Yesterday at Buttonwillow for our DE, the temperature was not all that hot, but I could only get in 2 laps at race speed before my CHT gauge started hollering at me. Here are the maximum values from yesterday:
Cyl #1 384 degrees
Cyl #2 357 degrees
Cyl #3 433 degrees
Cyl #4 402 degrees

I have the alarm set at 400 degrees, so each time it reached that temp, I backed off and let it cool down and finished each session with just a Sunday drive. Here's what I have:
My engine is a 2270 built by Original Customs
2 40 DLRAs:
150 main jets
180 air correction jets
34 venturis
9164.2 emulsion tubes
75 idle jets
50 pump jets

Both carbs are accurately sync'd and the a/f gauge shows between 13 - 14 all through the progression to WOT
The timing is set to about 30 degrees

I am running a stock cooling system with the thermostat and flaps working properly. I pulled engine tin to look for obstructions. None.

I am running a Sebtrab 8 x 10 oil cooler but my temps are over 220 when pushing it hard. No fans.

I am not sure where to go from here: alternate cooling, larger oil cooler, fans? Any suggestions would be appreciated.

13 to 14 is way too lean.
Especially the 14 number

Ignore how rich it gets below redline and shot for around 13.1 maximum lean at redline. Ignore the 11's and 12's you see on the way to 13.1

OK, I will shoot for 13.1. Any idea why 3 & 4 are so much higher? Is it just the way the engine was designed or do you think something else is going on there?

3 will run hotter.
However I wonder what is going on in that bank. Sometimes you need to adjust the linkage at rpm and not just idle.

Fans can be an abstruction at speed. Oil cooler exit is more important than fans on a track car.

The timing should be fine but sometimes I've found different readings between different timing guns. So worth double checking as too much timing will create heat





Your oil catch tank is also an obstruction to your cooling fan pathway. I like to mount my catch bottle on the rear of the engine bay and put nothing on the front firewall in the path of the air for the fan

Where is your external oil cooler? And how is the air currently extracted?

My can is right over the fan. Maybe I will move it.

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It is on the passenger side rear, as low as a dare to go. There is quite a bit of space behind it.

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Our cars are set-up really similar. Here's a pick of my oil cooler set up. I have ran up to 255-260f. There's some new ducting to try to "solve" my oil temps.
Even with that crazy oil temp I didn't run past 375F on the head temp. I had something make a nest in the engine tin before my last rebuild. Tons of leaves in there also. Over 400f + then. I wondered too if your catch can is blocking air too.

Whats your max oil temp and did you still have oil pressure?

I can't tell if the cooler is just hanging there or do you have a front shroud to direct funnel the air through the cooler?

Plenty of space in back, but without capturing the air and forcing it through the cooler you are likely losing a bunch of cfm's that would help to cool the oil.

Can you run a (big) tube from the front of the car to to the engine firewall in front of the fan? All the old guys used to do that and it works.

I think Foley's car has one of those tubes. He could tell you how much it helped.

I did some further checking of a/f and cyl temps yesterday. With the original setup I ran the car pretty hard on a remote stretch of road to try to simulate the track. The first run showed this:
13.5 at redline
#1 336
#2 291
#3 368
#4 339
This was with 150 mains and 180 a/c jets

After changing the 180s to 170s, I got a better a/f reading, but temps were higher. Maybe because everything was just hotter by then.
Second run showed:
12.6 at redline
#1 343
#2 311
#3 384
#4 357

At cruise on the way home, after resetting the CHT, I got the following max CHT readings at 60 mph in 4th gear:
#1 332
#2 300
#3 381
#4 341

Today, I am going to move my oil catch can and move my oil cooler down a couple of inches and rework the air scoop. My oil temps were running just a bit over 220 and my oil pressure was good. Tomorrow I will pick up some larger jets to play with and see what happens.

As I think about other fixes, I have come up with these ideas:

Installing Foley's remote oil cooler set up that eliminates the stock cooler and adds a deflector to get more air to 3 & 4.

Adding a GT all screen deck lid.

Installing a FAT fan setup with a 911 blower.

Installing NACA air ducts on the side of the car to get more air to the blower.

Comments welcomed.

Yup, I would move that box to the other side.

I moved it to where the original air pump was and just a bit higher. I also moved my oil cooler up. I felt it was picking up warm air from the engine. Everything ran cooler yesterday with 14 runs at the AX at Marina. I still may duct some cool air to it with a NACA duct.


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Update on heating issue. Bottom line, everything was still very hot, even after I installed the NACA duct and hose to the cooler. Hard freeway driving 70 -80 caused the temps to show very hot like before:

#1 max 334
#2 max 307
#3 max 437
#4 max 347

My gauge shows a max temp that can be reset.

