Engine Temperature Issues

[CamBiscuit]

I'm interested in hearing from anyone who does tarmac rallying (Ryan) and anyone else in general about any experiences with overheating on their cars during vigorous use in warmer temperatures.

Are many members running oil coolers or any other mods to help the situation?

I'm looking at doing some lap sprints here in Darwin and the Classic Adelaide later this year and would welcome any views or people's experiences.

Is it a case of the cooler the better?

[e72phil]

Cameron,

you are wise to consider improved oil cooling. Early 911's are really oil cooled rather than air cooled. And running the engine hard up where you live, extra oil coolers would be a wise investment.

There are a number of ways to go - factory correct or after market. RS style front mounted, trombone style in the front guard, later model 911, etc, etc.

Ryan, no doubt, will reply with is experiences.

if you have the std BEHR oil cooler fitted, you might be surprised at how much dirt and stuff is in there blocking it up if it hasnt been cleaned for a while so be careful and keep an eye on that oil temp gauge.

[alexwebster]

Cameron,
having run Classic three times in an 356, similar set up to the 911 in rallying, we run an external oil cooler and found that it significantly reduced the oil temp when driving hard.
However with the 356 we found that it sometimes ran too cool, so a themostat type arrangement would be best.
I know that with our 356 with a 911 motor in it at Mt Buller, it runds quite hot, and this year we considered after the event that we should put an external oil cooler on it to lower the temps.
With the oil you want to get some heat into it and not run too cool, but find that happy medium. Lowering the engine temps to somewhere in the mid range is much nicer than above 50%!
There is my help - Ryan can give you some other info on his RS rep.

[OBRUT]

cameron

firstly, heat is roughly proportional to power. my first motor (150hp carb'd 2.7) rarely had cooling issues but my current motor certainly does. your 2.4 might be fine with just the stock engine cooler.

i would firstly do some warm track days, keeping a careful eye on temps, and just see how well your current setup works. opinions differ on safe ranges but i like to keep things below 230F preferably around 210F.

if you're overheating on a track then you will probably also overheat during a decent stage in classic adelaide given similar weather conditions. (don't worry about targa tas you'll be too busy shivering to read any guages...)

if you're seeing high temps then i would use factory style cooling setups - being a thermostat, hard lines and a fender mount cooler or a RS style cooler in the front spoiler.

i found a well sealed cooler in the front spoiler to work best - but they are also more vunerable to damage. i destroyed one the first time i did targa tas in a fairly low speed understeer shunt. however, it was mounted to the spoiler itself. i have seen people recess the front of the tub and mount them there which would offer more protection. lots of suppliers sell a weld in/rivet in recessed part.

i now have a 3.2 carrera fender mount cooler. however, to make it work as well as my old front mount i've had to remove a battery box, cut an opening in my front spoiler, seal the sides of the cooler to the fender and also seal the underside of the spoiler to the cooler. but it is in a very safe position (ie. if i damage it then overheating is probably the last of my worries)

finally, don't forget to cool yourself. i did a one hour stint at eastern creek without water on a 40 deg day. i was so dehydrated when i came in that i narrowly missed running over the chief safety marshall in pit lane... needless to say my license wasn't signed that day

i used to have cycle water bottle holders mounted to my cage uprights but we've have had bottles come loose. this year we're trying backpack style bladders (camelback?) mounted to the rear of each seat with the hose running throught the harnesses.

[Mark Johnson]

Cameron,
I have a 1973 911E 2.4 that I have circuit raced in Historic Group Sc and also competed at Cassic Adelaide last year. My experience with standard behr cooler and the optional oil pipes [organ] that run along the sill to the front guard, but no oil cooler was that the car run at 265 degrees when punished. Too hot.

Not being happy with that temperature, I had an external oil cooler mounted in a fibreglass RS style front bumper/spoiler to make it look neat The plumbing from under the front guard to the centre front of the car has to pass thru the 'front bonnet lock panel'. You can use non genuine oil coolers and any of the Porsche repair specialists should probably know what would fit best.

You will need an oil cooler thermostat which would mount under the front area of the rear guard and are commonly preset at 180 degrees. Normal road driving will see the temperature guage sit consistantly at the 180, but punished on the track you might see upto 210 max. These are available off the shelf in the States or I am sure some of the local specialists should stock them.

Hope this helps.

[OBRUT]

mark

a little off topic - but how competitive was your 2.4E in Sc?

i realise that you give away rear tire width and some power to the 74/75 Carrera's but the matching brakes with less weight should even the score a little. (your car of course wins in the looks dept).

[CamBiscuit]

Thanks for the advice guys.

I'm not that keen to mount a cooler in the front bumper as I don't have the RS style with the 'slot'.

Following on from Ryan has anyone installed one of the wheel arch type oil coolers from scratch? I'm thinking maybe one with a thermostatically controlled fan to give additional cooling when driving in traffic when airflow is not so good. Does yours have the fan Ryan?

Once again your thoughts / experiences are appreciated.

[OBRUT]

i didn't bother with the fan as the car never overheated on hot days in traffic - only when pushed hard.

the same test applies - does your car overheat now when sitting? if no, then a fan is probably superfluous. as a guide - the factory didn't add a fan until the engine size got to 3.2.

my gut feel is that a 3.2 fender cooler would be more than adequate for your car - but to make it work as intended you may have to lose a battery box.

the tough bit will be finding a good set of a hard lines. you can use braided hose but it looks a bit odd. alt, elephant racing makes new hard lines with external fins they i've heard good things about.

[alexwebster]

I have some hard lines here Cameron if you want some, they came out of a wreck, so let me know.

[CamBiscuit]

Thanks Alex

I've pm'ed you