Regular gas in a 9.5?

I believe that it probably is, unless you wanted a different word.

I haven't had to reset gap on spark plugs in years. But a spark plug gapping tool (with gage wires) can't be more than 5 bucks at your local NAPA or whatever. Buy the right NGK spark plugs as stated in your manual, _that_ is critical. Every NGK I've ever bought has been properly gapped out of the box.

Bumpy sticks that spin and make the valves go up and down. But that's not important right now.

It's really a piece of cake. Undo those 4 screws (the torx screwdriver is probably also in the car's toolkit), undo the connector (there's a u-shaped slidy think holding it latched together, slide it out the only way it can go), and lift the DI cassette straight up away from the engine. Well, not "straight", at the same angle the engine is. Up & towards you maybe 10 degrees, you'll see what I mean when you get there. It takes a bit of force (just a bit) because you're disconnecting the spark plugs at the same time. Up & out, plugs right there. Make sure there's no crap around the plugs to fall in when you take 'em out, there probably won't be.

If any of the used plugs have tips which look different than the others, post a description here. Should be coffee-with-cream colored maybe dusty looking. Black, or slimy, or flaky, or gone, would all be problems but I'd be surprised by any of that.

Reply to
Dave Hinz
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Excellent point.

Thanks very kindly for the tutorial, Dave, and to Fred for giving me the plug heads-up to begin with. I'll be on those plugs like white on rice come this weekend, and may the automotive gods - Manny, Moe and Jack, as I recall - have mercy on my car's eternal soul.

I will report back.

M
Reply to
Michael Hudson

Sorry, Swedish car, I believe you'll be meaning "like brown on a m00se".

Try not to drop anything into the engine while you have the plugs out. That would be double-plus-ungood.

Reply to
Dave Hinz

Um, sorry about this, but regarding that "under trunk" spark plug wrench, I just had a look under the trunk flap. Lug wrench, check. Jack, check. Jack handle, check. Torx screwdriver, check. Spark plug wrench. Spark plug wrench? No apparent spark plug wrenches, and the Owner's Manual makes no reference to one. Either I'm looking in the wrong place, at the wrong thing, or it's been absconded with!

M
Reply to
Michael Hudson

Should be a tubular steel device, plated in that gold-ish color like the lug wrench. Hole in the side of it that the lug wrench fits into as a handle. Maybe not?

Reply to
Dave Hinz

Not. But one shouldn't be too hard to come by, should it? Are there different sizes or depths or grades or anything, or can I just pop over to Bond Auto a grab a generic spark plug wrench off the shelf?

Reply to
Michael Hudson

There are at least 3 sizes of spark plug wrench. When you buy the plugs (did I mention several times to get the correct grade of NGK only?), take one along with you and get a wrench that fits. It needs to go deep.

Reply to
Dave Hinz

Roger. NGK. Deep. And thanks again. And keep things out of the engine. Right. Tell me, why do I feel like I'm about to re-enact an early Bob Hope routine? And without Jayne Russell, to boot.

Over. Out.

M "Painless Potter" Hudson

Reply to
Michael Hudson

Just so you know, you're overplanning this whole adventure. Not criticizing, I recognize it because I've done it.

Ah, Jayne Russell. Thanks for the mammories.

Reply to
Dave Hinz

Overplanning? Nonsense! It's paranoia, a history of incompetence and deep seated feelings of inadequacy. Nothing more.

You're welcome. Now, pass me my head lamp and pith helmet, and let's get to work!

M
Reply to
Michael Hudson

Only if I get to be Bing, rather than Jayne. Wardrobe incompatibilities, you see.

Reply to
Dave Hinz

Not necesarily. The energy contained in the fuel is the same. If the engine computer (ECU) retards the timing it is because the fuel is burning too fast (pinging) and the combustion is happening before TDC. If the ECU does a correct job of backing off the timing is could have no effect on mileage.

Taken to the other extreme, if the engine was set-up to run low octane (fast burning) fuel and you fed it very high octane (slow burning) fuel it is possible to have incomplete combustion and be exhausting unburnt fuel. Obviously that would nbe counterproductive to fuel economy.

I agree with all of the above except the assumption of *better* fuel economy when running higher octane. The try both and see is the best approach.

Reply to
Fred W

Can't say about your fuel market, but the gasoline in the US claim to have the same cleaning agents (detergents) these days regardless of grade. Of course each manufacturer claims to have the best compared to the competition, but do not differenciate premium anymore.

I have not heard those claims of superior cleaning agents in "premium" fuels in over a decade. Back in the 60's and 70's it used to be a big marketing point...

Reply to
Fred W

In the late 80s here Shell advertised its petrol as having superior additives. Unfortunately they didn't agree with all engines and some ended up with fouled valves IIRC !

Graham

Reply to
Pooh Bear

The gas/oil companies lost a major suit brought by the US gov't just a couple years ago for claiming that higher octane fuels had any benefit at all aside from higher octane. They use the same additives in high octane fuel, it just has higher octane.

Reply to
Bob

Backing off the timing is going to seriously reduce power on a practical basis.

Reply to
Bob

OK, there goes my theory then...

Reply to
Johannes

Normally I would agree with you, that is if the fule octane was held constant. In other words, if the fuel burns at a constant rate (octane) then retarding the ignition would cause the fuel to not have enough time to complete combustion and you would lose energy.

But if the reason the ignition is that the engine is pinging due to early combustion of the fast burning, low octane fuel, doesn't it make sense that the fuel will still be fully burned during the power stroke?

Reply to
Fred W

I'm certainly not an engineer - but my crude understanding is that we advance the timing to start the burn earlier in the stroke and gain more power, but that it requires higher octane in order to do this.

If I am not misunderstanding your statement, it seems like you are inferring that we advance the timing to compensate for higher octane gas and that therefore we get the same power from lower octane and retarded timing. If that was true, there would be no reason to have higher octane gas - we'd just retard the timing on all cars.

Reply to
Bob

What you say makes a great deal of sense.

I think the idea is that we want the majority of combustion to be occurring during the optimum part of the power stroke so that the angle of the crankshaft is as close to perpendicular to the cylinder as possible for best energy transfer from reciprocal to rotational. Obviously, it is not a binary situation. There is a ramp up and ramp down of the combustion and the expansion of gasses.

To achieve this optimum angle at higher engine rpms requires igniting the mixture before the piston reaches TDC (advance). But with low octane fuel the mixture burns too rapidly and starts to expand before the piston reaches the top, causing pinging (preignition). The ECU retarding the ignition can reduce the preigintion, but that will not necesarily put the maximum combustion at the optimum crank angle.

And then there is the whole valve timing thing...

The other thing that does happen with low octane fuel is spontaneous combustion if/when the combustion chamber pressure and temperature are high. Higher compression engines make more power than lower compression ones (all other things being equal) and so the need for higher octane fuel. Boosting the intake pressure (supercharging or turbo charging) is the functional equivelent of increased compression (and increased displacement) and so requires higher octane fuels.

Reply to
Fred W

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