Engine Cold Seize

[Dean Lofthouse]

I was thinking of putting this under the tips thread but it may get missed and is quite an important tip.

 

I've heard may stories of peoples saws seizing for no apparent reason.

 

I have been into power tool repairs for over 14 years and we came across engines seizing quite a bit.

 

There is a thing called cold seize. Many of you may have heard about it but there are a lot of people who haven't.

 

This happens on air cooled engines and basically, what happens is:

 

If you rev the bollocks off a two stroke engine from cold the piston heats up quickly, but the outer cylinder doesn't because of the cooling air being blown around it. So the piston expands quickly and the cylinder doesn't, resulting in the piston picking up and seizing on the cylinder.

 

What you should always do is start your saws, never rev them from cold, and just place them on some soft ground ticking over for a minute or two before bringing them up to full revs.

 

The longer you leave it the better to warm the engine thru.

 

It makes me cringe, when a groundie starts a saw up and revs the bollocks off it from clap cold

[Andy Collins]

Been telling my kids about this for ages, re: their scooters, but do they listen?

[b101uk]

This also happens in piston engine air cooled aeroplanes but ALSO from hot! I.e. if you have your cowl flaps wide open then descend to fast on a cooler day you are at risk of cooling the cylinders down far to much causing a cold seizing of a hot engine.

[Lee Winger]

very good advice,thanks for sharing

[Arborist]

Blimey, I never knew that!

 

Thanks for the tip, I'm lucky I haven't ceased one of mine but I've always started the saws how i was taught at college.

[colin james]

when i done my lantra ticket we were told to leave it to warm up but never the reason why.

good tip!!

[Roger Day]

Makes perfect sense now, Thank you. premature piston smearing begone!!

[wills-mill]

Boing!

 

Nothing worse than a full-revs-abolutely-flat-out chain brake test on a cold saw Nasty

[TimberCutterDartmoor]

Good post. Makes me cringe when a) someone starts an engine, particularly a cold one with their foot on the throttle - ouuuuch! revving with no lube up top and b) blipping the throttle of a turbocharged engine before switch off - leaving the turbo spinning with no pressured lube. Why do the idiots do it?

Edited January 29, 2010 by TimberCutterDartmoor

[ukminch]

This also happens in piston engine air cooled aeroplanes but ALSO from hot! I.e. if you have your cowl flaps wide open then descend to fast on a cooler day you are at risk of cooling the cylinders down far to much causing a cold seizing of a hot engine.

 

Yep always interesting when this happens, going from glider tug to glider, but without the performance!!! Then you have to find where exactly you ditched the tow cable.

 

R