Starting Cold Chainsaws

[HarleyT]

No, just say that your theories/fears have little or no basis.

 

[1Alpha1]

It would be interesting to take temp readings, to see what spike of temps occur when shutting down. I would think that they would include piston temps as well, but I doubt that any of it really matters...
Aluminum dissipates heat almost immediately, magnesium, I don't know.
But including the carb and coil, well, who knows?
Infinite number of variables....

There isn't a person on this forum qualified to make any statements in regards to molecular engineering or metallurgy and how it applies (or doesn't) in regards to internal combustion engines and how well they regulate temp. changes, due to varying operating conditions, functions, situational extremes, or types of fuels.

If by some off chance there is such a member, please introduce yourself. It would be interesting talking to you.

 

[HarleyT]

There isn't a person on this forum qualified to make any statements in regards to molecular engineering or metallurgy and how it applies (or doesn't) in regards to internal combustion engines and how well they regulate temp. changes, due to varying operating conditions, functions, situational extremes, or types of fuels.

If by some off chance there is such a member, please introduce yourself. It would be interesting talking to you.

There used to be a few....

 

[fwgsaw]

OK I hope that someone will be able to give me a good argument on why not to race a cold chainsaw. I am in a volunteer fire department in central Missouri.There are several full time members on 24/7. When ever the new shift arrives and does the check of all the powered equipment, the saws are on the list.We have I think 5 saws.A 455, 435,235,and a small Stihl. The mix is the trifuel so gasoline is not an issue.
The problem that I have is that these guys start the saws and run them at full throttle. This really pisses me off. I try and enplane that this is bad for the cylinder and piston however,,they persist on revving the engine.
All my saws start and are allowed to idle for a few minutes to allow the piston and cylinder to reach the same operating temperature gradually.In my train of thought this allows even distribution of heat before increasing the RPM.
Yes in certain situations this procedure can be omitted. Like needing to cut s hole in the side of a burning building.
Anyway I hope possibly a few saw engine builders will give me some free advise that these guys will understand. Thanks, Ken

My 2 cents. In the 20 years I've been on our fire department I have seen our chainsaws ran by a lot of people that have no clue how to run a saw. We do training on ventilation procedures and rescue often but I never bring up cold start warm up procedures primarily because you should train as if it were real. If a saw can't go from a cold start which in most cases it's really not that cold to wide open throttle in a few seconds it would be useless to us. I can say that in a real fire that a saw gets abused pretty badly sometimes. I personally would concentrate my concerns on using really good synthetic oil mixed at 32.1 and good bar oil that flows well in the conditions it's being used. Unlike cutting firewood or logging a rescue saw will be used at a fire until it either makes the cut or just stops cutting caused from to much heat or broken teeth. I've seen chains that after making a couple ventilation cuts that were welded to the bar after everything cooled off. Even carbide chains won't last in the worst conditions. I feel the real danger of locking up a saw is in the cut when used on a fire department. Nails, asphalt, tin, sheetrock, wiring and insulation can really gum up the oil process as well so that can cause a really hard long pull on a saw even if your not pushing it. Also the big Detroit backup generators for hospitals went from starting too wot for years with no problems.

 

[1Alpha1]

There used to be a few....

Depends on what your definition of used to be.....is.

Used to be coal-fired furnaces in homes at one time too.

 

[Sleepy]

I'm not suggesting a cooldown is needed on a saw, but if I ever do, I wouldn't want it to idle. Remember, this is an air cooled engine. When the flywheel is turning slowly, it's not moving much air.
If I ever think a cooldown is necessary, I will take the load of the engine and keep it turning at a fast enough speed to maintain a strong airflow from the flywheel.
I routinely do this with my mower on a hot day because I don't like valve seats to come out or head gaskets to blow.

 

[CR888]

When I order new saws & O*P*E*from Stihl I pay for it & don't let them take it out the back for the cold WOT pizz rev tach tune. I cringed when they first did that to me. But I'll say this, whether its a automotive factory, four/two stroke bike or small engine factory if you ever go into one to do a tour to look around you will see tech's & engineers 'testing' assembled units. These guys show no sympathy for cold new engines. They run them hard, fast & cold without hesitation. I've seen this a few times.

 

[ChoppyChoppy]

[QUOTE="fwgsaw, post: 6141791, member: 14928" Also the big Detroit backup generators for hospitals went from starting too wot for years with no problems.[/QUOTE]


We have a 220 Cummins powered Gen set to run the planer/molder, it can be dialed down a bit by during the hertz lower, but there is still no idle.

It does have a block heater and oil heater, though I don't think any work (this is a Korean War era Gen set)

 

[1Alpha1]

Most of the big emergency generators I have seen, have a servo motor that increases the rpm's within about 30 seconds of start-up.

And most were in a dedicated room or bldg. that sheltered them from the weather, as well as block and oil heaters