Gt-40 Cooling (or Lack Thereof).

[BLACKJACK]

HEY, BOB,

THANKS TO ALL OF YOU GUYS - ESPECIALLY TED. THE RADIATOR IS IN, THE A/C COND. IS MOUNTED, THE FIBER GLASS IS TRIMMED;

AND THE DARN THING STILL RUNS HOT !!!

AMBIENT AIR TEMP HAS BEEN BETWEEN 50 & 70 F.

AS LONG AS I CAN MAINTAIN 30 - 35 MPH OR BETTER THE H2O TEMP STAYS BETWEEN 170 & 190. (MOSTLY VERY CLOSE TO 180) AS LONG AS I DRIVE VERY "MODESTLY".

WHEN I "GET ON IT" THE TEMP WILL RISE TO 200 F.

WHEN I'M BELOW 25 MPH OR STANDING IDLE IN TRAFFIC THE TEMP HAS CLIMBED TO 220F AT WHICH TIME I HAVE GOTTEN OUT OF THE "CREEPER LANE" AND RISKED A TICKET BY JUMPING INTO THE "HOV" LANES WHERE I COULD GET SOME SPEED.

LONG STORY SHORT: IT'S ACTING JUST ABOUT THE SAME AS IT DID WITH THE OLD RADIATOR & COOLING FANS. A GREAT WINTER CAR BUT NOTHING THAT I CAN DRIVE IN GENERAL IN WARMER MONTHS.

THE COOLANT CONSISTS OF 25% PRESTONE; 75% DISTILLED WATER; AND TWO BOTTLES OF REDLINE WATER WETTER.

I HAVE NOTICED THAT OCCASSIONALLY - NOT ALWAYS - WHEN I SHUT THE ENGINE DOWN THE IGNITION SWITCH AND KEY ARE VERY HOT. THE FACT THAT THIS IS INTERMITENT AND "MAY" BE RELATED TO THE COOLING FAN OPERATION - - IS IT POSSIBLE THAT THE COOLING FAN CIRCUIT MAY BE TAKEN OFF OF THE IGNITION SWITCH AND NOT RUN THROUGH A RELAY?? IF THIS IS SO - IN ADDITION TO THE POSSIBILITY OF TURNING THE GT-40 INTO A "CAR-B-QUE" COULD IT BE CAUSING A SUFFICIENT VOLTAGE DROP TO THE FAN MOTORS TO REDUCE THEIR RPM AND EFFECTIVENESS??

I'M REALLY GETTING FRUSTRATED "DESPERATE" . I'D LIKE TO BE ABLE TO DRIVE THE GT-40 TO CARLISLE AND TO DVSFII.

SECOND ISSUE: I RAN OUT OF GAS FRIDAY NIGHT ON THE WAY HOME AROUND MIDNIGHT. THE LEFT FUEL GAUGE READ ALMOST A HALF TANK AND THE RIGHT GAUGE READ OVER 1/4 TANK. MY FIRST THOUGHT WAS "FUEL CONTAMINATION" AS THE CAR HAD NOT BEEN DRIVEN IN ABOUT SEVEN MONTHS. NOT THE CASE - WHEN I TOPPED THE TANKS BOTH TOOK ABOUT 9.1 GAL. THEY HAD BEEN "BONE DRY". I KNOW THAT I'VE SEEN THE GAUGES READ LOWER THAN THEY DID FRIDAY WITH THE ENGINE STILL RUNNING. COULD SOMETHING HAVE HAPPENED TO THE CALIBRATION BECAUSE OF THE EXTENDED PERIOD OF NON USE?? WHERE DO YOU SUGGEST THAT I START LOOKING??

ANY THOUGHTS OR HELP WILL BE GREATLY APPRECIATED.

Y'ALL HAVE A REALLY GREAT DAY,

BLACKJACK

[Back in Black]

Do you have an oil cooler? Add one with an oil temperature thermostat, and that should help temps across the board. This will help you drive the car more safely while you work this bug out, and you also will have increased oil supply.

Second, did the gas gauges work correctly/accurately, before? If they were accurate before the electrical changes, it sounds like a wiring problem....could it be that your fan wiring gets overloaded, and shuts down when you are on the road? Or can you hear the fan operating?

[Cobranut]

BJ,

I don't know what engine your running in the 40, or how radical it is, so I'm doing a lot of speculating here.

