Fitting an oil cooler on with an Apollo installed

[Red SLR]

I see.

 

OK, in which case I think I shall ignore the oil pressure from now on, infact I think that goes for all the guages.... I dunno pay 20K plus for a car and it cant even tell you how hot the water / oil is...... *puts on bullet proof vest*

 

Simon.

 

X777CAT

 

Edited by - simon scott on 15 Aug 2001 18:24:28

[Tony Martyr]

Maybe this thread is getting a little out of hand. But IMHO all of the correct information is in there. The problem is that some contributors expect absolute answers where none are possible.

The method by which you check your oil level should be the same each time, the exact technique is no very important since you are looking for level change (oil consumption) rather than any exact measurement of oil in the system. The Caterham ‘engine off and wait for 30 seconds’ is as good as the engine running method – the levels may differ but the results, concerning when you need to put more oil in, will be similar. The k series dip stick bends into the sump so that there is a significant difference one side to the other – mock it up yourself and you will see that this is not a precision instrument. It is a measurement of change of level in an experiment carried out over time with the same procedure.

Since about 10% of the fuel energy will be turned into heat that will be absorbed by the oil, the oil temperature will increase when the average power goes up. This heat is taken away largely by air flow over the engine, hence the finned sump, the more surface area in contact with oil and flowing air the more cooling effect is seen. The air flow is directly proportional to road speed, unless the fan (which is coolant temp switched)is running therefore oil in a k series running on a short bendy circuit with 13 inch wheels will get hotter than the same car on Silverstone GP circuit running on 14 inch wheels. An Apollo tank increases the cooling effect. Oil coolers can over-cool oil so that the internal losses of the engine remain higher than normal. It should be possible to block air flow in cold weather. Cooling tests are run on all modern cars for tropical conditions, although probably not Caterhams but only when the engine power is considerably raised or the engine overly shrouded is ancillary cooling needed.

The temperature registered by the gauge is the temperature measured at the position of the sender, which is not the hottest or coolest point in its journey around the engine. In most engine tests we set the first alarm level at 120 C and bring engines down in power at 130 C. Unfortunate cars don’t measure the delta t across the engine.

When modern oils get hot the long chain molecules bunch up to try and compensate for the temperature thinning effect. The viscosity (resistance to flow down an incline) is proportion to the pressure that will be registered on the engine gauge. The temperature / pressure relationship will depend on the oil used. If the oil became so thin that the system pressure dropped below that required to force oil between the crank bearing elements then you would have an engine failure – this is very rare. More often the oil consumption increases significantly as oil gets past the piston rings easily. Try a summer on Mobil 1 ‘0 to 40’ and compare usage temperatures and pressures with Mobil 1 15-50 – No! life is too short.

As Peter implied oil can be additionally heated by churning friction that occurs when there is too much oil in the engine and the crank shaft is partially submerged. I think this is less likely with a K series because of the construction but it is possible. It can also be additionally heated by friction increasing – the paranoia begins to rise. Best cure, if the engine is healthy is to blank out the gauge for a few sessions

 

[Mick Day]

I'm going to tack this on to this thread as it's kind of in the same vein: when starting my engine (recently fitted Apollo) it takes a while to build oil pressure. How do other people cope with this? Or has PC answered this one by having a non-return valve in the restrictor line?

Mick

 

PS: where can I get a non-return valve?

[Brad Tipp]

1st off thanks to everyone who has replied. I've learnt a lot that I didn't know before, which I think is the point of these postings.

 

2nd. I said I would let you know how I got on with the Oil Cooler fitting. Well I'm half installed !!

The cooler is fitted (10 minutes)

The aluminium shroud is fitted to flow air from the bottom of the rad to the oil cooler is done (20 minutes of ali bending)

The hole is cut in the bottom of the nose cone (30 minutes of very careful Dremelling )

The oil pipes are not connected - AHHH there different threads!!

 

So I'm waiting on Tweeks to send me some converters to go from 5/8 ths to 1/2 inch so I can reuse some of the pipes in situ.

 

 

Once they turn up tomorrow I'll fit and test and let you all know the outcome. If it's positive I'll post a how to somewhere (?) on what to do. In the mean time buy a Dremel as it's great fun and I've suddenly found loads of jobs that need a 33000 rpm mini drill :-)

 

 

 

 

T 1 PPB - Superlight

 

"Well yes officer i'm not arguing, it's just that [insert excuse here]..."

[Red SLR]

Brad

 

Can you tell me where you got your cooler from and did it have all the bits to make it compatable with the Anti-cav tank?

