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Cooling system solutions
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TOPIC: Cooling system solutions

Re:Cooling system solutions 15 years ago #1289

Thank you Doctors ! My heater core went the way of a lot of parts off my car..... straight to the dumpster. Don't think I'll go looking for that.

What do you mean, upgraded fan ? What are you running ? What should a broke bloke pay for a used Turbo radiator ? A quick check found one for $180 used w/90 day guarantee. That seems pretty high to me.
Last Edit: 15 years ago by cullenwinter.

Re:Cooling system solutions 15 years ago #1290

  • Weston
  • Seasoned Racer
  • Destroyer of Chris
  • Posts: 277
I'm not sure where to get the fan since mine came with it when I bought the car, but used radiators should be well under $100.
#22 - Red 1983 Porsche 944 - Rocky Mountain

944 Pics & Video

Re:Cooling system solutions 15 years ago #1292

  • GaryM05
  • Senior Racer
  • Posts: 100
SvoChuck wrote:
Weston was saying we needed to better burp our cooling systems ... besides that I plan on relocating my oil cooler and putting a fan on it. michelle's car ran cool as did Gary's ...

Running alone (i.e. at the back) with no cars in front to obstruct the airflow might have helped my car stay at the 'cool' water temp of 210 ( ) in Sunday's race. Short-shifting once I noticed the temp get that high might have helped the temp stay there, rather than rise even higher, but I can't say for sure.

Beyond that, it's likely that the new radiator (flushed right before the event), fans, and thermostat in my car could have helped, too (I'd hate to think what the fins on a 20+ year old radiator might look like.) Also, the wire mesh screen covering the opening might have prevented some of the junk that was being kicked-up on track from getting in there and clogging it up, but you never really know about that.

Future cooling mods include an oil cooler, and potentially hard-wired radiator fans, as it was very demoralizing to see all of the heat-related problems that the group experienced.

I think that Weston's post has a lot of good suggestions and ideas for addressing this obviously critical problem that we're all finding ourselves having to deal with.

It sounds pessimistic to say it, but I'll bet that the money that one would save by choosing to skip just a single event would likely pay for some significant upgrades to engine cooling.

More cooling = more reliable racecars = better, cheaper racing, since we're not all having to drop out of races and spend money fixing expensive, heat-related engine failures.
Snyder Motorsports #10 944 Spec

Re:Cooling system solutions 15 years ago #1295

Ahh... cooling

I have raced my 944 with success in temps to 105F both with and without an external oil cooler.

Here are some tips.

1)You need the stock system work to 100%.
By that I mean all working perfecty.
- It needs to be bled correctly as air is bad.
- It needs to run on distilled water and a bottle of water wetter. Any coolant reduces the heat disipation capacity of the system.
- All hoses must be 100% leak free, No leak at all as any leak will cause over heating. Get a pressure tester to check for leaks when cold.
- NEW Radiator - The stock 944 one is fine and works great, IF if not clogged up. Nearly all old orginal radiators will not cool enough on track due to accumulate debris both inside and outside. A few weeks ago I spend 2hr clearning dirt rubber debris from the front part of my radiator. I was blow it clean. This was a new unit 5 years ago and even with screen the accumulate debris was considerable. 20 year radiators don't stand a chance because they are often corroded inside as well.
- New waterpumps. Again old water pumps can be marginal and fresh on will help ensure 100% operation of the system.

Ok now that the basics have been done work on the rest of the system
2) For 944's cut out the bar that goes between the fog lights. Removing this will improve airflow to the radiator and thus improve cooling. You really need to install a debris screen of a sizeable opening to prevent rocks from hitting the radiator.
3) I assume all of you have ditched the condensers right.
4) Know "Normal" temps. Both early an late gauge don't have number markings. However even a well running car in 95 to 105F temps will run the final white line on either temp guage. These temps are only 210F or so and the car will race fine all day at these temps. Going past that for a short time is ok especially if you are drafting a bit.
5) Direct wired fans. When running in the very hotest times I need to have both fans going full bore. I have both fans wired to switches and the battery. This way I can control when they start and stop. Not using both fans will cause temps even during racing to increase in really warm weather
6) Front undertray. It help prevent the air from under the spoiler from creating a high pressure zone behind the radiator. If this happens it restricts some flow and increase temps.
7) External oil cooler. I noticed a drop of 10-20F water temps by ditching the stock oil cooler and going with a 951 oil cooler. In the old days running a race in 105F temps put the cooling system to the limit. I would run, but would run hot right at the limit of what I liked (just past the last white line). With the external oil cooler the heat from the oil does not go into the water system and as such there is less heat to dissipate so the water temps are down.

