GD427 in action

GD427 in action

Monday, 8 June 2009

Fitting the Heater - 20:20 hindsight

With a bit of hindsight (there might be a few of these) a better way of fitting the heater would be to make a template of the heater face before drilling any holes and perhaps include an outline of the outside edge, place the template into position on the footwell side and then decide where you'd like the holes to be. Mark these on the template and then transfer these onto the heater face as marks where to drill the holes. Within reason and obviously taking care to avoid the heater matrix, the bolts should then be in a perfect position to enable easy fitment.

Saturday, 6 June 2009

Spit and polish

This is a picture of the rear left quarter when I initially started rubbing down the flashlines. Since then I had quite a bit of practice ! and I've also treated myself to an electric DA polishing machine so I thought I go back and see what I could achieve with a bit more experience under the belt and the means to finish the panel to a high standard.

Firstly I rubbed down the whole panel with 600 grit wet n dry in a horizontal plane, keeping the panel wet at all times. Next I used 1200 grit in a vertical plane, the idea here being that if any horizontal scratches are still showing after this process, they are from the 600 grit and you've still got more work to do. Next was 2000 grit horizontal again with the same idea in mind i.e. any vertical scratches are from the 1200 and you need to keep going. I used a microfibre cloth to dry the panel down and a very bright light in order to see any scratches left between grades.
After the 2000 grit I used Farecla G6 with the polishing machine again keeping the panel wet at all times. After G6 I used G3 which is a bit finer and after that some polish I had previously used on my other car called Menzerna Final Polish PO85RD. I believe the Farecla equivalent is G10. For a really excellent guide to using a DA polishing machine, head over to the Detailing World website and have a read of this:- it's aimed at "correcting" paint finish but the basic principles are the same.

Not bad eh!

Installing the Heater

I've been lucky enough to read a how a few other people have installed thier heaters so I've just basically copied what they did, no point in re-inventing the wheel as they say !
This is the heater, the difficulty in mounting this into the wheel arch cavity is that the mounting flanges on each side are very difficult to reach when it's in position. I understand this is even worse in the MKIV body shape which I have here. Standard fitting involves using self tapping screws to hold this in but I really can't see how you manage to get your hand in to tighten them up. So here follows the alternative tried and tested method of fiting the heater.

Firstly remove the flanges, this job was completed using a cut off wheel in the dremel. In truth it's only one side that causes the problem but the alternative solution is so neat I decided to apply it to both sides. Here you can see the flanges on the end caps which have been removed first to make the job easier

Heater temporarily reassembled to show how it looks with the flanges removed

Next, dril four holes into the face of the heater, after you removed the innards to prevent any damage, and fit four Rivnuts.

Make sure that the position of the rivnuts does not interfere with the heater matix. My holes for the lower rivnuts were drilled in line with the holes for the self tapping screws holding the heater outlet plate on.

Make a template of the heater face, carefully marking the position of the rivnuts.

Transfer this to the body by holding the template inplace with the heater outlet which is conveniently removeable from the heater body and then drill four holes to correspond with the position of the Rivnuts. I found this easier from the wheel arch cavity side.

Refit the outlet plate, bolt through from the other side and voila! Heater installed.

View from the footwell.

You can see in this picture that the top left bolt hole is a little close to the outer wall of the footwell and with the washers I was using it wouldn't fit. Not the end of the world I'll just have to use a smaller washer on this bolt. This basically occurs because the passenger footwell has a double skin injected with foam as a safety measure which isn't obvious (unless you think about it!) when looking back from the wheel arch cavity the other side which only has a single skin. See picture above. For reference, my holes were drilled in the heater face 20mm in from the outer edge. I'd suggest it ought to be about 30mm, at least for the top left fixing looking at the face to give you more room to insert the bolts.

Rivnuts & Jacknuts

In reading up on the tools needed to build this car I kept hearing about rivnuts and jacknuts. Well I've now got to the point where I've started using them myself. Rivnuts, rivet nuts or threaded inserts are the same thing just different terms used by different people. A rivnut works much like a standard pop rivet but instead of holding two panels together it's inserted just into one and leaves a threaded hole through the middle. This allows you to insert a bolt and either bolt another panel to it or maybe just a bracket, handle etc

The rivnut itself contains a thread and screws onto the mandrel, it is then inserted into a predrilled hole.

By squeezing the handles of the tool together, the mandrel is pulled back into the tool forcing the rivnut to deform and so griping the panel it has been inserted into. Then simply unscrew the mandrel from the rivnut using the knurled knob and you're left with secure place into which a bolt can be fastened.
Jacknuts are very similar but designed for weaker or brittle materials and perfect for GRP. When they deform they spread "fingers" to exert there grip over a much wider area. It is possible to use the same tool to insert a jacknut but care is required as a rivnut tool is designed to exert much more force than is needed for a jacknut. There is a similar but specific tool for jacknuts but it isn't up to the job of inserting a rivnut. Rather than buy both, I'll just have to learn to be careful !