066 twice seized - 2100CP?

[DaltonPaull]

Improvised presure test

I improvised a pressure test and I think the results where good.

What I did is cover the intake and exhaust ports with pieces of old bicycle tubes, plug the impulse line and adapt the spark plug fitting from my compression gauge to fit a bicycle pump. Because the valve on the bike fitting wouldn't stay open, I couldn't monitor the pressure with the gauge on the pump - so what I did was pump the saw up to about 7psi, remove the pump and wait five minutes. Then I released the valve and listened to the air rush out. I then pumped the saw up to 7 psi again and released the valve immediately and it sounded like the same amount of air rushed out. Not quite as good as monitoring the actual pressure, but I think it indicates that little air if any was leaking.

Sound good enough?

Baileys finally shiped out the compression release plug for the big bore kit and I should have it tomorrow. So, I think the plan is to put it together and give it another try.

Maybe I'll post a video of how it sounds/cuts once it's back together and see if anyone can hear any problems.

 

[excess650]

Baileys finally shiped out the compression release plug for the big bore kit and I should have it tomorrow. So, I think the plan is to put it together and give it another try.

Maybe I'll post a video of how it sounds/cuts once it's back together and see if anyone can hear any problems.

The 066 that I've run on the mill has a BB kit in it. The intake boot was questionable, and the base gasket too thick, so were replaced. It was tuned to 12,500 with dual port cover on the muffler.

I ran a couple of tanks through it prior to putting it on the mill, and then tried it on some 18" logs. It blasted right through with no problems. Later, I milled a 36" dead, dry oak log. It definitely loaded the saw, and I tried to not push it too hard. I made 9 cuts up to 30" wide and 8' long, paused between, and during cuts to allow the saw to idle a bit, move wedges, add fuel and oil, etc. Later, I pulled the muffler and had a look at the piston. It looks new!

Use fresh premium gas mixed with good mix oil. I'm running a synthetic blend at 40-1 for a little extra oil. Be sure to tune it rich. If it 4 strokes at 13,000, tune it richer to 11,500 - 12,000 for more fuel and its added cooling.

Check the squish with the BB kit. .025"-.030" is probably a safe number to shoot for. Be sure the base gasket clears the piston. The .5mm base gaskets that I've tried don't clear the skirt of the piston. They either need to be modified, or else find a different gasket. The 1mm gaskets do clear, but may lower compression too much. Don't modify the ports in the BB cylinder. Some reports of ring/piston failure have occurred with the BB kits, but it seems odd that the reports have come after the ports were modified. It makes me think that maybe they weren't chamfered properly and caught a ring. 395XP rings can be substituted for the grooved rings supplied with the kits. Be sure to check end gap and fit in the piston.

The 066/660 is a great saw and will run for a long time if maintained properly.

 

[DaltonPaull]

Thanks for the tip on the base gasket - I'll watch out for that. I've got a new Stihl gasket and the gasket in the gasket kit from Baileys - hopefully one will fit. Otherwise I gues I'll get out the razor blade and try to give it a trim.

 

[DaltonPaull]

Here's a picture of the piston from the first rebuild. Pretty ugly hugh? I'm not sure what's up with the discoloration on the pin? I'm putting in a new piston bearing this time....

 

[pa.hunter]

what oil mix are you useing

I bought a well used 066 a few months back to use in my Alaskan saw mill. A few weeks ago I was milling a 24" oak slab and the saw seized up - had some major scoring and stuck rings on the exhaust side and would not run. I bought a new piston from baileys, honed the cylinder and put it back together. Before doing any cutting I reset the mixture by ear. Then I started milling up some cherry slabs. The saw ran great with tons of power but just as I finished the last cut the saw died. I took off the muffler and sure enough, the piston was scored pretty bad.

I've got a big bore kit that I'm going to install on the saw but what should I do to make sure I don't ruin it again right away?

I'm planning to run it a little richer and use Stihl oil (unlike before)

Also, I'm planing to check out a Husky 2100cp later today. It comes with a 40 inch bar and is supposed to run well and be in good but ugly condition. He's asking for $300. I'm planing to do a compression check and see how it runs before I decide if I might want it. Would this be a good backup or alternative to the 066? What about the price?

just wondered 32:1 is what you should use and use good oil milling is tuff on saws

 

[epicklein22]

I improvised a pressure test and I think the results where good.

