Camshaft Wear

[The Gorilla]

Hi,

The Cam wear I believe is an inherent design
fault related to the way the S54 Head retains,
or in this case does not,
Oil in and around the Cam Bridges and
Cam Journals.

Most Cam Wear is caused by the lack of
Oil retained in the Cam Bridges and Journals
upon engine first start up after standing for
a period just like Crank bearings etc.

The damage is done in the first few seconds
from cold start.

I do not think the S54 suffers from any form
of oil feed or pressure issue to the camshafts
as I believe the issue is caused by lack of
oil retention, when the engine is switched
off and cools down.

Go drive a S54 really hard, get it nice and hot
then let it idle for about a minute or so to
disspearse heat sink and switch off.

Leave for a few hours to stand and cool down,
then take the oil filler cap off and look inside the
cam cover.

See how dry the Inlet Cam is around its Journals
and around the Cam bridges etc.
You would expect to see far more oil retained.

When changing out some S54 Cams a while back
it was surprising how little oil there was in
and around the the Inlet cam bridges and what
little oil was left in the Journals when the Cams
were removed.

10-60 synth oil does give a good coating to the
Cam lobes, Journals and bridges, but the lack of
oil retention is not what I would expect to
see on a high performance head.

The Cosworth 16v heads or the BMW S14 Heads retain
quite a lot of oil in and around the cam bridges and
journals, even if the engine has stood for a while.

If you run your finger over a Cam lobe there is
oil deposited on your finger, not so on the S54
Cams in the same circumstances.

Merc 16v and bmw S14 both Twin Cam heads with slant towards
the Exhaust cam meaning the Inlet Cam, sits higher.

So same design as the S54, Merc is shim under
with buckets but for the sake of this discussion
does not make any difference.

I run the Merc 16v engine of 15-50 syth oil and the
cams and cam bridges etc are always well covered
in oil when cold, no matter how hard and hot the engine
has got previously.

I do not believe this issue is mileage related but more
to do with the amount of times the engine is stop / started
from where a running engine has cooled down and is
then started.

Just my thoughts.

Regards,

The Gorilla.

[cantfind1]

Interesting......so are you suggesting a change in oil grade perhaps?

[shimmy]

is it worse if the car stands for long periods before startiig like weeks and could you add a cup full before start up?

[shane@mbtech]

Originally Posted by cantfind1

Interesting......so are you suggesting a change in oil grade perhaps?

Originally Posted by shimmy

is it worse if the car stands for long periods before startiig like weeks and could you add a cup full before start up?

Neither will help.

Gorilla is correct, but that is just one side to it. That will NOT be the only cause of cam wear.

Incorrect shimming,
lack of shimming,
sticking to the long oil change intervals even though the car is hammered on a regular basis on track.
Det can cause cam wear too.
Running in period not adhered to
Running in rev limits not adhered to
Poor metallurgy
Blocked exhaust,
Caviatation of oil under high rpm high G cornering.

These can all have an effect too

[dave wilkinson]

sticking to the long oil change intervals even though the car is hammered on a regular basis on track.

^^^^

personally i think this is one of the biggest factors. since owning mine its had two additional oil changes between each bmw stated service. and tbo i don't think thats over kill. bmw charge just over the £130 mark for oil and filter only. small price to pay for peace of mind. i am anal with mine tho, as in the trade and have a lot of mechanical sympathy

[shimmy]

My car has done 92k and the cams have shown no sign of wear at all.......but having a complete new engine at 75k miles probably helped