My 427 has 12.5/1 comp and a fairly radical cam. When I broke in the cam, it wanted to heat up. I kept it cool with a water spray over the radiator until I discovered the cause, insufficient initial ignition advance.

I now run 21 to 23 deg initial advance, and limit the total to about 40 deg. I had to make a bushing for the distributor to get this curve.

In 90 deg + weather, with a 180 deg thermostat, I never see over about 190 or so. Sitting in traffic, the fans still cycle on and off as the t-stat opens and closes, so I'd say I still have extra cooling capacity. Even on a hard run up the mountain, or on the track, I never see over 200.

What happens with late timing is a lot more of the mixture is still burning as it goes out the exhaust ports. This transfers a lot more heat to the water jackets, and less of it is converted into torque.

Tell us a little more about the combination, and let me know if this helps.

Good luck,

[BT SNAKE]

Hey Jack,
I hope you don't mind me jumping in here. I do believe
that you have air in the cooling system. The water pump
will palpitate while getting on it as you say. At idle the
pump has to try and draw through the air pockets but
it looses the battle most times. It kinda like trying
to pump water without priming the hand pump.
Jack, take and raise the rear off the ground about a foot
then fill the system. This will force most of the air to
the highest level. I know it sounds crazy but thats
what works. From my expierence this most likely
your problem.

Get her goin' Jack, I want to see that car at the Fling !

Hersh

[BLACKJACK]

THANKS FOR THE REPLYS, GUYS,

BACK-IN-BLACK: I DON'T HAVE AN OIL COOLER. THE OIL TEMP RARELY GETS ABOVE 120 F. I HAVE A 7 QUART OIL PAN AND DUAL FILTERS. IT'S ABOUT A NINE QUART SYSTEM AND HAS NEVER INDICATED A TEMP PROBLEM.

I CANT HEAR THE FANS RUNNING WITH THE ENGINE RUNNING. THE GREEN "COOLING FAN" LIGHT COMES ON AT 180 F WHICH MAY OR MAY NOT PROVE ANYTHING - DEPENDING ON WHERE THE LIGHT IS WIRED INTO THE CIRCUIT.

THE COOLING PROBLEM ONLY EXISTS AT LOW SPEED OR WHEN STOPPED IN TRAFFIC.

ON THE OTHER HAND - WHEN I FIRST CRANKED IT UP IT RAN IN THE GARAGE FOR ABOUT THIRTY MINUTES AND NEVER GOT OVER 180F. I HAD THE FRONT CLIP UP AT THE TIME.

THE FUEL GAUGES WORKED FINE BEFORE. THERE WAS NO ELECTRICAL WORK DONE SINCE. THE CAR DOES HAVE "FUEL CELLS" (NOT SURE WHY THAT SHOULD MAKE ANY DIFFERENCE). IT DID SIT IDLE FOR SEVEN MONTHS WITH "SOME AMOUNT" OF FUEL IN THE CELLS.


COBRANUT: THE ENGINE IS A BOSS 302 WITH LEMANS ALUMINUM HEADS I DON'T RECALL THE SPECS (THEY'RE TOAST NOW) BUT IT'S NOT REALLY "RADICAL". I'LL TRY TO LOCATE THE BUILDER AND GET MORE INFO ON THE SPECS.


HEY HERSH: I HAVE A "HIGH POINT PURGE VALVE" AT THE HEATER HOSE WHERE I BLEED OFF THE EXTRA AIR. IT MAY NOT BE ENOUGH THOUGH. I'LL TRY YOUR SUGGESTION TOMORROW. I'LL CREATE SOME WAY TO GET IT'S BUTT UP IN THE AIR. THINGS ARE A LITTLE TOUGH WITH FEW TOOLS LEFT AND NO ELECTRIC POWER IN THE GARAGE. YOUR EXPLANATION MAKES A LOT OF SENSE AND PRETTY MUCH DESCRIBES WHAT'S HAPPENING.

THANKS AGAIN GUYS - YOUR HELP IS REALLY APPRECIATED.

Y'ALL HAVE A REALLY GREAT DAY,

BLACKJACK

[a427sc]

Blackjack

A suggestion on how to bleed the air out. There is a new tool available that locks into the radiator cap and uses shop air to create a vaccum in the cooling system. First drain all the coolant you can get to easily, then hook up the sucker. In only a few minutes you will have a nice vaccum going. Shut the air valve, put the fill line in the replacement coolant, and open the valve. Since the system is in vaccum, no air to block up in the high spots thus a complete fill. If you run out of suction before it's full, lock the filler and suck on it a little more. Works like a charm on MR2's and all the difficult cars I have seen so far. Check with your local mechanic or tool dealer.

