Changed spark plugs and boots today on V8

[Tiger]

I installed the Bosch Super Plus plugs that I bought from AutohausAZ... along with the Bremi coil boot plugs.

The original plugs that I installed in 2001 was Bosch Super... regular copper plug with dual prongs as per factory spec. All burned good... white with a bit of rusty color on it. The center electrode show very very very mild wear... still has good sharp edge... very very very slight round edge. These plugs can easily go 50,000 miles without a problem.

As far as the BROD... only one shows it but not all the way around... more like halfway. The other plugs... like 3 shows very tiny bit of brown ring... and the other 4... clean as a whistle.

Two of my plugs got loose but one has no BROD and other has tiny tiny bit of BROD.

Now... the Bremi boot is very very interesting...

[Tiger]

Bremi boot is where design change was made on the new one.

The old Bremi boot has a 1/2" hole and seal the plugs at the metal base... when you push it down... the boot presses against the metal part of the spark plug to provide you the seal against oil leakage. With this design, I can see why BROD can happen... the ground is right there! and with oil seeping in, it makes it even easier to have electric leakage.

If you think about it... look at standard car with distributor cap and wires... they seal right on the ceramic portion of the plug... never touches the metal base of the plugs...

The new Bremi boot has 1/4" hole and seals against the ceramic part of the spark plugs... a much better design. I don't see any possibility of BROD with this design at all. I can't see how far it goes down but it is not like old boot where you have to push down 1/4" whil tightening... it is pretty much already down... so it is a tad shorter.

Still with the new seal, it makes it much harder to have electric leakage.

There is also another new trick with the new Bremi boot...

[Tiger]

The another new Bremi feature is very interesting.

I was checking the ohm resistance of the old boots... the old and new Bremi are both rated 1.8k ohm. All the old ones test anywhere from 1730 to 1880... all these numbers are acceptable

Here is where it get interesting. I can measure the old ones continuously... meaning if I put my two electrodes on both ends of the boot... I can continously read 1800 for as long as I want... it will always register a number.

The new Bremi boot does NOT allow you to measure continously. It will only allow you to take one instant reading only... like one spark only... no matter how long you keep your multimeter electrodes on it, it will not let you read anymore.

To get another reading, you must release one electrode and recontact it again... and the story repeats again... instant reading and then open circuit. I tried reading 3 of them and all of them has the same story... only instant one fire reading and then zip... nothing more.

[Tiger]

So does the engine run better?

Absolutely, it does runs smoother. It seems to burn the gas much better than before... before, you could smell alot of gas fume out of exhaust when cold... Now, it is much much less.

The engine does idle much smoother with that occasional engine rocks... but it is more like smooth for a while and then little shake and then smooth all over again. Before was more like shaking all the time.

I didn't take car out for a ride...but am very pleased with how the engine is purring. So, change out those Bremi coil boots! They are worth every penny of that $5.66 upgrade.

[Jehu]

I thought if i had oil in the coil boots my valve cover gaskets were unseated. Last time i changed plugs (Denso Iridium IK20) I found a few boots had oil inside and thought i remembered reading the VC gaskets had to be off somewhere to allow that. Hadn't seemed to be interfereing with performance though I didn't take any reading and since I wasn't set up at that moment to swap the gaskets I just cleaned the boots out best I could and reused them. If i want to replace w/new boots and I find oil returned in some of the existing boots is this definitely an unseated VC gasket and so should be refitted before replacing the coil boots? I kind of think I ought to be getting slightly better gas milage current; normally around 21 average hwy/city but power, running and idling all seem fine. Hell a local BMW dealership tech even told me it sounded better than most M60's he'd heard.

[Tiger]

My valve cover is also leaking at the spark plugs... I think 4 of them are leaking. Considering I had them (spark plugs) in for 6 years... I think it is okay to have a little oil.

I'd probably would have used Denso Iridium or NGK single electrode spark plug for smoother idle. Since I already ordered the plugs... I just stuck them in.

I am faced with another delimma... whether to change the cat converters or not. I will only go with the Magnaflow cat retrofit route. The reason I am thinking about this is that my dad always noticed that there are smokes coming out of the tailpipes... More excessive than other cars. Seems to be occuring more in BMWs than any other cars.

It was not coolant or oil burning, but rather, I believe, slight unburned fuel... which I believed is caused by the original coil boots for electrical leakage... so that the spark plug is not delivering maximum power.. and the cat will always burn the fuel... thus some smoke and some fuel smell.

I think this is probably the main reason why alot of our cats died and that we couldn't figure out why... since all my spark plugs are burning normally with no odd or abnormal indication at the electrode... No check engine light... and the last emission inspection was barely passing. I am inclined to think my theory is correct.

Previous inspections were super easy with no problem and super clean emission.

[Ferret]

If you're leaking oil into the spark plug bores, I'd fix the leak before changing your plugs... oil down there can cause nasty misfires if your plug leads are loose fitting.

Whoever last did the seals on my M60 needs their hand shaking - when they put it all back together they used haematite sealant and it doesnt leak at all now. Plugs are always dry when I take things apart to work on, very much like my old M50 after I got annoyed with it piddling oil everywhere and sealed it all up.

[Tiger]

The dealer did my valve cover gasket when I got the car... but a couple of years later when I changed the plug, it was leaking.

New coil boot eliminates the problem of oil.