ozVTR
10-01-2009, 12:45 PM
First up, I and no doubt the administrators of this site do not need or want rants or litigation in respect to “advise” given on this site. I do not claim to be a mechanic and in fact I am not! The following text is for “information only”, serious damage could be done to your car if maintenance is not performed correctly!
Normally I don’t have much to say on my how-to subjects but I’ll talk a bit about spark plugs. OH! If you own a diesel, well there is nothing to see here, move along LOL.
There are basically two types of common spark plugs, “normal” and precious metal (Platinum, Iridium, ETC). I wont bore you with all the details of electrode composition and ETC but here is a (very) quick rundown of the pros and cons.
Normal: Pros, cheap!! Available in a wide range of brands and specifications. Cons, can lasts as little as 5000Km before performance degrades. Level of degradation depends on engine quality!
Precious metal: Pros, much longer service life span, maintains engine performance for longer. Resists build-up of deposits on electrodes (less cleaning). Cons, expensive! May be difficult, or impossible, to get a plug in the right specification to suit your engine.
I do not believe that there is a significant increase in performance with the precious metal plugs over normal plugs but the real difference is in the service life. Both plug types can last more than 100000 Km but you will have to clean and gap the normal plugs far more times than the precious metal type. Oh, and with deterioration in performance comes a reduction in economy!
Ok, that was just an overview. Don’t ask me about specifics, that’s a job for the forums.
The 1.6L engines all seem to have Bosch FR8SE0 plugs and all the others seem to have Bosch FR7DE plugs (EDIT: please see the post following this one for an update). The gap (mentioned later) is the same for all, as is plug removal, inspection and insertion. My tute is on the 1.6L engine (sorry) but I trust the other, petrol, engines will disassemble in a similar manor. However I believe you do not have to remove any covers to get to the coil packs on the 1.4 and 1.1L engines. No doubt people will tell me if I am wrong LOL.
Only change the spark plugs on a cold engine. 1) Its stupid to work on a hot engine (duh)! 2) The plugs will go in and come out easier in a cold engine! Put all your tools and parts on a drop cloth, old blanket or suitable clean work surface. It is bad practice to “put down” tools or parts in the engine bay!!!!!
Fhew, now on with the show.
3183
The first tools you will need are a T20 torque tip and ¼” driver.
3184
Undo the six screws securing the top cover. These screws only require the handle and are only done up hand tight.
3185
3186
Remover the cover. Note the clip on the far right, it just pulls off the vent tube.
3187
3188
Remove the two vent tubes from the cam covers by pushing the yellow clips in. There isn’t much you can do with the tubes, you can’t get them out of the way. So just move them out of the road as you go.
3189
3190
3191
3192
The coil pack electrical connector is on the right hand end of the coil pack. To remove the connector requires that you remove the metal retaining clip. WARNING!!! This clip WILL fly off and disappear if unrestrained! You can very easily pry it off with a flat bladed screw driver but make sure that you hang on to it at all times! Push the plug down to disconnect it.
3193
Remove the four T20 screws holding the coil pack down. This may require the ratchet to remove the screws.
3194
Remove the coil pack by holding the base of the coil pack NOT the electrical connector. Lift the left and right ends of the pack, alternately, in small increments until it is free.
3195
3196
Inspect the rubber plug boots for damage, melting, burning and arcing. The boots should be pliable, if the boots are stiff and hard or are damaged replace them.
3197
You can now see the tops of the spark plugs in the cylinder head.
3198
You will need a t-bar (or ratchet), extension and a 5/8” (or 16mm) spark plug socket. The spark plug socket has a device inside that holds the spark plug in the socket while installing or removing the plug. Insert the socket and extension assembly into the cylinder head spark plug tube and on to the plug. The plug will require a medium amount of force to undo. Remove, service and install the plugs ONE at a time. REMEMBER, with the spark plug removed the cylinder is exposed, if any thing falls into the engine cylinder it WILL cost you dearly!!
3199
Inspect the spark plug electrode area. This area should be clean, dry and very slightly sooty. Small amounts of deposits are OK (this usually indicates impurities in the oil or fuel). What is not OK are thick crusty deposits, oil or damaged electrodes.
