Another 6 external oil cooler thread, Yes I have been reading build threads Options

[nditiz1]

Ok so the temps in the 6 are not what I'd like them to be. Could it be tuning maybe, but the 2.4 is running pretty good and the WB says I'm on the rich side.

I purchased a Mocal t stat. I had already purchased a stock 911 one, but it's bulky so I think I'll sell it.

Why do some run the lines up the passenger and some up the driver? Is it because the cooler up front only goes one-way? Just preference?

Where is the best mounting spot? Pics would be helpful. Andy put his inside the chassis. I'm looking for a more general mounting spot. Can it be installed up in the frunk as I have seen on others? What's the drawback there?

Thanks and sorry in advance for the millionth ask. I might do something similar to tomeric, but was just curious about these other things first.

[SirAndy]

Just a general observation, but a 2.4L (unless it's a track car and driven hard) should not require an external oil cooler.

Around here (SF Bay Area) we have several 3.2L conversions that run just fine with only the engine mounted cooler.

My 3.6L (which does *not* have a cooler on the engine) runs too cold with my current setup. It never gets over 180 (which is where the thermostat is set at) unless i take it to the track or i get stuck in slow traffic in Salt Lake City in the middle of the summer (no fans on the cooler).

(IMG:style_emoticons/default/popcorn[1].gif)

[jd74914]

Not what you asked, but definitely double and triple check your timing too. In many cases that’ll heat up an engine more that AFR. If it’s retarded (usually where you’ll see temperatures start to rise) you’ll also see false rich measurements from the oxygen sensor.

[mb911]

One other thing to think about and I have personally experienced it is the firewall pad. If it is still In place and depending on where the engine mount is installed can really reduce airflow. The one I experienced changed Temps by over 40 degrees just by removing it.

[IronHillRestorations]

Perry’s rear fender oil cooler install

[nditiz1]

So I was thinking about this while reading up on adding a cooler. I have read both sides where some needed a cooler and some did not for the same size 2.4. I don't believe this engine was getting hot when removed from its last place in a 911. I know the 914 can make any engine run hotter due to less air flow. I will check the timing again, but I was around 5 degrees last I checked.

Things to note.

VR1 20W-50 oil
I have no firewall pad.
I have a GT style engine lid
I DO NOT have the air diffuser flaps installed, could install and see
All engine seals are new and in place
Temps do not get super high ~210 - 220, BUT this is with driving at night with cool 70 degree air or early morning 70 degree air. The SC engine I have might get to 180 in the same conditions.
12 AN fittings/hose for all oil flows.

As temps go up my oil pressure suffers a little. At warm I'm around 3 bar at 3k, but when the oil reaches 210 I'm closer to 2 bar at 3k. So while that is still 10 psi per 1k it is definitely not what I want to see. This is what lead me down the path of wanting an additional cooler. Maybe with lower temps the pressure would stay higher.

[ClayPerrine]

Just a general observation, but a 2.4L (unless it's a track car and driven hard) should not require an external oil cooler.

Andy.. I am going to disagree with you on this one as your experience is specific to your location. Here in Texas, an external cooler is definitely needed for a 2.4L engine. I ran 240 to 260 with the 2.4 in mid summer before I put an external cooler on the 2.4. I mounted a 911 Carrera cooler in front of the muffler in the right rear corner, and put a fan on it. After that, the temps ran at 200-210 all the time. And I never ran a thermostat. It just didn't get cold enough for one.

With the 4.0L engine. I have TWO 964/993 oil coolers, mounted in the rear corners with fans on both of them. I run oil temps around 210 to 220 all the time. Even in the winter, the fans come on when I am driving to work. This one has a thermostat on it because I popped 2 coolers with overpressure on cold mornings. But that is the 964 oil pump puts out way more pressure than the pump in a 2.4 when cold.

Around here, you need an external oil cooler even for a 4 cylinder 2056 engine. Our factory six with the dead stock 2.0L engine runs a little too hot for my liking in mid summer, and I have debated on an external oil cooler for it.

Clay

[Superhawk996]

Just can't figure out for the life of me why there is this constant quest to try to keep oil at 180 F. 180 F isn't even a good temperature to run the oil -- at (too cool).

Do you realize that if you're driving a modern ICE engine (particularly one with turbos and direct injection) that you're not running 180 F oil? If its not desirable and/or possible to be done with a modern water pumper, I'd love to hear the logic behind how/why it is to be done on an air cooled engine.

Just sayin' (IMG:style_emoticons/default/stirthepot.gif)

Likewise, with respect to oil pressure, if you don't like the 10 psi / 1000 rpm's baseline, what are you wanting to see?

[mlindner]

I would install the air diffuser and how are you checking temp, gauge, infrared thermometer on lower case/oil filter.

[nditiz1]

Just can't figure out for the life of me why there is this constant quest to try to keep oil at 180 F. 180 F isn't even a good temperature to run the oil -- at (too cool).

