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Re: Cross threaded spark plug

Posted: 03 Apr 2013, 15:12
by what2do
Must be my paranoia but I'm thinking the op may just try a temporary fix until a helicoil is available. I just hope that if the temp. option is wrapping some ptfe around the threads, then start the engine and have a look.................for heaven's sake, hold your breathe as ptfe is highly toxic when melted. It'll make you madder than a hatter and you may end up purchasing a t25 - oops, too late for that!!!

Re: Cross threaded spark plug

Posted: 03 Apr 2013, 15:14
by what2do
Has anyone ever known of a helicoil winding out with the plug/bolt? Theoretically it shouldn't because after being wound in, the little tab snaps off (remaining in the sump in my case!!!) leaving a very very sharp point that is supposed to dig into the comparatively soft ally, mild/cast steel.

Cheers, Mitch.

Re: Cross threaded spark plug

Posted: 03 Apr 2013, 15:21
by jamesandtheopenroad
what2d wrote:Must be my paranoia but I'm thinking the op may just try a temporary fix until a helicoil is available. I just hope that if the temp. option is wrapping some ptfe around the threads, then start the engine and have a look.................for heaven's sake, hold your breathe as ptfe is highly toxic when melted. It'll make you madder than a hatter and you may end up purchasing a t25 - oops, too late for that!!!

Well the van is still running well so it's not an immediate problem, but thought I might try a little ptfe tape and/or some high temp sealant on the mating surface of the washer until I can find a garage/engineer I can trust to helicoil/temp-sert it.

However, may now give the ptfe option a miss...

Re: Cross threaded spark plug

Posted: 03 Apr 2013, 17:05
by what2do
I wouldn't dictate that you don't use ptfe, just don't inhale whilst viewing.

Re: Cross threaded spark plug

Posted: 03 Apr 2013, 18:18
by BOXY
I had a plug launch out of a Renault 5 whilst driving and it dented the underside of the bonnet. Don't get too close to a running engine with a iffy plug thread. From what I can remember I took the head off and got a local engine builder to heli-coil it for me for about £20.

Re: Cross threaded spark plug

Posted: 03 Apr 2013, 18:43
by what2do
Jeepers, that's what you call a wake up call!!!!!!!!!!!!!

BOXY wrote:I had a plug launch out of a Renault 5 whilst driving and it dented the underside of the bonnet. Don't get too close to a running engine with a iffy plug thread. From what I can remember I took the head off and got a local engine builder to heli-coil it for me for about £20.

Re: Cross threaded spark plug

Posted: 03 Apr 2013, 18:55
by BOXY
It was only a 850 L. The performance wasn't effected, just the engine noise changed.

Re: Cross headed spark plug

Posted: 04 Apr 2013, 02:22
by Allanw
kevtherev wrote:A time-sert would be better as there's no drilling and the coil wont come out when the plug is removed the next time it has to be changed.

Good man - I was just going to post: "Helicoils suck a***!"

The problem with them is, that they try to expand on the way out - IF they do, you often knacker the hole entirely. All it takes is carbon build up on a plug, and they can move.

I've never had a timesert come out, but I have removed a couple. If a timesert does come out, they aren't trying to expand like the spring type helicoils do. The hole stays usable, reducing the likelyhood of requiring a whole new head!

The timesert is far more dimensionally stable (why is there no :Geek: smilie?)

Re: Cross threaded spark plug

Posted: 05 Apr 2013, 15:30
by edoh
is this clack n rubbish?

http://www.fine-tools.co.uk/engineering ... _1857.html

http://www.carsdirect.com/car-repair/ho ... epair-tips