Oil cooler install

[RockBit]

I used Permatex High Temp thread sealant on all my senders. It appears to be electrically conductive so it won't interfere with the ground connection. It is available at any auto parts store.

I also use Valvoline VR1 10W30 in my FE. Oil temp runs about 185° F and is consistent in all seasons. I don't have an oil cooler hooked up. The oil temp sender is in the top of the wide area of the pan. 20W50 seems a bit thick, but it is best to check with your engine builder.

[w-lewis]

What kind of oil pressure readings do you guys show at idle and when accelerating?

[RockBit]

At hot idle (800 rpm) my oil pressure is 22 to 25. At 3000 to 4000 rpm I see about 65 psi.

[w-lewis]

Thanks for that info Rockbit. I just changed my oil and oddly enough, when draining it, I only got about 7 qts out, whereas I ordinarily fill it with 9 plus the filter, totaling about 9 3/4 qts. Assuming the remaining oil was trapped in oil cooler and lines, I lifted front of car, hoping to drain more oil out, yet none appeared. I subsequently filled with only 8 qts, including filter. My car doesn't have a dipstick (not sure why builder chose that), but it does have a small one on top of side portion of Canton oil pan. That small dipstick show pan is full. All of that said, your oil pressure numbers are slightly less than what I believe I've had in the past. After my oil change, my oil pressure show around 60lbs at idle and 80-85lbs when revving motor. Does those numbers indicate I've put too much oil in crankcase?

[RockBit]

I don't believe overfilling your pan will increase the oil pressure. It doesn't sound like you have overfilled it. Do you know the capacity of your oil pan, or which oil pan you have?

The oil pressure numbers you are giving are close to what I get when the engine is cold. Was it warmed up when you saw these pressures?

[patrickt]

Originally Posted by RockBit

I don't believe overfilling your pan will increase the oil pressure.

It won't. Unless you are sucking the pan dry (and thereby sucking air) when you aren't overfilling it.

[w-lewis]

I believe oil pan capacity is 9qts. I only drove it around the block to check for leaks. Hopefully, as you suggest, pressure will be a bit lower when fully warmed up.

[cycleguy55]

Originally Posted by w-lewis

I believe oil pan capacity is 9qts. I only drove it around the block to check for leaks. Hopefully, as you suggest, pressure will be a bit lower when fully warmed up.

I'm not running a SBF, but my cold start oil pressure at fast idle (~1500 RPM) with 5W30 is 80 PSI. Hot oil pressure at idle (~750 RPM) is 30 PSI. 2500 RPM hot is about 40-45 PSI. Temperature makes a big difference.

[patrickt]

I know we're not talking FEs, but when my engine oil is close to 90 degrees Celsius my idle pressure, and I idle at around 700 RPM when the engine is hot, is around 15 psi. It comes up instantly as the revs increase. This is perfectly normal for my engine. What would be too low at idle for a big FE? How 'bout less than 8 PSI. And what was the Ford Service Bulletin solution for a flickering oil light at idle when the FEs were really hot? Just turn the idle up a bit and it will go out.

[Morris]

You guy's might want to review this document from Pegasus Racing

Choosing and Using Engine Oil Coolers
Choosing and Using Engine Oil Coolers
Choosing the right engine oil cooler for a given application can seem like an overwhelming task. Setrab Oil Coolers come in so many shapes and sizes, it's hard to know where to begin. Even their application chart gives you multiple different choices for most engines. A few general tips will help you to narrow down the available options and choose the best one for your specific installation.
Before We Begin

For the purposes of this article, we will focus on plate-type oil-to-air coolers, such as the Setrab Pro Line. Finned-tube coolers and oil-to-water heat exchangers operate just a little differently. Since we don't offer either of those types, we're going to take the liberty of ignoring them.

Also, in order to avoid apples-to-oranges comparisons, please remember that all assertions imply "all other variables being equal." AGREED, you can change another part of the equation to get the answer you want. Like a track test or dyno run, changing just one factor at a time makes the effect of that change much clearer.

Start with the Chart

Setrab USA has gone to the trouble of providing us with a very handy oil cooler application chart (PDF format) that gives us a starting point without having to do math. The chart covers engine oil coolers, transmission coolers, and even power steering and valve spring coolers. Note that the chart is arranged by part number, not by application. Browse the chart a bit and you'll see that most applications are listed under more than one cooler size.

Oil Flow Restriction and Cooling Performance: Rules of Thumb

Here are some broad, oversimplified, very general principles to keep in mind when choosing a cooler. Remember that all of these imply "all other variables being equal."

Oil coolers introduce a flow restriction. Our goal is to minimize this restriction.
There is a direct relationship between plate length and restriction.
Longer plates (rows) = more restriction.
Shorter plates (rows) = less restriction.
There is a direct relationship between plate length and cooling effect.
Longer plates (rows) = more cooling.
Shorter plates (rows) = less cooling.
There is an inverse relationship between the number of plates and restriction.
More plates (rows) = less restriction.
Fewer plates (rows) = more restriction.
There is a direct relationship between the number of plates and cooling effect.
More plates (rows) = more cooling.
Fewer plates (rows) = less cooling.
Two coolers with similar cooling area will have similar cooling performance.
In the list above, the only apparent conflict we have to wrestle with is in plate length. Longer plates cool better (good), but at the expense of flow (bad). Fortunately, the last point in the list above suggests a good workaround: We can choose a shorter cooler to regain some of the lost flow, and simply add more rows to regain some of the lost cooling. Even better, adding more rows simultaneously improves flow even further.