Oil temp ran between 230 - 250

So, with this I decided to drop the engine and take a look around. First thing I found was an alternator cover inside the impeller. That had to be blocking a lot of needed air. The second thing I found were two broken blades. Probably OK for a stock motor, but not for this one, not the way I drive it. So I have a new impeller coming as well as Chris Foley's external oil cooler setup that eliminates the stock oil cooler and sends all the air to # 3 & 4, none to where the stock cooler was as it will be blocked off. There are a couple others things I will check, valve clearance and timing, but that is it for now.

I've read a lot of BS over the years about oil cooler locations.

It all boils down to BIG and in the nose if you're serious.....some classes make it tougher. Finger something out if you're in that position.

Believe me, that thought has occurred to me.

Oil temp ran between 230 - 250

Do you come in once the oil temp hits 250 or did it max out there?

I think the cooler up front is going to happen on my car too.
Shane

Warren,
would you like to be the guinea pig for my new oil pressure relief device?
I have a prototype ready for testing, just need a car with oil pressure gauge for monitoring.

Sure Chris, but like we talked about, only after I get this heating thing resolved.

Whats the intent of this device?
Is it something you can swap out without draining the oil?
I stay up at night worrying about oil temps, will this help me sleep?
Shane

This will eliminate the circuit in the crankcase which bypasses the stock cooler under high oil pressure conditions.
It can be swapped out without draining the oil.
I believe this will help a lot of us sleep better.

This is the first prototype, and is ready to be installed/tested.
We'll have a couple more ready tomorrow with a couple of minor changes.
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The weld build-up on the side orients the tube so the high pressure relief holes line up with slots in the case.
The plan for production is a screw which retains the spring and has an exposed head which fits in the slot.
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Have you messed with your timing or verified it with another gun yet? I agree you need to fix your fan and get the debris out though...

I could never get my car to cool the oil enough with a spin on thermostat and the cooler in the rear.

I will re-verify the timing when I get it all back together as well as everything else. While I have the engine out, I pulled the tranny to inspect the rear seal and clutch. Everything there looks good. I am also in the process of installing Tangerine Racing's Remote Oil Cooler kit which essentially removes the stock cooler, thermostat and cooling flaps. A blank is installed to re-route all air on the passenger side to 3 & 4. This should help, along with all the other little things I have found.

We'll see how much this helps my heating problems. If necessary, I will move the oil cooler to the front. Don't really want to, but may have to to keep this 2270 together. It doesn't hurt much in AX with the short runs, but with extended freeway driving, it just hasn't been getting the job done.

I found the same thing with my cam-ed/carb-ed 2056. Now granted I have a HUGE drysump tank in addition to a HUGE oil cooler up front now, but I can flog it as hard as I want and it stays at 180F.

Have you tried 180 air 160 mains or possible 190 airs 155 mains. Interested in the WOT numbers Also what venturis? 32mm i assume

I am running 160 mains with 180 A/C which got my WOT at redline a/f readings to around 12.0, through 34 venturis, but the cyl temps were still too high, especially #3. The oil temps were also running too high 230 to 250.

I am almost ready to re-install the engine with the few things I found wrong and with Tangerine Racing remote oil cooler kit. We'll see what happens.

Oil and head temps aren't directly related. Tune for head temps and add big ass coolers for oil temps.

My big ass or yours? There is probably a difference. Just kidding, got the point.

What are you smokin"?

Only good shit, but it's true. I've correlated the data and I believe Len and Jake have seen the same thing.

I'm following with great interest this thread as my car was running hot this WE at Fontana racetrack. I didn't push it as much because I felt uncomfortable when my CHT gauge reached 400. So I was at it in the curves but letting go in the straights.

I really need to improve my oil cooler setup though. I have it mounted under the engine GT lid and it definitely brings a lot of hot air to the engine cooling fan.

I have also read and notice that the heads could run hot while the oil was cool in some situation.

Looking forward to the follow up!

In a sense, Len & Jake are right.
That big lump of a T-4 head casting has insufficient cooling built into it.....air or oil. Heroic measures are necessary to make it work. It also fills up the valve covers with oil and insufficient oil circulation negates oil cooling at that point.

Len & Jake will sell ya some parts that might help.....but why bother?
At best the motor is a unreliable, non-power maker when it works.

Call bull shit all you want but the fact remains that that motor was never designed to be anything but an economy car engine and it shows. By the time (& money) one makes it a racer, you may have well put a 911 motor and have power AND reliability.

