Apr 292014

The trial fitting of the exhaust system had highlighted a couple of alignment issues. The geometry of the pipes to the rear of the silencers was amiss somewhere. The result was that a considerable amount of force was required to push the resonators up sufficiently so they could be attached to the rear mounting.

This in turn raised the rear of the silencer on their mounts so one of the exit pipes was in contact with the floor strengthening panel. This was made worse because the silencers were not welded centrally on their mounting straps.

Also all the load would have to be borne by the small flexible rubber mount, which is merely to stabilise the rear of the exhaust system and not designed to take much load. I don’t think it would have lasted 5 minutes out on the road!

At the time, the down pipes from the manifold hadn’t been fitted. So the makers, PD Gough, suggested everything would be brought into alignment once they were fitted. I was far from convinced. So it wasn’t too much of a surprise that the exhaust system didn’t fit once the engine was installed and the down pipes were in place.

The issue was now getting the entire system back to them to sort it out. I thought it would be easier in the long run to make the 300 mile round trip to be able to discuss the issues in person. To their credit, they were very helpful and offered to remake the tail pipes that pass under the rear suspension and remount the silencers to their mounting straps.

They also showed me around their workshops and the many 1,000s of original exhausts they use for templates. I suspect my fitting problems were simply because of the compounded effect of a couple of the bends being slightly out.

Fast forward several months; the underfloor heatshields had been fitted, the damp winter weather had passed enabling the touching up of the chassis rails where the chassis had been mounted to the painting rotisserie and the final adjustments made to the handbrake.

It was finally time to fit the exhaust in preparation for starting the engine.

The downpipes and silencer sections fitted without any major issues. Although I’m slightly concerned about the clearance between the rear down pipe and the torsion bar. Next to be fitted was the re-made tail pipes …. they wouldn’t slide over the exit pipes from the silencer section. Aaaargh!

The silencers were removed to see what was going on. The silencer exit pipes had an outer diameter of 45mm yet the tail pipes had been made from 44.5mm piping with a wall thickness of 1.2mm. So the internal diameter was almost 3mm too small – they’d forgotten to swage the pipes to accept the 45mm pipes.

These are meant to slide into …. …. these. I don’t think so!!

I can’t believe they hadn’t bench fitted it when it was re-made. Perhaps they overlooked this step in the rush to turn it around on the same day. Rather frustrated, I took the offending pipes to a local exhaust fabricator to see if they could open out the pipes rather than return them again.

Unfortunately their view was that the swaging could easily cause the pipe to crack due to the combination of a relative thin wall thickness of 1.2mm and the fact that the expansion slots had been cut at the ends of the pipe could.

Reluctantly the tail pipes have been returned to PD Gough to fix. So the starting of the engine must wait for their return.

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