Spark plug replacement - what do I need?
Discussion
A plug socket of appropriate size for the plugs.
These often have a rubber ring inside them so it's easier to fish recessed plugs out.
When you put the new plugs in if they are in a recess so you can't get your fingers in put them in the socket & start them by hand to reduce the risk of crossthreading.
If the socket doesn't have the rubber ring then a piece of plastic tube over the top of the plug so you can lower it into the hole & twist the tubing to start the plug to reduce the risk of crossthreading.
These often have a rubber ring inside them so it's easier to fish recessed plugs out.
When you put the new plugs in if they are in a recess so you can't get your fingers in put them in the socket & start them by hand to reduce the risk of crossthreading.
If the socket doesn't have the rubber ring then a piece of plastic tube over the top of the plug so you can lower it into the hole & twist the tubing to start the plug to reduce the risk of crossthreading.
Yes indeed,
A decent socket set, not something from the pound shop.
Plugs can get pretty tight if they've been in a few years. Make sure you've got a proper socket, keep the extension dead straight and then turn the handle as perpendicular as possible. And mind your knuckles! Many have been skinned when the plug suddenly starts to move.
Be very careful not to get the new plugs cross-threaded. When correctly aligned they'll spin straight in very lightly.
Be careful not to over-tighten. They can be done medium hand tight if you don't have a torque wrench. Better a bit too loose than too tight.
And don't muddle up your HT wires! Easiest way to avoid this is to replace one plug at a time. Make a note of which plug came from which cylinder. Then when they're out you can compare the electrodes to see whether all cylinders are performing the same.
Try not to let any crud fall into the cylinders.
A decent socket set, not something from the pound shop.
Plugs can get pretty tight if they've been in a few years. Make sure you've got a proper socket, keep the extension dead straight and then turn the handle as perpendicular as possible. And mind your knuckles! Many have been skinned when the plug suddenly starts to move.
Be very careful not to get the new plugs cross-threaded. When correctly aligned they'll spin straight in very lightly.
Be careful not to over-tighten. They can be done medium hand tight if you don't have a torque wrench. Better a bit too loose than too tight.
And don't muddle up your HT wires! Easiest way to avoid this is to replace one plug at a time. Make a note of which plug came from which cylinder. Then when they're out you can compare the electrodes to see whether all cylinders are performing the same.
Try not to let any crud fall into the cylinders.
My advice from sod's and reverse sod's law along the way.
Look now ie before you have the new plugs at what if anything is involved in getting access to them.
My ancient toyota I simply pull off a rubber lead and there is the plug deep down the whole (I've never seen a plug that isn't deep down!)
If you can get to them easily, check for debris that might be down there, torch etc and clean/air line (empty plastic bottle might suffice etc)
They can be tight on removal (take a mental note at that point you will not need anything like that effort when tightening them later) it can be easier if the car was running say an hour previously but it's not necessary per se.
It's not a bad idea to undo a bit and occasionally screw back in a half turn and repeat, especially if it feels tight (once started/cracked, you should be able to have your hand on the ratchet head, not end, for it to be doable to continue to turn, not super easy that way but steadily doable)
Care should be taken as a amature/beginner as any time saving is tiny compared to the hassle of screwing this up!
On installation I use the tip of having a rubber hose over the top of the new plug and using that to start it in the hole, it impossible to cross thread this way.
I would also tighten with a regular socket (remove with a dedicated spark plug socket with the rubber insert) as before I have had the socket extension leave the socket in there as the rubber grips the plug to hard after torqing up.
Also review the plugs and most have crushing washer, so you tighten them up and then you have to be firmer at the end, just read about it and go steady and you'll be fine. It's not one for and beginner to rush
Look now ie before you have the new plugs at what if anything is involved in getting access to them.
My ancient toyota I simply pull off a rubber lead and there is the plug deep down the whole (I've never seen a plug that isn't deep down!)
If you can get to them easily, check for debris that might be down there, torch etc and clean/air line (empty plastic bottle might suffice etc)
They can be tight on removal (take a mental note at that point you will not need anything like that effort when tightening them later) it can be easier if the car was running say an hour previously but it's not necessary per se.
