Turbo Diesel Valve Springs in a 16V?

[drew at scirocco.cs.uoguelph.ca (Drew MacPherson)]

Diesel valve springs (turbo or normally aspirated are the same) may be 
stiffer, but I doubt it.

Because solid lifter diesel heads used the same springs as gassers, the
hydro springs are most likely to be different because of a unique
characteristic of the hydraulic lifter on the diesel.  Engineering changes
to the VW diesel head were generally to reduce engine operating
noise (major issue with passenger car diesels.)  For example, it was
necessary to implement a different injector nozzle when hydraulic lifters
were introduced (due to the change in cam profile on the hydraulic cam) to
minimize diesel knock.

A further piece in the puzzle is that the outer diesel valve springs
appear to be variable rate - that is they are colour coded, and my paper
A2 Bentley talks about the need for them to be installed with the
larger-spaced coils downwards (or the other way around - I can't confirm
because the paper Bentley is in the shop and the CD-rom version is sadly
lacking in many of these details - another reason why paper is better.)

Personally, I would be inclined to use diesel valve springs on diesels, 
and purchase sport valve springs from a reliable tuner for that purpose.  
That's my 2 cents, anyways.

 In the meantime, diesel spring part numbers for hydro heads are:

	028 109 623 A (outer)
	028 109 633 A (inner)


Drew


On Sat, 24 Jan 2004, Sal Guzzo wrote:

> A 16V question for tha list...
> 
> 
> A friend of mine is planning on building up a 16V head very soon.
> 
> Does anyone know if there are there any advantages of replacing the stock valve springs on a 16V with
> those from mk2 Turbo Diesel?  I've heard that the Turbo Diesel springs are stiffer than the stock 16V
> ones, and allow for revs up to 8000rpm with no valve float.
> 
> Any comments?
> 
> Thanks.
> 
> Sal
> 67 Peugeot 404
> 81 Scirocco 16V
> 84 VWabbit
> 87 Audi 5000
> 00 Mazda B3000
> 
> 
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> 

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