JasonA Posted January 11, 2006 Report Share Posted January 11, 2006 In my research of Northstar spark plug gaps, I came across this article, which is very interesting from a few standpoints. Us long-long-long timers will immediately know why. http://www.contactmagazine.com/Issue54/EngineBasics.html Jason(2001 STS, White Diamond) "When you turn your car on...does it return the favor?" Link to comment Share on other sites More sharing options...
BodybyFisher Posted January 11, 2006 Report Share Posted January 11, 2006 A classic, it's on my hard drive... Pre-1995 - DTC codes OBD1 >> 1996 and newer - DTC codes OBD2 >> https://www.obd-codes.com/trouble_codes/gm/obd_codes.htm How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/ Cadillac History & Specifications Year by Year http://www.motorera.com/cadillac/index.htm Link to comment Share on other sites More sharing options...
adallak Posted January 11, 2006 Report Share Posted January 11, 2006 Thanks, Jason. Nice find and sounds familiar! The saddest thing in life is wasted talent Link to comment Share on other sites More sharing options...
BodybyFisher Posted January 11, 2006 Report Share Posted January 11, 2006 I beat you by a month and a half posting this masterpiece, Jason...... http://caddyinfo.ipbhost.com/index.php?sho...0&hl=contactmag Pre-1995 - DTC codes OBD1 >> 1996 and newer - DTC codes OBD2 >> https://www.obd-codes.com/trouble_codes/gm/obd_codes.htm How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/ Cadillac History & Specifications Year by Year http://www.motorera.com/cadillac/index.htm Link to comment Share on other sites More sharing options...
Matt Posted January 11, 2006 Report Share Posted January 11, 2006 LOL. I printed much of that out . It is great info to keep in my car folder.... Link to comment Share on other sites More sharing options...
justgreat Posted January 12, 2006 Report Share Posted January 12, 2006 wow...to see that name....i really enjoyed the section on head designs...my alfa had the classic "hemi" head design...well before dc ever used it...actually, the "hemi" used by dc is a cross between the high dome of the alfa and a modern pentroof...the squish area is reduced in the dc hemi but nothing like a pentroof...the piston in a pentroof is millimeters from the valves on a compression stroke. based on the comments about the hemi not being suitable for racing apps, i wonder if it's better suited for street used where the c/c design lends itself to greater lowend torque than a pentroof c/c design..maybe another paper will surface. jackg 90seville 99k Link to comment Share on other sites More sharing options...
JasonA Posted January 12, 2006 Author Report Share Posted January 12, 2006 In regards to a true hemi design, I understand that for whatever reason, it's incredibly dirty, in terms of emissions. DC's modern "Hemi" is really that in name only. The combustion chamber doesn't really look hemispherical. Even with the compromise between a hemi and wedge design, the emissions are still borderline. Jason(2001 STS, White Diamond) "When you turn your car on...does it return the favor?" Link to comment Share on other sites More sharing options...
BodybyFisher Posted January 12, 2006 Report Share Posted January 12, 2006 By the way, this article is what I was eluding to in the other 'Tuning' thread.... At over 1 HP per cu in.... how much more retrievable horsepower do we think was left on the table before we open ourselves up to mechanical damage? The first paragraph of this article covers that issue. I am sure engine failure is the reason that the computer is so tight when it comes to tweaking and why safeguards have been carefully introduced. An engine that has a 6,500 RPM red-line I am sure has great potential for damage. Pre-1995 - DTC codes OBD1 >> 1996 and newer - DTC codes OBD2 >> https://www.obd-codes.com/trouble_codes/gm/obd_codes.htm How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/ Cadillac History & Specifications Year by Year http://www.motorera.com/cadillac/index.htm Link to comment Share on other sites More sharing options...
justgreat Posted January 12, 2006 Report Share Posted January 12, 2006 In regards to a true hemi design, I understand that for whatever reason, it's incredibly dirty, in terms of emissions. DC's modern "Hemi" is really that in name only. The combustion chamber doesn't really look hemispherical. Even with the compromise between a hemi and wedge design, the emissions are still borderline. i've seen pictures of the c/c of the current hemi: it's definitely not a high dome design which is a good descrpition of a classic hemi. there is a moderate peak to the c/c but the valves are closer to each other versus the high dome design of a traditional hemi. one major advantage to a pentroof or even a modified hemi such as d/c's, the heads are much smaller due to the proximity of the valves: it makes for better packaging. jackg 90seville 99k Link to comment Share on other sites More sharing options...
justgreat Posted January 12, 2006 Report Share Posted January 12, 2006 By the way, this article is what I was eluding to in the other 'Tuning' thread.... At over 1 HP per cu in.... how much more retrievable horsepower do we think was left on the table before we open ourselves up to mechanical damage? The first paragraph of this article covers that issue. I am sure engine failure is the reason that the computer is so tight when it comes to tweaking and why safeguards have been carefully introduced. An engine that has a 6,500 RPM red-line I am sure has great potential for damage. it really depends on the motor. the current generation of inline 4 cylinder engines that honda is producing have redlines that approach the level of my '86 honda v4 motorcyle...it's astounding where the engine development has gone. having said that, we're talking alot less reciprocating mass in a two liter 4 cylinder engine versus 4.6 liters in a vee design of 8 cylinders. also, what kind of torque output are we talking about in a high rev 4 banger for around town use? one of the major complaints made against the latest version of the civic is the total lack of a bottom end for every day use...yeah it's fun to wind it out to 9000 rpm but do this every day with every launch from a stop light? that gets old quick, imo. as far as the rpm limit on any motor, the internal components are built to withstand a certain level of revs...anythiong above that limit for a sustained period of time is asking for trouble...in for a penny in for a pound when it comes to engine mods: either do the entire engine or suffer the consequences....unless your talking about throwing in a "performance" air filter. jackg 90seville 99k Link to comment Share on other sites More sharing options...
BodybyFisher Posted January 12, 2006 Report Share Posted January 12, 2006 This is an amazing statement: Back in the 80s, running engines that made half a horsepower per cubic inch, we could artificially and safely induce pre-ignition by using too hot of a plug and leaning out the mixture. We could determine how close we were by watching the gauges and had plenty of time (seconds) to power down, before any damage occurred. With the Northstar making over 1 HP per cubic inch, at 6000 RPM, if the needles move from nominal, you just failed the engine. It's that quick! When you disassemble the engine, you'll find definite evidence of damage. It might be just melted spark plugs. But pre-ignition happens that quick in high output engines. There is very little time to react. Pre-1995 - DTC codes OBD1 >> 1996 and newer - DTC codes OBD2 >> https://www.obd-codes.com/trouble_codes/gm/obd_codes.htm How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/ Cadillac History & Specifications Year by Year http://www.motorera.com/cadillac/index.htm Link to comment Share on other sites More sharing options...
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