McFEZ

[BLACKJACK]

McFEZ,

THANKS FOR THE TIP. WILL IT WORK WITH A GT-40?? THE COOLING SYSTEM CAP IS BACK BY THE ENGINE. THE RADIATOR IS UP FRONT AND HAS NO CAP, AND BOTH COOLANT LINES ARE AT THE BOTTOM OF THE RADIATOR..

WHAT IS THE TOOL CALLED AND WHERE CAN I GET ONE?? MAN, I'LL TRY ANYTHING ABOUT NOW.

THANKS VERY MUCH

Y'ALL HAVE A REALLY GREAT DAY,

BLACKJACK

[Cobranut]

With both lines at the bottom, do you have a purge valve at the top of the radiator? It seems to me that would be the only way to get the radiator filled with water.


Or, on second thought, you could simply turn the car upside down while filling.

[BLACKJACK]

HEY DAVID,

NOPE - NO PURGE VALVE ON THE RADIATOR - I HAVE NO IDEA WHY IT DOESN'T. THERE ARE THE TWO FEED PIPES AT THE BOTTOM AND THE COOLING FAN THERMOSTAT - ALSO ON THE BOTTOM.

DID YOU NOTE IN BOB PUTNAMS EARLIER REPLY THAT "HE DESIGNED THE RADIATOR THAT WAY".

A PURGE VALVE ON THE TOP WOULD CERTAINLY BE A NICE FEATURE.

TURNING THE DARN THING OVER MAY HAVE TO BE CONSIDERED AN OPTION AT SOME POINT.

THANKS, AND, Y'ALL HAVE A REALLY GREAT DAY,

BLACKJACK

[ERA535]

BLACKJACK-

Here is a shot in the dark but you never know...

I see where you said that the ignition key gets hot sometimes, then you said that the fuel guages are reading incorrectly and the water temp guage is indicating a temp that is higher then it should.

Is there a possibility that there is a ground problem or some other kind of electrical issue in the wiring in your dash?

I think you should make sure that the temperatures that you are getting are real - maybe the guage is indicating too high.

Good luck.

Pat

[Bob Putnam]

Jack,

Easy things first.

The ignition switch is overloaded. The original Lucas unit wasn't designed for street driving. If you are willing to make the hole in your dash a bit larger, I'll send you our NEW IMPROVED! switch.

Cooling:

I think that you may still have a bit of air in your system. The best way to bleed it out is to tilt the front end up as much as possible and bleed from the top of the engine.

If that doesn't work, there are a couple of electric water pumps that can be wired to the fan circuit in series with the mechanical water pump, or used to substitute for a gutted pump.

[BLACKJACK]

PAT,

THANKS FOR THE REPLY. I DON'T THINK THAT IT'S THE GAUGE/SENDER BECAUSE MOST OF THE TIME THE TEMP STAYS RIGHT AROUND 180F. IT SURE WON'T HURT TO TEST IT THOUGH. "SOMEWHERE" IN WHATS LEFT OF MY GARAGE I HAVE A LAZER THERMOMETER THAT I THINK WILL READ HIGH ENOUGH. I'LL GET A BETTER LOOK AT IT TODAY BECAUSE THE AIR TEMP IS GOING TO BE 80+ DEGREES OUTSIDE.

WHEN I "LEAN ON IT" IT JUMPS UP 20 DEGREES OR IN TRAFFIC IT LOOKS LIKE THE SECOND HAND ON A CLOCK. OTHERWISE IT ACTS "NORMAL".

BOB,

THANKS FOR GETTING BACK TO ME. YEAH, NO PROBLEM, I'D LIKE TO INSTALL THE NEW IGNITION SWITCH. (I'M REEL "SQUIRELY" ABOUT THINGS THAT GET TOO HOT - OR GO BANG).

DO YOU THINK THAT AN ELECTRICAL RESISTANCE THAT COULD MAKE THE SWITCH TOO HOT TO TOUCH COULD BE CAUSING A VOLTAGE DROP THAT DOES NOT ALLOW THE COOLING FANS TO OPERATE AT FULL RPM??

I'M NOT SURE THAT I UNDERSTAND HOW TILTING THE "FRONT END UP" WILL ALLOW ME TO BLEED AIR FROM THE ENGINE. PERHAPS, DO YOU MEAN TILT THE "REAR END" UP???

