B7 RS4 engine a 'masterpiece' / B7 S4 engine a 'time bomb'

[BrittasBay]

Everywhere I read about the 4.2 V8 in the B7 RS4 being one of the finest engines ever built –
yet, the very same engine in its little brother is a ticking time-chain bomb?

I'm sure there's a well-known reason for this (RS4 using different components perhaps?) but's I've not heard about it.

Perhaps someone can assist here.

And while we're at it (!) perhaps there's a reason why the B6 S4, to the lay-man, the very same 4.2 V8 engine,
is essentially a game of timing chain Russian roulette?

There's a few nice B6 manuals come up and I'd love to know what you guys think.

Thanks

[Dr G]

Newer revisions of the V8 are fine (basically all the FSI/direct injection versions).

...and a B7 RS4 is PLENTY capable of giving you a 5k bill without popping its engine

[BrittasBay]

Thanks Dr.G - that's eh, reassuring!!!!

by newer version, you mean B7 and up?

[Dr G]

The FSI/direct injection versions of the V8 don't appear to suffer chain issues.

B7 S4 = old 'normal' 4.2 344 PS, indirect injection, can suffer chain issues.
B7 RS4 = Newer FSI/direction injection 420PS, chains seem to behave.
B8 S5 = Newer FSI/direction injection 4.2 354PS, chains seem to behave.

There is a small amount of crossover in that I think the first 4.2 FSI went into the Q7 (2006) at which time the S4 was still using the older engine.

[anonymous-user]

Not forgetting the FSI/direct injection engines clog up the intake manifolds with crud and need regular cleaning or swallow the vanes that break off.

Every engine has its weakenesses but singling out the S4 engine is a little unfair as the long life servicing is part of the problem with the chain tensioners. I suspect on a per cylinder basis the cost is no worse than snapping a timing belt which wrecks plenty of different engines.

Dr G is right, the RS4 can throw a £5k bill so easily.

[anonymous-user]

Dr G. How about the RS5. 450 PS engine? Is that a ticking time bomb?

[Dr G]

Engines seem fine; early RS5 gearboxes (before the facelift) can be fragile though.

All B8 RS4/5 are maintenance heavy with routine/schedule items frequently missed or scrimped on. You probably want 2-3k annualy to keep one fighting fit.