Cool Runnings...now it does!

[joecautela]

I'd like to relate a bit here and see if anyone else has run into this "problem". I'm running a 2.0 in my '67 and while the mtr was out this spring I put in a electric fan, switched thru a relay and contolled by a milano sensor adapted into the base of the radiator. The radiator is rebuild with a 3 row core vs the stock 2 row, and deleted the stock fan...Big mistake...1st incident was while sitting in traffic on Sat. because of an accident. I thought "how quiet" the fan is. Sure!! It wasn't running! Water temp at 120 deg cel and oil at 90!. Relay failed.. brand new out of the box. Worked for a month. Luckily everything held and no damage...Installed a new relay. This time a Milano unit instead of what was supplied originally...ok seems to be working fine....Drove to Philadelphia Sun am for the FLU all Italian car show and had a great time! Coming home into a massive..and I mean massive, what turned out to be a 18 mile backup..stopped dead and creeping..Now this is interesting... The water temp held fine...but the oil temp started creeping up till it got to almost 90 deg celsius and stayed there. Then the engine stalled and that was it. Pushed it to the side to let it cool. That was when the cops told me about the 18 mi backup and that I had 2 hrs to "get that thing running" or it'll be towed..Damn! To make a long story short. Not enough air being passed by the fan over the block. The rad was fine but not enough volume..and this is a BIG fan. It was 92 degrees and no wind..anyway...Vapor lock to the carbs due to so much heat....starter solenoid was so hot it stuck and wouldn't crank....I jumped out the relay for continuous running..After 45 min everything cooled off and the engine fired and I ran the rest of the way home with the fan running wide open...Today I put the mechanical fan back on...I let it idle for an hr straight in the driveway this afternoon and it was 91 degrees today..Water at 80 celsius and oil at 60-70 celsius. Didn't flinch.. Now the electric fan is a backup for more ventures thru NYC and traffic coming back on Sun nights. I guess that supposed extra 5 hp will just be a cost of staying cool. I wonder what the hp loss is when those electric fans come on at 25-30 amps? Thank God for having an oil temp gauge. You should have seen that brand spankin new VR1 Valvoline 20-50 that only had 230 mi on it when I pulled it. Like water!,changed the plugs too!. And that was on an engine that did not overheat. To those of you running fan only..I strongly recommend knowing where your relay is and how to jump it, and Install an oil temp gauge too! Cool Runnings Brothers!, Joe

[Fletch]

Thanks for the warning Joe,I've just set up my GTJ to electric fans...one for AC,one for rad....so time to fit an oil temp guage too.
Cheers,
Fletch.

[60sRacer]

I've had the same experience with my '67 Duetto. 2000 engine, large radiator, electric fan. I even have an oil cooler. Moved to So Cal from San Francisco, and tghe first summer day I had overheat problems unless I was cruising over 60 on the fwy. I even added a small fan to the oil cooler (its mounted in front of the radiator, low bracketed to the bumper bars in the nose. Even with full on fans working fine, temp would climb. Finally added a Euro fan (thinner blades, less HP used at high speed) without the original fan shroud, just bare fan. Works fine now. Air flow is the thing!! The electric fans push air nicely thru the radiator, but don't really get much volume of air thru the engine compartment; the engine fan really blows air inside the bay.

Robert

[joecautela]

Hey Robert, I know what ya mean about doin 60 and everythings fine. It's once ya stop that the temp climbs. I was telling an oldtimer about it and he said that "back in the day" this was a common problem, the vapor lock and hot oil. I also just recieved a new fuel pump. I've always been a little leery of the el cheapo square facet pump ( which turns out to be a diaghram style pump). I got the new facet pump that IAP lists which I believe is either a screw or rotary type pump. That should also enhance the fuel pressure and long term reliability. I'll keep the square for a back-up. Good luck, Joe

[Gary Williams]

This is interesting. Do you think lack of a mechanical fan is contibuting to the fact that my fancy headers are burning up everything close to them?

The car runs fine in our northern California weather. It's the heat from the tri-y headers that is the problem.

[60sRacer]

I solved the vapor lock problem with an electric fuel pump mounted at the fuel tank- pushes the fuel all the way to the glass filter and carb under about 4.5 psi, enough to prevent vapors even in really hot engine bay. Don't let it get above that - the Webber float seats don't like it. I even put a decel switch from an alfetta to turn off the pump in a collision - couldn't stand to see my baby burn; it's hard enough replacing the rear trunk lid (duetto) when an idiot rear ends me (happened three times in, oh, 37 years...).

