In here are some *tips* about tuning, and timing. If this article, isn't second nature to you, I'd suggest you reread it until it is.

And if you think you know it all, then try rereading it with a more open mind.

Yes, it's that good, IMO.

HTTP://WWW.Streetrodstuff.com/Articl...tion/index.php

And Doc agrees with me.

 

Printed the whole thing out. Will read it in greater detail later. From what I've scimmed through he has a lot of info being given away for nothing.
I already knew the difference between the 2 but I learned how to tell the difference between them. Not that the audible knock in a 14.5:1 compression engine isn't hard to hear... it's just well, so loud without a muffler .
I also like how he went into the design aspects like compression , quench, and probably most overlooked, the spark plugs. Just reading it makes me wonder about or little FSAE engine. We're a restricted car but anything below 10000rpm we're making more horsepower! We've polished the sharp edges out of the combustion chamber but have been using NGK Iridium tipped spark plugs that were ment for the stock engine compression and chamber design. The Iridium is suposed to have a wider temperature range than standard copper plugs but I bet it's worth looking into because we had a couple cases of pre-ignition on our open loop tunes.
Bruce, what do you recommend to the rest of use that aren't exactly elite plug readers? I'd like to learn while my eyesight is still good.

 

What I've always done for plug selection is to run the coldest plug possible that doesn't foul. Had many a folk at the auto supply store ask "what are you putting these in?". "You want what(!) plug?"

RBob.

 

Another informative article added to my notes.

 

Get a hold of the Buick Power Book, and study the section on reading the *ring*. The height of the color ring on the center electrode, will splain, alot.
While the new fuels burn with a lower level of ash, the rings still develope.

The biggie, is now with EFI you have DFCO, so you don't have to play the insane games of doing plug cuts, like in the old days. Well let me qualify that for anything on the street, that's got a decent ecm.

Get a magnifier.

Practice, and when your done practicing, do it some more.

Play the indexing game, see what happens. Try using 1-2 plugs of different heat ranges (at the same time), and see back to back what they look like.

You don't have to run at 6,000 rpm to get valid plug information. Again, the newer fuels burn with less ash, so you might need to drive 100 miles at cruise to stain the plugs.

And reread the section on how fast **pre-ignition** can totally destroy an engine. Kinda shreds some light on these claims that *detonation* won't instantly melt down a motor.





Did I mention practice.

 

Doc just had the same thing happen just the other day. But he was looking for a A/C, RY12. Then trying for a Champion 324 didn't help either.

 

That's what I've been doing after I get a tune real close and don't have to worry about the start-up fuel fouling the plugs. I've had great results from the Champion Truck plugs.

I get that at auto parts stores all the time. "Why do you want 8 plugs for a GMC Safari? They didn't put a V8 in those."

nope, THEY sure didn't...

 

GREAT article. Straightens out some things I wasn't clear on (the differences between the two, mainly.) I think I'll print it out and read it a few times at work tomorrow.

 

Great article. Learned a lot, and will learn more later when I read it again.

I'm surprised you've had such good luck w/ Champions. Everything I ever put them in ran like a lawn mower. I prefer A/C's. Just my opinion from bad experiences.

Mike

 

Very informative but I found some funnies hahaha


piston with a very nice bum pattern right in the combustion chamber


some 160-180 degrees of bum being compressed

Start out rich, retarded and with cold plugs

Rich and retarded... all I need is money and im there!
not saying I can type well just that the typo's or wording were funny to me.. :lala:
really gave me an idea of what im looking at now when I take my spark plugs out... seen a few chipped... not good

 

Awsome info, thanks for the heads up!!

 

Not meaning to bash Champions, but just as general info..

Champions are of rather soft material. This softness, leads to an easy decay of surface, so that an ion path can form, which is what allows the spark to jump the gap. A spark doesn't happen instantly, if you've seen pictures of lightning strikes with the *trailers*, being emitted in front of the actual strike, the same thing goes on in a combustion chamber. What makes a truck plug is that the center electrode is fatter, and has more material that cam be eroded off, before the gap starts to noticeably increase. In a car with a marginal ignition system this ability to erode more easily, and form the trailer, is an advantage.

