Magnecor Ignition Cable

[naru]

"You guys are discussing preignition,not detonation."

 

Ok, if induction prematurely ignites a cylinder, (I've called preignition pre-detonation for a long time), that cylinder will detonate...one of the worst forms of detonation there is.

Doug

 

Not necessarily.

Depends when it happens, how wide open the throttle is,.....etc.

[GeneralDisorder]

Ignition and detonation *are* two different things - the former happens when the plug ignites the mixture - the latter when something hot, or shear cylinder pressure causes the mixture to spontaneously ignite (no spark).

 

You would have to see the EJ plug wire routing to understand - the wires are not real close to each other and it would take some really bad wires to induce a spark in an adjacent cylinder. In practice this just isn't a concern.

 

GD

[Quidam]

Hey,

 

Here's a motor you've probably seen before. "Ultimate Subaru Justy Turbo". With a supercharger too. What has he wound up with? 2 hp per cubic inch? 3 hp? 4 hp per cubic inch? I don't know for sure.

 

Some here expect that it will blow up. I do too, if it's ran as pictured below. And I'll tell you why.

 

 

EDIT: These are Genuine Subaru plug wires. 20 yrs. old and 180,000 miles...to the best of my knowledge. Quality, stainless terminals but out of factory spec at 16.23. The factory spec is listed on the card.

 

Edited February 27, 2010 by Quidam

[Quidam]

Ignition and detonation *are* two different things - the former happens when the plug ignites the mixture - the latter when something hot, or shear cylinder pressure causes the mixture to spontaneously ignite (no spark).

 

You would have to see the EJ plug wire routing to understand - the wires are not real close to each other and it would take some really bad wires to induce a spark in an adjacent cylinder. In practice this just isn't a concern.

 

GD

 

Put it this way GD. Pre ignition of the cylinder gases via induction, end result is detonation. I told you I've always called this predetonation.

 

Forget the EJ for this discussion. How about looking and posting pictures of the EA-82T's that have been built. "In practice this just isn't a concern."

 

Says the man with the exploded EA-82T.

 

Doug

[GeneralDisorder]

Says the man with the exploded EA-82T.

 

Doug

 

I don't run EA82T's.... . Are you saying you have blown one up due to preignition from bad plug wires?

 

Turbo's have problems with detonation anyway - it's because of cylinder pressure's and fuel mixture issues. That's just something you have to watch out for with forced induction.

 

GD

[Quidam]

" it's because of cylinder pressure's "

 

Ah, when the fuel lights off prematurely it starts to build pressure...when it ignites normally, say 36* BTDC...All that pressure is normally timed to peak at about 12* ATDC. To have leverage on the crank.

 

Unstead, most of that pressure is pushing against the crank on the up-stroke, the compression stroke.

 

Doug

 

Edit: No, I've never blown up an EA due to induction. I know better, I learned the hard way with a small block Chevy and cylinder #7.

 

Edit: In the EA-82T example. The way the plug wires are factory routed, and seeing as induction can only happen to #3 and #4 on this engine...

 

If your EA-82 failed due to induction, it will show up first on #3, odds for # 4 are a little less. The plug wires need to be at least 12 mm apart, or so to prevent this from happening.

Edited February 13, 2010 by Quidam

[Quidam]

Here's one Mfg.'s TSB for example. Keep in mind that when a EA-82T has a verified induction situation to #3 and #4 cylinder, you may hear spark knock. The distributor retards the timing via input from the knock sensor.

 

But you haven't done anything to stop the inductance and it continues. This shows up most under load, of course. For a Subaru example.

 

The engine is getting pounded under load and eventually find the weakest link.

 

 

Date: December 30, 1998

 

Models: 1994-1999 BR/BE Ram

Note: applies to vehicles with 3.9L, 5.2L and 5.9L engines (gas)

1994 - 1999 (AN) Dakota

1994 - 1999 (BR/BE) Ram Truck

1998 - 1999 (DN) Durango

1995 - 1999 (XJ) Cherokee

1994 - 1999 (ZJ) Grand Cherokee

 

Symptoms: some vehicles may exhibit one or more of these symptoms:

• spark knock complaints with vehicle under load
  
• various single cylinder misfire (1, 3, 7,) ad especially 5 and/or 8
  
• surge in 4th gear with the Electronically Modulated Converter Clutch (EMCC) engaged (around 45MPH).
  
