diesel valve springs

[drew@dyermaker.cs.uoguelph.ca (drew)]

Although diesel engines DO run leaner, they don't run hotter for that
reason.  Overall, EGT's are generally higher on gas engines than diesels.
I'm not sure, lacking actual figures, how the combustion chamber temps
compare between the gas and diesel vw motors, but there's not that radical
a difference as the cooling systems are pretty much the same.  Diesels
obviously need high combustion temps to ignite the fuel (hence the high
compression) but typically ignition temps are only in the 1000F~ range I
believe.

As I posted before, VW only changed diesel valve springs when the hydro
diesel heads came out - prior to that, they were the same springs as used
on the gas engines.  Valve-piston collisions in diesels happen
occasionally, but generally only result in dented pistons - as the valves
are directly over the pistons and open straight down, unlike 16V valves
which open on an angle and tend to get bent... :)

Drew

On Fri, 5 Jul 2002, DEMETRIS  RAPTIS wrote:

> I think I read the same thing in a magazine about using diesel springs
> as Heavy duty .  Diesel engines run hotter than gasoline engines
> because they run much leaner. the higher compression would explain the
> use of stronger springs in a diesel engines, a spring failure could do
> alot of damage in the combustion chamber. demetri
> 

Drew MacPherson - '84 Wolfsburg Edition Scirocco TurboDiesel