spark plugs

[yorker]

I have "mighty" brand plugs in mine m8rf42, my wires are home made from Packard copper core wire- seems to work OK. No radio in mine so no reason to use the suppressor wires.

[msggunny]

Jacobs ignition

I do have a jacobs ignition and Magnecor wires...

I was looking into Jacobs a few years ago. What, if any, improvements have you seen with it? Are you running electronic ignition or still points?

I will try and squeeze every bit of performance (yes i know the 2.25 was never intended to be a hot rod) and economy i can out of my little engine.

[J!m]

The Jacobs is great because if it dies, it is a simple matter to convert to points (on the trail with NO TOOLS in about two minutes) and drive home on points until you can replace the module.

No other system can do this that I am aware of. I ran this in North Africa with no problems at all. (i did have a spare system with me of course, but never needed it)

With any electronic ignition, you MUST use suppression wires (Magnecor is the best). If you run points, it is not an issue as long as the wire insulation has not deteriorated to the point of cross-firing.

[xrover]

Since I just changed the plugs in my 72 SIII, I couldnt help reading this thread.

Took me 2 coffees to get thru it but, I see that there is a split decision between the cheaper Champion plugs and the Beru Ultra X's.

Now I am wondering if I should order them up since I went with the Champions (on the shelf by the way) that I can buy 100's of anywhere for a buck (plus or minus).

Any opinions, AGAIN????????????????????

[J!m]

I think you answered your own question with "I can get hundreds of them anywhere for about a buck."

What ever you decide on, keep a spare set (properly gapped) in your box of spares.

[jp-]

I think you answered your own question with "I can get hundreds of them anywhere for about a buck."

Cheaper is not always better my friend.

[J!m]

You are preaching to the choir on that one!

Please tell that to all those who bought the cheapest possible electronic ignition system they could find, and who then blame their $10.00 spark plugs for their ignition problems. (It's probably the distributor bearings that are shot, but that's for another post)

I say, Champion plugs and Magnecor wires. Change the plugs three times and pay less than the "high-end" spark plugs...

Champion plugs have been around a hell of a lot longer than you and I. Why? because they represent excellent VALUE that's why. When I was younger, we used to clean and re-use spark plugs. I still have that bench-top spark plug sand blaster at the house. Due to more availability and lower labor costs through automation, the huge company can offer excellent quality for a lower price. Don't like Champion brand? Use the Motorcraft (ford) ones then. Also excellent plugs, with a low price.

You need a good spark gap with good insulation. Get a plug, make sure its clean, is properly gapped for the ignition system and timing you run, and keep a set of spares.

"Cheaper" and "less expensive" are interchanged a bit too infrequently, with the perception that if you pay more it's a better product (this is called marketing, and I do this a bit myself). The sad truth is, this is far from the case in just about all things. Higher cost often indicates a higher margin, nothing more... (but this is obviously not the case in all things)

I do a lot of work on BMW's as well. When you switch to the "superior" platinum spark plugs (and this is in a current engine, making almost 100HP/Liter), the engine runs less smoothly and makes less power. How do you explain that? Simple. The ENTIRE SYSTEM must be selected carefully to work well together. In a 1940's technology engine, with it's horribly inefficient combustion chamber design, likes a big, fat spark to ignite the poorly mixed air/fuel mixture. A tiny electrode in a new-fangled plug just doesn't have the energy density to ignite it properly, and you get a miss-fire worst case; when it does fire the flame front is not uniform, and sometimes un-burned fuel will be expelled down the exhaust system (back-fire). These tiny plugs are prone to fouling, which is another problem of old design combustion chambers, because of the poor mix, they are prone to fouling plugs.

No, cheaper is not always better, but I look at it this way: if it's cheaper for this brand of oil over another, maybe you can afford to change the oil more often. If these "cheap" plugs work well and are less expensive, maybe they'll be changed more often, which means a clean, flat electrode with the proper gap. A clean, properly gapped "cheap" plug will work far better than the most expensive, worn, partially fouled improperly gapped plug.

Change them often. It doesn't take long for an old engine to eat them up for the reasons mentioned above. An efficient 2.2 liter engine makes 200 horsepower, not 80. That should say all that needs to be said. It's an old design, and has to be cared for constantly!

[jp-]

I do a lot of work on BMW's as well. When you switch to the "superior" platinum spark plugs (and this is in a current engine, making almost 100HP/Liter), the engine runs less smoothly and makes less power. How do you explain that? Simple. The ENTIRE SYSTEM must be selected carefully to work well together. In a 1940's technology engine, with it's horribly inefficient combustion chamber design, likes a big, fat spark to ignite the poorly mixed air/fuel mixture. A tiny electrode in a new-fangled plug just doesn't have the energy density to ignite it properly, and you get a miss-fire worst case; when it does fire the flame front is not uniform, and sometimes un-burned fuel will be expelled down the exhaust system (back-fire). These tiny plugs are prone to fouling, which is another problem of old design combustion chambers, because of the poor mix, they are prone to fouling plugs.

Exactly! If you read my earlier post you will see that I do not like the small contact point that platinum plugs use. I also pointed out the fouling problem.

Another problem with "conventional" plugs that you may have missed in my earlier posts is that they "shield" the spark from the mixture. That is why I like the Beru, they offer the benefit of side-firing (directly exposing the spark to the mixture) without the downside of a small central electrode as in the platinum plugs.

An efficient 2.2 liter engine makes 200 horsepower, not 80. That should say all that needs to be said. It's an old design, and has to be cared for constantly!

This would actually make for a good separate thread. The main question being: How can two engines of equal displacement make wildly different horsepower? The answer is not an easy one. If both engines are normally aspirated, it would seem that identical power figures would make sense. But design of cams, intake tracts, exhaust tracts, bores, strokes, combustion chamber shape, use of different carburetors, all combined make a huge difference.

Does the spark plug make a huge difference? Maybe not, but I can FEEL a difference in the Beru's vs. the Champions. I also run Magnecor wires.

[Alacrity]

J!m:

What Jacobs setup are you running?

[J!m]

I am running the Jacobs pro street I think it is. It comes with a new coil as well as the ECU module.

The points are retained, so it will work on ANY vehicle with points. You can set a rev limiter, spark boost at full throttle and a host of other features I have no hope of ever understanding.

Back to plugs: the spark being exposed is a good point. On a race engine, I always index the plugs, so the plug is exposed to cylinder exactly the same way.

Again, with the older combustion chamber designs, they did not have the luxury of Computational Fluid Dynamics programs on supercomputers to accurately map the behavior of the flame front in the chamber. As everything is changed (compression ratio, flow rate, intake runner surface finish just to name a few) the behavior in the combustion chamber changes. Add to the mix variable valve timing as well as spark advance with RPM etc. etc. With a slow burn, you cannot run as much timing, or you detonate. With a fast, controlled burn, you can run more timing. We all know more spark advance equals more power...

The "small" engine I pulled from my BMW is 1.9 liters, and it makes a peak of 138 BHP in bone stock trim on pump gas with full emission controls; almost double what the Rover makes at 2.2 liters. AND I get 30 MPG (but to be fair, that is not 4WD, so lets call it 25MPG) versus 10 in the rover. As the efficiency of the engine increases, so does the power, and fuel consumption drops.

And, yes, I have seriously considered putting that BMW engine into my series truck to see what happens...

[LaneRover]

Of course the BMW motor might not run as well with banana oil in the crankcase.

[jp-]

Indexing the plugs is a pain and is not required by side-fire plugs, another good reason for their use.