NeoTech 660 Build

[twalsh341]

Hi Everyone,

I'm new here, working on getting a clone 660 up and running. I'm planning on using this thing to mill, but also buck cants. I have another saw for limbing.

The original squish was .052", I wasn't really excited by the idea of a base gasket delete ( and when I measured squish without mine I was getting .015-.018". I turned the base down and am currently at .030" squish and think I'll keep it here unless there's a compelling reason to trim it down some more.

After the base trim, with .030" squish. I have the following timing numbers. Exhaust Crasks at 93 degrees ATDC, Duration 174

Intake opens at 79 degrees, and transfer opens at 122 degrees.

Blowdown: 29 degrees

Does the exhaust seem too low? Do the transfer ports need to be adjusted? Also you'll notice in two pictures showing the ring in place at 122 degrees to map the transfer ports that the exhaust end of the TP is slightly lower than the intake side. My understanding is that this ain't the best geometry.

I plan to open up the bottom of the transfers and blend them well, bevel all the port edges, widen the int/exh as far as skirt will reasonably allow. My questions are whether these timing numbers need to be adjusted and to where?

 

[Ronie]

Hi Everyone,

I'm new here, working on getting a clone 660 up and running. I'm planning on using this thing to mill, but also buck cants. I have another saw for limbing.

The original squish was .052", I wasn't really excited by the idea of a base gasket delete ( and when I measured squish without mine I was getting .015-.018". I turned the base down and am currently at .030" squish and think I'll keep it here unless there's a compelling reason to trim it down some more. View attachment 308374

After the base trim, with .030" squish. I have the following timing numbers. Exhaust Crasks at 93 degrees ATDC, Duration 174

Intake opens at 79 degrees, and transfer opens at 122 degrees.

Blowdown: 29 degrees

Does the exhaust seem too low? Do the transfer ports need to be adjusted? Also you'll notice in two pictures showing the ring in place at 122 degrees to map the transfer ports that the exhaust end of the TP is slightly lower than the intake side. My understanding is that this ain't the best geometry. View attachment 308372 View attachment 308373

I plan to open up the bottom of the transfers and blend them well, bevel all the port edges, widen the int/exh as far as skirt will reasonably allow. My questions are whether these timing numbers need to be adjusted and to where?
View attachment 308376

Welcome to the forum, I'm sure someone with experience will come along and help you out. I will say that I tried three after market cylinders with different timing numbers and none of them ran as good as the OEM cylinder with just the exhaust widen and a pop up.

 

[twalsh341]

That is a good tidbit, thank you.

 

[huskihl]

Exhaust is too high, but transfers will be too low after you lower the cylinder more. Id take a close look at the transfer bridge. Looks like it’s cracked

 

[twalsh341]

Reset my timing wheel and got some better numbers, EH 95 Tf 124 IN 80.

The dark red/black drip that I think you are identifying as a crack is a run of my layout fluid, I inspected well before fussing with it, but it does look like that there. How are those numbers looking?

 

[MustangMike]

I believe they are useable. A lot depends on how wide the ports are, and the timing.

I guess you just have to run it and see how it does.

 

[twalsh341]

Okay, so I needed some repair parts and got those installed. I've been having a bit of a time getting it to start and stay running. Today a landscaper who saw me getting frustrated came over and tuned the carb in a few minutes. When it's running it'll stay running at idle, although when I finished my first long slab cut it sat idling for about 1 minute, then stalled on it's own. After it cooled and I setup my next cut, refueled and oiled I had a bear getting it to restart. I got a couple pops, but no turnover.




The chain slows and stops if I lean on it. The saw doesn't slow, the clutch is slipping. I removed the chain brake band to see if maybe that was contributing to the hangup, but it still does it. Manual says it's either the brake band or worn clutch shoes or drum. Does the inside surface of the clutch need to be roughed up?

 

[smokey7]

Any saws chain will slow and stop when force is applied into the cut. Milling is slow not like cross cutting. Make sure she is set right on the high while milling. Hope the landscaper knew that when he turned it. They burn up quickly if lean and milling.

 

[MustangMike]

I also like to use square file chain when milling, and it seems to like the rakers dropped a bit extra as the chain does not self feed the same with the end of the wood grain.

 

[Nutball]

What's with the missing top cover on the saw?

 

[twalsh341]

I think the landscaper knew what he was doing, he dialed it right to settings that worked. if anything I think it's running a little rich. I've had problems with the muffler heating up too much.

I cleaned oil out of the clutch drum, but I was still having problems with the clutch slipping, I also ordered a tach to check things. I am not sure, but I don't think it's hitting high rpms, and might be why the clutch is slipping.

Had the cover off because it was hot. I've ordered a new hyway cylinder, as I think this one us too hot to run.

 

[JB-PlantHeirloom]

I had a spring break on my 660 clone clutch and replaced all three of them all with OEM Stihl, no problems since then.

Sometimes if the angle of your bar is not parallel with the log, you will struggle to get the saw to bite properly into the log, and will have to force it. Basically your are trying to move the chainsaw on a track parallel with the log, BUT, the angle of the bar is pitched up or down. Usually this leaves gouges in the wood, when it really should look like planed wood, at least on my chainsaw mill with a carriage.

The biggest improvement I made with the saw starting and running was replacing the Chinese trigger and choke rod parts (and spring) with OEM Stihl. I posted pictures of the differences a few weeks back.