Oil Cooler Mounting - 1.8 K Series VVC

[revilla]

My oil gets a little hotter than I would like it to when I drive it hard, especially on long fast dual carriageway runs when touring. It is filled to the correct level and still gets warm even when a bit low, so it's not just crank thrashing that I can avoid. Water temperatures are perfectly controlled, never really move from 80-85C under any conditions. It's been like this with two different engines now.

I only drive the car on the road; no track use whatsoever. I have a mechanical oil pressure gauge and the only time I ever see hints of surge is if I let the level get too low, so I don't want to go down the Apollo route, and I'd prefer an additional cooler rather than dumping the heat into the water with a Laminova or Modine.

I would therefore like to install a simple additional oil cooler. Installing a Mocal sandwich plate with integrated oil thermostat and piping to a cooler mounted up front looks very straightforward - my only question is around the best way to mount the cooler.

Wherever I mount it, I want it on rubber bobbins to isolate it from chassis vibrations. I've seen people mounting them off the steering rack bolts and from the the upper cruciform etc. but I would prefer to do it roughly the way Caterham do it, i.e. low down bolted to the radiator where the pipping would be short and simple and thereby piggybacking on the rubber mounts used for the radiator.

Something like this (without the aluminium winter blanking plate as I will be using an oil thermostat):

Caterham only appear to sell two similar brackets:

• Crossflow
• Duratec

​My guess is that the standard radiator used on the K Series is of similar width to at least one or other of these and I could drill holes in the side mounting flanges (as shown below) as required to position the brackets to my requirements.

http://caterhamparts.co.uk/img/p/43-5936-thickbox.jpg

Routing the pipes out of a sandwich plate underneath alternator belt straight forward to the cooler looks easy and on an SV chassis there is loads of clearance (photograph taken on a spare engine):

Questions:

• Did Caterham ever make these brackets in K Series form and if so, am I likely to be able to get hold of them (from Redline or ... has anyone got any spare please)?
• Has anyone done this on a K Series and if so, please could you send me pictures of the installation (as many and as detailed as possible please!)?
• Any thoughts on this way of mounting it or alternative suggestions?

Thanks,

Andrew

[John Vine]

Hi Andrew,

I can't answer your K-related questions, but I can confirm that the oil cooler on my R400D is mounted exactly as shown in your photo (the one with the blanking plate).  So, assuming your SV rad is the same width as an S3 R400D, I'd say that was the way to go.

JV

[revilla]

Thanks John. Redline confirmed that the cross flow brackets can be used on the K Series, but nobody has any stock. They couldn't say anything about the Duratec ones but from the pictures on the website they look like they are pretty much identical just with different hole spacing, and as I'm going to have to drill my own holes in the K Series radiator flange anyway it probably makes no difference. The Duratec ones are also in stock and half the price. I'm away for the next few days but I will get the bits ordered so I can have a go at it next weekend. I'll mock it up holding everything together by hand first and if the brackets aren't going to fit I should be able to return them and I'll just have to knock some mounts up myself.

[Dave J]

been there, if I were to do it again I wouldn't fit a cooler as its all heavy and even with a thermostat (which nearly always leak) you fewer circa 10% flow through the cooler which over cools the oil below about 20c ambient temps. 

I would fit a laminova and take the hit of half a bar drop in oil pressure that comes with it .

[revilla]

John, have you had any overcooling issues with yours? Looking at how the thermostat works I can see it just opens a bypass and doesn't shut off the flow to the cooler so I can see how overcooling might occur.

[John Vine]

Overcooling? Yes, especially as my sandwich plate (AFAIK) doesn't include any sort of thermostat.  Outside of summer, I blank off some of the cooler with Al foil, while keeping an eye on the oil temp.

I'm a great fan of the Laminova, too.  I had one (with Apollo) on my old SS-R, and it had the considerable bonus of warming up cold oil quickly.  I had no problems with cooling.

Are you sure you don't want to go the Apollo route?  If you do, the Laminova just plugs into the existing Apollo oil pipework.