Slow traffic here in LA summers is a real bear. Temps in the Valley or Vlaencia push over 100° F. Hot sun beating down. Slow traffic and the temp just creeps up.... Even my big Mercedes with two electric fans and a big viscous clutch engine fan, all running full out can't cool enough in slow traffic. First sign is the AC can't put out cold.......

In the Alfa, I stick to the fun back roads and coast side when it's that hot.

Robert

[60sRacer]

To help the header heat problem DO NOT paint them black; this has a high emissivity that radiates a lot of heat into the engine bay. Chrome is actually the best to keep the heat out of the engine compartment (low emissivity). Thermal wrap is even better, or a ceramic coat (silver for low emissivity), but the heat will then bake and eventually fail the tube headers. Open up the exhaust beyond the header as much as you can - large diameter tubes, no cat (not in a 67 GTV anyway). Some of us drop the front resonator for a straight tube - that also gets the heat away from the floor. I've even tried a straight pipe tail. Pretty loud with just the center muffler, but at road speed its a thrilling "Alfa Song". Can't talk in a roadster with the top down anyway....

Also, watch out for the header heat getting to the brake master cylinder. In the 67 it's under the car (floor mount pedals) and a bit near the exhaust. Make a stainless sheet metal heat shield between them, with a high temp insulation on the brake cyl side. too much heat can actually boil the brake fluid and you loose all braking. Check the brake reservoir - if it feels too warm, the fluid could be heating. Since my reservoir is just above the exhaust manifold, I made a heat shield for here too.

Robert

[Gary Williams]

I paid my grumpy header manufacturer/supplier extra for a "space age" coating that is supposed to be better than anything else on the market. It's a light bronze color. Behind the headers I have an all-stainless 2.25" exhaust system, put together with the advice of Peter Nitoglia, a VP at Magnaflow. Peter races a GTV. My car uses center and rear Magnaflows.

Instead of a stainless steel heat shield, I wrapped high temp insulation on the brake lines. Already lost a new brake master due to boiling the fluid. Now, with ATE Blue and shielding, it has been okay. It's all the rubber and plastic on the header side of the engine I'm concerned about (insulation on wires and cables, mostly). My engine compartment is pictured at: http://greend.com/Engine%20Swap.htm Peter's race car is also shown on the website, on the Scuderia Non Originale pages.

[60sRacer]

I've seen mixed opinions on the Spruel headers for street operation on the BB. Other than The cast headers of the 1750, do you have any experience with others? The line is that these headers are very narrow band at high RPM because of the short 4-2 section and similar 2-1 section - really good but only at high track rpm. Others have a longer 4-2 section to get best operation at non-track rpms, and a very short 2-1 section to mate with the stock exhaust. Optimum would be a long 4-2 section AND a rather longer 2-1 section, which would eliminate the front resonator. Off their tune point, the Spruell headers actually slow gas flow and increase engine bay heat, as well as reduce engine power.

I still think you get too much engine bay heat from any dark color on the exhaust manifold, and should wrap it with an appropriate heat shield. Simple radiative transfer issue - black or dark (in the visual band we see) often means a high emissivity in the infrared band where the heat from the manifold is - peak emission at exhaust temps is around 5 micron wavelength. You really want a low emissivity in this band to keep the heat out of the bay, and a high emissivity (black, especially flats) where you WANT to radiate heat - well past the front resonator in fact, though the airflow under the car is usually enough that any good black is OK. A polished or shiny (specular) surface helps reduce the heat transfer. Hence chrome plating is really good for this. Thermal wrap with aluminum outer layer is also very good - see any good turbo supplier, since they work very hard at keeping the thermal energy in the exhaust gas.

The ceramic coatings I've seen are good for visual looks and do not degrade with age and heat, but do not really offer the right thermal management in the bay.

Wraping the brake lines is good, but stopping the heat at the source is better. If you get some thermal wrap from a turbo supplier, run it past the MC. And add a heat shield. SI\ince this is a single circuit brake system, you really can't afford the risk of brake failure can you?

ROBERT

[Gary Williams]

Thanks Robert