• Perceived torque converter EMCC engagement/ disengagement around 45 MPH.
  

Diagnosis:

Using the Mopar Diagnostic System (MDS/MDS2) or the Diagnostic Scan Tool (DRB III), verify that all engine/transmission systems are functioning as designed. If other DTC's are present, repair as necessary before proceeding with this bulletin. If no other DTC's are present and the above symptoms have been reported by the customer, perform the repair procedure.

NOTE: This rerouting procedure should be performed before any other misfire, surge, or spark knock repairs are attempted.

 

The fix. Seperate the wires like above in the plug wire holder. They supply the new holder, so you can skip the center wire holder, creating the gap between wires. They supply the plastic wire loom covers to put over the wires where they intersect. They reroute the coil wire and specify no less than 1" between the coil wire and other wires. Interestingly they say if you cross wires, do it at a 90* angle.

 

I saw a picture of a 3L Subaru airplane engine. They bundled the wires together but had covers over all the wires.

Edited February 14, 2010 by Quidam

[Quidam]

Here's a snip from Jasper Engines:

 

Spark Plug Wire Induction Cross-Firing

Causing Engine Damage

The AERA Technical Committee offers the following information regarding spark plug wire

cross-firing on an internal combustion engine. If an engine continues to operate that way,

engine damage on only one piston or only one rod bearing may result. This can occur shortly

after rebuilding an engine, or anytime the spark plug wires are rerouted.

Induction cross-firing results from the magnetic field produced when an electrical current

passes through a spark plug wire, causing two cylinders to fire at the same time. If crossfiring

is allowed to occur, one cylinder has the spark plug firing ADVANCED 90° from the

proper time. With that amount of ignition advance, it is only a matter of time until a component

will fail.

During assembly of an affected engine, finding broken cast piston ring land(s) or damaged

connecting rod bearings on the cylinder which was firing too early, should be no surprise. In

these instances, the components have been operating beyond their intended designed parameters.

A hypereutectic or forged piston will last longer, only because they are stronger.

However, those engines will eventually fail, as well.

Listed below are some of the most common engines to be damaged by cross-firing. The second

underlined cylinder in each firing order is the one which is possibly firing 90° advanced.

Be aware there are many other engines not on this list that could exhibit this type of failure;

it all depends on how the spark plug wires were routed. If you see a failure for no

apparent reason, look over the engine firing order and spark plug wire routing. Also,

inspect the spark plugs themselves for signs of pre-ignition. If a picture reference is needed,

the AERA Piston, Ring and Pin Failure Booklet is available. A detailed definition of preignition

and detonation are included in the booklet.

Common cylinders to cross-fire are listed below in bold and underlined.

 

American Motors 1-8-4-3-6-

5-7-2 304, 360, 401

Chrysler Engines 1-8-4-3-6-

5-7-2 273, 318, 340, 360, 361-440

Ford Engines 1-5-4-2-6-3-

7-8 221-302, 332-348, 370-460

Ford Engines 1-3-7-2-

6-5-4-8 302 HO, 351-C, 351-W

General Motors 1-8-4-3-6-

5-7-2 Buick 215-455, Chevrolet 262-502,

Oldsmobile 260-455, Pontiac 325-455

Navistar 1-8-4-3-6-5-7-2 266, 304, 345, 392

 

Now, think EA-82T again, for example. This may be new to people...but it's old news too.

Edited February 14, 2010 by Quidam

[Quidam]

"Turbo's have problems with detonation anyway - it's because of cylinder pressure's and fuel mixture issues."

 

They do indeed, the compression ratio. And true engine management, or lack thereof.

 

Fuel mixture doesn't make sense. If it's that, fix it. But if you don't know the real problem, you can't fix it. "Fuel Cut"? REALLY, how do you know?

 

I believe I've seen people chase all sorts of things with the EA T.