180d opposed to this is the Autolites. They are a much harder material, and dont erode as easily. A/C are just slightly softer then the Autos.

Running 10-15,000 miles with a set of each will demonstrate the different erosion rates.

I've never had NGKs perform well in anything other then rotories, or motorcycle engines. I think it's an inherent characteristic of the design, and way they design them to establish the heat range. While you can select them, and be happy with one heat range, on any given day, they might read too hot or cold.

Sr Jacobs, in his *The Drs Guide to Optimising you Ignition System*, also agrees with most of this.

Again, plug reading is part art form, so opinions are gonna very.

 

Their OCR software needs some work, LOL. I wonder where the article came from originally.

 

Sorry to go off topic slightly, what are your opinions on the Accel short header spark plugs... thats what ive been running in my 307 because they keep the wire a good distance from the headers.. every time I check them they get completely black and some chip some porcelean.. this is a chevy 307 with a 600 holley VS I know it may need smaller jets but are the plugs bad quality also?

 

I'm not sure if they're the Denso, like the split fires, if they are, nothing would surprise me.

If they're sooty, then leaner or hotter plug.

Fragmenting the porclean, is a no-no. A big time no-no, did I mention fragmenting a plug is a big no-no?.

If you have a close plug, I'd say pull the header off, and fix it. While dimping looks bad, to you the engine don't care unless you pinch off like 1/3 of the cross sectional area. Right up by the port the gases are so hot, and **thin**, so they *bend* very easily.
And during the *scavenge* part of the cycle it's the slug of gases moving way down stream that form a low pressure area along that column that helps, again 1" in a tube 3' long isn't going to matter much if at all. Toss in a muffler and headers really don't work as well as often predicted.

Just what I've seen, I'm sure others will have seen the opposite.

 

I dont think the wires would get melted but they were 10x easier to change with the extra clearance and I didnt want to chance burning up my $30 wires.. denting in the headers doesnt sound like something I want to do.... I can fit different plugs without altering my headers.. so ill try, but what plug would be better than my accels?

 

A/Cs or Autolite, IMO.

 

" Engine Basics: Detonation and Pre-Ignition


by Allen W. Cline


This article was originally published in the January-February 2000
(Volume 10 Number 1) edition of *Contact!* magazine. This magazine is
published bi-monthly by the Aeronautics Education Enterprises (AEE), an
Arizona nonprofit organization."

Allen was the lead designer of the NorthStar engine.

RBob.

 

If the car is that rich, its probably the reason you are burning wires. Extreme exhaust temps, could be oil to, that will also burn in header when bad enough and cause lots heat..

 

Thanks for the link....I Just might pull a plug or two while the wife is christmas shopping Friday.

With these fast burn heads, not needing as much timing at wot. As a general rule. What is the MTB for this type of head? Allen mentioned 20* in the article.

 

Wow!

That was good reading there!

Words to live by :-) Im just glad on all the wonderful things that have happened to me and my cars(water/valve springs/oiling issues) the one that I have managed to elude thus far is pulling the plugs and finding them melted, metal flaked, or eating themselves alive. *Im knocking on wood*

Thats great article


later
JEremy

 

I have a TPI topend Motown 350 4-bolt main block stroked to 388 with forged Aluminum flat-tops, and GMPP fast burn aluminum heads - 10:1 CR, fully operational emissions system.
After some setbacks (not engine) I got it running and I'd like to ask some questions for anyone to answer.

1. What should my base timing be? (currently 8°)
2. What should my total Timing be? (89' ARAP is set 41°)
3. What spark plug heat range do I need?
4. Do I need a different Knock Sensor? (current L98)
5. Why is my idle low when cold, and high when warm? Doesn't that seem reversed? I read at Corvetteforum's Scan & Tune to set the stall saver spark enable thresholds to zero to solve the problem, does anyone have any comments on this? I like to have some input before I do this. I've increased the Desired Idle RPM vs Coolant Temp 200rpm across the board didn't seem to help at cold idle.
6. Are there any suggestion/recommendations before I go for the smog test?

 

8's a good all around number, less and the motor tends to just windmill without starting, and more can make a hot restart troublesome.

