Roll Bars Revisited

After the dust had settled I went back and had another look at the roll bars. In fairness, the holes weren't too far out but they did need a little bit of work. I've narrowed the problems I had down to two reasons.

1. The first set of bars fitted fine but for the second, it wasn't obvious which way the holes needed enlarging when they wouldn't initially fit. They appeared to be tight against the bodywork but in reality there were simply leaning forwards because of the third leg hanging into the cockpit. If I'd had the chassis level I could have checked the vertical.
2. I hadn't taken account of the flex required in the third leg, I allowed for the main legs but cut the rear hole to fit the bars in their unflexed state. Once flexed to fit the mounting points, the hole had been enlarged in the wrong direction.

I didn't take pictures of every step in the repair but with the few I have and a desription, hopefully you'll be able to follow what I did.
The first thing I did was to tape a piece of 1mm rubber mat around the roll bar where it passed through the body. I then cut a curve into a square of grp matting and glassed it in on the underside of the rear deck, up to the rubber mat wrapped around the roll bar. The rubber mat was to protect the roll bar and once removed, to give me some clearance to remove the roll bar afterwards.



When it had set, I filled the gap I'd created with Isopon p40 filler and then when that had set, removed the rubber mat and then the roll bar itself leaving a new fillet of grp filling the space which I had previously over enlarged.



Now because I had filled up to the roll bar itself, the repair was too much and needed cutting back to give the required clearance of 5mm all the way round.
Prior to making this repair I had cut two doughnuts out of a 1mm rubber sheet, both with the same outside diameter but one which had the same inside diameter as the roll bar and the second with the diameter that the hole needed to be, including the 5mm clearance. With the roll bar in position I placed the first doughnut around the roll bar and marked the outside circumference. With the roll bar removed, I placed the second doughnut into position, carefully lining up the outside circumference with the marks made for the previous doughnut. I now had a reference point to enlarge the hole, along with the repair, to give the neccessary clearance.



Once the hole had been enlarged to match the inside circumference of the second doughnut, the filler was also cut back on it's surface ready for gel coat to be applied.



Once the gel had gone off, it was rubbed down level to the bodywork and repolished before the roll bars were refitted to see if it had all been a success...



There may still be a little fettling required but it looks good to me and with the grommet fitted, nobody would ever know...!



A couple of gratuitous shots to show how it's looking.

Better Pictures...

Because of the poor weather we've had, most of the recent pictures have been taken in the garage and weren't particularly good. As well as promising myself to learn how to use my camera properly, I also vowed to take some pictures outside as soon as the weather cleared, so here they are... other than temporarily fitting the air intake, no further progress, just better pictures :-)









Two things before I go, firstly a quick hello to my old friend Casey and secondly, if you want to see what this build has been all about, you have to stop by Steve's pages (link on the right hand side) and check out the fun he had at a recent trackday. Direct link here
Don't forget to watch the video's, fantastic stuff.

Getting there

Here's a picture of the engine bay after I got rid of all the engine harness, fuse box, ecu connector etc. and shoved it all though the bulkhead into the area behind the dash. I still need to fit the air intake onto the front of the engine where you can see "LS3" written on the black cap.



I've also opted for a bit of bling and fitted these stainless steel pipes rather than lengths of silicone hose which take the hot water from the engine and feed the heater which is hidden under the nearside wing.

Engine Harness

The engine harness was already fitted to my engine when I had it delivered, rather than unplug it all to pass the connectors through to the engine bay from behind the dash I chose to pass the fuse box, ecu connector etc. back the other way. In order to do this a 64mm hole needed to be drilled through the bulkhead and the fuse box and ecu connector dismantled to get them through the hole.






I had some stainless rings made up which I used to clamp two pieces of rubber sheet with holes cut in the middle against the bulkhead to form a seal for the harness to pass through. Probably easier to show you a picture than try and describe in detail. Each sheet has a split in it so it could be placed around the harness rather than pass the plugs through the holes. Each split is 180 degrees apart from the other to give the rubber greater strength to support the weight of the harness.

Front



Back



Another job done, the engine bay's looking much tidier with all that wiring out of the way, I'll post some more pictures later.

Roll Bars part 3

Yes they're fitted, yes it was hard work and yes I made a hash of it !



I'm probably being a bit hard on myself but I don't feel this part of the build has been my finest moment. I basically followed the method shown on both Steve and Simon's site but just didn't make a very good job of it. Rather than simply rehash someone else's guide, I'll tell you where I went wrong and the pitfalls I found.

I chose to simply raise the rear of the car rather than all four corners. I believed that bolting the 12mm rod tightly into the chassis mounts would be enough to ensure it was perpendicular i.e. vertical in comparison with the chassis. Maybe it was, the problem is that I had no way of checking as I knew the car wasn't level so I couldn't use a spirit level to check. My advice, at least get all four corners off the ground even if you not sure the ground is level, it shouldn't be far out and a spirit level on the rods will give you a fair indication if they vertical.

