.. 
- Drivers side sill rust- EmissionsOK- the CAT was basically a straight through tube- so no huge surprise I guess, although wouldve been nice if it had gone through anyway.
..I struggled to find a replacement CAT anywhere on short notice, but thanks to the Rogue (Rouge? 
) family a second hand CAT with a full core, but rusted out flange arrived the next day: thanks guys 
I welded on a new flange and figured that was the emissions sorted.
The sill however.
...the MOT tester said it was bubbled, so he poked it and put his finger through it lol. It came back looking like this:
So a bit of wire brush action exposed the true extent of the external tin worm problem:
I figured I needed to unpick the spot welds along the lower seem, and cut a straight line down the sill to weld in a patch- so a bit of cutting action:
And we find the cause of the issues- at some point the rear arch was smashed in allowing water into the sill.
As you can see at this point I discover the true extent of the rot on the rear arch:
So to the repairs.
...first an old datsun sill we had in stock was slightly ammended to make the outer sill plate:
And a new inner plate to replace the rusty arch- this was a bit more complicated to make:
Luckily I've got access to a spot welder
(makes things soooo much easier), so we spotted in a drop plate:
Then used this to hold in the new arch patch:
Which spotted in to look like this:
At this point my battery died on me.
...but basically I etch primed the inside of the sill. Then spotted the outer plate in along the lower sill (as per factory spec 
), then seam welded the upper and side joins into the existing sill.Smoothed it all out, little bit of filler.
..then some decent sealer on the inside of the arch and a flash of primer:
Yes- still needs proper smoothing in and painting up- it ain't perfect, but given this is a fully track orientated car- it doesn't need to be! And best of all- my local MOT tester passed it
Happy days!
