nice to start getting those in the kits. Wonder if they have always had access or they finally heard us and started making them or getting them????


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That is a good question. I had to file a paypal dispute to get them motivated. They provided all of the parts I requested including another carb, but no heat tape. I think thats the only thing they don't have.

They also gave me a partial credit for a couple things that popped up after they shipped the parts.

 

[emanaresi]

This is what I'm going to do with my build when I receive it. Considering I ordered my kit about a week ago, what is the likelyhood of it having the shutters, etc.?

I also wanted to take a moment and recommend Wolf Creek Saw Shop... got my big bore kit from them and they treated me like a king when I had an issue with the cylinder. They didn't even bother with a bunch of back and forth email - they called me immediately and worked with me to come up with a great solution for all involved. They have an eBay store as well as a website. I'm not involved with them in any way, I just wanted to pass along a great source for 660 big bore kits.

Lastly I've looked at NWP, Hyway cylinders and I can tell you the Nikasil plating on the Hyway cylinders is amazingly thick. This will be my cylinder of choice for this build and future builds.


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My guess is there is very little chance it will include the shutter, bushings for top cover, nuts for felling dogs, or bolts for muffler.

 

[RoverRebellion]

My guess is there is very little chance it will include the shutter, bushings for top cover, nuts for felling dogs, or bolts for muffler.

I assume you remedy this with OEM parts?


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