3200
The plug should be generally in good condition, no rust or heat stress on the metal casing. No cracks or damage to the white insulator. The arrow on the left points to a “rusty” ring around the insulator. This is not uncommon and only indicates that there is an insignificant pressure leak. The arrow on the right shows the thread is brown and discoloured and looks oily. From the factory the plugs are installed with an “anti seize” compound. This compound is “tacky”, oil on the other hand is thin and “wet”. It is used to stop the plugs from binding in the cylinder head. The anti seize will discolour with time and is nothing to be concerned with. Do not be tempted to wipe off the compound on old plugs and I highly recommend obtaining some and applying a small amount to the threads of new plugs.
If the plug requires cleaning use a small brass brush to remove any deposits on the electrode area. To remove any contaminants on the threads use a clean rag.
3201
Check the gap between the electrodes with a feeler gauge or plug gauge. The gap should be 0.9mm ±0.1mm. So, no less than 0.8mm and no more than 1.0mm. If the gap is too wide, bend the outer electrode with a set of small pliers and then check the gap again. If still too wide repeat. It should take a small amount of effort (not effortless) to push the gauge in and out of the gap.
3202
Insert the plug back into the socket, then screw the plug into the head by hand, the plug should go in smoothly with only a small amount of resistance, no catching, no binding. The resistance should be the same all the way down until it gets to the bottom and seats. If it gets harder and harder something is wrong unscrew the plug immediately. I highly recommend using a torque wrench for doing up the plugs (even a cheap one is better than guessing). They should be torqued to 2.5 ±0.2 mda.n (who makes up these standards)! That’s 2.5 Kg/M, or 18 foot/pounds.
From here it is just the reverse order with the following notes; I do not have a specification for the tension of the coil pack bolts. They should be tight but not so tight the veins in your forehead pop out while doing up the screws! Use a short handled ratchet, never use the torque wrench to do up small screws unless you have a torque specification!!
The six screws that hold the head cover on only go into plastic, do not over tighten these, they should be just “snugged” down. To screw a screw into a precut thread, insert the screw through the cover and into the thread hole. Turn the screw slowly backwards while applying light downward pressure, when the precut threads and the screw threads match the screw will pop into place. You should now be able to screw the screw in without any resistance and without cross threading.
Build-ups of deposits and/or accelerated electrode wear, are usually due to poor fuel and/or poor oil. Having a look at your plugs from time to time will give you a very good indication of the state of your engine.
Normally I don’t have much to say on my how-to subjects but I’ll talk a bit about spark plugs. OH! If you own a diesel, well there is nothing to see here, move along LOL.
There are basically two types of common spark plugs, “normal” and precious metal (Platinum, Iridium, ETC). I wont bore you with all the details of electrode composition and ETC but here is a (very) quick rundown of the pros and cons.
Normal: Pros, cheap!! Available in a wide range of brands and specifications. Cons, can lasts as little as 5000Km before performance degrades. Level of degradation depends on engine quality!
Precious metal: Pros, much longer service life span, maintains engine performance for longer. Resists build-up of deposits on electrodes (less cleaning). Cons, expensive! May be difficult, or impossible, to get a plug in the right specification to suit your engine.
I do not believe that there is a significant increase in performance with the precious metal plugs over normal plugs but the real difference is in the service life. Both plug types can last more than 100000 Km but you will have to clean and gap the normal plugs far more times than the precious metal type. Oh, and with deterioration in performance comes a reduction in economy!
Ok, that was just an overview. Don’t ask me about specifics, that’s a job for the forums.
The 1.6L engines all seem to have Bosch FR8SE0 plugs and all the others seem to have Bosch FR7DE plugs (EDIT: please see the post following this one for an update). The gap (mentioned later) is the same for all, as is plug removal, inspection and insertion. My tute is on the 1.6L engine (sorry) but I trust the other, petrol, engines will disassemble in a similar manor. However I believe you do not have to remove any covers to get to the coil packs on the 1.4 and 1.1L engines. No doubt people will tell me if I am wrong LOL.
Only change the spark plugs on a cold engine. 1) Its stupid to work on a hot engine (duh)! 2) The plugs will go in and come out easier in a cold engine! Put all your tools and parts on a drop cloth, old blanket or suitable clean work surface. It is bad practice to “put down” tools or parts in the engine bay!!!!!
Fhew, now on with the show.
3183
The first tools you will need are a T20 torque tip and ¼” driver.
