Hi

My spark plug gaps seem to be fine, but the ring and two spacers around Spark plug #1 are caked in carbon, and so is the white section. #2 is also covered in carbon, but to a slightly lesser degree, with a little bit of carbon on the white part as well. #3 has no carbon deposits on the white bit, the two spacers, or the ring. #4 is even cleaner.

The threads on #1 and #2 have carbon deposits, #3 has a bit less, and #4 has much less....

Pictures attached.... (they are Denso IK22s BTW)

What does this mean?

check this thread for pics....

http://www.mini2.com/forum/engine-dr...does-mean.html

 

1 & 2 are leaking, 3 leaks but not as bad. They look pretty rich but I can't realy tell from the pics ( pretty dark ). The plug color should be grey to medium grey brown. The leaking can cause a bad burn & give you the black color. You could clean them, reinstall & check them in another K or so. Realy, from the pics it looks like the only problem was loose plugs.
How well was the engine running?

 

Any time I've ever seen that it has been caused by :
Improper sparkplug seating
Improper boot seating allowing tip to nut arcing

 

make sure the wires are on good, and drive the snot out of it. Then check again. Our cars run rich, no matter what you do.

Matt

 

I don't wanna overtighten them though, surely?

I torqued them down a lot harder than usual, the car seemed to have a bit more power, but same driveability.....

how much is 20ft-lbs of torque approximately? i once heard a quarter turn past hand tight.....

BTW, do i clean them with carb cleaner or similar?

thanks for the help guys....

 

"how much is 20ft-lbs of torque approximately? i once heard a quarter turn past hand tight....." and a little.... ( only a little )

 

so 90 deg with a 12 inch long ratchet? I tried that, it felt like i was gonna break it!

 

Seriously, a quarter turn past hand tight will result in a wide range of actual torque values. Hand tight for someone with not a lot of strength in their forearms might approximate to 8 ft/lbs. A quarter turn on a 6 inch ratchet might get you to 12 ft/lbs. A quarter turn on the same low strength forearm tightening with a 12 inch ratchet might get you to 30 ft/lbs. If you don't want to roll the dice on stripping the threads, get a torque wrench.

 

Ya see??? This is why they made torque wrenches.


Yes I've heard the contact + 1/4 turn thing too(it's been around forever and really relates best to crush washer designed plugs). What wasn't mentioned was since this was a used plug it will make a HUGE difference in how far you rotate the plug to meet the torque spec.

 

and the metal feels soft. I'd never do it without a torque wrench...

Go spend the $, you will be much better off.

Matt

 

You guys are almost right. Crush the washers on the plug, then 1/4 turn. Here's a quote from Randy Webb

"If you have replaced the spark plugs in your head (or if anyone else has), please check that the torque spec is 18-20 ft/lbs.

We have had a couple of cars seemingly loosen up, and the result can be BAD.

All you need to do is use a deep 16mm socket on an extension, loosen the plugs a bit, then tighten until you feel the crush washer crush, then take it another 1/4 turn.

I've seen this on a set of Bosch, Accell, and Denso plugs now - so I have been checking all of them lately. There is an issue for whatever reason of them loosening. Check every 5000-10000 miles to be sure they are torqued. "

But I agree with Matt, either buy a torque wrench if you like to work on your mini a lot. It will be usefull if later projects. If not, I'm sure somone in your local Mini club has a Torqe wrench they're willing to let you borrow. -- Johan

 

Past tight and a little & only a little. I can get close to 60# with an 8" wrench, let alone a 12". Torque wrenches are pretty cheap insurance.

 

please get a torque wrench . and only torque them in a cold head. the aluminum threads dont like being run in and out while hot i've heard. and since minis are prone to pissing plugs out the heads and caution is well heeded by me .don't forget the anti seize on the threads too .

 

yeh i only work when the head is cold too...i've heard the same....

I will get a torque wrench

thanks guys

 

is the Al expands more than steel as it gets hot, so your torque to 20 when the head is hot, and the thing cools and it's like torqing to much more. Especially since you'd be putting in cold plugs.

Matt

 

makes sense

 

wats teh effect of over torquing the plugs

 

screwed up threads most likely.....

Matt

 

Worst case you have to use a thread insert (like Heli Coil or a similar product). Absolute worst case is you buy a new head if things are too screwed up....

 

a t wrench is necessary
My local parts store will even loan tools including t wrench.

A plug color and carbon check to be done corretly must be done after a spirited run and, you need to shut off the engine and coast to a stop then check.

any other method will give inaccurate readings.

I have been doing plug checks on 2 and 4 stroke race bike and most reciently for formula BMW

If you take good photos I would be happy to read

 

Still a valuable art Been doing it for over 40 years...