Engine Temp and Engine Wear
Engine Temp and Engine Wear
(OP)
Can anyone say what kind of damage is done to effectively every internal moving part of an engine when it is operated before reaching running temp?
Are the amounts of expansion each part experiences enough to create brief periods of rapid and/or extreme wear due to increased play when not up to running temperature?
Would it be best to let the engine warm up at idle, thereby allowing the engine to operate at its lowest load, or would driving gingerly speed up the rise to opererating temperature(and full expantion), and allow the engine to spend less time running at less than optimal temperature?
Are the amounts of expansion each part experiences enough to create brief periods of rapid and/or extreme wear due to increased play when not up to running temperature?
Would it be best to let the engine warm up at idle, thereby allowing the engine to operate at its lowest load, or would driving gingerly speed up the rise to opererating temperature(and full expantion), and allow the engine to spend less time running at less than optimal temperature?





RE: Engine Temp and Engine Wear
Not really, no. Excessive idling can be far worse. Just don't start up when it's so cold that the piston cooling jets (if so equipped) can't squirt the pistons.
RE: Engine Temp and Engine Wear
Ken
RE: Engine Temp and Engine Wear
High dollar race engines are routinely preheated before startup to avoid the wear you speak of. This is done by using quick connect/disconnect fittings on the engine coolant hoses. The hoses are then connected to an electric immersion heater with a built in pump that heats the engine coolant to normal operating temperature. The heater is then removed and the engine is started. Here is a link to one made by Earls http://www.earls.co.uk/qdc/03_pre-heater.pdf.A similar process can be applied to the oil.
Air cooled piston engine engines used in propeller driven general aviation planes are often preheated using a propane powered forced air heater. Ducts from the heater send hot air into the opening that cooling air normally flows thru.
The part of the engine that is most effected by a cold start up is the cylinder bore, piston rings, and pistons. This is because the biggest cold clearance in an engine is between the piston and the cylinder bore. Preheating the engine helps put some heat(and thus expansion) into the pistons reducing this clearance..
The next system to be effected would be the valve train in an engine without hydraulic lifters.
Bye
RE: Engine Temp and Engine Wear
Fuel economy is better when the engine cooling water temperature is about 250 F according to some WWII aircraft studies.
RE: Engine Temp and Engine Wear
"Cold temperature operation may allow the blow-by gases to condense in the crankcase. This puts water and acids in the oil which can lead to corrosive wear."
I thought part of the reason for warming up an engine (prior to putting it under load) was because these same gases originally condense on the cold cylinder wall, causing undue ring to cylinder wear. Is this incorrect?
RE: Engine Temp and Engine Wear
RE: Engine Temp and Engine Wear
at 40F fuel was consumed at 3.8 gal/hr power produced was 26 hp and cylnder wear was .008 in. At the other end of the test temp was 180F fuel was consumed at 2.8 gal/hr power produced was 29.5 hp and cylnder wear was .0003 in.
It seems like warming up quickly would make a big difference over the life of an engine.
Also if anyone knows where I might be able to find more data on this I would be very appricative.
RE: Engine Temp and Engine Wear
"They'll stay there longer if you warm it up slowly..."
Are you saying that in a conventional gas engine (ie-no pre-heating features) you will get better engine longevity if you rev it up right away on a cold start?
RE: Engine Temp and Engine Wear
RE: Engine Temp and Engine Wear
RE: Engine Temp and Engine Wear
So let me repeat the question. Are you saying that in a conventional gas engine (ie-no pre-heating features) you will get better engine longevity if you rev it up right away on a cold start?
Not looking for an argument here, just clarification.
RE: Engine Temp and Engine Wear
I'm saying that in most "cold" (15degF to 70degF) startups, you should run the engine for a few seconds (5 to 30, longer for colder), then drive it gently until the coolant temp gauge moves. The idea is to get the oil to the rings/bore and cam/follower interfaces (amongst others) before you apply high loads. "Start engine, idle for a few seconds, drive" is probably what the manual for your car says, if you have a look at it.
Letting the engine idle until the temp gauge is at "normal" will add uneccessary hours to the engine (bad for wear), may result in extra hot piston/cold block running (potentially bad for wear), may result in more rapid oil degradation due to water and corrosive components condensing in the sump, and more.