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I have recently bought a Supaloy A7 Head off e-bay.
It has had Helicoils fitted by the vendor one looks ok all the threads being in line and the same distance apart but the next three have large gaps between the threads and the gaps are irregular. If I screw in plugs will the threads self adjust?
Will the plugs be secure and not blow out?
Tony, sounds a bit odd. I'm off to an A7 meeting tonight and will ask opinions. Have not used Helicoils myself so unsure.
Thanks much appreciated.
Hi Tony, Several different opinions about this as usual. Consensus though is that assuming the previous owner had used the correct drills and taps the coils would adjust. If the head is still off the car have you tried screwing in the plugs to see how they fit? You can then observe from underneath, the fit and also see if they want to pull out. If on car gently fit and see if they screw in easily. Any feel of binding stop and remove. Suggest using copper slip on threads to help removal. If they screw in and seal then you should be OK. Worst way is if they are wrong the plug holes could be drilled out and tapped (if enough room) and 18 - 14mm converter inserts used.
These are available from Austin Specialists. They were used to screw into the 18mm plug holes so that modern 14mm plugs can be used.
Hope this helps. Please let us know how you get on.
Thanks for the information. Currently I have sent the Head back to the guy who did the work for his comments .
I am reassured with wahat you sain about drilling ,Rethreading and using inserts so thanks much appreciated.