Let's take an example from the Setrab application chart and do just a little math. Say we have a high-performance engine putting out about 325 HP. The chart suggests at least three possibilities: Series 9 with 20 rows, Series 6 with 25 rows, or Series 1 with 50 rows. All three of these coolers have an effective cooling area right around 75 square inches, so their cooling performance is similar.

But the Series 9 will have the most flow restriction (longest rows x fewest rows), and the Series 1 will have the least restriction (shortest rows x most rows). As it turns out, the 25-row Series 6 will have about half the pressure drop of the 20-row Series 9, and the 50-row Series 1 will have roughly 1/10th the pressure drop of the Series 9!

Using real numbers, with a 10 GPM flow rate as an example (not uncommon for an engine running 6000 - 8000 RPM), the 20-row Series 9 will introduce a 5 psi pressure drop from inlet to outlet. (Note that a single 90 degree fitting in your oil line could cause more restriction than that.) The 25-row Series 6 will cause a 2.6 psi drop. The Series 1 will show less than a 1 psi pressure drop. The flow restriction from the Series 1 option may not even register on your oil pressure gauge.

Installation Factors

There are just two general rules when it comes to mounting the cooler. (Remember, "all other variables being equal.")

Oil coolers require airflow to take heat away. More airflow is better.
Cooling depends on the difference in temperature between the air and the oil. Cooler air cools better than warmer air.
The airflow equation is a little complicated. As airflow velocity increases, the additional benefit decreases (the graph begins to flatten around 40 mph). The important takeaway is that your oil cooler needs to be exposed to airflow. The largest oil cooler will be ineffective if it's sealed in the trunk or mounted flat up against the firewall. Air must be able to get into the cooler, and it must be able to get out of the cooler. This is what carries away the heat.

In many cars, this suggests mounting the cooler near the radiator. After all, Detroit / Stuttgart / Tokyo spent a lot of time and effort to locate the water radiator where it would get the best airflow. It seems like a no-brainer to follow their lead. But that leads to the second point above.

Air temperature has a direct effect on oil cooler efficiency. Hot air does not cool as well as cool air. This is why we turn on the AC when we're hot, and not the heater. Mounting the oil cooler behind the radiator can reduce the efficiency of the cooler by as much as half. A better solution would be to mount the cooler in front of the radiator. The trade-off is that the efficiency of the radiator will be affected by the air coming through the cooler, but the effect should be much smaller because the cooler is typically smaller than the radiator. An even better option would be to mount the cooler next to the radiator (assuming there is room) or below the radiator (if it can be protected from damage).

The air temperature difference also means that if we run two oil coolers, they should be plumbed in parallel, rather than in series. If you run two coolers in series, the oil in the second cooler would be cooler (closer to the air temperature) than the oil in the first cooler, making it much less efficient. Another bonus to plumbing in parallel is that it has the same effect as adding more rows to the cooler: Less flow restriction for an even happier oil system.

Much more information about mounting oil coolers for maximum air flow with minimum drag can be found in Chapter Nine of Tune To Win by Carroll Smith.

Final Tips

Always mount the cooler so that it is fully supported, but isolated from vibration and chassis flex.
Whenever possible, plumb the cooler into the low-pressure (scavenge or return-to-tank) part of the system.
If the cooler must be pressurized (as in a wet sump oiling system), locate the cooler after the filter.
Mount the cooler with the outlet fitting (or both fittings on a Pro Line cooler) at the top to avoid air pockets.
If your cooler is too efficient, tape or block off part of it to bring oil temperatures back up to the desired temperature.
Buy Setrab Oil Coolers:
Setrab Oil Coolers
Setrab Series 9 (Wide) Pro Line Coolers
Setrab Series 6 (Medium) Pro Line Coolers
Setrab Series 1 (Narrow) Pro Line Coolers
More Technical Information:
More Oiling Systems Technical Documents and How-To
pdf icon Setrab Oil Coolers Suggested Application Chart


High-Performance Plumbing Technical Documents and How-To

[Morris]

Originally Posted by patrickt

I know we're not talking FEs, but when my engine oil is close to 90 degrees Celsius my idle pressure, and I idle at around 700 RPM when the engine is hot, is around 15 psi. It comes up instantly as the revs increase. This is perfectly normal for my engine. What would be too low at idle for a big FE? How 'bout less than 8 PSI. And what was the Ford Service Bulletin solution for a flickering oil light at idle when the FEs were really hot? Just turn the idle up a bit and it will go out.

A quick note regarding the Oil Temp of 270* Degrees

Conventional oil turns to Coke at 270*degrees... but now with Synthetics oils they will go up past 450* Degrees....

At 270* the motor breather will start smoking and smell just like oil burning... many times this happens when the air is not going thru the cooler and the motor just gets to hot.... more things could go wrong... but usually if you just kool the motor down you are OK...

With the Synthetic oil .... the motor just gets hot and keeps running until you have a part failure. then you have to service the motor.

[patrickt]

Alright, that's about 132 degrees on my Smiths gauge. I think my Brad Penn is partially synthetic, for whatever good that is.

[trularin]

If I may; what are you going to do with the car?

Track with a lot of high RPMs and engine braking - yeah okay. Put in a temp gauge and see what you are hitting.

Street, Bob is correct, you really do not need it AND, if you are out and about on the street, you may actually add to the heat of the engine compartment.

Hope this helps.

Tru