It's not a bad idea to undo a bit and occasionally screw back in a half turn and repeat, especially if it feels tight (once started/cracked, you should be able to have your hand on the ratchet head, not end, for it to be doable to continue to turn, not super easy that way but steadily doable)
Care should be taken as a amature/beginner as any time saving is tiny compared to the hassle of screwing this up!
On installation I use the tip of having a rubber hose over the top of the new plug and using that to start it in the hole, it impossible to cross thread this way.
I would also tighten with a regular socket (remove with a dedicated spark plug socket with the rubber insert) as before I have had the socket extension leave the socket in there as the rubber grips the plug to hard after torqing up.
Also review the plugs and most have crushing washer, so you tighten them up and then you have to be firmer at the end, just read about it and go steady and you'll be fine. It's not one for and beginner to rush
Panamax said:
And don't muddle up your HT wires! Easiest way to avoid this is to replace one plug at a time. Make a note of which plug came from which cylinder.
A quick photo might also be worthwhile if it helps with ensuring exactly the right routing path of the leads. Of course the one-plug-at-a-time method will almost certainly mitigate this risk but I like to learn the hard way.Make sure to support the ratchet well undoing the old plug, ie keep it straight on the plug, its too easy to crack the insulator at which point the plug has got to come out then whatever happens...if this does happen to you for goodness sake vacuum any shards of insulator out so they don't drop in the plug hole when you fish the plug out.
Suggest 6 sided socket (all sockets if poss not just spark plug jobbies) because they are less inclined to slip than 12 sided.
Plugs can be harder to remove than they used to be because they now get left in for many years/miles where at one time new spark plugs were almost an annual event, used to be cheap as chips too not £15 apiece like the ones on our Subaru...and oh boy arn't they fun to change.
Suggest 6 sided socket (all sockets if poss not just spark plug jobbies) because they are less inclined to slip than 12 sided.
Plugs can be harder to remove than they used to be because they now get left in for many years/miles where at one time new spark plugs were almost an annual event, used to be cheap as chips too not £15 apiece like the ones on our Subaru...and oh boy arn't they fun to change.
Super Josh said:
Set of feeler gauges to check/set the gap? Or do we assume that plugs no come pre-gapped?
Josh
Many are fine out of the box but check the gap.Josh
There was a competition for young mechanics on TV a few years ago. Part of it required a plug set change.
Most just took them out of the boxes & fitted them without looking.
The gap of one plug in each set had been completely closed - sort of thing you might meet if someone had dropped it & just put it back in the box.
Of those that didn't check most realised that the sudden misfire might be caused by something they'd done & found the issue. A couple didn't & spent the rest of the time allowed looking for the cause, assuming that it couldn't be the plugs because they were new.
That model has plug top coils which are secured with an M6 flange bolt (8mm head), remove the bolts and the coils should just pull off giving access to the plugs. There is a vacuum hose and a large diameter air hose in the way of plug 2 , the vacuum hose can be unclipped and moved to one side, the large plastic air hose will need to be unbolted and moved over a little to provide access.
Dave
Dave
Edited by DVandrews on Tuesday 13th June 10:24
Edited by DVandrews on Tuesday 13th June 10:24
paintman said:
Super Josh said:
Set of feeler gauges to check/set the gap? Or do we assume that plugs no come pre-gapped?
Josh
Many are fine out of the box but check the gap.Josh
There was a competition for young mechanics on TV a few years ago. Part of it required a plug set change.
Most just took them out of the boxes & fitted them without looking.
The gap of one plug in each set had been completely closed - sort of thing you might meet if someone had dropped it & just put it back in the box.
Of those that didn't check most realised that the sudden misfire might be caused by something they'd done & found the issue. A couple didn't & spent the rest of the time allowed looking for the cause, assuming that it couldn't be the plugs because they were new.
DVandrews said:
That model has plug top coils which are secured with an M6 flange bolt (8mm head), remove the bolts and the coils should just pull off giving access to the plugs. There is a vacuum hose and a large diameter air hose in the way of plug 2 , the vacuum hose can be unclipped and moved to one side, the large plastic air hose will need to be unbolted and moved over a little to provide access.
Dave
Yes, looks pretty straightforward...Dave
Edited by DVandrews on Tuesday 13th June 10:24
Edited by DVandrews on Tuesday 13th June 10:24
Scootersp said:
Care should be taken as a amature/beginner as any time saving is tiny compared to the hassle of screwing this up!