OK, after re-installing the engine with some modifications that I will show you, I believe I have done everything I can do to lower my cyl head temps and oil temps. I think JP Stein may be right about these engines, one can only do so much. Oh, I am sure there is more I could do, but I am not sure I would be getting the bang for the buck. I have already spent a small fortune. Am I where I want to be? Maybe not, but I am definitely feeling better about my temperatures. Here is what I did:

When I removed the engine, I found a few minor things wrong that I corrected. I found my missing alternator cover inside the impeller. I also found that I had two blades missing. Corrected both of the problems.

I also installed the Tangerine Racing remote oil cooler kit, which eliminates the stock oil cooler and re-routes that air to #3 & 4 cylinders. You can see the plate installed where the air used to go down to the stock oil cooler.

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I have positioned the oil cooler in several different spots in the rear passenger side of the car. None seemed to work better than others. Here is one of those positions:

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I then added 3" hose and a NACA duct:

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It was about this time, I installed Chris Foley's pressure relief valve. Didn't see a big difference, but Chris assures me that oil was now for sure going to the cooler and that is a good thing. I think all these little things add up to more improvement.

Next, I made an single inlet shroud to pick up most of the cooler air from the NACA duct. That helped, but I was still not satisfied, so I made a dual inlet shroud and picked up more air from the engine compartment, close to the new GT lid I bought. Here's the shroud on the workbench.

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Here it is installed.

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You can see the inline oil thermstat in the above left

To be continued.........

Here's another shot:

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Here is the engine compartment inlet:

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Well that's the picture story, but here are the numbers.

Before I did any of this, I made sure my A/F mixture was correct. After playing with main jets, I ended up with this:
12.0 at WOT 160 mains, 180 a/c jets and timing at 30 degs

My #3 CHT was 397 degrees and my oil temp was 250 degrees with hard driving.

This when I removed the engine to install the cooler bypass

My CHT on #3 went down to 350 degrees, but my oil temp was still 240 - 250 degrees

I then added the manifold to the front of the cooler
Oil temp down to about 240 and CHT #3 was 348

I then added the other hose from the engine compartment with the dual inlet shroud and a pair of Spal 5" fans.

At 70 - 80 on the freeway I stay at or below 220 degrees HAPPY WITH THIS!!!
CHT #3 were still a little high at 360-375 but not bad for running in 4th gear at 80 mph.

Foley's is not a big fan of oil cooler fans, but with these fans, it definitely brought my oil temps to an acceptable level. I am convinced that in order to take this car on the track for more than two laps, I would have to move the oil cooler to the front. Any other suggestions are welcomed, but right now for normal freeway driving and auto cross, I am good. I may play with the jetting a little more, but right now I think I will let all of this settle in.

Warren,

Not sure what your fear of the track temp stems from. I have been wrestling with these issues too (I have a thread going with my issues here in the paddock too).

I am in Central Florida in blistering conditions (track surface temps at and above 127*, ambient near 100*, and humidity north of 90%), with a warmed over 2.0L, pushing the car pretty darn hard around Sebring, and once the oil gets to a certain temp it just stays there. (That's a Hemingway way run on, and on, and on sentence if I have ever seen one.)

Now the gauge does read 260* but what I am finding is the gauge has a a fairly large error. There is a bit of a debate as to what the error actually is and I will be testing it next time out but I don't think my motor is actually seeing anything over 240* oil temp after a 25 min session. (BTW I too am running the CF bypass bypass and his rear mounted cooler.)

But as my favorite saying goes, there is only one way to find out

Good Luck,

Miguel

in the last 20 years of playing with these cars.... I've seen it over and over
a lot of people (even myself) play with rear coolers and all of the incremental steps to get the temp down. In the end, its more effective and quicker to install a front cooler. But glad you have things under control to where they are manageable.


I have literally seen these threads since this website began (and the websites that preceded this one)... folks chipping away at their oil temps and learning on their own time after time that a front cooler, with frontal air is basically necessary for a track car. I know some really amazing fabricators make rear coolers work on the rear of a 914, but its not the quick and easy way to get the job done.

I am confused about a few things here..

1) I was under the impression that the top side of the 914 engine lid was in a low pressure area. That in fact, the bulk of the cooling air came from the bottom side. Perhaps this moreso in a street car with the rain guard in place. This leads me to really wonder:

a) the oil breather catch tank placement should not really impact engine cooling at all and

b) if the top side is a low pressure area, why the orange hose from the cooler up thru the engine compartment?

2) Have you been able to confirm that the oilcooler is actually working? Can you get a line temp, inlet and outlet sides of the cooler to know if there is a temp difference?

Don't know the class rules you are contsrained by, but I noticed significant oil cooling advantages moving my oil cooler from under the engine lid cover to a front mounted unit that actually got airflow.


