Dakar Rebuild - part 6
Putting things back together!
Now all that has been sorted, I decided to drop the new engine and box in as soon as I could.
It's at this point I was pleased I'd forced myself to buy a shedload of those little plastic ziplock bags. All the various fasteners were bagged and tagged to ensure I don't have to rely on my brain too much:
A couple of measurements of the previously evicted engine transmission and the new one prove that, dispite the two transfer cases differing in appearance hugely, they mount with exactly the same mountings and rubbers and so no fiddling with the engine mounts was required.
Getting the gearbox back in to the Dakar is always a pain as it's probably the single heaviest assembly in the vehicle. I used the engine lifter to hoist the front end of the car into the air, slid the box underneath and then used a trolley jack under the off- and near-side mountings with the engine lifter steadying the assembly from the front. After much jacking, shuffling and swearing the mounts were bolted through the chassis and the rubbers then tightened.
The engine then went in fairly easily (note to self - purchase load leveller for hoist!) and then the torque converter - which had remained firmly strapped into the bellhousing throughout the entire procedure to ensure it didn't eat the oil pump drive through becoming dislodged - was bolted up to the flex plate. Due to the weight of this assembly, I wasn't really in the mood for taking lots of photos, but here are a couple of the finished articles:
I guess I've become rather paranoid about this thing overheating, and so I've decided to replace the standard spec engine and transmission oil coolers (heat exchangers in the radiator end tanks, and a pipe with corrugated wire wrapped around it) with "proper" discreet air-cooled units that will be mounted in front of the radiator. Here's one of the coolers (originally off a JCB 3CX, I think!) in a test fitting:
There's also not a hope in hell of the grille covering this lot, so to start with I'm just going to omit fitting one. Once I've finished fiddling (as if!) I think I'll use a mesh over the front rather than the existing chopped up Discovery grille.
I am of the opinion that this is well into "overkill" territory as Eliot's 5.7 twin turbo uses the same radiator. From the Dakar 4x4 mailing list:
Given the water rad is cooling a 5.7 engine with the extra load of water cooled turbos and having oil coolers in front of that (again with the heat load of the oil going round the turbos) and now charge cooler rads in front of all that - so far it's never overheated - bearing in mind that the bottom half of the rad is blocked by the bodywork - it shows how over specified the radiator is.Pictures of Eliot's charge cooler setup can be seen here. I guess that shows just how badly knackered my little 3.9 was! Ho hum...
Radiator header tankI'm also playing shape-sorters with the contents of the engine bay. I want to get the expansion tank higher than it was (i.e. so the water level can be above that of the fill turret) and so should help bleeding of the system. Previously it was little more than head level and I have a sneaking suspicion that may have contributed to the previous engine's misbehaviour.
I've now mounted it about 8 inches further back than it was, which involved chopping and extending the coolant pipes attached to it. The result, though, is to have the tank a good four inches higher than it was previously. Although it looks well above the bonnet line, the arch of the bonnet top covers it nicely.
I'm going to add a crossmember to the two radiator braces to allow for fitting of some proper bonnet pins (or those really cool Aero catches that were demo'd on one of the Owners' Club DVDs) and also make up a pair of supports for the front of the body shell as presently it's not secured to the front of the chassis at all. I am sure this is what has caused the shoulders of the shell to crazy-pave at the stress points as there's a lot of GRP up front that's just flapping around in the breeze.
Fuel tankFor the moment, I'm going to reuse the Range Rover's plastic fuel tank. I've dropped it in place and, once some decent straps are welded up, it should prove quite a nice fit. The batteries can then fit either side of it and a load floor with some cargo netting or similar will fit over that.
There's a battery isolator being fitted on the inside rear quarter to allow all the electrics to be knocked out in one. It isn't strictly necessary, but it's a neat safety feature.
Speaking of which, I'm keeping the Range Rover's inertia switch that was mounted at the centre rear of the transmission tunnel (rear passenger footwell). It appears to be wired in series with the fuel pump relay on the coil side, so given a sufficient enough thump, it cuts the power to the fuel pump.
A little bit of fabrication on the filler tube (forgive my crap welding and the appaling white balance of my camera!...) has allowed the existing filler hole in the back of the shell to be reused:
Met up with Jon and a couple of other Dakar owners first thing on Sunday - always good to catch up, especially as I've been distinctly absent from many of the Dakar events over the past couple of years. That will change this year :-) As well as being able to see the useful little tweaks that the other owners have made to their vehicles, Stoneleigh provides a huge range of stalls where you can get all those useful little things that tend to be awkward to get hold of elsewhere.