On installation I use the tip of having a rubber hose over the top of the new plug and using that to start it in the hole, it impossible to cross thread this way.
I would also tighten with a regular socket (remove with a dedicated spark plug socket with the rubber insert) as before I have had the socket extension leave the socket in there as the rubber grips the plug to hard after torqing up.
Also review the plugs and most have crushing washer, so you tighten them up and then you have to be firmer at the end, just read about it and go steady and you'll be fine. It's not one for and beginner to rush
Would just like to echo this. People speak in a pretty blasé way about plugs. It is possible to get it wrong in an expensive way with aluminium heads. Do take your time threading the new plugs in and don't, whatever you do, go in with the spark plug in a socket on the end of a ratchet or bar. Start the plug in it's thread on a rubber hose of similar. Personally I use the correct socket on an extension, and fingertips. Lower the spark plug into it's hole, and under the weight of the plug and the tool only, turn it anti-clockwise- and you'll feel the plug drop into engagement with the thread. Then go clockwise and run it home- fingertips still. Finally, don't over-tighten. On installation I use the tip of having a rubber hose over the top of the new plug and using that to start it in the hole, it impossible to cross thread this way.
I would also tighten with a regular socket (remove with a dedicated spark plug socket with the rubber insert) as before I have had the socket extension leave the socket in there as the rubber grips the plug to hard after torqing up.
Also review the plugs and most have crushing washer, so you tighten them up and then you have to be firmer at the end, just read about it and go steady and you'll be fine. It's not one for and beginner to rush
Pretty much what everyone has said although modern engine might have a multi electrode plugs so maybe no need to check gap
Best advice I ever got was to turn the plug in by hand a few turns but then wobble it. If it can wobble then it’s not cross threaded.
Ask me my how I know Google Heli Coil
(1977 MK2 Capri) lesson learned
Best advice I ever got was to turn the plug in by hand a few turns but then wobble it. If it can wobble then it’s not cross threaded.
Ask me my how I know Google Heli Coil
(1977 MK2 Capri) lesson learned
HustleRussell said:
Scootersp said:
Care should be taken as a amature/beginner as any time saving is tiny compared to the hassle of screwing this up!
On installation I use the tip of having a rubber hose over the top of the new plug and using that to start it in the hole, it impossible to cross thread this way.
I would also tighten with a regular socket (remove with a dedicated spark plug socket with the rubber insert) as before I have had the socket extension leave the socket in there as the rubber grips the plug to hard after torqing up.
Also review the plugs and most have crushing washer, so you tighten them up and then you have to be firmer at the end, just read about it and go steady and you'll be fine. It's not one for and beginner to rush
Would just like to echo this. People speak in a pretty blasé way about plugs. It is possible to get it wrong in an expensive way with aluminium heads. Do take your time threading the new plugs in and don't, whatever you do, go in with the spark plug in a socket on the end of a ratchet or bar. Start the plug in it's thread on a rubber hose of similar. Personally I use the correct socket on an extension, and fingertips. Lower the spark plug into it's hole, and under the weight of the plug and the tool only, turn it anti-clockwise- and you'll feel the plug drop into engagement with the thread. Then go clockwise and run it home- fingertips still. Finally, don't over-tighten. On installation I use the tip of having a rubber hose over the top of the new plug and using that to start it in the hole, it impossible to cross thread this way.
I would also tighten with a regular socket (remove with a dedicated spark plug socket with the rubber insert) as before I have had the socket extension leave the socket in there as the rubber grips the plug to hard after torqing up.
Also review the plugs and most have crushing washer, so you tighten them up and then you have to be firmer at the end, just read about it and go steady and you'll be fine. It's not one for and beginner to rush
I'm happy to buy the right tools to do the job properly, the plug removal socket being the main item by the looks of it.
support the ratchet head so youre pulling straight and not trying to twist it when undoing them
screw the new plug in all the way by hand , if it goes in 4/5 turns by hand its not cross threaded , if it becomes tight after a turn then back it off and try again
its no big deal at all , dont stress too much
screw the new plug in all the way by hand , if it goes in 4/5 turns by hand its not cross threaded , if it becomes tight after a turn then back it off and try again
its no big deal at all , dont stress too much
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