Daily Driven Trombones

[Ouzo12]

This question is for all you SCers out there that drive them everyday and specifically in the hotter climates. Do the cars have any problem maintaining good temps while stuck in traffic with the trombone type cooler. I have read ( I think on this site) that the oil lines do the real cooling while the trombones just route the oil back to the tank. Logic would make these cars not very good for the bump and grind of traffic. Can you guys give some real world impressions on this set up. While the later Carrera set up is sweet, it’s a bit $$ for the financially challenged.

[Bill Verburg]

I only had oil temp issues on track days, back in those days there wasn't a lot of cooler choice like today. I replaced the trombone w/ a Turbotrol and never had another problem til I put a 964 engine in it.

[SCWDP911]

Originally Posted by Ouzo12

This question is for all you SCers out there that drive them everyday and specifically in the hotter climates. Do the cars have any problem maintaining good temps while stuck in traffic with the trombone type cooler. I have read ( I think on this site) that the oil lines do the real cooling while the trombones just route the oil back to the tank. Logic would make these cars not very good for the bump and grind of traffic. Can you guys give some real world impressions on this set up. While the later Carrera set up is sweet, it’s a bit $$ for the financially challenged.

I live in the west Tennessee area, between Memphis and Nashville. It gets smokin hot here in the summer. This was my first summer with my 83 sc cab. I have the stock oil cooler setup still. I had no oil temp issues at all. If I am in the city and at idle for a while, it might get barely above half on the gage, but it usually stays below the halfway mark on mine. Hope this helps.

[klaucke]

I think the 28 row brass cooler is a slightly less expensive alternative to the Carrera cooler, and it is still very effective if not quite as good as a properly set up Carrera cooler.

[tijnes]

My SC with 3.2 still has the trombone cooler. I've had overheating problems in the summer but only in stop and go traffic on really hot days (I495 LIE westbound on sunday nights). This is after an hour of not getting over 3K RPM's in first gear moving one car length each time. Other than those times I rarely get the temps over 9 o'clock on the meter even in summer. I will install the carrera cooler with fan at some point, finances permitting.

Martijn

[Paulporsche]

According to Bruce Andersdon the brass cooler is more effective @ dissipating heat in traffic as it is less dependant on air flow.

@ speed and w/ a fan I think the fin type cooler is better.

[JMatta]

Originally Posted by v8_ranch

If I am in the city and at idle for a while, it might get barely above half on the gage, but it usually stays below the halfway mark on mine. Hope this helps.

Barely over half on the gauge? You're killing it!

Put a cooler in that puppy before she blows.

[Won]

To each their own but if Porsche deemed "half on the gauge" (~105C) unhealthy then they wouldn't have made that temperature be the middle of the guage, would they?

I had trombones with half crushed oil lines, and it would easily reach the halfway mark while stuck in traffic on a summer day. Now I have a 28 tube brass cooler but when there is no airflow (i.e. stuck in traffic) the temp will still creep up. All "radiators" need airflow to do their job as thermal radiation is not a very effective way of heat transfer in our environment. I cut a hole on the valance just to the outboard of the fog light mounting holes and as soon as I get moving, the temps will drop back down to just above the first white mark. I'll probably put a fan on my brass cooler before next summer just so I can minimize heat build up in traffic.

Good luck!

[SCWDP911]

Originally Posted by Won

To each their own but if Porsche deemed "half on the gauge" (~105C) unhealthy then they wouldn't have made that temperature be the middle of the guage, would they?

I had trombones with half crushed oil lines, and it would easily reach the halfway mark while stuck in traffic on a summer day. Now I have a 28 tube brass cooler but when there is no airflow (i.e. stuck in traffic) the temp will still creep up. All "radiators" need airflow to do their job as thermal radiation is not a very effective way of heat transfer in our environment. I cut a hole on the valance just to the outboard of the fog light mounting holes and as soon as I get moving, the temps will drop back down to just above the first white mark. I'll probably put a fan on my brass cooler before next summer just so I can minimize heat build up in traffic.

Good luck!

+1

I should have clarified that most of the time, mine runs just above the first mark, and as mentioned above, only creeps to the midway point when stuck at a standstill for 5-10 minutes, which fortunately for me (as I no longer live in So. California), is a very rare occurence now...

[Tim Hancock]

Mine only got "too hot" when driving aggressively on hot days, stop and go in 90 temps would stay around 10:00 on the gage and never go too high. I eventually installed a 28 row brass and it definitely made my temps lower. DIY crushed oil line repair and oil cooler upgrade

To answer your question, my '79 SC was OK in stop and go during hot weather, but it was not OK if I drove it like I stole it on hot days (85 + degrees).