WHERE ON "THE TOP OF THE ENGINE" IS THE BEST POINT TO BLEED THE AIR??

IS THERE ANY WAY TO INSTALL A BLEED VALVE ON THE TOP OF THE RADIATOR WITHOUT HAVING TO TAKE IT BACK OUT??? OR IS THAT NOT NECESSARY??

WOULD YOU PLEASE SEND ME THE INFO ON THE ELECTRIC WATER PUMPS. I DON'T THINK I WOULD WANT TO REMOVE (GUT) THE MECHANICAL PUMP BUT IT MIGHT WORK TO HAVE A SUPPLEMENTAL PUMP FOR OPERATING AT LOW SPEEDS / HIGH TEMP CONDITIONS.

ANY THOUGHTS ON WHAT MIGHT HAVE HAPPENED WITH THE FUEL GAUGES??? I BELIEVE THAT THE GT-40 HAS THE ELECTRONIC FUEL LEVEL SENSORS. I KNOW THAT IN LARGE AIRPLANES THAT TYPE OF SENSOR WOULD SOMETIMES GO "NUCKING FUTS" FOR NO REASON. THEN RE-STABILIZE AFTER TOPPING UP THE TANKS.

THANKS, AND - - Y'ALL HAVE A REALLY GREAT DAY,

BLACKJACK

[ERA535]

BLACKJACK-

When you temp guage jumps 20 degrees "like the second hand of a clock" - this is symptomatic of an electrical problem, not an engine problem.

Pat

[petek]

Blackjack,

re: ignition switch

Look at it this way, if the ignition switch was good for 10 amps and you tried to take 20 amps through the switch, the contacts in the switch would heat up. As the switch heated up it's ability to carry current falls, let's say it went from 10 amp capability to 5 amp capability ... but you are still trying to draw 20 amps through the switch ... so the switch continues to heat up.

AND making it all that much more interesting, as the switch heats up the reistance at the contacts increases and so does the voltage drop across the switch.

It's entirely possible that the voltage drop across the ignition switch is causing your temp gauge to read high and making your fan act funny.

[Cobranut]

Jack,

On my car, I wired everything that pulls appreciable current thru relays. ie: fans, headlights, fuel pump, preluber, even the horns.

The only thing that feeds directly thru the ign sw is the ignition system.

I agree with Bob, the switch should not get hot. I'd either replace it per his suggestion, or rewire all the major components thru relays.

If your temp gauges are electric, the drop across the switch may affect their readings, same for the fuel gauges.

Good luck,

[ERA535]

BLACKJACK -

2 things...

I have yet to see a bleeding problem that resulted in the temp guage acting in a predictable linear fashion....wild swings are the norm, ranging from way hot down to cold - but the needle will always move smoothly. Quickly maybe, but smoothly. It will never snap up and down like a second hand on a fake Rolex.

I have seen many cars that have (usually ground) problems to the dash that result in the temp guages jumping around - and indicating too hot.

Your radiator needs some way to purge it of air.

Pat

[Jim Holden]

BJ:

Getting the air out of the system takes some time. As I recall (#2038 is gone to the other coast now), we jacked up one end of the car and then the other. Then drove it around the block (which meant up and down hills) to try and get the air out. It took awhile.

I had also run a small bleed (as in the original original cars) line from the upper right side of the radiator to the purge tank on the firewall/bulkhead. (ERA does this on the 427SC as a matter of course.)

Keep at it.

Morty MacTavish

[a427sc]

BJ

Several options with the sucker tool. Very cheap unit from MityVac retails about $80, crummy adapter for radiator, single inlet, you get what you pay for. Basic unit from Airlift/U-View, single inlet/filler fitting (have to shut valve and switch from suction to refill adapter), solid brass radiator adapter, quality piece for about 110-120 retail. Deluxe U-View/Airlift, same body but with 2 fittings (one for refill, one for suction with a button valve...very easy to add a little vaccum to system if needed) available from some tool outlets and of course, from Snap-on at about 150.

Since I know a Snappy dealer real well, I can get you a deal if you want. E-mail me if you are interested.

