Helicoil in cylinder block?

[crynsie]

One of my spark plugs was not tightened up properly at the last service and has been rattling around an stripped the thread in the cylinder head.

I have two options, to try and find another cylinder head (hard and expensive) or get the thread helicoiled with a steel sleeve.

Going back to the muppets who did the service is not an option so I am left with the two options.

Has anyone helicoiled a spark plug cylinder and what were the results?

Is it worth it for a short term option or just bite the bullet?

Will the steel sleve react with the alloy head and what about the different heating and expansion rates (alloy vs steel in the same block)?

TIA


Si

[nadroj]

Helicoil = better than new!

[soundbeltfarm]

i had a helicoil put into a sparkplug hole in a ute i had and it went good as . they just said it was my call as to whether they do it or not and they didn't guarantee anypart of it.
but i had that ute for years after it and it was all good.

[neels]

I had a steel insert put into a CB360 cylinder head after the spark plug stripped the threads on the way out, had no problems with it afterwards.

[roadracingoldfart]

Nothing wrong with a Helicoil or Re-Coil insert at all .
If you have never done one get a bit of advice or guidance about the depth of the insert compared to the material you are using it in . Like anything , they are good if they are used in the correct way.
Good luck .

Paul.

[Woodman]

I used to go to garages and do it in place when I was in the trade. We used recoil brand, not the original helicoil which require a special mandril thing to fit them.
Recoils work fine and are easy to fit.

if doing it in place i.e. with the head still on put a fair bit of grease on the tap to catch all the alloy bits, and make sure the tap doesn't catch an open valve and bend it. I gave no guarantee whatsoever in regards to the bits of alloy causing any damage etc, but in saying that I never heard of any issues.

[Warr]

What he said
Helicoil = better than new!
And yes can be done without removing the head. But with obvious precautions.

But back to
Going back to the muppets who did the service is not an option
Why not .. Give them the opportunity to put it right and tell them its at their cost.
Make it a win-win situation.
You win by getting problem sorted and if they do it for reduced / no cost they may win back you as a customer :)

[marsheng]

If it is a race 2 stroke I would be very carfull. The plug temperature is critical and having a steel insert between the plug and aly head can change the plug range. If it is a commuter bike or car, no problems.

[crynsie]

Warr, the service was done before I bought the bike and I have no reciepts :( I think I know who did it, but I am not naming them on here as I can't be sure...

Marsheng, No not a 2 stroke (v4)

Woodman, thanks, you have put my mind at ease, but I have a price on a cylinder block if needed.


Thanks all for the advice :)

[roadracingoldfart]

If it is a race 2 stroke I would be very carfull. The plug temperature is critical and having a steel insert between the plug and aly head can change the plug range. If it is a commuter bike or car, no problems.

If its a single i dissagree with your theory , if its a multi , just to be sure of uniformaty then you could do all the cylinders.
The ramp angle of a metric thread is so small i dont believe it will affect a cylinder heat to a point of needing to change the plug range , the material content is simply a spiral joiner.
When i built the NS400r racebikes we used to always use re-coils in the plug threads and several other alloy parent metal zones just so the thread was stronger and lees likely to wear with muliple removals / fitments. I have done the same for years be they 4 or 2 stroke.

Paul.

[emaN]

Yep, did it on my RF a few years back; still have the bike, and she's done a few trackdays since then, and spent lotsa time at high-revs, always been mint.
Mind you, the experience has got me into the habit of checking plugs more often now!

[Pixie]

What he said
And yes can be done without removing the head. But with obvious precautions.

But back to
Why not .. Give them the opportunity to put it right and tell them its at their cost.
Make it a win-win situation.
You win by getting problem sorted and if they do it for reduced / no cost they may win back you as a customer :)

If they can't fit a plug correctly,would you trust them to do a thread repair?

[crynsie]

Different workshop Pixie :)

Apparantly all done and the engine is running again...now just need to find the readys to pay for it

[quickbuck]

Different workshop Pixie :)

Apparantly all done and the engine is running again...now just need to find the readys to pay for it

Nice......

As for not doing it up properly, I would actually suggest that the opposite happened.
Those plugs are darn small, and it only takes a little extra fitters torque to strip the threads, and you can never tighten it properly again.