Spark Plug Size

[ricky66]

Hi all,

To cut a long story short my daughters '95 7AFE powered (rebadged) Corolla Hatch developed a light knock in the valve cover area around number 3 cylinder. At first I thought it was the injector but later found the spark plug cap was proud of the cover due to crud around its base. Once I managed to clean a bit of it out the plug cap went back in and, hey presto, no more knock. The motor ran smooth and steady with no miss at all. I was confident that it was nothing serious as the car has only done 135,000 kilometres (80,000 miles) and has full service history provided by its one previous elderly owner.

Anyway, I also discovered I don't have a plug spanner long or thin enough to reach the plug, which leads me to my question...
What size is the hex on these spark plugs, I'm assuming it'll be metric, and how long does the plug spanner need to be to reach it. Probably about time we treated it to a fresh set of plugs anyway.

Any help appreciated, thanks.

 

[Donabed Kopoian]

Plug Spanner? You mean Spark Plug Socket?

They should be 5/8" like most spark plugs are. Just to be certain, which country are you from? (In U.S., pretty much all spark plugs are 5/8" and usually the 13/16" spark plugs are on lawn equipment).

If you can't reach the plug with the socket and ratchet alone, get a 3/8" extension bar. Usually a 6" will do the trick.

 

[fishycomics]

Do not use multiple extensions, if you do not know your cars depth, you can take a longer one first, get a measure, and then grab a shorter one, each model car varies. Since this sounds like a neglected change, no inspections, first time,

Have Anti-Seize to get on, be careful not to get it on anything else!

Ceramic plugs are going to give one day, and be careful not to snap a plug in there. been there and done that. and gotten it out in time.

a Stubborn plug will come out if you take the time. I am no muscle bound young punk, but I can manage a tough pug lol.

plugs

showing Spray

 

[ricky66]

Thanks mate, 5/8 sounds like a starting point. I'm in Australia and we're metric here and mostly (my generation) use English terms for tools. I've got plenty of sockets, extension bars, speed bars etc and a few plug spanners (long thin walled tube with hex pressed into the ends) but can get any down the small diameter hole to the spark plug.
Might just get the plug number out the book and check them out at the local parts shop and buy an a deep, thin walled socket. This might do the trick, can't get my normal deep sockets down the plug hole, its too tight.

 

[fishycomics]

Am sure you got a friend a neighbor ask them before buying

 

[Scott O'Kashan]

"...the spark plug cap was proud of the cover..."?

 

[Donabed Kopoian]

Get a spark plug socket (it will have a rubber washer in it to protect the spark plug stem from being fractured, a regular deep socket lacks this), and the rubber washer doubles as a holder so you can push the spark plug in the socket and have it stay in place while you gently lower it into the engine (just dropping them in can change your gap and cause misfires).

And as fishy said, use anti-sieze on the threads, and the PB Catalyst won't be a bad idea either.

 

[ricky66]

"...the spark plug cap was proud of the cover..."?

Yup, the square shaped rubber cap at the top of the tube that slides down over the spark plug was sitting about 5mm above the valve cover and couldn't be pushed home by use of brute force and ignorance.

It was an odd knocking sound that was produced which prompted me to investigate further. Once I cleared out some of the grunge which had collected around the base of the plug the cap pushed home.

Thanks everyone for advice re thread anti-seize, rubber cups in sockets etc. I have changed lots of plugs on bikes, cars, outboards etc and don't envision any dramas with this simple little motor. I reckon most of my plug spanners (sockets) are in my tool box stored up at our property in anticipation of use on our quads and dirt bikes.

I have old plug caps and an NGK rubber tube for inserting plugs down the holes and compressed air and contact cleaner to make sure no filth gets into the chambers. Just looking for some info on sizes etc for this particular engine and ideas on what other guys are using to extract the plugs.

Cheers, and thanks.