[Willie Williford]

Ok so you are going to try to stick a sharpie at least 3-1/2 inches down a recess hole and get a valid mark on the sparkplug........Good luck.

Put a sparkplug socket (The type that holds the plug in place) onto the plug and mark the top of the socket closest to the center line of the head (Forward). When you eventually pull the plug out with the socket, it should be easier to determine which way the plug electrode is pointing. Where the electrode wire is welded to the plug body should end up towards the rear of the car. (Viewed like the plug is in the engine)
HTH
Willie

 

[red1dr]

Tell you what Red1DR, I'll do what you suggested since I am going to swap out my plugs anyway. As far as I can tell from all the maintenance that was done to this car prior to my purchase ( I have years for receipts dating back from 2001 till 2010) that no plugs were ever changed.

I will use my Sharpie paint pens to mark the 12 noon position on my stock plugs prior to their removal and replacement. I will take pics of course and post them up on my own thread during my sparkplug change.

Thanks for doing this!! My guess (but I'm not putting any money on it!) is that the plug "gap"
will be more or less aimed at the intake valve that is not affected by VTEC.

 

[red1dr]

You do recall correctly.....I owned a 1.5L 1984 CRX that had the CVCC design. The valve cover says 12 valve but Honda does not count the tiny valve used for the CVCC design.

Thanks Joe, nice to know my memory is somewhat intact. I remember being very perplexed at finding 16 valves when the valve cover said 12.

One of the intake valves open normally based on the cam lobe. The other intake valve only opens slightly to create a swirl in the combustion chamber in conditions of light load under 2700 RPM. Under heavy load @ 2700 RPM and above, VTEC kicks in and the second valve (that normally opens slightly) now opens fully like the other intake valve.

So to go into lean burn does the ECM simply reduce the amount of fuel injected, or are there other changes??

 

[joecvt]

So to go into lean burn does the ECM simply reduce the amount of fuel injected, or are there other changes??

I believe the rest is handled by the ECM (no other mechical changes) since the ECM can monitor engine load / air fuel mixture and change fuel injection on/off timing and spark advance or retard. The ECM also controls the purge cycle.

The MT does have a higher compression ratio compared to the CVT due to different pistons but that is a constant mechanical device between lean burn and non-lean burn mode on the MT model.

JoeCVT = Just your average CVT onwer

 

[Rainsux]

Spark Plug Gap?

I just pulled my plugs and found Autolite Double Platinum APP 5325 plugs, gapped to .045. I've been searching, but I can't find the correct gap. Lots of indexing info, though, which I will try when I put them back in. Can anybody tell me the correct gap?

Thanks!

Sam

 

[JimIsbell]

I believe the rest is handled by the ECM (no other mechical changes) since the ECM can monitor engine load / air fuel mixture and change fuel injection on/off timing and spark advance or retard. The ECM also controls the purge cycle.

The MT does have a higher compression ratio compared to the CVT due to different pistons but that is a constant mechanical device between lean burn and non-lean burn mode on the MT model.

JoeCVT = Just your average CVT onwer

Then technically there is no reason that you could NOT burn straight ethanol in the car as it would automatically adjust the mixture for a good burn???

 

[satchel]

I just pulled my plugs and found Autolite Double Platinum APP 5325 plugs, gapped to .045. I've been searching, but I can't find the correct gap. Lots of indexing info, though, which I will try when I put them back in. Can anybody tell me the correct gap?

Thanks!

Sam

.039-.043" or 1.0-1.1mm

 

[Rainsux]

Thanks!

I gapped them correctly, and two of them indexed correctly. The other one was off about 90*. It does seem to idle smoother and maybe have a little more low end power. It still doesn't like hills.

The next question is whether the platinum plugs will make any differnce. They didn't look very old.

Sam

 

[joecvt]

Then technically there is no reason that you could NOT burn straight ethanol in the car as it would automatically adjust the mixture for a good burn???

The ECM has firmware and uses mappings designed for a certain fuel type. I'm not sure how far you can go with pure ethanol. Sensors are used for feedback and the ECM will "try" to perform whatever it was designed for but if the fuel does not fall into the "norm" of what the ECM is expecting, you may get engine misfire codes and such.

JoeCVT = Just your average CVT owner

 

[MN Driver]

Then technically there is no reason that you could NOT burn straight ethanol in the car as it would automatically adjust the mixture for a good burn???

Considering the limited power of lean-burn, to put a fuel that, although has higher octane and could probably adjust timing to a more optimal spec, ethanol as a fuel has less energy content than straight gas. I'm already bothered enough by the lack of lean-burn performance that is likely largely affected by the 10% ethanol that is available here that if I put E85 or straight ethanol in, I think I would be kissing lean-burn in 5th gear goodbye completely.

 

[mahout]

Thanks for doing this!! My guess (but I'm not putting any money on it!) is that the plug "gap"
will be more or less aimed at the intake valve that is not affected by VTEC.

