Exhaust Part One

After the tension of the engine install, the exhaust is a much more straightforward proposition. I began as per the assembly guide, installing the rear bracket. As seems to be the case on the build on some days, a two minute job extends to take 20 minutes. A 10 minute job a couple of hours. This was one of the former.

I’d previously spotted the thread for the exhaust mount is full of paint. When I offered up the bracket and bolt, there wasn’t even the suggestion that that thread would catch. Here, at last, was the chance to use my shiny new tap and die kit, this time with some hope that I’d have the right size and pitch of tap to clean the threads. A quick check with the thread combs to check I had the right pitch (1.25mm in this case) and I set about cleaning out the paint. As before with the thread into the gearbox, the initial start is crucial to prevent cutting a new, unwanted thread, and frequent partial turns to clear the tap cutting surfaces into the flutes are critical.

A squirt of light oil on the flute and a careful pick-up of the start of the thread and I was off. As soon as it felt tight on the clockwise rotation, I reversed it out a touch, and advanced a spot more.

A few minutes later and the thread was clear and bolt in place. I’m pretty sure the picture of the bracket in position in my version of the assembly guide is printed upside down.

Another anomaly in the guide is that the exhaust installation instructions start with the bracket to support the silencer, and towards the end the instructions tell the builder not to install the silencer before the rear wings in case it gets damaged. The new guide can’t come soon enough, but not for this builder.

On to the down-pipes. I removed the gasket held on by the bolts and wiped down the face of the cylinder head with a piece of kitchen roll soaked in acetone to remove any traces of the adhesive tape that was keeping any foreign bodies out of the cylinders. Shining a torch into the exhaust ports let me see the black exhaust valves sitting there waiting for action.

I protected the exit hole in the bodywork with four pieces of cardboard and a fair bit of masking tape, particularly around the corners of the hole. Then as per the guide I worked from the rearmost cylinder to the foremost. Having had the exhaust polished, if there was any numbering on the pipes when they arrives, that was long gone. However, it’s not hard to work out what goes where. The first three went in easily, and the fourth just took a bit of additional management through the hole as there is less space to manoeuvre.

Next the collector. Getting all four pipes into the collector at the same time is a bit of a faff, but with a wriggle and a push they fitted snugly. Fitting the springs was a snap with the cable-tie trick. Two cable-ties to compress the spring and extend the reach of the loops. A bit of a help with a screwdriver over the hooks and they were on.

After tightening the bolts to the required torque, the pipes are very stable. I also tried the silencer on the bracket/collector and it looked great. All good to go once I get the rear wing installed.





2 thoughts on “Exhaust Part One

  1. I am really enjoying your build diary, thanks for making it. Can I ask how you got the pipes polished? What type of shop did it, what process did they use? have they stayed shiny over time? thanks!

    • Hi Jeff. Thanks, glad you are enjoying the blog.

      I used a local metal polishing business to polish the stainless steel pipes. He used a combination of spinning mops and polishing compounds to get the shine. I asked him to retain the mandrel marks (deep grooves) caused during manufacturing when the pipes were shaped, because to remove them would have added hours to the job and a lot of cost.

      They were done about 2 months ago and have remained shiny, although the car has not seen any weather. The header pipes are now discoloured from the heat of running the engine, but I am fine with that. Hope that answers your questions.

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