Propshaft Posted April 10, 2021 Report Share Posted April 10, 2021 Hi , noticed that my spark plug holes are getting really sloppy has anyone rethreaded them with the head insitue Quote Link to post Share on other sites
john.r.davies Posted April 10, 2021 Report Share Posted April 10, 2021 (edited) The usual advice when doing a similar job is to heavily grease the tap, and to withdraw it frequently to clean off swarf. But if the threads are "sloppy" then they are worn, not damaged or in need of cutting. I wonder - can such be Helicoiled? That requires drilling out before putting the insert in, so really a bench job. Edited April 10, 2021 by john.r.davies Quote Link to post Share on other sites
Nigel Triumph Posted April 10, 2021 Report Share Posted April 10, 2021 If you're lucky, running a thread chaser or tap through the plug holes may 'revive' slightly worn threads and make them serviceable for a bit longer. As John has said, use plenty of grease to prevent any debris falling into the cylinders. I wouldn't want to attempt fitting Helicoils without removing the head, because of the amount of swarf caused by drilling and tapping for the new thread inserts. Other's opinions may differ. Nigel Quote Link to post Share on other sites
stuart Posted April 10, 2021 Report Share Posted April 10, 2021 In Ally heads I have used inserts that are available specifically for the purpose, loads of grease around the tap and spin it over with all plugs out to clear any debris. Wouldnt be so keen on doing that in a steel head. Stuart. Quote Link to post Share on other sites
Propshaft Posted April 10, 2021 Author Report Share Posted April 10, 2021 Has any one done it on a tr7 Quote Link to post Share on other sites
Ransomes256 Posted April 10, 2021 Report Share Posted April 10, 2021 I do not know which method was used on TR7 heads but out of interest were the spark plug threads cut or rolled as if rolled using a roll tap may improve the plug fit as opposed to using a cutting tap which could make the fit worse. Neil Quote Link to post Share on other sites
john.r.davies Posted April 10, 2021 Report Share Posted April 10, 2021 (edited) "propshaft" appears to own a Moggie, not a TR7. Edited April 10, 2021 by john.r.davies Quote Link to post Share on other sites
Propshaft Posted April 11, 2021 Author Report Share Posted April 11, 2021 Propshaft i.e. Me owns two moggies a lcv and a two door I also own a very nice tr7 I have been a member of the tr register for approximately 17 years . Thank you all for your input Quote Link to post Share on other sites
john.r.davies Posted April 11, 2021 Report Share Posted April 11, 2021 (edited) No offence, Propshaft! But your TR7 isn't mentioned in your "Cars Owned" list"! FYI, the answer to my question is Yes! Do a Google for "helicoil spark plugs" John Edited April 11, 2021 by john.r.davies Quote Link to post Share on other sites
Propshaft Posted April 11, 2021 Author Report Share Posted April 11, 2021 No offence take John. Thanks for your help Quote Link to post Share on other sites
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