Wide-open throttle + cold engine = bad idea?
 

Hi guys, I got a question. I live in the second house down on a small country lane that lets out on a big 2-lane arterial, right in the neck of a blind corner. Almost every morning when I turn out onto the big highway, someone comes flying around that corner and is not pleased to see me grinding my way up past 20 mph. (It's not unsafe, but it is inconvenient for them.)

I'm tempted to start giving the 240 the full-throttle acceleration treatment just to cut down on the birds I'm getting flipped and unsafe passing behavior that usually ensues as they blast around me coming out of the corner (and maybe to blow a little black smoke back at some of the more obnoxious ones). Should I do that? Or would that shorten my engine life? Conventional Wisdom says "don't do it," but Conventional Wisdom drives a petrol-powered car and doesn't have this problem.:cool:

Thanks!

--Finn

Get on it!
 

I wouldnt hesitate to get on it. As long as you have allowed enough time for the engine oil to be evenly distributed throughout the engine and all components are now being lubricated, there will be no detrimental effect from flooring a cold NA diesel engine. These are not super high tech engines that require proper clearances only acheived after reaching normal operating temperature. If this engine revved to 15,000 rpm or more, I might change my opinion.

This is just my opinion BTW

I live on a similar road at the moment at school, and while I am not happy to HAVE to do it, I do it every morning. I usually let it run for a minute or two after I start it before I drive way, which is usually enough to get my engine temp at least a needle width off the "cold" pin before I romp on it though.

I have to turn left across 2 lanes and then accelerate up about 1.2 miles worth of up hill slope with no relief, though, so it's pretty much foot on the floor until the light at the top and I still never quite make the 45 posted limit.

To answer: it may not be the world's best thing for the engine, but getting killed on the road isn't the world's best thing for you, and I've been doing the same thing to mine for a while now and it hasn't died.

I always let mine warm up at least a couple minutes, or more depending on the temperature, especially first thing in the morning. As long as you do this there will be no harm to your engine.

Just don't be like those idiots back when I was in tech school and rev your engine all the way as soon as you start it and then take off like a bat out of hell...I'm sure that caught up to them eventually, but hey it was probably coming out of mom and dad's pocket so why would they care, right!

I would not go WOT when the engine is cold. These diesel engines are not too much different than a gas engine in that the oil needs to heat up and thin out, as well as metal expanding. As in a gas engine, you'll make it more prone to excessive wear more quickly than if you let it warm up. That being said, not that you can't drive it (seeing as that is the easiest way to warm it up) but I wouldn't mash it while cold. Not to mention a turtle would probably beat them up a hill when cold....

I have an '83 240 auto and can relate to your situation. My view, when in this type of situation, is that the life of my engine is not the priority. My safety and the safety of other drivers far outweighs the potential for shortened engine life. "Do unto others" type of thing. Just my .02.

My driveway is so steep I need full throttle right out of the garage to get up it and in colder weather it definitely needs a minute {or more] of warmup just to be able to make it at all!

Depends on how bad you want the pistons scored. Being a Merc engine, maybe it can handle it.

My friend got a hold of a very old (think mid-40s or earlier) Studebaker. Had about 40k on it only. But the engine needed TOTAL overhaul. The lady who had it did not know how to properly operate the choke to start it, so she revved it for a while or something to get it warmed up. Eventually the engine seized.

Never fully load a diesel (or petrol) motor when cold. Its a good way to blow seals & gaskets, grab bearings & have pistons do strange things. I have seen diesels (not MB) that have spun rod bearing shells from this. Best you make some changes to your driving to accommodate. Just sit in the emergency stopping lane at slow speed until the temp needle has move a little. Best not let ones ego get in the way of sound judgment. If idiots want to blow past you at 70, let them. They dont get there any sooner than a second or 2. If they honk at you, just wave back. They only come up fast like that because they are trying to hurry you along. The speed limit is the maximum not the minimum !!!

I would also enter the carway with hazards on.

Diesel generators are often idled or very lowly loaded until the oil gets up to temp. I'm not a fan of idling to warm up, but rather taking it as slow and easy for as long as possible. In that you do not have a turbo, I think you are in better shape when it comes to getting on it earlier, but I'm still not a fan and it is bad for the engine. Given your situation, I'd fast idle the car for 30 sec first, then take as circuitous a route to this onramp as is practical. Get the juices flowing.

IMO you're a good candidate for a block heater... Which will help a bit.

I asked my favorite machinist about this subject. He said he starts it up (his diesel) and waits til the oil pressure stabilizes and drives it normally. They won't heat up til they are loaded anyway.;)

It depends on what you mean by "drive it normally". For most people that doesn't mean a wide-open throttle acceleration to highway speed.

To me it means proceed to slowly amber onto the road as if you were rich and didn't need to be anywhere particularly fast - like the original owner of the car.

:)

Ken300D

Standby generators are usually fully loaded almost immediately, others like the ones in my coaches have about a 30second delay.

I'll agree that waiting until the internal temperatures are normal is always best, via driving with moderate loads and RPMs, but I don't feel that you're going to induce anything more than increased wear on the engine and with the years and miles on the car it's not like it's "swiss-watch" precision tolerances anymore, it'll probably still out-last the transmission and body.

Throttle doesn't matter, RPM does. Floor it but don't revv its nuts off until temperature is at least up to the first mark (60).