engine oil cooler question

[Toilet Duck]

Good morning knowledgeable fellows

I'm going to be upgrading the power in my atom and want to fit an oil cooler. I'm planning on using a mocal thermostatic sandwich plate and looking to stick the radiator in the space within the roll hoop where the OE air filter currently resides. As I'm going to switch to a less restrictive air intake set up, the OE air filter will be redundant and therefore free up all that space.

Is there an issue with this location? I'm conscious that this position is higher than the engine etc, I don't know if this will cause a problem e.g. would it make the oil pump work too hard, or will the oil run back into the sump when turned off leaving the oil radiator "empty" and cause an issue?

Also, can you have too big a cooler even if it's thermostatically controlled? I assume that the stat will open incrementally rather than just fully shut/fully open? If that's the case, surely it would open just enough to allow sufficient flow to cool the oil to the specified temp (circa 80 deg C I believe) and not open any more?

random google pic of atom to show roll hoop position relative to engine etc:



Cheers for any help

[GreenV8S]

I don't see any problem with what you're proposing. This design puts the oil cooler in series with the pump output so it will reduce oil pressure slightly but that is normal and inevitable. Note that you will be increasing the overall volume of the oil circuit and if you have very long hoses or a very large volume oil cooler you need to ensure the sump capacity is sufficient. The stat will keep the oil cooler circuit isolated during cold starts. During hot starts the engine would presumably have been run recently so oil galleries should all still be full and I don't see a bit of extra volume in the oil circuit being a problem.

Are you planning to upgrade the engine cooling system too?

[Toilet Duck]

GreenV8S said:

I don't see any problem with what you're proposing. This design puts the oil cooler in series with the pump output so it will reduce oil pressure slightly but that is normal and inevitable. Note that you will be increasing the overall volume of the oil circuit and if you have very long hoses or a very large volume oil cooler you need to ensure the sump capacity is sufficient. The stat will keep the oil cooler circuit isolated during cold starts. During hot starts the engine would presumably have been run recently so oil galleries should all still be full and I don't see a bit of extra volume in the oil circuit being a problem.

Are you planning to upgrade the engine cooling system too?

Thanks very much.

When you mention ensuring "the sump capacity is sufficient," in what way do you mean (sorry if it should be obvious!)? Will I need to overfill to get a higher than normal reading on the dipstick to account for the extra oil in the oil cooler and lines? As it is, I overfill by approx 5mm on the dipstick as this is what the factory recommend for track use (I also have a baffled sump). When the engine is cold (and after being "hot" from driving etc), I assume all the oil will have drained back down from the oil cooler (as its higher than the sump). However, when the engine is hot I assume the level in the sump will be lower than before I fit the oil cooler as some of the oil will now be "lost" in the oil cooler and lines.

Absolute fag packet calculations at this stage, I'm estimating around 0.8 litres of oil in the oil cooler and lines.

Do you know if OE Honda oil filters have a non return valve inside them? I'm guessing that may make a difference?

Regarding upgrading the engine cooling, I'm hoping that switching from a Jackson Racing supercharger (which generates a lot of heat) to a more efficient screw type charger will lessen the "heating up" of the engine, I'm also going for a chargecooler system using the largest core that will fit so again, I'm hoping this will reduce inlet temps significantly and therefore allow the engine to run cooler, even though it will be pushing more power. The Ariel factory offer a "hot country" option whereby another radiator is fitted in series. Worst case I could look to have another radiator fabricated and go down that route, but I'm awaiting to see where the chargecooler rad will be best located first, hopefully it won't need a second cooling rad.

Would an oil cooler take a significant loading off the water coolant circuit i.e. if I cool the oil down will that reduce some of the heat that the water needs to take away from the engine, thereby allowing it to run cooler?

The other thing which I've read conflicting things is regarding the OE water cooler on the Honda K20 block. Water flows around the oil filter housing which helps warm the oil up quicker, and also helps cool the oil when up to temp. However, if I fit an external air to air oil cooler, am I best bypassing the OE water cooler? Numerous places sell blanking plates to block of the pipes. Obvously you loose the benefit of warmeing the oil up "quicker", but if left in place won't the oil temp be "held" to the water temp due to the water/oil cooler?

Thanks again

[GreenV8S]

The oil level that matters most is when the engine is running i.e. with the oil circuit filled. However, when the engine is stopped the oil will gradually drain back into the sump; a cold check will normally show a higher level. By increasing the volume in the oil circuit you will be increasing this difference. You need to ensure the 'hot' level is not low enough to allow oil surge and the 'cold' level is not high enough to cover the crank or any oil seals. You mention 0.8L which is enough to pay attention to but unlikely to be a problem. If you did have problems in this area you could address them by orienting the oil to air radiator so it didn't drain back to the sump.

