PART 3 -

TROUBLESHOOTING, AND POWER!

Priority this time is to eradicate whatever is wrong at the rear. That banging from the rear subframe said something was badly broken. Whilst laying beneath it, idly pawing at the car, the Bear found the cause, a bolt that would usually attach one of the diagonal cross brace bars from diff to bottom plate was missing. Assuming this would be flailing about and causing the noise, an easy fix seemed to be to replace the bolt.

Not so. Whilst peering at it in dismay, his fur matted with old diff oil, a rather large crack in that bottom plate presented itself, joined by a crease further forward. Alarm bells rang. Being a Bear of occasional action, and with no honey in the vicinity, he wrestled the rear subframe out of the car, and the full extent of the damage was clear.

It’s what we call broken. So we fixed it. We had another handy, an X300 item, which is different only in the details. Bear welded additional bracing to that, fitted it, bolted it all back together, and then started plotting upgrades. Those rearmost mountings, the diagonal rubber-bushed bars, well they differ as the cars get later. The V8 subframe braces these to each other to make a much stronger and more sensible unit, and we happened to have one handy. Bear reasons that there is no purpose to the rubber bushes, and whips up four aluminium ones.

The whole thing then gets posted back in the car after a coat of gunmetal paint, with two new front mounting bushes. Hopefully with the rear end attached it should behave a little better.

As that’s being fitted, crunching noises from the car suggest that the shell itself needs some attention, and out comes the welder to repair the mounting points. The car may have the odd rust issue, but it’s not going to win on our watch!

You might think that would be enough, but clearly it’s not the Kutuka way. The quest for more weight continues. Ten further easy kilos vanish, including the rear window lift motors, the glass being bolted in the up position for ever more. It’s not much, but every little helps.

Wait, there’s more. We’ve had a look at the exhaust, and we’ve had the car on the rolling road. We took the exhaust off on the rollers, and there was a startling improvement, something in the system aft of the downpipe is killing the car’s power. This car has been on at least 3 rolling roads that we know of before we took it to one. Nobody had ever apparently thought to try this before, which does rather reinforce my suspicion that you get a better service when the project is being looked at by the more obsessive type. Like, say, David. The idea that something is good enough really never seems to occur to him.

 A big-bore stainless system seems to be in order. With the Jefferys clan now deeply distrustful of professionals, we somehow end up with this job. This is a new one, because we’ve never made an exhaust before, and we don’t have the facility to properly weld stainless steel. Oh dear.

With the old system off, we redesign it, taking a little bit out of some of the bends, 90 degree bends become 60s, 60s turn into 45s, and everything gets bigger, we’re working in 2.5 and 2.25” pipe. We can’t bend this stuff, we have to buy it pre-bent. We find a cheap enough place, but the need to cut pipe square and true also means we invest in our first bandsaw. It’s getting awfully involved this racing lark.

A pile of bends and tube are fetched by a Bear, as the bandsaw arrives in the boot of the Kutuka X300, and an orgy of sawing commences, the various pieces cut to what we think is the right length, and the Bear sent out again to have the ends flared to allow the thing to slot together.

From the wilds of the south arrives a David and his fancy welding gear, with a helmet that makes him look like Iron Man. Only in blue. Blue, as we all know, being the superior colour.

It takes us two days to come up with a working exhaust, including clamps and hangers. Could have been faster, but a lot of it was design on the spot, and with the diff refusing to be symmetrical, getting clearance on the offside proved to be more difficult than expected. It would also have helped had the silencers we specified as 2.25” bore had actually been 2.25” bore, and not 2.5. The trouble with cheap suppliers is….

Clearance between driveshafts and the body is key. The pipes that came off, standard design, showed the impact marks of the shaft UJs hitting them, and of the two X300s we've broken at this point, both had flattened their exhaust pipes here. We're increasing the bore by half an inch, and working to ensure that we get more clearance than standard despite bigger bits requires a degree of patience.

The gradual process of heating, bending, trimming and welding takes time. Fortunately our pet McGivern is a patient soul. We really hate how well he can weld. Truly annoying. Bespoke pieces are churned out from his one-man production line with irritating precision.

Final assembly shows some clearances to be a little tight, reducing the angle on some bends was a gamble, but it just works. It would be better were the car properly stripped underneath, but it fits. Making the round straight-through silencers fit in apertures meant for oval offset silencers involved an angle grinder, and a big hammer. Don't tell the owner....

Igniting the fires in the engine produced a deep, rasping bass note, classic modified 6 cylinder. If we’re judging on noise alone, we just made this car faster. Only track testing will now tell, we need it to drag race a standard car of equivalent weight. There aren’t any quite as heavy, but if we can get him to chase an F class XJS we’ll know if it worked.

To Silverstone!

On race day Matt hunted down and passed the two leading class F XJS, visibly reeling them in down the long Silverstone straights. He came home 2^nd overall in the saloon race, his best ever result by a country mile. We’re prepared to suggest that the modifications work….

STAGE