What I did is cover the intake and exhaust ports with pieces of old bicycle tubes, plug the impulse line and adapt the spark plug fitting from my compression gauge to fit a bicycle pump. Because the valve on the bike fitting wouldn't stay open, I couldn't monitor the pressure with the gauge on the pump - so what I did was pump the saw up to about 7psi, remove the pump and wait five minutes. Then I released the valve and listened to the air rush out. I then pumped the saw up to 7 psi again and released the valve immediately and it sounded like the same amount of air rushed out. Not quite as good as monitoring the actual pressure, but I think it indicates that little air if any was leaking.

Sound good enough?

Baileys finally shiped out the compression release plug for the big bore kit and I should have it tomorrow. So, I think the plan is to put it together and give it another try.

Maybe I'll post a video of how it sounds/cuts once it's back together and see if anyone can hear any problems.

Gonna make this short and sweet. The test you did doesn't mean jack. Take the saw to the dealer and have it properly tested. Any leak will eventually get worse and you will be starting over again!!!

 

[DaltonPaull]

I appreciate the input (short but not sweet.) You forgot that you are talking to someone who wants to work on his own saw. A better answer might be "there's no substitute for monitoring the actual pressure, even if the pressure drops from 7psi to 6psi in five minutes you have a leak that needs to be repaired and there is no way you could hear the difference...."

If I ran the saw for a living I suppose I'd be off to the repair shop but that's not the case.

 

[RPM]

It was a real BC logger's saw that is now in semi-retirement. Rode hard, put away wet, and now not used nearly enough.

Mark

LOL

 

[user 19670]

I appreciate the input (short but not sweet.) You forgot that you are talking to someone who wants to work on his own saw. A better answer might be "there's no substitute for monitoring the actual pressure, even if the pressure drops from 7psi to 6psi in five minutes you have a leak that needs to be repaired and there is no way you could hear the difference...."

If I ran the saw for a living I suppose I'd be off to the repair shop but that's not the case.

Well, thar ya are! The decision is made.
Makes me wonder what this thread was all about anyway? Online opinions without the option to actually see and feel the parts don't mean much. All anyone can do is guess. Takes money to put a saw back together just to "see what happens".

Anyway, major scoring will never be repaired by honing. You wanted to do half a job and you got what you paid for. Now you don't want to take advice?

 

[BobL]

\

What I did is cover the intake and exhaust ports with pieces of old bicycle tubes, plug the impulse line and adapt the spark plug fitting from my compression gauge to fit a bicycle pump. Because the valve on the bike fitting wouldn't stay open, I couldn't monitor the pressure with the gauge on the pump - so what I did was pump the saw up to about 7psi, remove the pump and wait five minutes. Then I released the valve and listened to the air rush out. I then pumped the saw up to 7 psi again and released the valve immediately and it sounded like the same amount of air rushed out. Not quite as good as monitoring the actual pressure, but I think it indicates that little air if any was leaking.

Sound good enough?

Not really.

- You have to be able to watch a pressure gauge. Just as important as a big leak is a small one since this may turn into to a bigger leak after 5 or 500 minutes of saw use.
- where's the opposite test - under vacuum?
- it's also useful to be able to turn the crank over with it under pressure/vacuum to see if it leaks under different positions.

 

[DaltonPaull]

I'm working on getting together a kit to do a proper pressure test. I'd like to be able to do it with the flange installed in place of the carb so that I can check the entire final assembly.

I pressure tested it again using my air compressor and although I still wasn't 100% sold on the method, the results looked good. The saw is back together with the BB kit now and runs great. I'm keeping a close eye/ear on it and doing more things that I'd never thought of before like letting it idle to cool down after a long cut and pausing during a really big cut. When I have the pressure test kit together I'll test it again, more accurately and go from there.

Makes me wonder what this thread was all about anyway?

Different people have different opinions and give different advice - some good some bad. There is no way to follow all of it. But the point of this thread for me when I started it, was to learn more about what problems can cause scoring on the piston. I feel like I've learned a lot - when I started I didn't even know what I pressure test was. Now I have a repair manual (thanks to lumberjackchef) and am continuing to grow my knowledge.

Anyway, major scoring will never be repaired by honing. You wanted to do half a job and you got what you paid for. Now you don't want to take advice?

I wasn't sure if it could be saved or not - I ordered a $30 piston and a BB kit at the same time just in case. Sure, it ended up being a waste of $30, but I wanted to give it a try and next time if the scoring won't 100% hone out I'll know better.