JV 

[revilla]

First of all sorry that all of this long reply will end up as one long paragraph as I'm on my mobile. I'm really not convinced about an Apollo. I'm sure they work well for what they are designed to do, but my impressions from working on cars with them fitted is an engine bay full of fairly flimsy looking extra complexity and I don't like extra complexity that I don't need. I run my car on the road only. I don't just mean that I don't go on track very often, I'm a fairly rare kind of Caterham owner in that I've never been on a track in anything ever and don't have the urge to start now, so it is truly road only. And I'm running 15" wheels with road-oriented T1Rs that slide gracefully at levels of G well below what seems to trigger oil surge on track. I have only ever seen the slightest signs that it was picking up a bit of air once and that was recently after under-estimating the oil consumption while running in a new engine and letting it get rather lower than I should have done. Even then it was only the slightest flickering on a mechanical oil pressure gauge that responds very quickly. Under all normal conditions, oil surge is just something I don't suffer from. The only problem I have is that if I really cane it hard for an extended period on a very hot day, the oil temperature steadily creeps up to around 110C or even a little above. Water temperature is perfectly well controlled on my car, it sits at 80-85C whatever, under all driving conditions. Even sitting in a traffic jam in 30C ambient temperatures it never goes up above 85C. In summer or winter it is no different, never overheats or over cools. For this I am very grateful as I know a lot of people have real issues with the K cooling system. I heard from an ex-Rover engineer that internally they only considered that a car justified an oil cooler if it was going to 140C but I also know Dave Andrews says 110C is the maximum he would be happy with. So some would argue that I don't even have a problem; I would say I am borderline with a very small problem. So adding an Apollo seems like overkill just to get the benefit of a little bit of cooling effect. Adding a Laminova is one possibility and I get the befits of a quicker warm up too, but the sensible place to plumb it in on my setup would be in the top radiator hose and routing the oil hoses around the long primary exhaust system down to a sandwich plate would be a bit long and messy. But the main thing that concerns me about a Laminova is losing my exemplary water cooling behaviour. Dumping the excess heat from the oil straight into the water may just leave it getting hot in traffic which would not be a price I would like to pay. I may of course be completely wrong on that. The other disadvantage of a Laminova compared to the oil cooler setup I was considering is the cost. I reckon I can do the whole installation I had planned for around £130, which is cheap enough to make it worth trying and if it doesn't work out it won't be the end of the world. It is a completely "bolt on" solution which could be removed in a few minutes if I wasn't happy with it. My plan was to use a thermostatic sandwich plate and a very small cooler, maybe just a 7 row cooler. I think this should be enough given that I'm obviously only just exceeding the current ability of the engine to cool its oil, it would also minimse the extent to which I'm blanking the radiator and by using a small cooler it should provide more resistance to flow to encourage the oil to take the bypass route when the thermostat opens, minimising over cooling. At the moment I still think it's well worth a try. I will of course report back on results, good or bad, and I can always move to a Lamimova setup if I find I need to. But thanks for all your input, I do appreciate your comments.

[Bricol]

I run an apollo on a road only 1660K car, and it still gets hot oil on long, hot runs - 115/120 on high speed runs down France into Italy.  Never noticed it get that hot in the UK.  I have a mechanical temp gauge in the apollo tank, and run a 6 speed box into a 3.9 diff - so high speed is very high revs.

I have considered the laminova cooler - Rover, when they were still going, used one as an OEM cooler on various models - I've bought good used ones for 20 quid, and brand spanking new ones for 30 quid.  The same as the aftermarket laminovas, they can be dismantled for cleaning, and the standard end caps/connections fit.

Although I have to admit I've not yet got around to actually fitting one . . .

[John Vine]

Yes, from your description I'd agree you hardly need an Apollo. 

Given that you're going to need a sandwich plate and oil hoses whichever way you go, it would be worth trying to borrow and instal a Laminova on an experimental basis.  As a bonus, the Laminova won't require a separate thermostat.

(This discussion has prompted me to consider replacing my rad-mounted cooler for a Laminova.)

ETA: Bricol, can you point me to a source of £30 Laminovas?

JV

[revilla]

John ... Only one problem with your suggestion ... I've just this minute ordered the bits for the small thermostatic cooler! Will see how it goes. You may well be right and I may need to go to a Laminova in the end. Had to jump one way or another or I would have been dithering around for ages. This way seemed cheap and worth a try. Thanks for all the advice and suggestions as always.

[John Vine]

Good luck!   Looking forward to reading about your experiences.

