Hiya to all thought I would be a good dad and change my daughter's spark plugs as now on 60000 miles and no proof of a change all came out easily enough but refitted them I different matter as feels like number 1 and 3 have only gone in abit and the feels like I would cross thread them if I was to tighten them any further anyone had the same problem to note NGK plugs come out and denso ones in any help would be appreciated thanks
General 500 1.2 2017 fitting Denos spark plugs
- Thread starter Jaymc1975
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General 500 1.2 2017 fitting Denos spark plugs
Yes will try that thanks
Agreed. It shouldn't be necessary to do more than hand tighten using a socket extension bar until they're properly seated.
There have been a number of threads on here where folks have encountered stripped plug threads (if you'll pardon the pun). It's surprisingly easy to get them cross threaded as a standard socket extension doesn't give you quite the right angle. I find that a universal joint next to the plug socket helps considerably. Higher quality, slimmer tools would also likely help, particularly if in 3/8 drive.
I use a proper size box spanner with a rubber insert to grip the plug! when taking the olds ones out i always run a hoover around the plug holes as its a debris trap down there! if your going to try refitting them old ones its worth-
A) spraying a amount of wd 40 around the hole first to clean out/lube the threads!
B) Also worth trying the old mechanics trick for spark plugs with difficult access!-which is to fit a length of tight fitting rubber hose over the top/ ceramic and use that to twist the plug into the hole- if it cross threads the rubber hose just slips round and wont tighten enough to cause damage! check the denso plugs as you remove them for signs of cross threading or thread damage!- make sure to keep a note of which plug comes out of which hole! .
If you have access to a borascope camera you could check the hole threads for damage before proceeding any further!,
A) spraying a amount of wd 40 around the hole first to clean out/lube the threads!
B) Also worth trying the old mechanics trick for spark plugs with difficult access!-which is to fit a length of tight fitting rubber hose over the top/ ceramic and use that to twist the plug into the hole- if it cross threads the rubber hose just slips round and wont tighten enough to cause damage! check the denso plugs as you remove them for signs of cross threading or thread damage!- make sure to keep a note of which plug comes out of which hole! .
If you have access to a borascope camera you could check the hole threads for damage before proceeding any further!,
Not had an issue with Denso, which ones did you get? IXU22/VXU22
Can be tricky to get back in I must admit
Can be tricky to get back in I must admit
I'd suggest that when you took the old plugs out, the soot and gum that collects around the bottom of the plug and into the first few turns of thread will have been drawn up the thread, making the new plugs a bit notchy to screw in.
Take them out, clean the thread and then try again, carefully, until you can screw them in more or less all the way by hand.
Don't try to clear out the hole using contact cleaner or WD40 etc. as there is a lot of grit in there and you don't want that in the combustion chamber.
Nothing wrong with the plugs or thread.. if they fit, then the thread is the right one.
Ralf S.
Take them out, clean the thread and then try again, carefully, until you can screw them in more or less all the way by hand.
Don't try to clear out the hole using contact cleaner or WD40 etc. as there is a lot of grit in there and you don't want that in the combustion chamber.
Nothing wrong with the plugs or thread.. if they fit, then the thread is the right one.
Ralf S.
Put some 3in1 on the plug threads?
Did you compare the thread between old and new?
Denso are a big brand for Japanese car parts, though spark plugs are more specialised and expect someone else make them for Denso.
I'd always go for standard plugs changed annually than the long life ones that are meant to last for years.
Carefully going back and forward if they are tight should free them. But you should be about to put them right down to the washer by hand.
Denso are a big brand for Japanese car parts, though spark plugs are more specialised and expect someone else make them for Denso.
I'd always go for standard plugs changed annually than the long life ones that are meant to last for years.
Carefully going back and forward if they are tight should free them. But you should be about to put them right down to the washer by hand.
The only issue then is that oiled threads exert less torque. If the fella is using a torque wrench to tighten the plugs, to get to the torque required the plugs will be about 40% too tight. which could strip the threads or break the plug
Ralf S.
Common sense hopefully prevails and hand tight using a plug spanner not a torque wrench?
Many folks overtorque spark plugs; a standard full size torque wrench is unlikely to be sufficiently accurate at the required torque setting. I also have a motorcycle torque wrench (5-40 Nm) and I wouldn't even use that on spark plugs. If you're using a 1/2" square drive ratchet system, be careful.
Inexperienced folks would likely do better to angle tighten them.
On a 1.2 with 12mm plugs, 15Nm (10lb ft) is an absolute maximum if you're going to lubricate the threads.
If you've ever removed plugs from a brand new 1.2, you might be surprised at just how little torque is required to loosen them.
We do see a few 'stripped plug thread' threads here from time to time.
I've attached NGK's setting sheet.
Inexperienced folks would likely do better to angle tighten them.
On a 1.2 with 12mm plugs, 15Nm (10lb ft) is an absolute maximum if you're going to lubricate the threads.
If you've ever removed plugs from a brand new 1.2, you might be surprised at just how little torque is required to loosen them.
We do see a few 'stripped plug thread' threads here from time to time.
I've attached NGK's setting sheet.
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All sorted now just weren't putting them in at the right angle as 1 and 2 to the left and 3 and 4 to the right thanks for the help everyone would say though the denso plugs are slightly smaller in length that the NGK ones