CHT temps.. maybe a piece of black tape on the guage would help

We have almost identical set-ups, with identical results. I have some pics under "recent Sebring abuse".
Ran my car, without the fans, and got to 250 degrees.
I'll be moving to front cooler/hood exit. Not waisting anymore time with this rear set-up. All the ducting didn't change a thing. I thought that big duct that is just before the engine would change temps. No luck.
Now the only question is what type of front cooler to use?

The Mazda RX7 cooler is a great fit....btdt....search the threads on it, though because they really need the modification taking out the turbulizer strips which really restrict the flow if you have 20w50 in cooler temperatures. The mod consists of cutting off one tank, removing the strips and then welding the tank back on. Also, block off the thermostat hole if you install a t'stat closer to the engine as most do....

I've got an RX7 cooler sitting gathering dust .....$45 shipped if you want it.

John

the stock cooling air comes in through the engine grill
is separated from the bottom side by the tin work and rubbers
is sucked into the stock fan, to be blown over the cylinders and then exits out the bottom of the cylinder fins

thus the oil catch tank anywhere near the intake air path for the fan is a barrier to more air getting in. The distance between the firewall and the fan housing is only about 5 or 6 inches and not any too large to start with

I've always mounted my oil catch tanks on the rear of the engine bay (under the last inches of the rear trunk lid)

the problem with a cooler in place of the rain tray or under the engine lid, is that you are pre heating your intake charge, and also pre heating your cylinder cooling air...

I have seen one fabulous idea using a cooler 25 years ago... with long enough hoses that it mounted on the engine lid for street, and then relocated for track use to a mount using the targa-bar ski rack mounting holes... similar to the go pro mount someone made a month ago.

that car had absolutely clean air hitting a very small cooler with short lines.
it was a great idea and then relocated back to the grill for street use

really surprised no one has copied it yet
a perfect lemons idea
I've bragged about it for ever....

And when you do finally put it up front...manage the air in and especially out..don't just hang it there ...air is much more effective going thru the cooler , than across the stalled mess in front of it

agree'd
and make the exit about 2x as large and less restrictive than the entrance

I used 3 different exits on a small frontal cooler and found oil temperature reduction on each less restrictive exit

Brant said:
the stock cooling air comes in through the engine grill
is separated from the bottom side by the tin work and rubbers
is sucked into the stock fan, to be blown over the cylinders and then exits out the bottom of the cylinder fins

thus the oil catch tank anywhere near the intake air path for the fan is a barrier to more air getting in. The distance between the firewall and the fan housing is only about 5 or 6 inches and not any too large to start with

I've always mounted my oil catch tanks on the rear of the engine bay (under the last inches of the rear trunk lid)

the problem with a cooler in place of the rain tray or under the engine lid, is that you are pre heating your intake charge, and also pre heating your cylinder cooling air...

I have seen one fabulous idea using a cooler 25 years ago... with long enough hoses that it mounted on the engine lid for street, and then relocated for track use to a mount using the targa-bar ski rack mounting holes... similar to the go pro mount someone made a month ago.

that car had absolutely clean air hitting a very small cooler with short lines.
it was a great idea and then relocated back to the grill for street use

really surprised no one has copied it yet
a perfect lemons idea
I've bragged about it for ever....


Brant

OK, I moved the can away from the firewall, but maybe I will rework the bracket and move it even further back.

I am intrigued with your idea about a temporary track air scoop of some kind that could feed my auxiliary through the engine compartment hose while on the track. I will fiddle with this a bit and report back. Dam, I thought I was done for awhile, but then I guess we're never done with these cars.

For what its worth, I have measured over 120 degrees on my inlet air with only 85 or so outside air temperature.....now I don't have any rubber between the tin so for sure I am sucking in hot under car air. Going to test it this weekend with duct tape....not sure where to use the WD-40 though...

your venting box, is probably good.
I doubt there is a lot to be gained
any tube (drier duct tubing) taped to the outside targa bar should bring cooler air into your cooler. at least a couple of degree's

we are now running a scoop at the back of the window well opening and picked up a lot more cool air for our trans cooler and a noticeable difference on its gauge:

here

Here's a datapoint:
Ran my 2L 4 hard last weekend (ambient temps ~80-90) and two morning runs saw 250-260 degree oil temps with the stock cooler only.

Hooked up my dual front oil coolers during the lunch break and could not get the oils temps UP to 200 in the afternoon.

Setup is: 12AN sandwich adapter at filter, 12 AN up the pass long heater tube to 1 setrab oil cooler mounted under each headlight bucket in series (engine-pass side cooler- drivers side cooler - back to oil filter bracket) this setup still retains the stock cooler.

Cooler vents come in through foglamp holes through coolers and vent out through wheel wells.









I have better pics of the finished product I'll see where I put them.

Will the headlights still function when done?
Post more pics when you get a chance. I like what you got going on here. Looks nice so far!
Shane