Out of interest, which sandwich plate did you go for?

JV

[revilla]

Can't do a proper link from Android, but this one: http://www.mattlewisracing.co.uk/product.php/972/149 (Mocal OTSP1C 13/16UNF Oil Cooler Thermostat Sandwich Plate Rover K series Pre SD1 Rover V8)

[John Vine]

Thanks, Andrew.

Linky.

JV

[Stridey]

My car has an oil cooler added by previous owner, but I found the water always ran hot, which I put down to the water rad being partially blocked by the oil rad.

I fitted a bigger fan to compensate and this seemed to work well. Went from 9" to11".

What I'm trying to say is that fitting an extra rad, blocking the water rad may increase your running temp and lead you down a path of new issues.

[John Vine]

Thanks for the pointer to the Matt Lewis website -- very interesting.

Their Duratec sandwich plate with thermostat looks like this:

whereas my sandwich plate (photo from my build) looks like this:

That looks very like a standard, non-thermostatic, SP1.  The CC website suggests it's for the C400 racer:

So, it seems I have no thermostatic control over oil cooling, which does match what my my gauge tells me (and the need for blanking in the winter)!

JV

[revilla]

@Stridey - Yes I get what you are saying and this is one reason why I have gone for the smallest oil cooler, which I think will still be sufficient and which should minimise the effects of blanking, or passing hot air over, the radiator. But only time and experience will tell whether this will deliver what I'm looking for without unacceptable side effects or not. I will be looking at both oil and water temperatures closely over a range of conditions for a while to see what is what.

@John - Yes I would guess yours has no thermostat looking at those pictures.

[Bricol]

Ebay was my source - a quick look reveals they've gone up for second hand ones - item number 191948008985
 

 

[7 wonders of the world]

Providing the oil cooler is mounted very close to the radiator with the fins oriented the same way as the radiator it will cause minimum disruption to the air flow and should have little effect on the water temp.

Adding a larger fan again should not be required, if your relying on this to keep the water temp under control during normal driving then you may have other issues - under normal condition this should only be controlling the temp whilst stationary or in slow moving traffic, a 9" fan is more than man enough to handle this on any engine as power output required for these conditions will be the same irrespective of level of tune or engine capacity.

Larger fans on race cars are there to increase airflow during racing and running in close proximity to the car in front which naturally starves the radiator of a clean uninterrupted flow of cool air. 

Many Duratecs came with an OE fitment of a Modine oil to water heat exchange fitted under the filter, this can simply be plumbed into the heater circuit - however this has he same problem as a Laminova ie it tries to stabilise both oil and water to the same temp whereas in reality these two cooling circuits are designed to run at different temps.

Stats should be used in order to maintain the ideal operating temps of both oil and water, running without a stat of blanking radiators etc is crude and for variable road conditions ineffective - for track use where your running within a more constant operating window they can be an option, but will need to be monitored and corrected for changing ambient temps.

 

[John Vine]

it tries to stabilise both oil and water to the same temp whereas in reality these two cooling circuits are designed to run at different temps.

What would you consider to be the ideal temps?  I'd imagine coolant should be 80-85C, and oil at least 85 and preferably nearer 90C.

 

Stats should be used in order to maintain the ideal operating temps of both oil and water, running without a stat of blanking radiators etc is crude and for variable road conditions ineffective - for track use where your running within a more constant operating window they can be an option, but will need to be monitored and corrected for changing ambient temps.

So, if I've read that correctly, I should consider replacing my sandwich plate with a thermostatic one?  I do 5-6K miles a year, with maybe 2-3 trackdays.  I'm left wondering why CC should fit a non-thermostatic plate as standard on the R400.  Perhaps they expect most use to be track-oriented?

(ETA: Apologies for the slight hijack, Andrew!)

JV 

[John Vine]

Ebay was my source - a quick look reveals they've gone up for second hand ones - item number 191948008985

Thanks, Bricol.  Is that really a Laminova?  It doesn't look like one, although I guess it operates the same way?

JV

[7 wonders of the world]

On a Duratec water circa 82 degrees and oil circa 100-110 degrees.

NB - temperatures will be dependant on where you measure the liquid, most coolants are measured at the point where it leaves the engine en route to the radiator ie the hottest point.

