6 replies to this topic

[Austinminimark]

hi guys
i have a metro turbo engine which i fully rebuilt put it all together and found the previous owner had slightly shagged the sump plug thread on the housing.
not a big fan of the helicoil stuff available.
ive been looking at the saab m16 thread tap my friends has and i think it will work perfect.

heres the dilemma ive built all the engine with all new gaskets and seals and i do not want to break down the engine again.
so ive basically got to tap it all built together. ive thought about having a chunk of ali welded on the outside of the box with the m16 thread so that filing dont go inside but then it might heat the casting up to much.
if i tap it there is going to be ali swarf in the bottom of the box with i cant get out with a magnet obviously so i could flush the engine but what should i use??

please help
thanks
mark

[myredmini]

I used a helicoil kit on mine before it was stripped and cleaned prior to a rebuild.. Didn't want to risk swarf in the engine or box.. My plug now tightens very well and doesn't leak at all..

Dan

Also to flush, a cheap 20/50 engine oil is fine, Wilkinsons is about £8.50 a gal

Edited by myredmini, 03 June 2012 - 01:32 PM.

[jaydee]

A mate did that with engine in situ, afaik he used some grease to avoid swarf coming into the 'box, but he didnt come into further details.

[dklawson]

Two things...

The grease method (on both the drill and the tap) is very effective at capturing the swarf. Whatever drain plug solution you pursue, the grease method and careful cleaning afterward will be OK.

Second, there is NOT sufficient size difference between 16mm and the standard 5/8 UNC for re-tapping the existing sump drain to be effective. (5/8" = 15.875mm). If you really hate the HeliCoil idea (and there is nothing wrong with the HeliCoil solution) then you will need to use a larger tap and drain plug than M16 unless you weld a bushing in place. I would NOT weld onto an assembled gearbox... but that's just me.

A quick online check indicates that you may be able to find drain plugs in both 11/16" and 18mm sizes and there MAY be magnetic drain plugs available for them. Those plugs could be used by re-tapping the existing sump opening.

[mini13]

also I wouldnt be overly concerned about a few soft bits of ally swarf, a load of grease on the drill & tap, and a fish round with a cotton bud will be sufficient.

[Austinminimark]

thanks guys going to look mybe at using the helicoil kit but i dint reli think they were anygood.
the engine is only teporary until anouther one is built anyways so i suppose this could be a quick fix.
cheers

[Surfbluegarage]

we helicoil alot of gearbox sump plugs in situe and never had a problem with them yet most of them come back for services every year and still going strong..
just use plenty of thick litium grease or something similar when u drill (slowly) the hole bigger then tap it to the right size (5/8th unc 11 tpi) honestly you wont have a problem.