I found a set of rear lights for £12 from Martini Car Parts that, while not exactly the epitomy of style, are exactly the right size and shape to fit the rear of the Dakar. My existing rubberised ones seem to have dissolved over the past few years!
01/05/06: Transmission filter changeBefore the prop shafts, exhausts and gearbox crossmember were refitted, I thought it would be prudent to change the transmission's oil filter. Pulling the sump is a nice easy job, but true to form I managed to sheer one of the sump clamp bolts off in the process (you can just see the offending article in the following photo, bottom right). I'll drill and re-tap this later this week. Thankfully the sump didn't resemble the bottom of a gravel pit, so hopefully this transmission will last for a while :-) You can also see the new cooler lines and unions here:
The filter is the large black square in the centre of the picture. The pick-up nozzle and filter are retained by three torx head bolts. Changing the filter is just a case of removing these three, pulling off the filter, replacing the O-rings on the valve body and pick-up nozzle and then screwing it all back together. Stripped bolts notwithstanding, it takes about a half-hour to do and can make a suprising difference to the feel of the gearbox! It's a cheap operation, too: the filter service kit comprising of the filter, two O rings and a new sump seal can be had for £20 from this eBay shop.
02/05/06I've started to route the Range Rover's wiring loom through the Discovery bulkhead. Initially I thought I'd have to punch a hole in the bulkhead, but it turned out there was a hole directly under the instrument binnacle where the cabling for the discovery instrument cluster used to run. Using a Land Rover precision adjustment tool (a #2 soft-head mallet) the lip of the Discovery windscreen support was flattened which allowed the loom to pass into the void between the original windscreen location and the Dakar's windscreen. It then enters the engine bay via the gap between the shell and bulkhead to the left of the brake master cylinder.
The oil cooler sandwich plate was tightened in its final position, the oil filter and cooler were then pre-filled with oil and fitted, and all of the oil unions tightened. The engine was filled with seven litres of oil, which got it to the full mark on the dipstick, however as the various pipes and coolers fill this will probably drop dramatically.
03/05/06 Filled the cooling system this evening with the prescribed 50/50 antifreeze:water mix. No leaks as yet :-) Also finished up the engine-end of the fuel lines. Main battery feed was shoved through a length of toughened plastic conduit and this will be attached parallel to the rear brake line under the vehicle when the line is replaced. The conduit emerges in the rear load area adjacent to the fuel tank where the battery will be placed.
04/05/06Replaced the gearbox crossmember with the help of two trolley jacks and a large Land Rover precision adjustment tool. Prefilled the transmission oil cooler and then threw eight litres of ATF into the gearbox. Chucked a litre-and-a-half of ATF into the power steering resovoir, released the steering box bleed nipple, jacked the front axle off the ground and viciously waggled the front wheels from lock to lock to expel all the air (accompanied by satisfying gurgling noises from the box!). I need to solder up the ends of the battery cables, and then I'll run the electrics off a current-limited supply for an initial test - probably tomorrow night. With any luck we'll get a first-start on Sunday!
One thing I'm aware of is that the flexible oil cooler hoses are going to rub in their present position, so I took an old lump of radiator hose, split it down its length and zip-tied it around the lines where they pass sharp corners. Looks quite neat:
05/05/06Soldered up the battery cable and attached it to the starter terminal, and hooked the accessory feed line to the binding post on the bulkhead. Did some continuity checks between the battery earth and various parts on the vehicle - all appear good. Also stuck the meter across the ECU plug to check that the various injectors and sensors were providing sane readings and that there were no unexpected shorts. Again, all good. Fitted the exhaust downpipes, then connected that to the centre box, renewing all the rubbers in the process. Exhaust bracket on silencer was beaten with a Precision Adjustment Tool until it presented itself better to the 'Y' pipe. Copious quantities of exhaust sealant were applied to the union before tightening it up. Tailpipe support was zip-tied to the chassis as there's no rear bumper for it to attach to yet!
The engine bay is now pretty well complete with the exception of some add-ons like the wiring for the air horns. Everything is where I want it and there seems to be more room in there than before. Not sure if this is just my imagination or if things have been arranged a bit better... Either way, I'm quite pleased with the result:
This page was last updated: 12th July 2006 at 1:59pm BST