driving before engine warms up
 

ok. i know this is gonna sound like a noob question, and yes i did search but found nothing. first off, i have an 87 GXL, stock. i know of the potential hazards of driving a piston engine before it warms up to normal temp. what are the risks of doing this to the rotary?(13B by the way). i have also heard that you are not supposed to shut it down before it warms up either. why is this? just so i know before i f**k something up.:Wconfused

Dont know the tech sides of it, but I do know its not good to drive without warming the car up. Especially T2's, turbo has to be warmed up and cooled down for a minute or so before shutdown.

Dont really know what exactly would happen. ive always let mine warm up at least to where the gauge starts to move. with the turbo motor ive always let it warm up all the way. the reason some people say to not shut them off before there warm is because of potential flooding issues i believe.

just be easy on it while it's warming up. On my nonturbo I would try not to take it above about 2000-2500 as it was warming up, and barely put the throttle down at all.

there is an eccentric shaft thermopellet thingie that reduces the amount of oil in the engine while it is cold. That's one reason why you shouldn't get on it. Plus cold oil in general does not protect bearings and seals well.

Early motors used to crack around the spark plug holes due to the temperature difference between a cold motor and the combustion chamber (redlining a cold motor). So you can drive a cold motor, just don't go redlining until the motor is at Operating temperature. Oil needs to be warmed up too.

As far as the "don't turn it off before it's warmed up." Well, most 7's tend to flood if you don't let them do their start-up procedure. You know, turn the key, car revs to 3K rpms for about 5-10 seconds.

It then drops to around 1500rpms until it's fully warmed up (750RPMs).


Rule of thumb: let the car do it's start-up and once the RPMS do the initial drop just drive under 3500RPMS until it's fully warmed up.

I have a T2 and i've always let it warm up a little before i start driving it. I dont know what would really happen if i didnt but, i think it's just better for the car to be atleast a little warmed up and let things get running through it before you start driving. As for the shut down, i let my turbo timer run for a minute or i rev to 3k and and turn it off.

u should let your turbo cool before you turn it off but if you drive like a sane person the last 2 miles of your trip home then you won't need to cool down.

I never understood why people let the car warm up before driving on the street. Race conditions yes. Street conditions no. I turn on the car and let it run until the oil pressure is up. Then drive. Don't drive hard until it is up to temp. To me all that letting a car idle is going to do is waste gas.

I completely agree about letting a car cool down after a hard drive, especially if it is a Turbo.

Also, Your transmission and Diff also need to come up to temp before driving hard. If you let the engine warm then it is fine but you are risking possible damage to other components.

Two things you can do if you are really concerend. 1. A preoiler 2. Block heater

Ding, ding, ding. we have a winner.

For shutdown, this is really only for turbochargers that aren't cooled with radiator fluid, which the stock units are, so it's unnecessary if you have the stock coolant lines hooked up. edit: ^^^ Yes, let it cool after extended hard driving (5+ minutes, after less time if it's hotter out).

Warming up? Well, you don't want to push it until it's at full operating temperature, but that can take a while. I usually fire it up in the morning (right now about 40 degrees Fahrenheit), let it idle 30-60 sec, and leave, taking it easy until the motor is warm.

Pretty much the same thing I do for mine. I've always found it to be safe practice.

Even though it's already been said in this thread, I just have to respond.

There are no potential hazards to driving a piston or rotary engine before it warms up to normal operational temperature. None. Every engine is designed with the fact that it will be cold started in mind. Clearances are set such that they are not too tight when the materials in the engine are cool, and are just right once things have reached operational temperature (and thus expanded). This has been the case for many, many years. Wherever this old-wives-tale of needing to warm up an engine came from, I wish that person had just stayed indoors and amused themselves instead of breeding their misinformation into general society.

The only guess I have for the beginning of the warmup myth is that it is based on old carburetor technology which would result in engines running very poorly when cold.

EFI systems maintain the proper A/F ratio regardless of engine temperature, so the engine should run just as well cold as it does hot.

All that warmups will give you is a hole in your wallet from wasted fuel, wasted time, excess pollution, moisture buildup in the engine, carbon buildup from incomplete combustion (rich ratios, cool engine temp), etc. etc.

Now that said, don't beat on the engine until it has reached operating temperature. As mentioned above, clearances are not set until the engine has reached the temperature at which it was designed to operate. The engine is "tight" until it has warmed up which can result in poorer lubrication until the temp stabilizes.

With the rotary, it is far easier to flood when the engine is short started. This is generally not an issue if the car is in good tune.

Wouldn't the car give you 3k rpm hesitation before warming it up?

Personally i've never experinced the flooding problem. I constatnly have to move my 7 from drive way to road and vise veruses. I just wait for oil pressure to raise and then move it. Also i don't get the cold start 3k rev up, is that bad?

I start it up and go. I don't have to worry about getting the revs too high while still cold, since I'm sitting in traffic for 15 mins before I get to the interstate.

i know it isnt good to run a deisil till its warmed up

That's because it has no spark plugs. A cold diesel motor acts as a heatsink and will drop the compressed air at TDC below ignition temperature. Glow plugs will run it at idle until it's up to temp, but isn't effective at speed as they can't provide energy fast enough.

This statement in itself doesn't make any sense. :) It's "not good" to run a diesel until it has warmed up, but it's impossible to warm up the engine without running it. Catch 22.

The issue with a diesel is that when the engine is cool, the fuel will simply not ignite. Diesel engines are compression ignition and the massive metal block can wick heat away from the compressed air such that the fuel will not ignite when injected. This was solved many, many, many years ago by the addition of glow plugs that preheat the air as it is compressed in the cylinder. More modern engines have preheaters in the intake manifold.

For the most part it's similar to a piston engine. i.e., you can drive it cold but don't push the car hard or you'll wear out the engine faster. The reasons why this is might be a little different, but basically you come to the same conclusion.

I wait atleast a minute before driving mine lately in the mornings. Ususally though, I go outside and crank it so it can warm up for 5 or 6 mins. And even then, I dont dare go over 3K until the needle starts to register...