[BoogieOnSkis]

I've experienced a problem with overheating just once.

I was waiting to park my car in the Corral parking at Concorso Italiano. This was about three years ago.

Ferraris were lining the shoulders of the roadway with stream rising from their engine compartments.

I turned on my engine compartment heater blower motor and avoided having to follow the Ferraris' lead.

By the way, I used my car as a daily driver in the San Jose area and frequently visited family in the San Joaquin Valley.

Use your heater blower motor when you are worried about high oil temps.

[Superman]

Those of you who think oil temps are not a problem until the needle gets to the top of the gauge should do a Search and read up on this matter. What you would find is that when the needle gets to the mark that's at about 10:00 on the gauge, the oil is getting too hot. At that point, it is getting into the 250 degree F range, at which oil breaks down.

[Won]

Lubemaster77 - Oil Question

By the way, 10:00 mark is ~120C = 248F; halfway ~105C = 221F, just hot enough to get the water out of the oil. Of course the oil will see higher temperature inside the engine/P&C and so on, but there are already more than enough threads on that matter.

[Ouzo12]

Thanks very much for the input guys, def. some great insight on this matter.

[RWebb]

1. "just hot enough to get the water out of the oil"
- No. The water will volatilize at any temperature - don't confuse this with boiling (and the b.p. under pressure differs from 100 oC in any event). Put a pan of water out in your kitchen - the water will be gone in a few days, even at room temperature.

2. The trombone is just a piece of pipe, like the rest of the oil pipe. It may even get a little less wind where it is. Thus, the cooling it will do relative to the entire external system is proportional to the length of the loop rel. to the length of the horizontal piping -- you could figure maybe 20%.

3. The big brass tube cooler is better at stop & go traffic b/c the heat exchanger system is frequently in a transient condition with minimal air flow. The brass cooler acts like a 'thermal mass' which gives you 'thermal inertia', absorbing the ehat for a limited period of time and then dissipating it. A Carrera cooler (many fins) has less 'thermal inertia' but acts better to convect away the heat once the car is moving and generating wind. A fan can help a lot in traffic.

4. Be sure the car is in a good state of tune - if slightly out, these cars can tend to run hot.

5. Try adding a fan if your cooler is nt doing the job in traffic.

6. Don't drive in extreme heat. This is my solution! My car has no A/C and I am more susceptible to heat than the car's motor is.

[RoninLB]

dump the trombone.

[911pcars]

If the marginal trombone "cooler" suffices, stay with it. If the engine overheats due to excessive oil temps., then improve the oil cooling. You've heard the solutions. Oil temperatures >250º may not affect a good oil. However, elevated oil temperature is a direct reflection of elevated engine temperature. When parts become too hot, they expand; sometimes beyond design spec. That's when clearances decrease and the oil film becomes too thin for adequate metal-to-metal separation.

I prefer the option of driving a car under most any operating circumstances - not just under "ideal" conditions. Anything less is considered domestic hot rod car philosophy and reveals a deficiency in car design or your modifications. Yep, PAG sometimes didn't foresee our operating conditions.

If the engine overheats in stop and go driving, don't avoid driving the car. Do what's necessary so you can drive it.

These seem to be truisms as they relate to air-cooled 911s:
- Airflow via a fan directed at an efficient oil cooler mitigates excessive heat buildup in most low-speed scenarios.
- A real oil cooler (w/airflow and adequate surface area and volume) does the job for high load, high ambient air temperatures.
- The exception are 3.6 engines. - they require multiple, efficient coolers or one very large one.
- A bumper-mount cooler, even a smaller one w/o a fan, is more efficient than a fender-mount cooler (again, due to airflow or lack thereof).

Sherwood

[Trotskyite]

I live in Las Vegas, but have only had this car ('82 SC) for a couple of months. It ran really hot when I first bought it, but now that it has cooled off a bit, it will run up to 9'oclock and stabalize. Ambient temps right now are about 85. Should I richen it up a bit? I am definitely in the market for a Carrera cooler, but they are really expensive. Any alternatives that have been developed in the last 20 years?

[SCWDP911]

Originally Posted by Trotskyite

I live in Las Vegas, but have only had this car ('82 SC) for a couple of months. It ran really hot when I first bought it, but now that it has cooled off a bit, it will run up to 9'oclock and stabalize. Ambient temps right now are about 85. Should I richen it up a bit? I am definitely in the market for a Carrera cooler, but they are really expensive. Any alternatives that have been developed in the last 20 years?

Has anyone here already wired up a fan to be used with auto function based on temps? With the 911 electrical system being what it is, what have those of you who have done it, found to be the best way to tie in an electric fan?