Just be careful drilling the sump as most twist drill bits will 'bite' and suddenly pull in. Not far behind the sump plug is the pick up strainer and the pick up pipe itself. You don't want to damage either of these.

I have usually found the Helicoil taps will wind in without drilling.

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Yeah, thats why I'd rather get someone experienced to do it, I was peering down the sump plug and could see the pickup strainer and was thinking the same thing.

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68 Morris Cooper S Mk1 (*ex 78 1275 LS 4th last built, 70 Morris 1500 OHC & 70 MiniMatic)

Be EXTREMELY careful if you're going to do that. I have found out the hard way that EVEN ON ALUMINIUM you can very easily break helicoil taps if you don't pre-drill..... If you MUST do it without pre-drilling, pay attention to the way it feels.. if its fighting you at all STOP before you break the tap.

Usually the exisiting hole is a smaller diameter than the minor diameter of the thread for the helicoil.... meaning you're trying to force the hole bigger if you do it with out pre-drilling.. instead of cutting the hole bigger.... taps are not designed to work this way.

Any tap will break if your not careful. Done a few this way without problem. Might be the crap taps you use......hang on......

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I'm sure you have, I'm just saying I wouldn't really encourage anyone else to do it. I've used genuine Helicoil and Recoil mostly, but from time to time other brands.

All I'm saying is, for someone who's not done it before, or has limited experience, I'd rather see them learn to do it the right way before they try doing it the "Good enough for the bush" way... they're more likely to have sucess.

edit: as for the quality of them, they are pretty damn good... besides,,, its not like you have a choice, you HAVE to use the Taps they give you in the kit

Mine has been helicoiled in the past. Try as I might, i cannot get a proper seal with the washer. I think this is because the helicoil is not square to the mating surface.

I think this will always be the danger with helicoiling, especially using a hand drill and in situ -i.e. that the hole is not square to the mating surface of the washer.

cheers
michael

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the world is a book, and those who do not travel read only a page
66 Mini Minor sponsored by http://www.lifeonthehedge.com.au/ The Dog Harness Specialists
It was a pleasure ausmini. I'll miss all you misfits and reprobates

Mick,
This is exactly why 4myego went the way he did. It works a treat.

It is next to impossible to keep the drill and the helicoil tap dead square to the outer face when doing it in situ.

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DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R.

Gee guy's you'd have to be a fair way out for that! The threads on the sump plug and the helicoil too are not what I'd call 'precision' - by any stretch! There is enough clearance between them to pull it up square - unless you were a long way out!

I have seen helicoiled ones leak, yeah, but only because the helicoil wasn't wound in far enough and that last bit of it stops the washer seating.

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If the copper washer doesn't seat flat, it will leak. Been there, had one someone else did. It's a 5/8 UNC thread and yes, it is a pretty close fit.
You just try and do it square up under there, in the car...on stands.
Solution on this one (before we swapped cases) was to wipe Loctite on the outer few threads before screwing it in. PITA but it worked.

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DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R.

Yeah, of couse it will (leak)! if it won't pull up square.

I have done quite a few, in the car. Not the nicest of jobs to do, but take a bit of time and presto

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I just hate the idea of doing them insitue..... gah

Helicoils are fine. But only as good as the person who put them in. Take your time do it right and you won't have a problem.

That said, I'm rather taken with 4myego's idea. Its very similar to a Time-Sert.. infact I wonder if you can get Time-Serts that size?

I think helicoils are mainly desidned to work in blind holes and not holes that
go through metal or alloy like a sump. on my moke it's helicoil was becoming tighter and tighter to get the sump plug in or out and I had a good look one day and the helicoil
had wound itself into the sump by 5-10mm and was only gripping the alloy by a couple of turns and some of these where broken, I managed to dig it all out then re threaded the hole and had a friend make up a new sump plug in a slighty bigger diameter, I retapped the sump in the car but was about 0.0005° out of square so has a slight oil leak
(just like the new then )

What size helicoil do you guys use? I did look at using another but I think the guy said I'd need to drill the sump out quite a bit bigger or maybe that was the only sizr they had

BTW it was not done by me, if it was it would be square dammit

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the world is a book, and those who do not travel read only a page
66 Mini Minor sponsored by http://www.lifeonthehedge.com.au/ The Dog Harness Specialists
It was a pleasure ausmini. I'll miss all you misfits and reprobates

Me too. The good old railways learnt me to chisel & file things flat and drill holes square....

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DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R.

Blind holes are actually a little bit more difficult because you need to get the tap all the way mostly to the end of the hole, and get the insert's removable tang out. If you don't get the finishing tap far enough in, the insert will be pushed in to a narrower diameter as you install it into the lower part of the hole, and give you problems when you try to tighten a bolt home..

If your thread insert moves in use, use a few drops of stud lock as you put the helicoil in. Wash the area with acetone or Loctite's own proprietary surface cleaner before doing so.

Much easier with small (5/16th, 3/8th, 1/4) sizes however.

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SooperDooperMiniCooperExpertEngineering

All garage work involves equal measures of enthusiasm, ingenuity and a fair degree of irresponsibility.