So those are ways to keep the cooling system operating.
When it comes to oiling and rod bearings.... see the next post.
Joe Paluch
944 Spec #94 Gina Marie Paper Designs
Arizona Regional 944 Spec Director, National Rules Coordinator
2006 Az Champion - 944 Spec Racer Since 2002

Re:Cooling system solutions 15 years ago #1297

Rod bearings and bottom end life.

Rod bearings are the only weak spot on these cars.

It is a long story as to why (roots in the 928 motor development really), but there is no one fix it solution. There are how a number of little things to be done to minimize the risk.

(In order of effort to implement)

1. Run oil to the full level never under full and never over full. So check the oil level before each run session.
Some motors burn oil and some do not. Most do at least a little but and letting the oil level drop is just asking for problems. Also overfilling the oil can result in increase oil frothing with is another source for issues. Make it your routine to check the oil level at each session to make sure it on the mark.

2. Run high quality heavy oil. Don't run anything less than a 20w50 oil or similar. Running thin oil to make hp is a great way to spin a bearing. I run AMSOIL 20w50 Series 2000 racing oil. It is alot more expensive than Mobil 1, but also holds hot pressure alot better. Also change the oil every 2-3 events. Old oil breaksdown more easily and gives less protection. I think the Redline racing oils are also good.

3. Fresh Rod bearings It is not easiest to do, but 20 year old rod bearings are often ticking time bombs. Years of use has opened the clearnaces and open clearnaces need more oil flow to maintain the oil film layer between journal and the bearing. Fresh bearings run a little close and as such need less oil flow and this give you more margin incase something bad happens.

4. Baffle the oil pan. There are many kits to baffle the oil pan by putting rather crude looking trap door in the bottom of the pan and putting ring around the oil pick-up tube. Doing this helps prevent the oil from getting pulled away from the pickup in long hard left turns. Keeping the oil level full also helps this issue, but a baffle is the best way.

5. External oil cooler. Either along with the stock one or just 951 system. Keeping the oil cool helps alot with making sure the oil can do its job. Hot oil is thinner and provides less protection as it seeps through gaps faster. On the very hotest days my oil temp runs to may 250-260F. Not great, but ok. The other thing to watch is oil pressure if you don't have a temp gauge. If it drops of from normal it is getting hot and running in clean air can help. I have run races where I close drafted a car infront to 20 laps and saw oil temps going up and pressure droppoing. So I began to pull out in clean air on the main straight and soon saw temps go down and pressure come up 0.5 bar in 2 laps.

6. Fresh main bearings. This goes along with rod bearings, but can only be achived when pulling the engines as the crank needs to come out do this. One critical thing to remember is that the supply for the rod journals comes from excess oil supplied to the main bearings. So old worn main meaings have less excess oil than tigher fresh main bearings. You will never spin a main bearing because the oil will starve the rod bearing long before the mains. Even so open main take away oil that should go to the rods

7. Cross drilled crank. The main journals are cross drilled, but in most cars the rods are not. I have seen a few rare cases where some motor seemingly have crossdrilled rods too, but don't count on it. Drilling the rods helps oil flow. You can do it 180 deg from the existing hole on all 4 or just #2 & #3. The reason for just 2 & 3 goes to oil flow on the entire crank and 2 & 3 are the weak flow points and it seems that doing just those two helps balance th flow.

I would say that 99% of all rod bearing failures are the #2 or #3. I don't believe I have ever hear of #1 or #4 bearing failure that could not be linked to a specific unique issue.

Also nearly all the rod bearing failures I have seen (I have seen plenty and experinced 2 myself) were a result of poor oiling practices (ie letting it get too low or using too thin of an oil), old rod bearings, build problem or failure of the oil pickup tube due to improperly timed balance shafts. (Hint if you have vibes at 3000 rpm or a cracked fuel rail your oil pickup tube could be craked too).

When driver follow the advice about thier cars and motors last a good long time in all conditions.
Joe Paluch
944 Spec #94 Gina Marie Paper Designs
Arizona Regional 944 Spec Director, National Rules Coordinator
2006 Az Champion - 944 Spec Racer Since 2002

Re:Cooling system solutions 15 years ago #1298

  • 944cer
  • Seasoned Racer
  • Posts: 193
Is the 6 blade fan the high draw fan? If so...then it seems to me we could run 2 six blade high draw fans?
Is there a better and is it worth it, than the 160 degree thermostat I bought from NAPA?
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