# KDS Keltec Ferrari F355 GTS Restoration Part Four.



## Kelly @ KDS (Aug 4, 2008)

*Hi Guys,

I thought I make the most of this strange situation/opportunity while we are all in the coronavirus lockdown to compile the Very comprehensive Ferrari F355 thread.

This thread will be a very long in-depth thread of the full restoration that we carried out a few years back on this Ferrari F355 GTS.
Hopefully will help with those detailing blues and kill a few hours while reading through it too.

PART FOUR The general mechanical work.

Let's start with the drive shafts. 
I noticed that the CV boot gaiters showed signs of rubber fatigue.
So it seems silly while the engine was out not to tackle the task, I quick strip-down of the shaft ends.*



*I gave the CV joint multiple degreasing and clean to make sure they are spotless, a tiny bit of grit will very quickly wear the joint and its moving parts.*





*While the brake discs were removed to repaint brake callipers more on that later, I noticed the hand brakes shoes are somewhat worn.*



*So a pair of new hand brake shoes were fitted. *



*Notice the hub face all clean and void of rust of surface; this is often missed when people have their brake discs changed if there is enough contamination of the face this will not allow the disc to fit flat and flush and could cause a brake wobble feeling.

One of the air ducts that run under the engine and gearbox had a crack with a piece missing, so that was replaced with new Ferrari part.
*





*Researching I found out that the 355 race challenge cars had uprated cooling fans, so of course I purchased two new fans *



*While the exhaust box out of the engine bay it seemed like the perfect opportunity to give it a polish up.

Before *



*
At this halfway point through the polishing process.
*



*I thought, what have I started, so many hours of polishing on something you can't see once back in the car. 
Anyway here is a finished photo. *



*I carried out a few exhaust modifications to help longevity and reliability with an increase in sound at the same time; let me explain what I did and why.

The 355 exhaust system was a very sophisticated design and one of the first and only system like this on a Ferrari.

It had two separate exhaust systems that connected at the manifolds this diagram will help explain it.*



*These photos here show the 2 shared exits on each bank.*





*So back to that exploded parts diagram to help me explain how it works.*



*The manifold connects to the catalytic converter part number 21, as well as part number 4 the upper system. 
Part number 4 also has two smaller cats in the pipe, so the car has four cats from the factory.
Both 21 and 4 connect to the exhaust box part number 5. 
During low engine speed below 4000 rpm exhaust valve that sandwiched between part number 4 and 5 is closed.

All the existing airflow from the engine has to pass through the two primary cats and then into the backbox through the more complex silenced internals of the box. The result is exhaust flow only exiting out of two of the four tailpipes.

When under a certain percentage of the throttle or above 4000 rpm the exhaust valve opens allowing the exhaust flow to be exited (shared) with both paths. 
When the valve opens, the gases flow through a much shorter unsilenced direct route, which is how it got through noise regs and still had that screaming F1 sound at 8000rpm.

So onto modification 1.

The standard control valve is what you would call "normally closed" this means an action has to be made upon the value to make it open, in the dormant state its shut.
So if the control signal fails, or even the vacuum pipe fails the valve never opens, this means under high load and engine speeds, the exhaust heat would increase past the safety limit. The backpressure would be the same; this could result in unwanted premature wear and tear.

Capristo came up with the solution, which was to design and more robust better-made control valve, which is "normally open" so removing the failure issue. 
This did mean slightly replumbing the pipework to swap around how the car operates the valve.

This photo shows the factory and Capristo next to each other. 
*



*
The next modification (mod 2) was to remove the cats in the upper system that comes into play above 4000rpm, what I noticed was for many years everyone was removing the primary cats and then encountering running error faults etc but leaving the other secondary cats in place. 
Seemed counterintuitive to me.

Here are some photos of the exhaust being cut open and modified and weld back together void of cat material. *















*I always buy factory parts so that I have two options, factory and modified; this gives me the opportunity of returning to the factory set up in the future.

As can be seen here. Saying that you would never know the shiny cleaner pipe is not factory.
*



*New sealing ring gaskets in readiness for fitment of the system.*



*After the exhaust was all completed is was time to address the suspension.

Ferrari did offer very late in production an upgraded suspension and steering rack modification s standard and an option on earlier cars. 
Ferrari 355 Fiorano handling pack
The final 100 355s made were also built with a competition-based suspension pack. Called the Serie Fiorano, these 100 cars had a wider track, stiffer springs and thicker anti-roll bars. They also had a competition steering rack, bigger brakes and some carbon fibre trim. The Fiorano handling pack was an option for all F355s, but was only standard on these last models.

You can imagine it took a long time to source and purchase a FHP set up, but somehow I did, I do remember searching for many years as these are like rocking horse poo poo.

Here is a photo of standard and the FHP roll bars and steering rack.*



*The spring are still available to buy new.

So I set about stripping down the original set up to replace the springs.*



*
The factory set up is height adjustable Coilover suspension, the issue with such an old car and the adjusting ring being a dissimilar metal to the shock body is corrosion. 
No matter how much soaking with realising fluids, even slightly heating up and using freezing spray the collar would not budge. 
So I had no choice but too very carefully cut the collar with any damage to the shock body when you consider the costs of new shock absorbers it made for an agitated day. 
*









*
The other area to address is the cooling radiators. 
The rads where inspected some were swapped out for new, and some were tidied up. *









*
That concludes part Four the general mechanical work.
Many thanks for reading any question, fire away.

Part One is found https://www.detailingworld.co.uk/forum/showthread.php?t=419835

Part Two is found https://www.detailingworld.co.uk/forum/showthread.php?t=419841

Part Three is found https://www.detailingworld.co.uk/forum/showthread.php?t=420020

Part Four is found https://www.detailingworld.co.uk/forum/showthread.php?t=420272

Regards Kelly Harris

Website - www.kdskeltec.co.uk

Youtube - https://www.youtube.com/user/kdskeltectv

Facebook - https://www.facebook.com/KDSKeltec

Instagram - https://www.instagram.com/kdskeltec/*


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## WHIZZER (Oct 25, 2005)

as always great work


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## JB052 (Mar 22, 2008)

Quality


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## RandomlySet (Jul 10, 2007)

Very nice work :thumb:


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## LSpec (Apr 7, 2013)

wow I cant wait to see final result


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## Bill58 (Jul 5, 2010)

Fantastic work!


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## TheMattFinish (Jul 17, 2011)

Superb Kelly, cant wait for the next thread


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## Andyblue (Jun 20, 2017)

Another fantastic read, thanks for sharing :thumb:


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## Stoner (Jun 25, 2010)

Great thread - looking forward to seeing the finished article.


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## NRDetailing (Jul 9, 2018)

Amazing Restooo !!!


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## bluechimp (Dec 21, 2017)

These make for such good reading! Thanks for sharing.


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## Hocks172 (May 18, 2018)

Amazing work!!!


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## ALANSHR (Jun 29, 2007)

superb as always


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