cooling down a 3.0 at DE

[s2per]

I really enjoy the newly found power of my (now) 3.0 powered '72T, but I had some high temps at my last Sebring DE event; like just under 250! Quick facts:

--'78 3.0, stock CIS, early exhaust and gutted 2 into 1 muffler, fresh tune-up and valve adjustment
--Fresh RF wheelwell-mounted 930 oil cooler, factory brass lines, later model (larger) oil tank (with apologies to the '72 purists)
--Stock front bumper with fog light opening unplugged, no shrouding around cooler though
--Thermostat seems to be opening OK, front cooler temp showed 230 to match 230 on gauge in pits
--Ran car fairly hard (about 9/10ths) for 20 minutes, then backed off due to temps; 80 degree ambient, BTW

Will shrouding below and around the cooler help significantly, or do I need to look into different pulley combos, ducktails, etc.? Never had a problem with the big front-mount cooler on the last car, but would like to avoid that if possible. Ideas?

[Wil Ferch]

Ducting to the front cooler definately helps, especially a blanking plate from below...a search on this forum will show a few examples and testimonials.

Wil

[Emission]

Originally posted by Wil Ferch
Ducting to the front cooler definately helps, especially a blanking plate from below...a search on this forum will show a few examples and testimonials.

Wil

This alone was a huge improvement to help keep my car cool on the track!

[s2per]

Thanks guys; looks like I'll be getting out the shears and thin-gauge aluminum this weekend!

[Grady Clay]

Tim,

Two fifty is too hot.

First I would check to see if the bottom of the front cooler is at the same temperature. There was a thread about this a month or so ago. Search on my name and Chuck Moreland.

In addition to sealing around the cooler and ducting, you might consider installing an electric fan á la ’88 911 Carrera.

The ’78 and ’79 911SC has smaller engine cooling fans (reduced from 245 mm to 226 mm.) You should find an 11-blade fan with the 80-84 mm pulley and housing. When you do this, pay attention to the mounting depth of the alternator in the fan housing. The good news is you already have the largest (134 mm) crank pulley.

For DEs, the least expensive and most effective is the “Rubbermaid Solution.”

Best,
Grady

[rattlsnak]

Make sure the service bulletin was done. I chased a problem like this on a 78 3.0 for a few months several years ago, before running across the bulletin. It involves replacing the oil relief springs in the engine and the pickup assembly. Mine actually got so hot, so quick, it lost power. Once it cooled off it ran fine again. I was good for about 3-4 laps before it would get too hot.

[s2per]

Two fifty is too hot.

Agreed. I believe BA added an adjective in his book...

In addition to sealing around the cooler and ducting, you might consider installing an elec tric fan á la ’88 911 Carrera.

Wouldn't that be most effective at low speeds?

I've also read with interest about the "Rubbermaid solution", but I think the humid, sea-level air here might negate some of the gains.

Make sure the service bulletin was done. I chased a problem like this on a 78 3.0 for a few months several years ago, before running across the bulletin. It involves replacing the oil relief springs in the engine and the pickup assembly.

How do check this without "surgery"? My engine came out of an early car like mine, with no papers

[porschenut]

Originally posted by Grady Clay
For DEs, the least expensive and most effective is the “Rubbermaid Solution.”

Best,
Grady

Grady, I wonder if an adaptation of the rubbermaid solution to the front oil cooler would work. Suppose I repositioned my right side headlight washer nozzle so that it squirts directly onto the oil cooler in the path of air flow...good idea?

[flipper]

How bout a cool collar?

[Bill Verburg]

The oil cooler is certainly sufficient given reasonable air flow(enlarge hole under bumper) and gasketing around the perimeter

One would think that all the SC engines were fixed by now but.....

There were 2 issues related to oil scavanging and overheating on those engines

A quick search comes up w/
1

2

3

I am sure that ther may be more

[juanbenae]

has anyone done a shroud around a cooler that did not come equipped with one? I have a mocal unit and was thinking a shroud to direct more air into the radiator surface would be the ticket. i have done some searches but come up empty. anyone know of a thread describing an attempt at shrouding? i see above aluminum sheeting is discussed, i was thinking a rigid plastic of some sort??

[s2per]

I'm planning on using light gauge aluminum sheeting and if necessary, some foam stripping. As with many of home/auto projects, Home Depot should supply the materials. Or I find it at one of my construction job sites , like, hmmmm, roof flashing maybe?

[rattlsnak]

Bill, nice,.. those are exactly what i was talking about!

[grudk]

I have a '78 ROW 3.0 engine with ssi/early exhaust in my '74, and was seeing 250 plus in So Cal this past summer (though at ambient air temps 95 plus). I went with a 72 row front-mounted oil cooler, and it has fixed the problem -- overkill probably but I may put in a bigger engine at some point.

[trekkor]

Yep, bigger cooler.


KT

[Zeke]

Is that your T-stat "waynup" front there? How does it know when the oil on the other end of the car is hot?

Oh, it has a by-pass.......

OK, where'sd you get that?

Next question (since I had a 914) If you are using the steering rack area as an exit, where is the source of incoming air? I actually agree with your choice of location for the cooler since I have long maintained that the underside of the car, at the front, is a high pressure area and not conducive to air flow along the bottom of the car. Whereas, when you get back as far as the steering, that should be alow pressure area. So, I begs to knowz, are you "vacuuming" the air out?

[dd74]

Does the plastic duct that Pelican sells (which replaces the side marker) help much with lower cooler temps? I have an electric fan, but am also considering one of these ducts.

To replace the pulley/fan assembly, does the engine need to be dropped?

Thanks.

[rlh930]

Let me ask a stupid question. Do you still have the battery box in the right front wheel well? The battery box on my '73 definately affects airflow through my wheelwell mounted cooler. I'm on the fence between removing the box or going to a center-mounted cooler.

[juanbenae]

Originally posted by s2per
I'm planning on using light gauge aluminum sheeting and if necessary, some foam stripping.

i would consider 3/16 fuel line or the like. slit it down one side and slide it over the duct material at it's edges where it may or may not contact the fender well. seems a more effective way to sheath the sheet metal edge.

[911pcars]

" I wonder if an adaptation of the rubbermaid solution to the front oil cooler would work. Suppose I repositioned my right side headlight washer nozzle so that it squirts directly onto the oil cooler in the path of air flow...good idea?"

If possible, a larger oil cooler and/or more air flow is recommended.

However, a water spray can lower air temperature 18-20ºF. Is that good enough? The process of a liquid changing into a vapor absorbs the max. amount of heat. The problem with using a windshield/headlight washer or equivalent nozzle is that the water spray is coarse. You'll end up running out of water and slow down the vaporization process due to droplet size. The trick is to balance water droplet quantity and size with the rate of evaporation while maximizing the quantity of water carried onboard. Water weighs 8 lbs/gal. so you don't want to carry more than necessary.

This nozzle produces 65 micron-size droplets. At ~60psi., one nozzle sprays for ~1.5 hours for each gallon of water.


Sherwood
Seine Systems
(blatent adv.)