 

Ta

 

X777CAT

[Peter Carmichael]

I wrote this last year as a guide for Jo taking my car out with the new engine, but it has bits in it which are relevant to all. The figures for oil pressure are in psi and are read off the Stack dash. Your figures and gauge calibration may vary...

 

Oil Pressure Theory:

The most important thing for the engine staying in one piece is a constant delivery of oil at the CORRECT WORKING TEMPERATURE to the working bearing surfaces. This is what OIL PRESSURE is all about. OIL LEVEL is just a condition for guaranteeing that the OIL PRESSURE is OK. Without oil, the bearings seize in an instant turning the smoothly rotating/sliding engine internals irreversibly into a flailing metal mincing machine (bad). With regards to oil level:

 

 Too little means imminent disaster.

 Just enough, means that shortly there will be too little (engines consume oil).

 A good amount, means that you can run the engine and it will be happy until you next check the oil level.

 Too much means that the engine will expel oil into a catch tank and the level in the engine will settle to the maximum possible (this can get messy if the catch tank gets full).

 

When you start a cold engine, the cold oil is thicker and it is more reluctant to get squeezed through to the working surfaces in the engine. This shows up as higher oil pressure. The high pressure does not infer that the engine has a healthy supply of oil when the oil is cold and thick. This is why it is important to warm up an engine carefully before using high rpm and wide throttle openings. The oil temperature takes longer to come up than the water temperature. In general it takes fifteen minutes for the OIL TEMPERATURE to come up to temperature.

 

 

Normal oil pressure (OILP):

 

The oil pump is run at engine speed. When the engine spins at higher rpm, the oil pump pumps more oil. Rather than just generating more and more pressure if there is more oil being pumped than the engine needs, a pressure relief valve bleeds excess oil back to the low pressure side of the pump.

 

When the engine is turning slowly (idling), the oil needs of the engine are low and the pump is delivering a small amount of oil. This means that the warm, idling oil pressure is expected to be low (~53 psi).

 

When the engine is warm and at normal running speeds, the oil pressure is expected to be ~73 psi.

 

When the engine is cold and at normal running speeds, the oil pressure will be a bit higher than the warm pressure. Say, ~80 psi from cold start.

 

When the engine is cold and idling the oil pressure will be slightly lower than the running pressure. Say, ~74 psi.

 

When the engine is not running, there is no oil pressure.

 

 

Oil pressure summary:

 

 Cold start, idling: 74

 Cold oil running: 74-80

 Warm oil iding: 48-55

 Warm oil running: 73

 

If checking engine running health, this is the first and most important instrument figure to be looking at.

 

 

Oil temperature (OILT):

 

 Cold start - no reading below ~13 degC

 May take as long as fifteen minutes to reach 45 degC

 45 degC is the minimum before you should use more than 5000 rpm (unless 45 degC never turns up, in which case you use 500rpm more at a time until it shows up)

[Brad Tipp]

Peter,

Fantastically useful last post. I think lots of us amateurs will find it useful, and we should get if put somewhere more general on the site.

 

Simon,

I got the kit from Caterham, but not with the right bits :-(. I have just got the extra bits to make it work and once I finish fitting it tonight I'll do a post on which bits to get and where to get them from so you don't have to make the same mistakes.

 

 

T 1 PPB - Superlight

 

"Well yes officer i'm not arguing, it's just that [insert excuse here]..."

[John Vine]

Thanks, Peter, for a most informative post.

 

As you say, gauges and calibration vary, but my (bar) figures for a 1.8K SS seem to be a good deal lower than yours, and particularly the hot ones. I also have an Apollo tank fitted, which I'm told can drop pressure by 0.25bar (in my case, it also delays pressure build-up on starting).

 

Taking 1bar=14.7psi, these are my readings (your figs in brackets, rounded):

 

Cold start, idling: 4 (5.0)

Cold oil running: 4 (5.0)

Warm oil idling: 1 - 1.5 (3.25 - 3.75)

Warm oil running: 3.5, and maybe only 3 when trackday hot (5.0)

 

When I asked the Caterham factory for typical figures, they said:

 

Cold start, idling: 4

Cold oil running: 4.5

Warm oil idling: 1 - 1.5

Warm oil running: 4.0

 

They felt my figures were nothing to fret about, adding that the standard (non-hydraulic) gauge had a tolerance of +/-1bar!

 

JV

[Peter Carmichael]

Caterham's comment on their gauge is I think *accurate*. +/- 1 bar at full scale sounds about right, although I imagine it is fairly linear and repeatable if the instrument earthing on the car is good.

