Thanks for the replies..
As you probably know, given the location and the angle Its tricky to see some of the detail. Ive ordered a set of LED mirrors to hopefully get a better view of things.
dursley92 wrote:or is the helicoil sitting proud of the head surface?
Nope..I checked that as originally I figured that may be the issue, but flush and a few mm below the surface
xvivalve wrote:Are you using the allen key operated cap headed screws?*
If it is bottoming out them simply use sufficient washers under the cap head to allow you to torque it down.
*If your cap heads are conventional posidrive, then replace them. £7.00/set posted.
New set of 5/16 UNC capheads are being used. Im using SS, but Im getting some galling so may change back to the mild steel type.
Ive also tried packing with a few more spring washers, and whilst it tightens down to a point where Im unable to tighten further, it still leaks down on that bottom right hand corner.
I also thought it may be the gasket slipping, so instant gasket-ed the rubber gasket in place on the cover...and it still leaks.
I think what has happened is the previous owner has drilled but then not fully tapped down the hole before inserting the helicoil. Whats then happened is that they have wound the helicoil in and at the lower point, with no threads lower down the hole (or the thread being shallower) its tapered the helicoil inwards (so image a cone type of thing).
When I screw the caphead in it 'bottoms out' or locks before all the others.
I may turn this the other way round..If I fit a set of 5/16 UNC studs in the holes, then use a set of domed 5/16 UNC nuts to bolt it down it will remove this problem.
Only consideration is that can you still get the cover on and off with 1" or so of stud sticking up?
Another thought is that is there anything else in that area that could cause an oil leak?
Although I 'think' its the cam cover gasket leaking is there anything else around that area (either back of head or under the exhaust manifold) that can leak? The oil is not being burnt on the exhaust though...so wherever it is coming from in that region, its missing the exhaust luckily.
Its difficult to see under there being a slant engine and then from underneath the subframe gets in the way
Anyway...sorry for the long winded reply.