Cool spark plugs

From recommendations I've always used NGK BR7EFS spark plugs - with heat range 7.

After a rolling road session I was told to use a cooler spark plug as the insulator nose was chalky white all the way up after a full throttle sweep.

A too 'hot' spark plug has less cooling, causing the plug to run hotter. On a road engine in traffic this is preferred but on full throttle it can get too hot and become a glow plug instead of a spark plug. Car manufacturers compensate for this with more fuel that cools the plug. On a race engine we can prioritise differently.

As 'cooler' plugs transfers more heat to the engine top it instead lowers the temperature of the tip of the spark plug and allows a more optimum air/fuel ratio on wot without overheating, and a overheating spark plug can cause pre-ignition which is disastrous for an engine. On the flip side are possible troubles starting when cold and carbon fouling when the engine is used at low speed. Very extreme engines even use two plugs with different heat ranges. If any of this will be a problem for me we'll see, but too cold is better than too hot in order to avoid engine damage.

As NGK doesn't manufacture a similar but cooler BR8EFS plug, I had to switch to Iridium. As a bonus iridium plugs require less voltage to fire and therefore allow wider plug gaps, which in turn gives a more stable combustion and less risk of miss fire.

Denso IT24 was cheaper than NGK TR8IX, and Denso is also what SBDev recommends. So I ordered a set from eBay.

Sources:

• Four-Stroke Performance Tuning, 4th edition, A. Graham Bell
• http://www.sbdev.co.uk/Duratec/Electrical%20components.htm
• https://www.ngk.com/Spark-Plugs-NGK-c593.aspx

Bad earth troubleshooting

My engine has been a bit "moody" when idling. It can idle smooth, and then suddenly change idling speed. Some of the dash gauges has also been flickering a bit. It haven't bothered me much but today I took my USB oscilloscope and started troubleshooting as I figured it must be electrical. My suspicions were the alternator as it use to haunt me.

But I was wrong. Here is the voltage between the battery negative and the engine loom ground:

I moved the loom's ground connector from a pedal box cover screw, to the engine block. Now it look like this:

The scales are different but you get the point. One could argue that bumps around 50mV won't do much harm but at least now the oil pressure gauge is more stable. It feels like the engine runs smoother too, but that might just be placebo.

MOT, autumn and nothing much

The yearly MOT was a bit different. First attempt they refused to inspect the car as the guy said he'd not manage to get into the car as he was too big. So he sent me home with my money back. I'll never use them again.

When I should do the second attempt I realized the car was just running on three cylinders! With just minutes to spare I found the fault was a loose wire to one of the coils. I managed to fix it temporarily with a piece of wire and insulation tape and got there just when my registration number was showing on the display.

He did the inspection with me waiting in the car, only to get out to pay the bill. No troubles, no complaints.

This year I had the cage still on the car. No-one mentioned it. I won't bother to take it off any more.

I haven't driven the car at all for some time. Today is a cool but dry autumn day so for the first time in a very long time I took a drive out on the country side.

This car is really fantastic to drive!

Just wonderful.

Finally some driving!!

A "test drive a Radical SR3" event at Mantorp. I was also invited but drove my own car.

The engine runs great! The car handles great! Even the weather was great! My driving - not so great, but who cares? Well not that bad, today's best was 1:22.3. Compared with my all time best 1:21.8 it is all right considering I had no "rabbit" in front of me and I was feeling a bit rusty. The Radicals didn't stand a chance with those inexperienced drivers.

But of course...

Fuel surge and alternator problems!!

This spring when my engine broke, it was because of the small wire from the alternator went loose and it stopped charging the battery. The fuel pump couldn't keep up with the lower voltage and the engine run lean. Things got hot inside the cylinders and the engine got damaged.

Today the alternator broke completely.

The same symptoms - no power on the long straight. But this time I knew, and backed off the throttle immediately. Also the no-charge light on the dash was lit this time.

I also experienced fuel surge in the long right hander "Parisern" when the fuel level was below half. I always had that problem, even with the stock CSR200 engine. Today it annoyed me more than ever before.

I need a more robust fuel system! I can't risk loosing my engine because the alternator fails, or if a connector jumps loose.

Anyway I got five or so laps on film. Here are a couple of them. I'm not very satisfied with my driving here, as soon as I try to push hard I get sloppy and miss the apexes.

Brise starter

This is the second time my starter solenoid has broken. It is a mechanical failure where the plastic actuator arm inside the coil has broken off. The starter motor has also been very sluggish lately and not always been able to crank the engine when the engine has been hot!? If it is the solenoid that has been causing that too, I don't know. I do know it's not the battery, because I've replaced that one too. And it is not the wiring either.

I've been forced to ask a random person for help at a parking lot many times. So I just want it fixed and have installed a new Brise starter because "they're the best" according to a reseller.

And the difference is??

I don't know. I just hope it works better than the old one. The casing looks very similar for sure. It appears to turns the engine with much more determination than the old one. I read somewhere the gearing is different and that is probably why it copes better with high compression engines like mine.

New engine loom

Last time I rebuilt the engine I bought a generic Duratec loom from SBDev. Very nice quality and well made loom. But as it only had wiring for controlling the engine and not for fans, starter relays, dash gauges etc I made my own loom for that.

It worked fine but it looked like crap. Now when I'm waiting for engine parts and have nothing better to do I decided to do it again but with some more effort this time. I also wanted wiring for a few more sensors to the ecu and a future data logger.

The new loom have these connectors:

• Starter solenoid
• Starter relay
• Water temperature (dash)
• Alternator warning light 
• Fan 1
• Fan 2
• Fan relay
• Oil pressure sensor 
• Oil temp sensor 
• Fuel pressure sensor (future)
• Data logger (future)
• Chassis connector 
• MBE 1 (existing connector on engine loom)
• MBE 2 (new)
• +12
• GND

I started by doing a template with some wire, tape and zip ties.

Then the actual wires.

Lots of heat shrink tubing, and some of the connectors

And here it is!

Heat shrink tubing, the best since sliced bread

I haven't tested it in the car yet, but what could possibly gone wrong? ;-)