 

My pressures will all be higher because:

 

1. It was November and the ambient temps were pretty cool.

2. I am running Mobil 1 Motorsport 15W50 oil in a race-spec engine.

 

Worth noting that the need for extreme care in bringing the oil up to temperature is purely because I use the treacly Mobil 1. Engines that don't exceed 8000rpm will be better off with a thinner oil (0W40). In a Supersport, 15W50 *is the wrong oil*[!]

[Peter Carmichael]

The relevant Haynes manual lists oil pressures for the K-series hot and cold, idle and running. Having looked at it at the weekend, I believe it said the oil pressure relief valve starts opening at 4.1bar.

 

This means that from a hot idle (i.e. oilp significantly less than 4 bar), if you gently rev the engine watching the oil pressure gauge:

 

1. The gauge will indicate an initial rise in pressure in line with the revs

2. The pressure will level off as the pressure relief valve starts to open at 4.1bar. (typically at less than 3000rpm)

3. The pressure will (may) still rise slightly with more revs, but this is just because (like any closed loop control device) the pressure relief valve has a non-infinite *gain*.

 

This will give you an idea of where the true 4 bar marking is on your gauge. The oil pressure relief valve is a very simple device and IME problems are few. Problems tend to arise when an engine failure puts muck and corruption into the oil paths and a lazy rebuild doesn't clean it up. It is very unlikely that it won't open in the range 4-4.2 bar.

 

If you never see the pressure level off, that is when you know you have an oil pressure problem. Either: a) the pressures are so low (shagged bearings/shagged oil pump) that you never reach the 4.1 bar, or b) the pressure relief valve is stuck and so does not control the oil pressure at all. Very low idle pressures can be because the pressure relief valve doesn't close properly, but you are talking about a blockage that 2-3bar of pressure differential (spring pressure compared to oil pressure) is unable to close, so it is quite a fundamental failure.

 

Generally these engines don't have oil pressure problems and that's why we all like to use nice modern designs, eh?

[old captain slow]

For what it's worth, my 1600K SS + Apollo used to run at well over 100C 0n the track and 90C + when cruising at 80 - 90. Changed the oil, filter and foam baffle and magic oil now runs at around 80C cruising and about 95C on the track. Don't know if there is a connection, but it could be something to do with oil flow v blocked filters?

[Red SLR]

Ta Brad

 

Simon

 

X777CAT

[Tony Martyr]

Quote

In a Supersport, 15W50 *is the wrong oil*[!]

Unquote

Peter- I think you are being uncharactoristically dogmatic or perhaps the exclamation mark indicated provocation?

The choice between the two grades of Mobil 1 depends on your requirements. The crucial factor so far as Caterham owners is concerned is not shown in the viscosity figures and is film strength. Both Mobil 1s have very high film strength which prevents metal to metal contact under extreem conditions of heat and pressure. The huge advantage of 0W-40 is that it protects the engine during (cold) start up and for the 90 seconds in which some 80% of engine wear takes place. It is one of the best oils for the worst phase of the engine and oils life, that between first rotation and coming to temperature.

Some readers may be interested to know that Mobil 1 is synthasised from gas and looks like water before they add dyes to make it a nice golden colour that we can accept as oil.

OW-40 is the right oil for modern saloons on the school run. Caterhams on a track are giving it the ideal conditions were life is easy for it. At the other exteem the 15-50 will give better results at the high temp end in terms of boundary lubrication and consumption.

The choice for all Caterham owners between the two oils is a second order effect compared with warm up techneque and first 12 minutes of use. I am still amazed that owners will warm up a car by starting them from cold and letting them idle. This maximises the dilution of oil with condensate and really does damage.

Before anyone reminds me that in the US they remotely start their cars while having breakfast to get the temperature correct before getting in I would say that in the USA oil is changed every 3000 miles and untill very recently the engines have been designed quite differently from European ones.

After comparing the two grades I use 15-50 on a Supersport engine and can live with the marginal increase in churning losses for the extra protection and decrease in consumption at 120 deg C

 

[TorAtle]

Any reason why you guys don't use Castrol RS10-60?

[Blatman]

I am still amazed that owners will warm up a car by starting them from cold and letting them idle.

 

What would be the correct procedure for bringing the oil up to temperature in order to minimise the wear and tearquestion.gif And would the procedure be the same for an engine with/without hydraulic tappetsquestion.gif

[Peter Carmichael]

Tony,

 

Thanks for keeping me honest. My point was exactly the one you emphasise: with the 15W50 oil you need to take specific care warming it up, so for most owners it is more protective to use the 0W40 grade.

