When do you consider an engine 'warmed up'?

[Lowend]

Interesting topic that generates a lot controversy interested to see what people say.

How do you determine if your engine is warmed up and safe to wail on?

Most people would talk about water temperature. Ie coolant gets hot enough to open the thermostat. I personally consider this a bad metric. Water changes temp pretty easily and can get 'warm' more quickly than oil.

In my thinking, the two things you really care about are oil temperature and combustion chamber temps. I don't have a way to measure combustion chamber temps fro the driver's seat, so oil it is.

I know for many roadracing cars, 150 deg F is considered the minimum oil temp for lapping. I've used that as a baseline for my car, although operating oil temp on my C5 is more like 200-220.

How do you look at this?

 

[COPO]

New cars, start and idle for 30 sec and drive. Old carbureted engines, 1-2 min. When to hammer it, IMO for a non carbureted car, once it reaches operating temp. For carbureted cars I wait until my oil pressure is at its steady warmed up driving/operating psi. Note that the oil pressure is still high even when the coolant stat reaches operating temp which is in 5-10 min depending on the outside temp.

 

[larrylarry]

After about 10 minutes and I’m above 150 water temp.In the winter my water temp hardly gets to 170* even after driving for 20 minutes. Usually by the time I’ve driven out of the neighborhood it’s good to go.

 

[camaro71/holland]

I would say, engine oil viscosity is matched to the outside temperatures and to bearing clearances in your engine. So to me, a warmed up engine is one with the correct oil temperature to form a layer on all critical surfaces.

Short answer: when the oil has reached its operating temperature.

 

[G72Zed]

Interesting topic that generates a lot controversy interested to see what people say.

How do you determine if your engine is warmed up and safe to wail on?

Most people would talk about water temperature. Ie coolant gets hot enough to open the thermostat. I personally consider this a bad metric. Water changes temp pretty easily and can get 'warm' more quickly than oil.

Im my thinking, the two things you really care about are oil temperature and combustion chamber temps. I don't have a way to measure combustion chamber temps fro the driver's seat, so oil it is.

I know for many roadracing cars, 150 deg F is considered the minimum oil temp for lapping. I've used that as a baseline for my car, although operating oil temp on my C5 is more like 200-220.

How do you look at this?

I'm with you on your thinking Lowend, I also fully agree with camaro71/holland as well.

Depends what you mean by "wail on" it, if "wail on it" means absolute full power power pulls/runs to max rpm or qualifying laps, then yes, it's critical. Piston material comes into play as well, such as 2618 or to a lesser extent, 4032, you need heat in them there chambers so the pistons "come around"......

Revving in a few low gears at partial throttle whiffing to 6,000 rpm in your street car going to get coffee or a case beer, as long as it's good and warmed up. I find that most old school V* engines oil temps follows the water temps by about 10* or so.

When I was drag racing in my teens/20's, I like to run it with hot oil and cool water temps in the <120* at the line. When I'm on the road course I do a few laps to get things up to temp, I like the water at 170-180* and the oil at 190* to start my session, most times the oil get's to 260-270* or so.

Look at CUP before qualifying, ice water circulating in the heads at the same time oil going through a boiler heating the oil to 300+*, just before you are called to the line for your 2 lap qualifier, the quick disconnects are pulled and they are gone....

I was on the dyno all day yesterday and today....the oil temps we aim for before a full pull is around 175-180*, it's amazing how much power one can "lose" with cold/thick oil and increased psi....I hate high oil pressure...but many like it as it gives them the "warm and fuzzies",....it gives me the gd "heebie-jeebies".

GM was smart with the C5 with engineering the target oil temps at 200-220, those C5's are considered "old" now, but they still kick newer "sports cars" ass that are 10-15 years newer on the track....

 

[FS87LT]

Y'all are correctly oriented toward engine temps (coolant and engine oil), BUT what about the oil temps in the transmission and rear axle, too? Stiff grease there can absorb horsepower too, unless you might have syn lubes in them.

By observation, having watched the ATF temp progression on the late-model Silverados I've driven at work for the past years, the ATF temp closely mirrors engine coolant temp, just a bit behind it.

 

[mallard]

Here in Western Canada, winter temps can drop to -40 or worse and that was cold enough to prevent "converter creep" from moving a warmed up auto trans car because the differential oil was too thick from the cold. The car is in drive, take your foot off the brake and it doesn't move until you give it some throttle.

 

[muscl car]

For me I like to see at minimum of of 160° water temp and 140° to 160° trans temp

 

[BonzoHansen]

i don't know if i am remotely right, but i don't have an oil temp gauge so i go by oil pressure. I look for it to be at its usual warmed up idle psi, not the higher pressure when its cold.

 

[G72Zed]

i don't know if i am remotely right, but i don't have an oil temp gauge so i go by oil pressure. I look for it to be at its usual warmed up idle psi, not the higher pressure when its cold.

You are correct Sir....if no oil temp gauge is used, observed hot oil psi is the next best thing, pressure is resistance of flow.