Cooling a 2.7l Type 4 easier/harder/same as a 2.7L flat six? Options

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Only a slightly theoretical question at this point – is there anything inherently different, or different in practice, between the oil cooling set up needed to keep a 2.7 L flat six cool versus the same displacement 2.7 L big Type 4?

It would seem like the flat six would have smaller displacement per cylinder and that might have less heat and more cooling fin surface area?

Kind of an interesting topic I think / hope.

Happy Friday.

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@superhawk996 - Great discussion, thank you.

I know the answer is it depends, but staying in the realm of theory can you cool the oil enough to offset the heat from the less than optimal cooling that goes along with the bigger cylinders?

In other words if the oil cooling set up was highly efficient/capable and you kept temps in the 180-190 range does can that offset the heat soak from the larger piston combustion area.

I do have aluminum fins on the iron bores - good memory!

[Superhawk996]

@superhawk996 - Great discussion, thank you.

I know the answer is it depends, but staying in the realm of theory can you cool the oil enough to offset the heat from the less than optimal cooling that goes along with the bigger cylinders?

In other words if the oil cooling set up was highly efficient/capable and you kept temps in the 180-190 range does can that offset the heat soak from the larger piston combustion area.

I do have aluminum fins on the iron bores - good memory!

@Tdskip

I know lots will disagree but I fundamentally disagree that oil temp in the 180-190 range is desirable. That is too cool. Oil itself has no issue with being 240F-250F especially on an air cooled/oil cooled engine. Just look at how the gauges are calibrated. Red Zone doesn't even begin unitl 300F using the 200C taco plate and 250/260 using the 120C or 150C tempsensor.

The iron bore is a bigger limitation on heat rejection. This is where Nickies have a big advantage. Very thin wear surface and the rest is aluminum for greater heat rejection.

The bottom line is the six is going to run cooler cylinder (and oil temps) and have better durability since you're getting more relative cooling from the H6 aluminum cylinders. As previously stated. Same for the H6 heads.

However, with a larger volume oil pump and enough oil cooler upfront and getting cool airflow, a 2.7L T4 would survive for a while. The bottom line is that a T4 that big (2.7L!!!) is going to be challenged for longevity. That is a 35% displacment bump.

If your shooting for a 180F oil target, my gut says you can't get there but I haven't done the modeling or math to prove that.

If you allow for an oil temp target of 240F and just plan on chaging the oil every 3-4K miles, my gut suspects you could get there with enough oil cooler and this monster T4.

I think if you look at Jakes 2316 engine as a baseline, he even states that engine wasn't intended to have as good of a lifespan as his 2270. You are way beyond either of those known data points that have some dyno durability behind them.

As I think about how to do the math or modelling, it would 1st need to start with a baseline known oil flow rate, oil temp in and out of a baseline cooler, known cooler area, and known airflow temp and airflow rate. That's quite a bit of data acquistion. Not impossible but it would become a project on it's own. From that known data, you could do the math to see what needs to be changed to hit a oil temperature target on the outlet of the cooler.

To get back to your OP question. I think you're going to need more oil cooling on a T4 2.7L engine than you would need on the H6 2.7L engine. You could determine the baseline oil cooling area (inclusive of case area) of the H6 2.7L and then upsize T4 by some % as a start point. Purely a speculative guestimate.