When the roll bars are reversed with the third leg hanging into the cockpit, the weight of the third leg pulls the bars forward so when trying to bolt the first two legs in and your having trouble, it appears that you need to create more clearance at the front i.e. the direction the bars are naturally leaning toward. This is exagerated if you only jack up the rear of the car!

The bars (well mine at least) were slightly sprung and needed pulling apart to get the mounting holes lined up with the holes in the chassis. I'd worked this out for the main legs and made a wooden brace to fit between them inside the boot which held them apart at the right distance. I kinda overlooked this with the rear leg which caused me some problems. I took great care to open out the holes in the bodywork for the legs to fit though only to find than when flexed outward to fit the chassis mounts I'd enlarged the holes in the wrong direction. Yup, I did this twice !

The roll bars are now fitted temporarily but firmly bolted in place so I know they're in the right position. I still need to open a few of the holes out a little to create a 5mm gap around the legs for the grommets to fit but several of the holes will also need a little repair work. Fortunately, depending on your point of view, I've been here before and already have the materials I need !

This is the best, you can see where I've scored the 5mm clearance still to be opened out



And the worst, big enough to get my finger in !

Roll Bars part 2.

Well here's part two. I opened the holes out in the boot floor just enough to pass two lengths of 12mm threaded rod (the securing bolts are approx 12mm, half inch I think, hence the use of 12mm rod) though the roll bar fixings. The rods had been cut to length and long enough to reach the underside of the rear deck. I used a brace between the two to make sure they stayed parallel to each other and used a nut top and bottom of the roll bar fixing points to secure the rods in place.



I used the ends of the rods as a reference point to mark the underside before removing the rods and drilling though.



With the rods placed back into position I opened the hole out to reveal the ends of the threaded rod where I'd previously drilled a 6mm pilot hole to act as a guide for the pilot drill on the hole saw.



After a quick double check to ensure the rods were straight and hadn't been pulled out of alignment I set about drilling a 51mm hole through the rear deck. I decided to use a holesaw the same size as the leg and open it out as required rather than drill a bigger hole to start with. Whilst the final hole will be 61mm giving 5mm clearance all the way round, I erred on the side of inconvenience and a bit of fettling to get the legs to fit rather than run the risk of an error by trying to drill it to the correct size in one operation.



Once the two holes had been drilled I was able to place the roll bars into position albeit with the third leg pointing forwards awaiting the third hole to be drilled. Apologies for the poor pictures, I wasn't sure what the weather was going to do so I had to carry this out in the garage.



The whole process was repeated for the other side and I have to say it all went rather smoothly.



Unfortunately I haven't been able to complete the fitting as I don't have a holesaw of the correct size to cut the clearance holes in the boot floor for the main legs. I realise this isn't seen and I could've just cut something out using the Dremel but there's no rush. For this reason the roll bars are sitting a little high in the photos. Once the holes in the floor have been cut I can mount the main legs with the third leg pointing forward (as in the pictures) and use a template to cut the hole in the rear deck for the third leg. I have thought about using a similar method with the threaded rod to mark the third hole and may decide to take a different approach.

Roll Bars part 1.

Part 1 !! I’m not sure how many parts this will end up in as I haven't been looking forward to this bit, and keep putting it off.

The main issue is that the mounting points for the roll bar legs are now beneath the floor of the boot. Add to that, externally there is little to reference on the rear deck to mark where the roll bars should come through the body. The only way to calculate where to cut the holes in the rear deck is to transfer the reference holes from where they bolt onto the chassis up through the floor of the boot and then continue up onto the underside of the rear deck before cutting holes for the roll bars legs to fit through which have to be no more than 5mm out of alignment. I'm going to largely follow the method used by Simon and Steve on their sites, there's a few bits I haven't quite got my head round yet but in thinking it through have come up with my own solution.

First off, I cut down some 12mm studding long enough to bolt through the roll bar mounting points and reach up to the underside of the boot floor. I then drilled a 6mm hole into the end of each piece of studding before bolting them into place. With some rough measurements taken from underneath I guesstimated the position of the studding in relation to the inside of the boot floor and drilled some small exploratory pilot holes, using each as a reference from underneath until I had located the approximate centre of the studding and then opened this hole out with a Dremel to just a little larger than 12mm.

The plan is now to use a hole saw from within the boot, using the 6mm hole drilled in the centre of the studding as a guide for the pilot drill, and drill the clearance holes through the boot floor for the lower half of the roll bar legs. All of the exploratory holes I drilled were within the diameter of the hole saw and were through material to be removed anyway. A picture would probably help…



Here you can just see the guide hole drilled into the end of the piece of studding beneath the floor



Ahh, foiled, my new handy dandy right angled drill attachment wasn't big enough to take the holesaw arbour so I had to compromise with a ratchet and socket.



One down, five more to go. I need to buy some new holesaws as I don't have the sizes I need so I'll probably have to wait until the weekend to make any more progress.