[V7 SLR]

Stop me if I'm wrong, but Tony's comment about not warming your engine up at idle seems obvious. If at idle your oil pressure is less than what Peter quoted as the operating pressure (4.1 bar) then you can only be doing you car damage. The pressure isn't high enough to force the oil into the spaces between bearing faces.

 

I've always started my car up and driven it. Seems wrong to most people but I simply ensure the revs are high enough to achieve operating oil pressure and no more. I lazily drive the car, not revving highly nor labouring the engine. It's just like a gentle running-in procedure.

[Peter Carmichael]

The pressure isn't really the issue at idle because there is less load on the bearings. The oil films are completely untroubled in the bearings. The load on the cam noses at idle is pretty high, but they are lubricated by splash, so again oil pressure is not the issue. If this were not the case, oil pumps would be designed to supply running pressure from idle. Engines idling do not need much oil pressure.

 

As far as I understand it, the problem is that the muck and corruption that comes out of the combustion process condenses in places that it doesn't when the engine is good and hot and the amount produced when idling and cold is large. This includes some pretty nasty acids. The oil isn't getting around as fast, so it takes longer for it to slosh over the condensate and pick up the muck in solution; the nasties have more opportunity to do damage. These nasties are the same things that make handling used engine oil a bad idea. Getting the engine warm fast is a good idea.

[V7 SLR]

Ahah, so it's flow that's required, rather than pressure..!?!?

[Tony Martyr]

You need pressure to have flow and heat to have easy flow and if you have too much heat you have flow out of the wrong places and low pressure. Pressure is the result of resistance to flow.

0w-40 oil is *best* at start up because it is thin and zips round the engine and up to the head to create a film on the cam lobes.

When the engine is cold and during the warm up there are all sorts of deferential expansions taking place with gives the oil a hard time, but the film strength of modern synthetics can take care of that. The problem at warm up is the condensates, the water and soluable acid products and the fuel residues. You need to boil of the water quickly. In test cells we have a common warm up sequence which typically takes the engine to 40% load within a minute of confirming that oil pressure is above trip level.

15-50 oil is *best* if you run frequently at elevated temperatures and are too mean to accept the greater oil consumption of the thinner stuff BUT you don't get as good protection at cold start - So Peter and I agree !

[Blatman]

Forgive my mechanical ignorance, but pestering you lot is cheaper than a new enginewink.gif

What is the "trip" level of an engine (all different I guess), and does Tony's suggestion of increasing heat rapidly mean that revving the engine shortly after start up to around 2.5-3k rpm (in neutral, not driving) would assist in warming up the various surfaces to rid them of these nastiesquestion.gif

I have two engines to worry about, both using Valvoline semi synth. A solid lifter NA Cosworth using 20w50, (my hillclimb car, so ALWAYS warmed) and a Vx 2l, using hydraulic tappets and 15w50. I'd really appreciate your views.

[Tony Martyr]

Blatman: Do NOT equate reving the engine with warming the engine. It is power that generates heat not revs. Revs plus torque is power. Work is heat and heat is work is first law of thermodymamics

[Blatman]

So if you can't warm it by letting it idle, and your posting suggests that revving it is also not the ideal way, how do you increase heat in order to boil away the condensatesquestion.gif Should I just start them up and drive them as per V7's posting, being careful not to over rev/labour the engine.question.gif

Answers in laymans terms please, 'cos I'm sure I'm not the only one here who's wonderingwink.gif

[Mike Bees]

Maybe you should change your moniker from 'Blatman' to 'Layman' - although on second thoughts I guess Blatgirl might not be too impressed.

 

I think that when Tony says "deferential" he probably means "differential", otherwise:

 

Cylinder head: "Ooh, I'm getting bit warm Mr Block, I think I'm going to need to expand a bit soon."

Block: "Good day to you Mr Head, and may I say you're looking fine & well-flowing this morning. I too feel the imminent inception of expansion tingling at my long bolts, but please after you."

Head: "No no, after you Mr Block..."

 

Etc.

 

wink.gif

 

Mike

[Blatman]

Mike

No "long bolts" in any of my proper car enginesteeth.giftongue.gif

I (almost, I thinkwink.gif) understand the expansion differential between head and block, (I'm not a complete fool!) but what I am after is the "best" way to warm up the car to minimise the wear caused by the initial start up sequence. Tony and Peter are alluring to a process without putting it in simple terms. Frustrating for us luddites! Unless of course, I am worrying about a set of circumstances about which I can do nothing at all. I would like the answer to be technically correct, but I'm also thinking about all the other blatchatters out there who would also like to know the *best* way to deal with the start up/warm up procedure, but who aren't Ba (eng) qualified!!!!!smile.gif