ArneeA

My guess is that there are few people on this board that has years of education and experience; including those who claim having multiple years of experience in "thermal testing."

That's not what you said. You said: "There is absolutely no risk to the engine of cooling down too fast even in sub zero temperatures."

Again, I urge you to try pulling a spark plug when the motor is hot and see what happens and WHY it happens.

Nevertheless, that is that. Enough pissing match for me.

Have a good day!

Tippy

It would be optimal if the motor stayed at operating temperature indefinitely.

Our jet engines are simply measured in hot/cold cycles the parts go through.

You could relate this to the reciprocating engine too.

1999Porsche911

What in the world does removing a spark plug from a hot engine have to do with engine cool down? Seems to me you are changing the debate into something you might be able to defend. What a text book teaches you is most often absent of any real world truth.


Please name just one componant that can be damaged by turning off a hot engine in sub zero climate.

Tippy

I guess you can edit a post without anyone seeing.

Someones post magically disappeared

ArneeA

Text book? Ambient temperature is lower than internal temperature. When you pull a plug when motor is hot, it will cause stress cracks on the head. Why? You figure it out, you seem to have everything figured out already.

A text book makes one understand WHY instead of empirical results from "years of experience."

Enjoy your long weekend. Do they have 3-day courses on physics? Maybe you can get one over the long weekend.

/out

1999Porsche911

WHY are you still talking about spark plugs?

I didn't expect you would answer my question about what component would be damaged by shutting diwn an engine in cold climates. And if you did provide an answer, it probably would not have anything to do with the subject of this thread.


As far as your spark plug fetish. Can you tell me what material a spark plug thread can be coated with to eliminate any possible damage to both the plug and the head? HINT: Virtually all plugs have this coating.

Don't be afraid to continue your education using GOOGLE.

Blackness

I knew I was wasting all that money on those damned engineering text books.

Tippy

I have had my fair share of schooling from Engineers who cant even change plugs in their cars.

Engineering gives you knowledge that cannot be learned through tinkering.

1999Porsche911

Yup, text book knowledge is the way to go. You don't need the experience on top of it. Just memorize the pages and you're good to go. I guess that's why medical, engineering and physics books have not had any revisions in the past 200 years. The academics had it right all along.

Book learning is only the beginning of knowledge. Experience is needed to prove or disprove the theories that have been crammed into your head. Theory often does not work in application.

RockSS

This is an interesting and timely discussion. This weekend we had some very hot temps. here in the Bay Area. My thermometer in the car showed up to 100F while I was on 280 doing about 80mph. I had the AC on the whole time and engine temp was fine, well within normal. Even in stop and go, after getting off the freeway the temp. never changed much at all. The next morning the car, in garage overnight and a warm evening, the car was pretty close to stone cold. These are only my observations.
Anytime you rapidly cool anything, metals included you run the risk of problems. This is especially true in air cooled airplane engines were you try to avoid shock cooling at all costs. We have seen many cracked heads, usually around the spark plug holes in airplanes, especially in training aircraft where the pilot is asked to perform tasks that require rapid reductions in power outputs.
My .02 cents.
Tony C

Tippy

I have my A&P but only have experience around jet engines - recips, only in cars and tech school.

When a jet engine cools off, the rotor will expand on top from the rising heat and shrink on the bottom causing "rotor bow".

CosmosC4S

Excuse me...um, do all these theories only apply in physics? Do they apply in biology as well??
Um...um...is it all right to pull it out when it's still hot from peak temp and exhaustion? Will it damage my piston or its related components??

I've kinda been doing that all my life, and am a little concerned.....

Marlon

Would placing the spoiler in the up position help dissipate engine heat upon shutdown???

ArneeA

Apparently, you don't get my point.

I should have expected as such.

Have a good weekend!

1999Porsche911

No effect. You want the heat exiting the bottom of the car anyway.