914 Maddog Inner Long Chassis Stiffening Kit - Grind and Primer

After loads of welding, it's time to grind the welds smooth-ish and get some primer on them. So that's exactly what I did! I didn't grind the welds flat but I took them down to a level where they wouldn't be noticeable beneath a carpet..if indeed I do carpet the interior.

Here's the driver's side.. 

Lower Firewall left.. thrilling!

More shiny metal!! Lower Firewall right..

The Longs: Driver's..

Passenger's..

...and after plenty of wire-brushing and degreaser, it's time to lay down a nice coat of tough 2K Epoxy Primer. I've got some new stuff made by Lechler which is lovely and smooth. I never thought I'd feel strongly about paint(!) but this stuff, dare I say it, is alot nicer than the stuff I got from Rustbuster and was alot less expensive too....does anyone care?? I should go on 'Watchdog'! Here's the passenger side sprayed up in RAL 7035 Light Grey.

914 Maddog Inner Long Chassis Stiffening Kit - Weld

So to start welding.. It was important to really keep the heat to a minimum so I really took my time doing this. I cooled each weld with compressed air and avoided welding in the same area for too long. I'd weld on one side for 3 or 4 plug welds then move to another area.. For the bead welds I'd do an inch then cool it with the compressed air. It goes without saying that it's a very good idea to brace the door opening to help prevent it from distorting during the welding.

Here's a shot of the Firewall corner. You can see where the screws have been removed; these can easily be filled with weld. I'd only take the screws out when there were plenty of close welds to hold the plate tightly in place.

Here's the Driver's Long. You can see the indent for the handbrake. The metal needs to be hammered in this area to fit snugly.

Here's the welding of the firewall section pretty much finished. There's a ton of welds here because of the extra holes I drilled. You can probably make out the separate inch long beads along the edges.

Here are the beads along the top edge close up.

I wouldn't remove the screws until it's pretty much surrounded by the welds, but then that's just me being ultra-careful!

Work in progress! You can see the door braces..

I cut off the bottom edge of the sections so I could weld them to the Long itself. You can see the short separated beads. I guess you don't really need to do this but I figured it might add a bit of stiffness and I'm also thinking I may not put carpets in the cabin so finishing the edges cleanly like this just made sense visually. ** ref comment below.

More details....

 ...and more...

..and job done!

** See far right of picture above and picture below. I decided to take the opportunity to better weld the actual Long to the outside of the wheel arch. The factory welding is sketchy at best and I thought a bit of extra welding would be a good idea to strengthen the join... If you do this, be aware there's a nice load of weather proofing 'tar' on the other side of the metal which will happily go up in flames if you're not careful!!

914 Maddog Inner Long Chassis Stiffening Kit - Prep

Knowing I'm going to be putting alot of power through this chassis and after a bit of research and advice from the great folks at 914World.com I decided to weld-in reinforcement to the Longs inside the cabin. I bought the 3 piece kit from Maddog Motorsports http://maddogsmotorsports.org

Here's what you get in the kit.... 2 folded sections that go inside the main Longs and a flat plate that connects the sides along the base of the firewall.

I spent time prepping the three sections. They had a good deal of Black Oxide covering them which I removed with a Strip Disc on an Angle Grinder. I've found in the past that it's more difficult to weld through the oxide, you get alot of spatter and the weld isn't as clean - I guess it could be contaminated with the oxide....so best spend the time and effort removing it I reckon. You can see the oxide on the right of the pic below...and the shiny stripped metal to the left.

The holes in the sections were roughly 6mm diameter but I decided to drill them out to 8mm for a little extra strength. I also drilled a number of extra holes which I felt would add a degree of strength and stiffness. As soon as the sections were stripped and drilled, I sprayed them with Weld Thru Primer to prevent re-oxidation..it can happen pretty quickly!

Obviously I needed to strip the Longs and Lower Firewall of paint and clean them up ready for welding. Here's some more shiny pics of the Longs ready to be welded onto..I forgot to take a pic of the Lower Firewall...doh!

...and sprayed with Weld-Thru primer.

It was worth taking the time to fit the sections carefully into place with self-tapping screws. The screws obviously hold the sections really closely against the car to help create solid welds and get maximum reinforcement.

Here's the Lower Firewall section screwed into place..

A little bit of hammering and bending is needed to get the sections to fit in certain areas - such as the handbrake recess, firewall corners and centre...see pic below. I got a bit carried away and decided to clean out the weld-thru primer in the holes with thinners. I reckon you get a better, stronger weld when welding directly onto bare metal..hopefully I'll only have to do this job once..oh yeah, make sure the thinners have completely dried before you start welding!!!..