McFEZ

PS Hi Jimmy

[BLACKJACK]

TODAY, WITH THE OUTSIDE AIR TEMP. AT 87F, THE H20 TEMP READ 180F FOR ABOUT FIVE MILES; THEN, UP TO 195F FOR ANOTHER FIVE MILES; THEN UP TO 215F FOR ANOTHER 5 MILES; THEN 230 FOR ANOTHER FIVE MILES. I "LIMPED" IT INTO THE DRIVEWAY AT 240F AS IT STARTED DUMPING COOLANT INTO THE STREET.

MY AVERAGE DRIVING SPEED WAS 55 TO 60 MPH FOR THE FIRST TO SEGMENTS (ABOVE), AND 40 TO 45 MPH THE REST OF THE WAY. EACH TIME THAT I STOPPED FOR A TRAFFIC LIGHT (THERE WAS NO APPRECIABLE TRAFFIC TODAY) THE TEMP WOULD CLIMB BUT NOT COME DOWN AFTER I RESUMED SPEED. IF I "GOT ON IT" IT WOULD ALSO CLIMB A FEW DEGREES AND NOT RETURN AFTERWARD.

I'M REASONABLY CONVINCED THAT THE PROBLEM IS NOT ELECTRICAL (WITH THE POSSIBLE EXCEPTION OF THE HIGH RESISTANCE WITH THE COOLING FANS). WITH EACH INCREMENTAL INCREASE IN H2O TEMP THERE WAS A CORRESPONDING INCREASE IN OIL TEMP AND A CORRESPONDING DECREASE IN OIL PRESSURE. THE MOVEMENT OF THE THREE GAUGES WAS NOT AT ALL RANDOM THE CHANGES WERE DIRECTLY RELEVANT.

PAT: - - - IT DOESN'T "SNAP" LIKE A FAKE ROLEX, BUT RATHER GLIDES LIKE A REAL ONE. THE CHANGE IS SMOOTH BUT "MUCH" FASTER THAN A TEMP GAUGE WOULD NORMALLY MOVE.

JIM: - - - I AGREE, THE RADIATOR SHOULD HAVE A PURGE/BLEED VALVE AT THE TOP. A DRAIN VALVE AT THE BOTTOM WOULD BE NICE ALSO. I'M TEMPTED TO PULL IT BACK OUT AND TAKE IT TO A RADIATOR SHOP AND HAVE THEM INSTALLED.

PETE & COBRANUT: - - - YEAH, I DIDN'T DO THE WIRING AND I HAVEN'T, AS YET, REALLY "CRAWLED THROUGH IT". MAINLY BECAUSE THE GUY WHO BUILT THE CAR DID SUCH A GREAT JOB ON THE DETAILS. I'M A GREAT BELIEVER IN RELAYS. (PROBABLY COMES FROM TOO MANY HOURS FLYING THE LOCKHEED ELECTRA. P-3 TO YOU NAVY TYPES). I'M GOING TO PHYSICALLY TRACE OUT THE FAN FEED AND CONTROL CIRCUITS AND PROBABLY RUN A 12 GA. FEED CIRCUIT FOR IT.

McFEZ: - - - I'M VERY INTERESTED IN THE "U-VIEW AIRLFT COMBO KIT. I SAW IT IN AN AUTO PARTS SHOP CATALOG TODAY. I'LL SEND YOU AN E-MAIL.

ANYBODY: - - - KENNE-BELL MAKES A VOLTAGE BOOSTER FOR ELECTRIC FUEL PUMPS, CALLED THE "BOOST-A PUMP". ANY THOUGHTS ON INCREASING THE VOLTAGE TO THE FANS. THE FAN LABELS SAY 12 VDC BUT STSTEM OPERATING VOLTAGE IS 13.8 (TYPICALLY). AN INCREASE TO 16 OR 16.5 VOLTS SHOULD INCREASE FAN SPEED BY 10 TO 15%. ANY THOUGHTS ON THAT??

I REALLY WANT TO GET THIS CAR ON THE ROAD. I PLAN TO DRIVE IT TO CARLISLE AND ALSO TO DVSF. BUT NOT UNLESS I CAN GET THE TEMPERATURE UNDER CONTROL.

THANKS VERY MUCH FOR ALL THE GREAT SUGGESTIONS. THE HELP IS REALLY APPRECIATED.

Y'ALL HAVE A REALLY GREAT DAY,

BLACKJACK

[ERA535]

Blackjack -

If it doesn't "snap" I agree that it isn't an electrical issue.

The fact that it goes up predictably makes me think that it may not be a bleeding issue.

How long ago did it start doing this - did it start doing it in conjunction with some other repair or modification? Did it ever run cool?

Pat