3184
Undo the six screws securing the top cover. These screws only require the handle and are only done up hand tight.
3185
3186
Remover the cover. Note the clip on the far right, it just pulls off the vent tube.
3187
3188
Remove the two vent tubes from the cam covers by pushing the yellow clips in. There isn’t much you can do with the tubes, you can’t get them out of the way. So just move them out of the road as you go.
3189
3190
3191
3192
The coil pack electrical connector is on the right hand end of the coil pack. To remove the connector requires that you remove the metal retaining clip. WARNING!!! This clip WILL fly off and disappear if unrestrained! You can very easily pry it off with a flat bladed screw driver but make sure that you hang on to it at all times! Push the plug down to disconnect it.
3193
Remove the four T20 screws holding the coil pack down. This may require the ratchet to remove the screws.
3194
Remove the coil pack by holding the base of the coil pack NOT the electrical connector. Lift the left and right ends of the pack, alternately, in small increments until it is free.
3195
3196
Inspect the rubber plug boots for damage, melting, burning and arcing. The boots should be pliable, if the boots are stiff and hard or are damaged replace them.
3197
You can now see the tops of the spark plugs in the cylinder head.
3198
You will need a t-bar (or ratchet), extension and a 5/8” (or 16mm) spark plug socket. The spark plug socket has a device inside that holds the spark plug in the socket while installing or removing the plug. Insert the socket and extension assembly into the cylinder head spark plug tube and on to the plug. The plug will require a medium amount of force to undo. Remove, service and install the plugs ONE at a time. REMEMBER, with the spark plug removed the cylinder is exposed, if any thing falls into the engine cylinder it WILL cost you dearly!!
3199
Inspect the spark plug electrode area. This area should be clean, dry and very slightly sooty. Small amounts of deposits are OK (this usually indicates impurities in the oil or fuel). What is not OK are thick crusty deposits, oil or damaged electrodes.
3200
The plug should be generally in good condition, no rust or heat stress on the metal casing. No cracks or damage to the white insulator. The arrow on the left points to a “rusty” ring around the insulator. This is not uncommon and only indicates that there is an insignificant pressure leak. The arrow on the right shows the thread is brown and discoloured and looks oily. From the factory the plugs are installed with an “anti seize” compound. This compound is “tacky”, oil on the other hand is thin and “wet”. It is used to stop the plugs from binding in the cylinder head. The anti seize will discolour with time and is nothing to be concerned with. Do not be tempted to wipe off the compound on old plugs and I highly recommend obtaining some and applying a small amount to the threads of new plugs.
If the plug requires cleaning use a small brass brush to remove any deposits on the electrode area. To remove any contaminants on the threads use a clean rag.
3201
Check the gap between the electrodes with a feeler gauge or plug gauge. The gap should be 0.9mm ±0.1mm. So, no less than 0.8mm and no more than 1.0mm. If the gap is too wide, bend the outer electrode with a set of small pliers and then check the gap again. If still too wide repeat. It should take a small amount of effort (not effortless) to push the gauge in and out of the gap.
3202
Insert the plug back into the socket, then screw the plug into the head by hand, the plug should go in smoothly with only a small amount of resistance, no catching, no binding. The resistance should be the same all the way down until it gets to the bottom and seats. If it gets harder and harder something is wrong unscrew the plug immediately. I highly recommend using a torque wrench for doing up the plugs (even a cheap one is better than guessing). They should be torqued to 2.5 ±0.2 mda.n (who makes up these standards)! That’s 2.5 Kg/M, or 18 foot/pounds.
From here it is just the reverse order with the following notes; I do not have a specification for the tension of the coil pack bolts. They should be tight but not so tight the veins in your forehead pop out while doing up the screws! Use a short handled ratchet, never use the torque wrench to do up small screws unless you have a torque specification!!
The six screws that hold the head cover on only go into plastic, do not over tighten these, they should be just “snugged” down. To screw a screw into a precut thread, insert the screw through the cover and into the thread hole. Turn the screw slowly backwards while applying light downward pressure, when the precut threads and the screw threads match the screw will pop into place. You should now be able to screw the screw in without any resistance and without cross threading.
Build-ups of deposits and/or accelerated electrode wear, are usually due to poor fuel and/or poor oil. Having a look at your plugs from time to time will give you a very good indication of the state of your engine.