Club 80-90 Forums

I have just opened the crankcase on my MV engine to find that the sump plug has been helicoiled in the past, so the question is for long term security should I have the hole Tig welded and then redrill and tap the plug hole, I'm not sure that I would trust a heliciol as a long term solution. any thoughts please.

M16 it if there is enough material.. use a citroen sump plug..

Helicoils are fine and long lasting as long as the thread was cut properly and the coil was fitted correctly

toomanytoys wrote:M16 it if there is enough material.. use a citroen sump plug..

Just measured the O/D of the helicoil it appears to be 16mm so may remove it and see if a Citroen plug fits. Don't want to leave the Helicoil in because it's wound in and sticking up from the bottom of the sump by about 15mm and lots of crud has built up because the oil cannot empty completely. (beware those using a vacume pump)

crud builds up in all sorts of nooks, no matter where you drain it from, unless the PO was diligent and changed the oil twice a year...

I don't think you can simply remove the helicoil and wind in a M16 bolt, as the helicoil pitch will be the same as the original sump plug thread (M12/M14?)

I had an insert split, it was a solid type rather than a coil. It came out with the sump plug. The fix for me was to fit M16 Renault plug straight into the thread left by the inset. It was 1.5 pitch and 12mm long. £3.95 from local auto factors. Hope this helps
Rich

Thanks for the replies, will check pitch with thead gauges. I don't I would sleep soundly knowing that the helicoil was waiting to wind into the sump and some point in the future.

How did u get on weimarbus?

i have got to re-tap the sump on my autosleeper. the original M14 threads are stripped. luckily we have all the taps and tools i need at work so i can borrow them. so my plan is;

drill out the original threads with a 9/16th (14.25mm roughly) drill nice and slow to keep the drilling swarf from flying into the case.

Tap M16x1.5 again nice and steady, put loads of tapping grease on to keep hold of the tapping swarf, also keep removing the tap and cleaning the crap off and re-applying the grease. Ensure the tap stays square to the sealing face of the sump at all times.

Once tapped, i will heat some cheap motor oil up and pour it through the engine to flush out any rogue pieces of aluminium swarf that got in the case.

always use a fresh copper compression washer as this will help get the best seal without having to overtighten the sump plug, this is what causes the threads to strip in the first place.

does this sound about right to you guys??

any additional advice then fire it my way.

perfect
then buy a renault or citroen sump plug and a couple of crush washers

Certainly do your utmost to keep swarf from entering the sump, having now striped the engine I could see swarf stuck in the oily crud in the bottom of the crankcase and also evidence where some had got into the flywheel end main bearing and two of the conrod bearings. Fortunatly the damage was to the bearing shells only and the crank journals are ok