Stripped Thread in Aftercooler Cap Bolthole

[Paul Greenhalgh]

I remove my aftercooler top caps annually to inspect and clean out the raw water tubes. This year, on re-installing, I used new bolts and lock washers. Though I thought I was as careful as ever, I stripped the last/bottom few (aluminium) threads off one aftercooler.

I took Tony’s advice, found on that Other Forum from years ago, to try the bolt without the lock washer….and this did allow the bolt to be re-installed and tightened to what seems like an acceptable torque (see photo).

Question is, should I leave it like this? The cap is not leaking (at least not after a short run). I know about helicoils and could use one if that’s recommended. I also wondered about using a thinner, lighter lock washer: I may be wrong but the new ones seem thicker/heavier than the originals.
Advice please? Do I leave well enough alone or…..?

Topic

[Rob Schepis]

Tony speaks through experience of having these units apart on his benches 7 days a weeks for decades. I speak for how I know that my mind works: “fix & forget ” rather than “wonder & worry”. You have viable options…

[Tony Athens]

Leave as is until next time–Then re-thread, stud or heli-coil..

Tony

[Paul Greenhalgh]

Rob: taken off every 5 years ( I only rack up 85-100 hours/year) and serviced ‘Seaboard Way’. Not due for 18 months…but you are dead right, access easy (walk-in/stand-up engine room) so no issue with fitting a helicoil. Do I need lock-washers at all…or should I use them but change to much thinner/lighter ones?

[Rob Schepis]

It’s not about being careful – it comes down to the fact that compressing a steel lockwasher is more than the aluminum threads can handle.. When was the last time the aftercoolers hit the bench and were broken down and cleaned and pressure tested…and then reinstalled the Seaboard way? If it is stripped and you removed the lock washer and that got it snug it’s only snug because of a thread or two… I’d helicoil it and even if it’s not the right time to get it on the bench access looks good to helicoil it in place..

[Author]

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