[Quidam]

When a spark plug fires, it creates a great deal of electromagnetic interference (EMI). Uncontrolled, this can show up as static in electronic devices, or much more seriously, in electronic ignitions, fuel injection, and engine management systems. This interference with EFI and engine management systems can cause "cross talk" between wiring harnesses resulting in poor running, misfiring and decreased performance.

 

That's some of what NGK has to say about EMI. I can't measure it but I have no reason to doubt it.

 

For an EJ with symptoms, it may be your plug wires.

 

Doug

[Quidam]

From a Subaru TSB.

 

Sometimes the Check Engine Light illuminates because the computer detects misfires. Subaru released an improved spark plug wire set to solve the problem. The ignition coil should also be inspected for carbon tracks or short circuits between the contacts.

 

Doug

[Quidam]

Hey,

 

Here's some anecdotal stuff for you. EF-12 Justy coil wires.

 

OEM orange-10.96 (70,xxx miles and 19 yrs. old)

 

Red-------- 6.18

 

Blue------- 10.13 ("SUPRESION CORE")

 

Blue 6.5mm----.86 ('MAG CORE')

 

Factory range in Ohms, 4.59-10.71

 

The distributor in the head is Denso for EFI.

 

The other one is Hitachi for feedback with 2 wire. An Hitachi is used with a vacume canister for the '87 EF-12.

 

 

 

EDIT: Hey, check this out.

 

MPG/Plus Gas Saving Ignition Wire Set, Green

 

 

 

MPG/PLUS GAS SAVING IGNITION WIRE SET

• <LI type=circle>Granatelli Performance Ignition Wire Set is GUARANTEED to boost your MPG to 15%! <LI type=circle>Boosts horsepower and torque and ensures a smoother running engine <LI type=circle>Rates 0-ohm resistance (compare to 4,000-7,000 ohms for conventional wires)
  
• Easy DIY installation
  

Granatelli's MPG/Plus Performance Ignition Set is an easy way to significantly increase your gas mileage…not a bad idea these days! Also increases horsepower and torque for better engine performance and a more responsive ride. The MPG/Plus Performance Ignition Set features 0-ohm resistance solid stainless steel core wires plus an RFI/EFI Hybrid Protection Ring that prevents stereo noise and allows full coil power to reach the spark plug. The result is full power, a hotter spark, more complete combustion, better fuel efficiency, more power and better overall performance…without replacing the coil! Premium technology throughout: stainless steel inner core for high tensile strength, silver plated copper outer core for high conductivity, EPDM insulation, fiberglass braiding for strength, 500° silicone jacket and boots and heavy-duty stainless steel snap-lock terminals at the spark plug! Meets or exceeds OEM specifications. Limited lifetime warranty.

 

What do you think about that? I understand it all except, "an RFI/EFI Hybrid Protection Ring ".

 

I need to know exactly what that means to Granatelli.

 

If I remember right, these were the people who made good money in Chicago getting cars and trucks started in the cold.

 

Points ignition. Clean, gap, and or replace.

 

Doug

 

 

Doug

Edited March 8, 2010 by Quidam

[idosubaru]

I didn't read all of that and you're more versed in this than I but sounds like typical over-hyped marketing to me. From what I've read ignition wires don't increase hp or mileage. When gains are seen it's because something was wrong, not because something was improved. "full power" "hotter spark" - all typically verbose language for someone trying to sell something.

 

what is it you're looking for exactly?

[Quidam]

Hey Gary,

 

It ain't rocket science.

 

Doug:Flame:

[idosubaru]

Hey Gary,

 

It ain't rocket science.

That's what I'm saying to the last 4 pages of replies. This is really simple stuff.

 

What did you say your goal is?

[Quidam]

Hey Stupid,

 

Shut the hell up, K?

 

Sincerely,

 

Doug

 

engineer my rump roast

[johnceggleston]

PLEASE some body lock this thread and get us out of here.

[idosubaru]

Make me! ?? No need to lock, I can avoid it since I'm the problem.

I was asking a question. Sorry I rubbed you wrong, I'll avoid your thread. Most folks have a goal in mind so I was wondering what yours was. That was a real question in both of my last two replies, not sure why it sounded so inciting? It's typical to start by knowing what the goal is and asking and answering questions to get there. Maybe you said earlier and I should have revisited?