Sump studs size and thread

[Ruairidh Dunford]

Don't forget to drill the sump to suit those two bolts.

[John Mason]

Yes drill and tap to 5/16ths BSW.

John Mason.

[Charles P]

Ah, youth and enthusiasm, I’d have gone home.

Relative youth Alan, not absolute
When a magneto HT wire nut rolled down the scuttle and into the open oil filler spout I very nearly packed up. However I'd have to wait until the hill closed at the end of the day to fetch the trailer, so I took the oily route

Charles

[Chris KC]

 Coupled with a silicone sump gasket, leaks from the sump area are a now thing of the past and the sump is easily removable (although why you'd want to is a subject for another thread ) and re-fitted.

Steve

I do the same Steve, but my one suggested modification is that with an alloy sump it’s best to shave 1/8th off both front flange corners. If you don’t then removing the sump with the engine in the car may become difficult, as I found when I needed to do this in the Wiscombe paddock between first and second practice 

Charles

They can also snag on the frame when you're doing it up under the car - don't ask me how I know this.

[Colin Morgan]

As there was a noticeable drip from the sump whilst the car was in the garage last week, I did a check on how many sump bolts would still tighten 'fully' - turned out that three were 'a bit soft' and two were 'soft'.  Seemed (last week) that best course of action was to Helicoil them - so over the weekend put the car high up on axle stands and removed the sump and now have five new Helicoils fitted. 

Am in the process (mail strike today not helping) of obtaining a new set of bolts, as some of those I have taken out were decidedly worse for wear - not to say necked.  If a bolt snaps off in situ then it is a whole different problem?

Once the bolts and oil are back in, I will know whether or not a bit of extra tightness has helped?  From what has been said above, given a couple of the Helicoiled holes aren't blind, further sealing may yet be necessary... will find out in due course.

Update edit: The sump bolts are now tight after Helicoiling those that were weak and the oil is back in. But the sump still drips - possibly because a couple of holes that were previously blind now break into the crankcase following the drilling for Helicoiling - so this now needs some investigation. I get the impression that thousands of other Seven owners have been down this route - stopping drips from the sump perhaps needs a more sophisticated approach - say studs? - as others have spelt out.

Further Update: Turns out none of the Helicoiled holes has broken through - the leak came from two of the bolts not being tightened properly - one that was Helicoiled and one where a new bolt had been substituted instead of stretched one - both were stiff to tighten, felt like there was a risk of shearing the bolts so took it very gently. After ensuring all the bolts are properly tight, there is still a slight drip this evening. The next stage might be to try some sealant or Locktite to improve matters, should this prove necessary?

Update two weeks later: Tightening the bolts did not help. Still dripping seriously enough to need attention. Made a gasket out of 2mm cork sheet to replace the paper one. This was fitted dry (with a cotton loop threaded through the front end holes to help hold it in place) and tightened carefully - just holding the socket drive in the palm of my hand - so probably less than 5 ft pounds torque. It is - so far - leak free.

[Colin Wilks]

Don't forget to drill the sump to suit those two bolts.

I think Ruairidh was talking about sizing the hole in the sump itself. Bit of a bugger if you've got it all fitted bar your new fat jobs and then you realise the new bolt won't go through.

Have to say I can't see the difference between drilling and tapping 5/16" standing on your head and fitting a helicoil so as to keep all the bolts the same. Plus if you make a mess of the drilling and tapping you are starting to run out of meat in the crankcase to then helicoil that hole!

[Ruairidh Dunford]

You are correct, Colin. That is exactly what I was referring to.