Do you realize that if you're driving a modern ICE engine (particularly one with turbos and direct injection) that you're not running 180 F oil? If its not desirable and/or possible to be done with a modern water pumper, I'd love to hear the logic behind how/why it is to be done on an air cooled engine.

Just sayin' (IMG:style_emoticons/default/stirthepot.gif)

Likewise, with respect to oil pressure, if you don't like the 10 psi / 1000 rpm's baseline, what are you wanting to see?

Great points Phil. I think some of the stress I'm feeling is because this engine is new to me and I just got the car back on the road. With the SC engine which was also new to me. I have had a few years in some hot temps and I think it once got up to 230. After I installed SSI it has never gone up there since. It is rock solid drive all day in 90 plus weather.

With this engine I would imagine a simple drive to be somewhere around the same. I did not like seeing the temps creep up as I drove it more. The temp gauge was heading towards the 120C mark from the 100C. While that is still not super stressful, highway driving cruising at 80mph was causing the temps to go up. I want to see temps go up sitting in traffic on a 95 degree day not blasting down the highway with cool air 70f. This makes me think as the engine got hotter is was not able to shed the heat. My fear is that it would keep going up. With that pressure going down. I think there was a time at 4k that I was under 3 bar so it is borderline with the rule of thumb 10:1000. I would like pressures to be 1bar:1k when hot, temp>210f

To mlinder- I will check with the gun on the filter and the bottom case. I was using a stock 911 gauge. I swapped out the entire gauge for another and they were still reading the same both the druck and temp. I guess the senders could be inaccurate.

[mskala]

A few years back I did some experiments under 'relatively controlled' conditions to
work out what affects temperature on my 2.3L 'E' without external cooler.

It sounds like you already have most of the best stuff, like GT lid and good engine bay
sealing. I assume you have underbody flaps installed?

You can also go to a later fan/pulley which will increase air flow ~30%. I eventually
reversed that, but I couldn't really compare the fans directly due to time involved.

[Superhawk996]

I'm going to tell you a long story as quickly as I can.

Early in my career I was responsible for customer attributes. One that was created:

Gauges shall display at mid scale at normal operating temperatures (old attribute - pre dated me)
Gauges shall be linear (I added this thinking I was being smart)

Electrical / instrumentation argued with me that I shouldn't add the 2nd attribute. Being youthful and a racer, I was tired of seeing gauges with a large dead band that made them largely idiot lights. I fought for the attribute and they begrudgingly agreed but with a warning of "don't say we didn't warn you -- you own this".

Shortly after launch we started getting significant warranty for engine overheating. Why?

Turns out that customers were seeing the thermostat opening and closing. When the thermostat would close, the gauge would creep up (subtle . . . but easily noticeable). When the thermostat would open the gauge would drop back down.

Turns out I was wrong (not the first time - not the last). . . . most customers can't handle a linear gauge without freaking out and visiting the dealer. After the first model year, a dead band was added and I revised the specification to remove the linearity.

Now take a look at these gauge calibrations and you tell me where you think Porsche engineers DESIGNED the engine to run and whether the calibrations are linear. Now also ask why early 911's had numbers but later 911's (and 914's) didn't have numbers.

[Superhawk996]

I would like pressures to be 1bar:1k when hot, temp>210f

Oil pressures are affected by several things but trying to use oil temperature to control them is counter productive

911 / 914 engines are sort of an odd animal because they are air cooled first and foremost. This has a lot of downstream consequences for things like oil temperatures and oil pressure.

First things first:

Do you know anything about the bearings and/or clearances of your 2.4L engine?

If Ollie's is to be believed, they (and other 911 engine builders) seem to want to run early mag case engines on the loose side. I believe this is for two reasons:

1) a loose engine makes more HP.
2) a loose engine is less likely to spin a bearing early in it's life (when the builder and/or machinist is on the hook!)

I went though this with my own 2.4L build and trying to get bearing clearance at .0025". Several sources seemed to be pretty happy with .0035" or even .0004" which is where I started with a fresh line bore (in spec but toward high side), aftermarket bearings, and a standard crank that was in spec (but at small end). I ended up spending another $2k+ to get the crank reground and to go to Porsche OEM bearings to get the clearance where I wanted them. How many folks would have just accepted that and put it together at .0035 - 0.004" to avoid the extra costs? The effect on oil pressure would be predictable.

Do you know what oil pump is in it? Early magnesium pumps have more internal pump bypass loss than later 4 rib aluminum pumps?

Do you know if the oil pressure bypass modifications were done and/or are you now using the right oil pressure relief springs / pistons that would be required with the oil bypass modification?

See where this is going. None of these things that affect oil pressure are dependent on temperature.

Second:

911 / 914 engines are an an magnesium (2.4L 911) or aluminum case (914 / later 930 & 3.x 911's) supporting a steel crank shaft. There are vastly different thermal expansions between those materials.

The bottom line being that unlike a cast iron block supporting a steel crank, you'll lose oil pressure faster as temps increase. Bearing clearance is opening up as things warm. All this is accounted for by design but expecting pressure to not drop a little as things get warm is not a realistic expectation.

