Techtip3

SAVVA Technical Tip 3

Exhausts

Exhaust systems are a component we never worry much about, unless of course when they have holes
in them or they fall off, however, there could be another potential problem we never really give
much thought.

I’ll recall a series of events, which I recently encountered.

Last year I purchased a 45-year-old Bentley S2 (V8 6.3 litre) that had not been in regular use for many,
many years. On taking delivery of the vehicle it was “recommissioned” before using it, i.e. changed the oil,
water hoses, fan belts etc. In the year I have had it, it has run extremely well – until a month or so ago,
when it started loosing power. It started and idled without any problem but had no grunt as the revs increased.

The first thing to blame, were the SU fuel pumps so they were removed and rebuilt – no better. Likewise the
SU carburetors, they were rather dirty so they were cleaned and new diaphragms fitted – no improvement. Out
came the distributor – cleaned and reset – still the same. Replaced the coil and condenser – same. And so it
went on and on.

It was a case of what now? What else could it possibly be? Then, in desperation, on the advise of a chap who
has been working on cars for many years and is very experienced - and as a last resort, I took an angle
grinder and cut the exhaust system off just before the main silencer – result, full power, all 6300 c.c’s
could now breath again. On examination by the local friendly Speedy Exhaust shop it was determined, after
cutting it open, that over the years the rust build up inside the main silencer had gradually blocked the
cked causing the engine to perform way below standard and perhaps even overheating the engine at higher revs?
Keep in mind most of an engines heat is dissipated through the exhaust. If the gasses can’t get out, the engine
could overheat.

The answer - fit stainless steel systems on cars that are not in regular use.