Lean cruise means lots of timing, good mileage, but puts more heat into the oil. I'd rather run 36, and have a longer lasting engine.

Heat range is a matter of how you tune. Pick one, and start reading them to see if you got what you want.

You want a K/S that is most closely matches your cylinder bore, and is of the right resistance.

Too lean during cold run will make for a low rpm. Sometimes setting the commanded rpm higher in fact makes matters worse. Gotta experiment some.

 

Grumpy,

That 36 Total timing you use, when working with a 730 is that the field SPARK ADVANCE MAX.

If so I currently have it set at stock with 42deg.

How is that 42 calculated? I am pretty sure this has been covered heaps of times. But is that 42 calculated without the base timing added or with it.

Or does that 42 mean that if you add higher values then 42 in the spark advance tables they will not affect it as the ECM will only give a max of 42? So if you had 44deg in some spots in the spark advance tables the ECM would only give you what ever the max constant is set to in this case 42?

 

It's the max value. What you get when everything's taken into consideration. If you set the max setting to 32d, the most the engine will ever see is 32d.

 

Now I get it! For the life of me I couldn't figure out what "180* of bum" was...hehehe...

I like very nice bum pattern.

Oh -- I just saw another one: "Start out rich, retarded and with cold plugs...". I know those people!

But really, everyone should read that article in the first post (Everyone who's not already read it -- this is an old post.).

 

This is another good read and the link is still good.

 

Great read!!
One thing that really caught my eye was when he said "if you do a full throttle 0-60 blast, the engine will likely run up to 6000 rpm at 11.5:1 or 12:1 afr. But under sustained load, at about 20 seconds, that afr is richened u by the PCM/ECM to about 10:1. That is done to keep the spark plugs cool, as well as the pistoncrowns cool."

This caught my eye because it makes me wonder if we have the ability to change this "richer" value, based on certain conditions such as wot duration and increased load for an increased duration?

Another reason this caught my eye is because I never factored in preignition due to a longer duration under wot or a longer duration of higher engine loads, and I don't think alot of people factor that in. Most probably get their target afr all the way to redline, and figure that it's good and don't think twice about buildup heat on the plugs. But, I was planning on tuning in open loop and leaving in open loop basically because I trust my wideband over blm's that the computer uses, which are provided via inaccurate narrowband. But after reading that I would like others opinions on this. Is there a function in our ecms to provide more fuel over over extended duration, based on a kpa value? I am using tuner pro and don't remember seeing one for closed loop or open loop, or is this what the pe function takes care of?

 

The EBL has this feature. Along with other code that I have developed. It is worthwhile and does have advantages. There is also the SA side that can be modified.

As for stock GM mask's that we use, I don't know of any that have this functionality.

RBob.

 

Any reccomendations? Setup is in sig, and I am running stock plugs. Any tips/tricks on what I can adjust in my bin to account for the heat buildup on the plugs and allow for richer conditions due to this? Should I just tune it a bit richer all the way through redline? Anything i can adjust in pe to help out, or any tiing adjustments that will aid? I plan to shift around 6500 rpms, and thanks to your extended ve patch for my axcn bin, I have a bit more control of the fuel.

I guess I should tune conservative and not beat on it all the time. Do you reccomend a colder plug, and if so how many steps colder?

Thanks

 

For plug recommendation, third post of current thread: "What I've always done for plug selection is to run the coldest plug possible that doesn't foul."

For a street tune keep it conservative. Stay on the rich side along with WOT SA timing being correct.

RBob.

 

$58 did, I believe.... didn't the Turbo Buicks also have something like this?

Dig

 

Did they? Which tables? I am leaving it up to you.

RBob.

 

$58/59 has an extension to the PE system. If MAP is at 100KPA or more for a period of time, then PE AFR gets reduced by a KPEAFDLT amount.

Makes sense now, when you take it in the context of this article.

I don't play with the Buick stuff (T31)much, but wasn't there an AFR vs. Time table?

Dig

 

I see it now. On the $58 code there is also a MPH qualifier. So, once over a MAP and MPH value for a period of time there is a single step wise reduction in AFR. Funny thing on the AMUW GrandAm calibration it isn't even used.

RBob.