So if you're getting 3 bar at 4k (or even 35 psi) when things are hot, I wouldn't be freaked out. If you have 3 bar at 6K, I'm slightly more concerned.

1 bar = 14.5 psi. So you're targeting a 45% increase in pressure over the standard rule of thumb? What if anything did you do to the pump and/or bearing clearances to have this expectation? That puts you at 87 psi at 6,000 rpm. Do you know what pressure your oil pressure relief valves are set at?

For reference, my Miata (cast iron block / steel crank) spun 7200 RPM at about 60 psi and went 228k miles without a rebuild - finally the body rotted out before the engine gave out. Food for thought.

[mb911]

I'm going to tell you a long story as quickly as I can.

Early in my career I was responsible for customer attributes. One that was created:

Gauges shall display at mid scale at normal operating temperatures (old attribute - pre dated me)
Gauges shall be linear (I added this thinking I was being smart)

Electrical / instrumentation argued with me that I shouldn't add the 2nd attribute. Being youthful and a racer, I was tired of seeing gauges with a large dead band that made them largely idiot lights. I fought for the attribute and they begrudgingly agreed but with a warning of "don't say we didn't warn you -- you own this".

Shortly after launch we started getting significant warranty for engine overheating. Why?

Turns out that customers were seeing the thermostat opening and closing. When the thermostat would close, the gauge would creep up (subtle . . . but easily noticeable). When the thermostat would open the gauge would drop back down.

Turns out I was wrong (not the first time - not the last). . . . most customers can't handle a linear gauge without freaking out and visiting the dealer. After the first model year, a dead band was added and I revised the specification to remove the linearity.

Now take a look at these gauge calibrations and you tell me where you think Porsche engineers DESIGNED the engine to run and whether the calibrations are linear. Now also ask why early 911's had numbers but later 911's (and 914's) didn't have numbers.

100% Agree. I went back and fourth with @Jwinner on this on his car. I disagree that 180 is the right temp as you mentioned. I run a pretty hot 2.4 engine (hot meaning not stock) and do not run and engine cooler just 1 in the front. I did this as a way to try out some of my new designs and products. it works very well for me and would support a much larger engine. Now if doing another build I would probably just do what Perry did if at all for this engine.

Specifically Nick. My suggestion would be to add a small cooler either in the right side wheel well like Perry did or just a small one by the transmission. That will be sufficient for your needs.

I think with the mag cases everyone gets real nervous about head studs pulling.

[nditiz1]

Ok so it sounds like the lower flaps could help in cooling. Let me take it for a hard drive and once up to full operating temp 210 I'll open it up to 6k and see where my pressure is at. I have a feeling it will be around 4bar which is fine. The question is then will the temp continue to rise? At what point do I need to shut her down to not cause damage to the engine? 250 260?

As far as the blue print of the engine it is a complete unknown except for the leak down numbers being almost 0 across all 6 cylinders. So I know that it is healthy. It also looks as though it was rebuilt at some time as the cooling tin is shiny plated. Another unknown is this engine could have possibly been suped up with different cams or even displacement bumped up to 2.5 per the PO.

[Superhawk996]

. . . cooling tin is shiny plated.

That really isn't helping things. Radiating heat back at parts.

Might look cool but I'd rather have black. Not suggesting this solves anything but plated tin isn't ideal.

[Superhawk996]

The question is then will the temp continue to rise? At what point do I need to shut her down to not cause damage to the engine? 250 260?

Things will eventually come to an equilibrium.

People gonna hate on me . . . but . . . . 240-250 is certainly not out of reason.

Personally, as you work your way through this I'd be more concerned with rate of increase. 240 and steady . . . no concern. 240 and still rising rapidly . . . then I'd back off to light load but high rpm to keep air flowing and cool things down.

[nditiz1]

. . . cooling tin is shiny plated.

That really isn't helping things. Radiating heat back at parts.

Might look cool but I'd rather have black. Not suggesting this solves anything but that isn't ideal.

Agreed, not chrome, but from my days wrenching on beetles "chrome won't get you home, keep it black"

[SirAndy]

Temps do not get super high ~210 - 220, BUT this is with driving at night with cool 70 degree air or early morning 70 degree air.

My last post here. If you are seeing 220 at 70 ambient without driving the car hard something isn't right.

An external cooler with good air flow will make your oil temps drop but it won't fix whatever is causing this in the first place.
(IMG:style_emoticons/default/popcorn[1].gif)

[nditiz1]

The question is then will the temp continue to rise? At what point do I need to shut her down to not cause damage to the engine? 250 260?

Things will eventually come to an equilibrium.

People gonna hate on me . . . but . . . . 240-250 is certainly not out of reason.

Personally, as you work your way through this I'd be more concerned with rate of increase. 240 and steady . . . no concern. 240 and still rising rapidly . . . then I'd back off to light load but high rpm to keep air flowing and cool things down.

With this in mind I will track how fast it goes up. I would say it did not increase quickly. I think it increased faster on the highway vs back roads which makes sense. It also went back down once I was off the highway, back to 210. 45 minutes drive