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

[The Gorilla]

Hi,

10-60 Syth oil is very good and
does do a tremendous job at many
temps.

The problem with say a Heavier oil
is that start up wear increases, and
a Lighter Oil may not protect so good
at the higher temps.

The 'finger'' design does not assist with
oil retention on start up, and like Lawsy
said there are other factors.

Its almost like if you could park the Car
at 20 deg so that oil was retained in the
head as opposed to it draining away.

Sort of almost too efficient design.

Motul do a 20-60 fully syth which a colleague
runs in his S54 engine, but its not a daily
driver, so not really a good guide, but
it does appear to leave a heavier 'film'
on the cam lobes than 10-60.

Regards,

The Gorilla.

[shimmy]

Do you mean 20deg sideways of front to back?

[Neil M]

This is a heavy thread and could get a lot heavier, when you start on the 'Liquid Engineering' aspects of an oils viscosity and performance under load/use.

As has been already said camshaft ware can be the result on many contributing factors, but in this instance I think we are considering premature ware which could be avoided, therefore the ability of the cams to maintain sufficient lubricant is paramount, particularly on start-up, whether it be a CSL or a Fiesta, 20-60 might well be the way to go - but who's going to tell the Boffins.

[The Gorilla]

Hi Shimmy,

Its side to side, ie]as you look
at a RHD Car the exhaust header side
is raised, so that the engine
is siting level across, rather than
canted down on the exhaust side.

Would just help the oil to ''pool''
as opposed drain away.

You then benefit from oil splash etc on start
up.

Start an S54 from cold and the Oil
feeds to the Cams etc are not instantaneous,
and even when the Oil light goes out the
oil feed to the cams is still not
fully pressurised.

As Neil M has stated, Oil Viscosity under
load and varying Temps is a strange
world.

Lot of people presume that if you
have got a really Good Oil Pressure then
your fine, which is not always correct.

Much better to have an average Oil Pressure
and really good flow, than a really high
oil pressure and lower flow.

I also think that the Paper elements in
the Oil Filtres add to the S54 problem in
that when they become ''polluted'' with
oil, they restrict flow which increases
oil pressure at the sensor point on
the S54 but means that less flow is
reaching its destinations [Cam/Shells etc].

This becomes critical at high load / high revs
in that oil pressure light will not flicker
as pressure at the sensor point is
good, but flow has been restricted
via the polluted filtre to
the point where the 'film' of oil that the
Cams and Bearings ride on is being
rotated out faster than its flowing in.

I think changing the Oil filtre more
frequently is better than frequent oil
changes.

On the S54 in the E30 M3 which is
Dry sumped, you can not run a
paper element filtre with a dry sump
system, so its a S/S 75 micron mesh filtre.

The oil pressure at say 4500
rpm is around 2.7-3.0 Bar but
oil flow, ie] the flow and return to the
oil tank is exteremley good.

Thus windage in the Crankcase aside,
lots of oil must be flowing into and
out of the bearings/ cams etc for the
scavanges on the pump to pump it.

The Oil pressure on the CSL at 4500 rpm
is around 4.0-4.5 bar but it runs paper
element type filtre on the std Semi Dry
sump set up.

The interesting thing though, is the oil
oversupply feed from the head back
to the sump, on the Dry Sump engine
always flows a lot more oil than the
std Car, which runs with a higher
oil pressure as measured at the
same pressure point.

This is what makes me believe that changing
the std Oil Filtre much more frequently may also
assist.

Regards,

The Gorilla.