I mark my plugs with an xacto knife scratch across the top of tyhe contact pin. Yes it takes a lite to see but no error either. And it has no effect on the electrical conduction.

 

[JimIsbell]

Ok so you are going to try to stick a sharpie at least 3-1/2 inches down a recess hole and get a valid mark on the sparkplug........Good luck.

Put a sparkplug socket (The type that holds the plug in place) onto the plug and mark the top of the socket closest to the center line of the head (Forward). When you eventually pull the plug out with the socket, it should be easier to determine which way the plug electrode is pointing. Where the electrode wire is welded to the plug body should end up towards the rear of the car. (Viewed like the plug is in the engine)
HTH
Willie

Thats the way I did it.....but....dont drop the plug on the way out or you loose the index....dont ask how I know.

 

[JimIsbell]

Considering the limited power of lean-burn, to put a fuel that, although has higher octane and could probably adjust timing to a more optimal spec, ethanol as a fuel has less energy content than straight gas. I'm already bothered enough by the lack of lean-burn performance that is likely largely affected by the 10% ethanol that is available here that if I put E85 or straight ethanol in, I think I would be kissing lean-burn in 5th gear goodbye completely.

Yes, BUT. The BUT has to do with the cost of the fuel. I dont mind loosing some power if the fuel is $2 a gallon or less. You can build a small still, get a license to use it (requires denaturing the alcohol with 1% gasoline), and ferment your mash from all sorts of things. The bottom line is Ethanol for $2 a gallon plus some labor.

OK, thats not much savings today with gas at $2.90 a gallon. But if fuel is $5 a gallon...predicted price for two years from now....or fuel is just NOT AVAIALBLE....then....well, its nice to knpw that our cars can run from home grown fuel...if the need arises.

 

[MN Driver]

Yes, BUT. The BUT has to do with the cost of the fuel. I dont mind loosing some power if the fuel is $2 a gallon or less. You can build a small still, get a license to use it (requires denaturing the alcohol with 1% gasoline), and ferment your mash from all sorts of things. The bottom line is Ethanol for $2 a gallon plus some labor.

OK, thats not much savings today with gas at $2.90 a gallon. But if fuel is $5 a gallon...predicted price for two years from now....or fuel is just NOT AVAIALBLE....then....well, its nice to knpw that our cars can run from home grown fuel...if the need arises.

I can respect that. In that case I wouldn't mind either.

 

[Corey]

Great thread. I'm at exactly 105K on my 03 CVT so I need to get plugs. What a is good, low cost source for OEM plugs?

Thanks

 

[Roen]

Majestic Honda still works out to be better than the dealership.

 

[red1dr]

Majestic Honda still works out to be better than the dealership.

Apparently Majestic Honda IS a Honda dealership in RI (they sell and service Hondas). They also sell parts online.

 

[Balboa]

Hate to revive this older thread but any long term updates on how well the Autolite XP5325s in place of the stock plugs. I want to change my plugs soon and from what I understand, these are good replacements so long as I can install the open end of the spark plug pointing towards the intake...that's what you guys mean by indexing correct?

I replaced my plus today with Autolite XP5325. I indexed them, not with copper washers (an indexing kit), but by selecting them from a group of 6 plugs purchased at Rock Auto for about $8. each including taxes and shipping. Thanks to Jim Isbell for the idea. So far they are not worse, possibly better, but it’s hard to tell with my irregular routes and this cold weather.

Here is how I indexed them. I assumed that the open gap should be aimed at the centre of the combustion chamber. I marked that opening with a Sharpie pen on the top of the plug and wound them in finger tight. I estimated that torqing them to 23nm would be half a turn. I moved around the 6 plugs until I had the best result and torqued those three down. Voila!

Jim Isbell thought that with the worst scenario of two tolerances, standard Honda plugs could be out by as much as 180 degrees. If I could make a correction here, Jim, I think they could be out by 180-45=135 degrees because Honda would have put the centre in the middle of the 90 degree “piece of pie”. That said, two of my original plugs were about 120 degrees off. Now, with my own indexing, all are within 30 degrees of correct which I believe is straight forward (or 12 o’clock).

But I think that getting as close as possible to 12 o’clock isn’t that important. What is important (for lean burn), is NOT BEING NEAR 6 O’CLOCK. Six o’clock makes for a “flame front shadow” behind the negative post. If I am correct then a plug 135 degrees to either side of 12 o’clock makes little difference as the flame front is unimpeded towards the main volume of gas.

Rick Hall
Caledon Ontario
2000 and 2005 Insights

 

[Eli]

The open end of the plug towards the non-VTEC intake valve, yes.

Like so:

 

[JimIsbell]

I still think 180 is the correct number. Remember, Honda didnt custom make the plugs for the cylinder. They ALSO had to make do with just 4 possibilities so there was still some error. They didnt get them "spot on" either....LOL

BTW, I am still getting great mileage after that plug change and indexing them the way I did.