I don't know how effective the oil-to-water cooler is on that engine, but the oil and coolant are thermally quite well connected via the block and head in any case. The oil will usually be hotter though when the engine is working hard so an oil cooler is a very effective way to cool the engine - as long as it is thermostatically controlled so you don't prevent the oil getting up to temperature quickly. It is common to stack oil and water coolers so the same cooling air passes through both of them. If you do that, aim to put the lowest temperature items at the front of the stack i.e. charge cooler/air con, coolant, oil cooler. Just make sure the stack isn't too deep (keep all the layers thin and low restriction on the air side) to keep the air flow up.

I suggest that getting the charge cooler as cool as possible will be more important than coolant/oil cooling.

[Toilet Duck]

GreenV8S said:

The oil level that matters most is when the engine is running i.e. with the oil circuit filled. However, when the engine is stopped the oil will gradually drain back into the sump; a cold check will normally show a higher level. By increasing the volume in the oil circuit you will be increasing this difference. You need to ensure the 'hot' level is not low enough to allow oil surge and the 'cold' level is not high enough to cover the crank or any oil seals. You mention 0.8L which is enough to pay attention to but unlikely to be a problem. If you did have problems in this area you could address them by orienting the oil to air radiator so it didn't drain back to the sump.

I don't know how effective the oil-to-water cooler is on that engine, but the oil and coolant are thermally quite well connected via the block and head in any case. The oil will usually be hotter though when the engine is working hard so an oil cooler is a very effective way to cool the engine - as long as it is thermostatically controlled so you don't prevent the oil getting up to temperature quickly. It is common to stack oil and water coolers so the same cooling air passes through both of them. If you do that, aim to put the lowest temperature items at the front of the stack i.e. charge cooler/air con, coolant, oil cooler. Just make sure the stack isn't too deep (keep all the layers thin and low restriction on the air side) to keep the air flow up.

I suggest that getting the charge cooler as cool as possible will be more important than coolant/oil cooling.

That's great, many thanks. I haven't measured up exactly for a definite size oil rad, but will try and ensure the hose fittings are on the top to "trap" the oil in the rad and prevent it from flowing back to the sump on shut down of a hot engine.

Ideally, the chargecooler rad will go in front of the water rad at the front of the car, but space is tight so it may require some fettling/bodywork mods to get that to work, if it is indeed possible. No other rads (including aircon ) on the Atom to worry about. It may be easier (packaging wise) to put the oil cooler at the front of the car and the chargecooler rad in the roll hoop, but I'm not sure if a large enough chargecooler rad will fit there.

Thanks again, very much appreciated

[227bhp]

Make sure both the inlet and outlet are mounted at the top, that way it can't drain back.

[Toilet Duck]

Another question for the experts. What is the "optimum" size hose to use? Doesn't help that they are a mix of AN/BSP/JIC/M fittings listed which confuses me . The Mocal thermostatic sandwich take off plate that I'm planning on using has 1/2" BSP fittings, so I assume there is no point going bigger on the hoses as the flow will be limited by the smallest part of the circuit? Or is there a benefit of going bigger? Looking at the actual Mocal oil rads, you can spec what type/size fitting to have. Is there a "best" type/size to go for, or again is there no benefit of going larger than the fixed size 1/2" BSP fitting on the sandwich plate?

One other question, I want to add an oil temp guage but there isn't an OE oil temp sensor on the K20. Is there anything "wrong" with fitting two sandwich plates together, one thermostatic one to feed the oil cooler radiator, and one like this purely to enable (oil temp) sensor fitment? You can buy purpose built extension bolts so in theory I don't see why it wouldn't work, but I don't know is there is an issue with stacking two together?

Cheers

[GreenV8S]

Best to size them big enough to have an acceptable restriction (for the flow you expect) and no bigger. I don't see why you'd need to go bigger than 1/2".

I don't see any problem stacking sandwich plates, but couldn't you just drill and tap the remote takeoff plate you already have?

[Toilet Duck]

GreenV8S said:

Best to size them big enough to have an acceptable restriction (for the flow you expect) and no bigger. I don't see why you'd need to go bigger than 1/2".

I don't see any problem stacking sandwich plates, but couldn't you just drill and tap the remote takeoff plate you already have?

Cheers.

I just thought that the bigger the flow (within reason) the better, as I understand the stat will close off the flow if the oil temp drops too much. I'll stick with 1/2" BSP then. I haven't got any tap's but might get some as you can never have enough tools, and I'd like a go at doing that. Will read up on them, my car is getting the power upgrade over winter so i won't be doing anything until then, gives me plenty of time to do research etc and compile a shopping list of shiny bits