spark plug thrown from engine

[1st rado for me 0]

Hi Guy's

 

Today I noticed a slight knocking noise coming from the engine, then wehn moving off from standing still a mighty banging noise came from the engine.

Upon opening the bonnet I could see that one off the ht leads was about an inch out of the hole.

When I removed it to look the spark plug was stuck in the end.

I can't manage to find my spark plug socket so can't try replacing it until tomorrow.

I know that the plugs were tightened correctly when I changed them about 8 months ago and never heard of a spark plug working loose, could something more major cause a plug to be pushed from it's hole?

The thread on the plug was fine but I could not see in the hole clearly enough to notice any damage.

I managed to get the car home the couple of hundred yards on three cylinders.

Don't you just hate it when you have trouble so close to home.

[bigtunes 0]

Mine did that a while ago, chucked the plug out of number 3 cylinder and put a nice dent in the bonnet.

Worst thing was waiting an hour for the AA as I didn't have any tools with me. The very nice man screwed it back in, and wrapped some tape round the plug end of the HT lead as that had split as well.

[rado-steve 0]

How Odd! Not heard of that before!

[Jim 2]

An old mate of mine (who is responsible for my Corrado problem!) managed to throw a spark plug out of his too.. though he did, by his own admission, thrash the balls off it and it did that when he was out gunning it one day. It was a 1.8 16v!

 

So its not the first time i've heard of that!

[Supercharged 2]

Arse - Helicoil time... What engine is it or was it FI's?

 

Plugs on FI engines should be about 5Nm tighter than NA to prevent this (hence the G60 figure is 5Nm than the other Corrado's)

[1st rado for me 0]

it is a 1.8 16v number 3 cylinder too did you have any problems afterwards?

I can't understand what would cause this?I was actually driving slowly traffic was busy I had given it a blast on the motorway for about an hour a couple of hours beforehand.

This engine was running fine I would have thought if the plug had worked loose it would have stutered abit?

 

No dent fortunately

[Dogzyboy 0]

This was just about the case in my mate's VR6 Golf last week. We only noticed it by chance, lucky it didn't jump out whilst driving really.

[dr_mat 0]

It might have pinked?

[coolrado 0]

I know that the plugs were tightened correctly when I changed them about 8 months ago

 

did you actually use a torque wrench though?

was the engine warm when you fitted them?

have the plugs been removed since you fitted them 8 months ago?

you should allways re torque the plugs after a short while, i know it doesnt mention it in the manual but i have allways done it after driving the car for about 300 miles and there is usually a bit of movement in them.

 

tightening up new plugs can be a bit deceiving sometimes as they use a crush washer, the first time it can seem like its taking ages to tighten up but if you remove it and re-tighten it it seems fine.

 

there are other weaker points in the engine that should go before a plug gets blown out.

[steveo29 0]

our polo randomly spat out a plug and all the thread in the head were gone...£28 for a helicoil and all is well again

[craigowl 0]

Coolrado is right (again).

About 30 years ago I changed the plugs in our 1.6 Manta and having read that overtightening plugs is bad, as a novice mechanic, erred on the side of caution - probably just crushed the washer and no more.

 

Later, on our return to Scotland up the M6, I put the foot to the floor to get an idea of max speed (the good old days - no fear of cameras etc and north of Preston, the M6 was really quiet.)

 

After a rest a bit further north, I decided to look under the bonnet after the thrash and just by chance found that the plugs were all loose in their 'oles.

 

A lesson learnt, never had that since.

[peanut 0]

for some odd reason this is a common problem with the I5 20v turbo engine as found in the ur20v, s2, s4 and s6. They never seem to stay tight once theyve been used once and the crush washer...well er...crushed.

Gav

[coolrado 0]

on my mr2 there where 2 torque settings listed in the manual for the plugs, one for new and one for re used, the torque setting was 3ftlb's more for the re used plugs so it obviously makes a difference.