1st Gen R53 Cooper S Most liked posts in thread: Blown Spark Plug

Umm, yeah.. You left out the "because racecar" bit.

 

I'm sorry, but it's not a design flaw when someone doesn't install the plugs properly........

 

Well, as I said before if the plugs are installed properly they don't come out. You do not have to re-torque them - ever - if you install them correctly.

There is nothing wrong with the heads, nothing different about them that requires any sort of different procedure than any other aluminum head.

But there seem to be a few people who don't understand the right way to install the plugs and that's what causes the problem. Then their misunderstanding gets reposted all over the net as fact.

Every one of these I've ever heard of that popped out were shortly after the plugs had been changed - improper installation. I've never heard of a plug installed by the mfr that came out.

It's pretty simple, tighten them down till they crush the washer, then torque to spec. Done.

Personally I've never had a plug come loose on any head, aluminum or otherwise in the 50+ years I've been putting them in internal combustion engines. Not one. And many, many of those were aluminum heads, including MINIs......

I'll bet the fellows who run professional shops here don't have them pop out either.....

 

I bought an R50 with blown number 2 which I found out later had been repaired. In the end I bought a used R53 head

 

If it was done right it will last as longer than the original threads......I would not worry about it.

The reason plugs come undone is either they were over-tightened and stripped the threads or they were not tightened properly, allowing them to work loose. Most of the ones I've seen have been due to the latter......

 

Welcome, thanks for joining Motoring Alliance, the FUN and Friendly MINI Community.

This is not terribly uncommon. Many have used the helicoil route with no problems.

 

Haha very funny Nathan. Actually it was before the race car days That's how I got the mini cheap off eBay. Mine was done with a insert which fell out with the plug. If your job was done correctly it should be fine

 

I agree. Never had the problem myself. But I've just done it by feel - which is not very good, or accurate.

What is the proper torque specs for the spark plugs for our MINIs?

 

Frankly, that's how I do them too.....crank it down till the washer is fully compressed, then turn it till it's tight - that's my method. Hasn't failed me yet and like I said, over 50 years now....

jrahn I don't know what to tell you, but there's nothing magical about Mini heads, and there are plenty of examples of the same problem on lots of other car forums too.....

 

Yes, I think that's the right spec.....

 

This happened to me when I first got my mini... driving along then sounded like a huge exhaust leak and no power.. got it off the road and saw the boot on #2 a little higher than the other 3. LUCKILY it just worked it's way out... retorqued it when I got home as it was vacuumed hose tight since that's all I had in the car at the time to put it on but it held till i got home like 15min later.. it's been fine since over a year now..

 

spark plug threads..

We have found the torque is the key in most of the cases. However we have also found that when the chambers crack, MOST of the time the crack goes into the threads. SO when you get the Heli-coil or Timesert installed make sure the shop LOOKS for the cracks and then make the adjustments . see the attached. Hope this helps..

 

The key is to crush the washer and tighten and then DON"T reuse the washer if you pull the plug for some reason.