Oils however are often measured in a variety of places (which results in a confusing aray of temps ) from midway down a DS tank, inlet feed by pressure sender or in the sump itself.

I would always look to measure a DS set up in the gallery in the sump ie the hottest point after its collected maximum heat from the engine.

I'd agree that the full flow kit CC offer is more track biased rather than touring.

Worth looking at the take off plates to as they are often quite crudely machined and benefit from a fettle with a dremel to remove sharp edges and increase radii on the corners, hoses, fittings and adaptors all need careful selection to in order to minimise pressure drops.

[John Vine]

Very helpful -- thanks.

JV

[revilla]

Interim update - I've fitted the oil and cooler and run it at idle but still waiting for the rain to stop before taking it out on the road!

The Duratec oil cooler mounts from Caterham were fine for the K Series. I drilled two holes in each of the side flanges for M8 x 35mm mounting bolts and had to put 12mm stand off spacers to move them forward a little to allow the curved arms of the mounts to fit around the square sides of the radiator, but this still left the cooler sitting very close to the front face of the radiator as desired. It feels very firmly mounted and being bolted to the existing radiator is isolated from vibrations by the existing radiator rubber bobbins.

The thermostat in the sandwich plate doesn't actually shut off flow to the cooler when below temperature, simply opens a bypass. There is clearly still some flow view the cooler as it starts to warm up well before the oil reaches 80C but not a lot and the oil warmup time at idle seemed about normal. It was noticeable however that the oil temperature was running a little cooler than before when left idling for a long period; not so much noticeable on the temperature gauge but the oil pressure settled at about 29psi instead of 20-21psi before.

Water temperature behavour when idling isn't affected, the fan cycles exactly as before and the temperatures are stable and behave exactly as always.

Revving to 4000rpm, oil pressure is maybe 4psi down on where it was without the oil cooler, around 56psi rather than 60psi. This seems to be in line with the expected pressure drop through the cooler.

I will report back again when I've had it out on the road!

[7 wonders of the world]

Ideally to maximise air flow you need to ensure your radiator tubes align with the cooler and are not at 90 degrees to one another depends which radaitor your running top to bottom or triple pass which runs horizontally.

The oil stat will always bleed some oil in order to keep the cooler primed otherwise you would suffer a sudden pressue loss as it opened - since the cooler would be partially empty, as in your install its running in the pressure hose as opposed to the scavenge hose in a DS system.

[revilla]

Just got back from a test drive.

So far, so good. In fact better than I even hoped for.

Under all "normal" driving conditions, including sitting stationary in traffic, blasting down a dual carriageway and country lanes, oil and water just sit absolutely pegged at 80°C on the gauge.

I then tried to get it hot. Really caned it for mile after mile. Previously oil would have been well over 110°C and possibly heading towards 120°C, and the water temperature would have been up by quite a bit. I really struggled to get the oil close to 90°C indicated this time, nothing would make it get any hotter, and you only had to back off for a few seconds to see it heading back down to 80°C again. OK, so it's not the hottest day of the year today and it may go a little higher on other days but I know from experience that it would have got a lot hotter previously under the same conditions. Water remained pegged at 80°C, so actually just a little cooler than it would have been before. I guess the engine was dumping heat out through the oil cooler which would have been going out through the coolant.

So then I tried the opposite. Constant 60mph, top gear, very light throttle, loads of cool fresh air flow and very little power just to see if I could provoke any overcooling. Maintained this for about 25 miles. The oil did drop off a bit, but only very slightly to maybe 76°C indicated, then it just settled. Water again just sat at 80°C. And again as soon as I started to drive normally again the oil went straight back to 80°C.

The only thing I would add is that I have reason to believe from comparison with other things (ECU temperature reading, fan switch operation, IR thermometers etc.) that my gauge under-reads by about 5°C, so in reality all of the above MAY be about 5°C higher.

I'm pretty happy with that!

@7Wonders - Thanks for that. The way I have installed it, the fins of the oil cooler and radiator are perpendicular to each other but it seems to be getting adequate airflow given the above. I appreciate that this may not be ideal but it was so much more straightforward to use the Caterham (Duratec) brackets and drill the side flanges to mount it this way. I will bear your comments in mind though if I do start to see any problems on really hot days.