Engine Basics: Detonation and Pre-Ignition - Page 2
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This is a discussion on Engine Basics: Detonation and Pre-Ignition within the Tuning: Electronic Engine Management forums, part of the Tech & Modifying & General Repairs category; wow thats a lot of reading. its too late tonight, but i'll be sure to check back when my eyes ...

  1. #16
    Registered User Wrinkleboi's Avatar
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    wow thats a lot of reading. its too late tonight, but i'll be sure to check back when my eyes work a little better.
    o-|-<) bryan

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  3. #17
    Registered User Lt. Boom Stick's Avatar
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    Simply amazing! That was full of good information, it was well written and I'm a lot more knowledgable than I was 10 minutes ago.

    Q: So what r u going to do?
    A: I'm gonna dip my balls in it!!!

    Just kiddin, I had to throw that in there. Awesome post and thank you once again!

  4. #18
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    thank you for posting that

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    Thumbs up

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  6. #20
    Registered complexx's Avatar
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    Very informative reads. I want more. Any suggestions?
    Never stop learning.

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    question on pistons..

    Hi..got a question on pistons.

    For a 4-stroke internal combustion engine, I do know that during the 3rd stroke(power), the spark plug ignites the air/fuel mixture which creates a pressure which forces down the piston.

    But what causes the piston to move up and down during the other 3 strokes? namely, intake, compression and exhaust.

    Do correct me where I'm wrong.

    Thank you.

  8. #22
    Registered User GPatrick's Avatar
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    Quote Originally Posted by aloozer
    Hi..got a question on pistons.

    For a 4-stroke internal combustion engine, I do know that during the 3rd stroke(power), the spark plug ignites the air/fuel mixture which creates a pressure which forces down the piston.

    But what causes the piston to move up and down during the other 3 strokes? namely, intake, compression and exhaust.

    Do correct me where I'm wrong.

    Thank you.
    Since that rod is connected to the spinning crank, another piston's power stroke pushes it up and down.

  9. #23
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    Quote Originally Posted by GPatrick
    Since that rod is connected to the spinning crank, another piston's power stroke pushes it up and down.

    Assuming engine is off and once u turn the ignition key, engine cranks to start itself right? So the piston would begin its intake stroke, moving itself down the chamber. At that point, what gives the piston force/energy for its motion? Since there is no power stroke as yet.

  10. #24
    Moderator timber's Avatar
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    Quote Originally Posted by aloozer
    Assuming engine is off and once u turn the ignition key, engine cranks to start itself right? So the piston would begin its intake stroke, moving itself down the chamber. At that point, what gives the piston force/energy for its motion? Since there is no power stroke as yet.
    If I understand your question correctly, you are correct to a certain extent. There is no power stroke while the engine is cranking, that is until a sparkplug fires. The ignition system is working while the engine is cranking over, and once a cylinder has fired, the rest of the system is being rotated by the force put out by that one piston. Until that first sparkplug has fired, the entire rotational assembly of the engine is powered by the battery through the starter motor. This is a very simplistic explaination, but this is basically how it works (assuming all aspects of the aforementioned are in correct working order, of course)

    Edit: Sorry for the resurection,didn't notice the damm date till I was done typing..
    Last edited by timber; 10-07-2005 at 01:13 PM.
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  11. #25
    Registered User geefunk's Avatar
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    very good to know, thanks for the article.

  12. #26
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    excellent article. i have a question for you.
    it is my understanding that as timing is advanced, at WOT, more heat is generated. is that just in the sparkplug or the combustion chamber/engine also?
    is this the same for idle?
    i have heard many say to reduce engine temp at idle to advance the timing. i dont see how this can be, besides, it does not matter as much what the timing is at idle because i dont drive my car at idle. i have a porsche 911 non turbo, yes you will blow my doors off, but thats ok. 911's have a hard time cooling because of oil/air cooling.
    also, i have been test a set of bosch W4 plugs, i was using W7's, with waht seems to be good results, although my oil temps seem to be higher, is this because the extra heat dissapated by the plug is going to the head, althought the head is air cooled, i dont understand why the oil temp is going up.
    thanks in advance and again, great article. i posted a link to on the porsche site.

    oh, one other question. you mentioned spark gap, is it good to run as wide a gap as you can. stock 911's have a capacitive discharge ignition, i have an MSD and i have run as much as .065 gap although stock gap is .045.
    Last edited by T77911S; 09-05-2008 at 07:21 AM. Reason: another question

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