Repair of oil feed pipe threads in crankcase

[Rob Harknett]

For what its worth. I have had less server damage. Just a crack through over tightening, as quite a few cases are found. Maikinr sure everything was clean, I tightened in the pipe union untill the crack opened, put in some araldite, slackened off the nut again so the crack closed. Its held and not leaked oil for over 20 years now.

[iandusud]

Now that sounds like a good bodge. Nowt wrong with a "good" bodge in my book.

Ian

[Matchymarty]

Did anyone end up finding out what the thread size is ? I need to fix my two oil feed threads with helicoils in my crankcases....

Cheers.
Marty

[Pharisee]

I had an oil pipe thread problem on the 18S. A previous keeper had cross threaded the top pipe nut. I didn't discover it until I had to have the engine out to cure an oil pump problem. Although it was cross threaded, the pipe was secure and while it was crossed, it wasn't actually stripped. In the end, after some deliberation, I decided to leave well enough alone and just fitted new pipes. That's worked OK for me. The new nut followed the 'crossed' thread and tightened up fully with no subsequent leak. You can see that the pipes are no longer parallel but it works for me and if I'd tried to repair the thread, I may well have ended up making it worse.

[Matchymarty]

Thanks for the heads up Pharisee, however my threads won't tighten up and are too far gone. I have to helicoil.

[Andy51]

Thread type is probably BSP, measure o/d and tpi, then look up BSP threads, they are not in 'logical', i.e. 5/16 or 3/8 sizes - the size is the bore of the pie, not the o/s dimensions as for BSC, BSW, etc. Andy

[Mick D]

Hi

If the lower thread is cracked then a helicoil will leak unless you seal the crack - the union seals to the spot faced area around the thread, there is no cone seat for the union to the crank case, (unlike the upper thread to pipe assembly).

Regards Mick