| Author | Message | ||
| Burnell P. Curtis (Burnell)
New member Username: Burnell Post Number: 18 Registered: 4-2002 |
I am back to trying to get this car to run cool. I want to make the water pump run slightly faster. The diameter of the pulley on the pump is 103mm and the crankshaft pulley is 110mm so the pump is running slightly faster that the motor. I need metric pulleys. Does anyone know where to get one other than having one made? Would someone with a later model (later than 75) measure their pulleys and see if they are different? | ||
| Hans E. Hansen (4re_gt4)
New member Username: 4re_gt4 Post Number: 9 Registered: 4-2002 |
Peter: Yeah, I know how A/C works. I guess where I wasn't clear in my message is that the added heat load of the A/C is enough (on my car) to tip it over the top, temp stability-wise. Therefore my conclusion that the cooling system on these cars is perhaps a little marginal. | ||
| '75 308 GT4 (Peter)
Intermediate Member Username: Peter Post Number: 1826 Registered: 12-2000 |
Hans, the reason why the heat jumped up is because the A/C condensor sits right in front of the radiator. The condensor is a heat EXCHANGER, it dumps the heat picked up by the freon from the evaporator (in the cockpit). Where do you think that heat goes?...  | ||
| joe saldana (Ironjoe)
Junior Member Username: Ironjoe Post Number: 52 Registered: 12-2001 |
I am currently running the cats-ass system it consists of a CSI electric water pump,a 14 inch Perma-cool 2950 cfm fan,Stant 20 pound radiator cap,recovery-can out of expansion tank, AND THE KICKER is a SHOGUNN TIC-TOC BOX.it CYCLES your pump THEN fan,and so-on.So it turns your whole system into a true HEAT-EXCHAGER with NO THERMOSTAT AT ALL.still getting excellent heat to heater core... | ||
| Bill Sebestyen (Bill308)
Junior Member Username: Bill308 Post Number: 196 Registered: 5-2001 |
Burnell, I apologize for addressing my posts to the wrong name (Greg). Greg, my last 2-posts were intended to try and help Burnell. | ||
| Greg Rodgers (Joechristmas)
Member Username: Joechristmas Post Number: 255 Registered: 3-2001 |
I am Greg. Read down in the post. I tried to give you some advice. | ||
| Burnell P. Curtis (Burnell)
New member Username: Burnell Post Number: 17 Registered: 4-2002 |
Final note: Bill308, who is Greg? Anyway, there was no thermostat in my car at the time. I had it out and the hot water recycle plugged. Ironjoe, I think you have it. The concept of a small pulley on the water pump intregues me. Think I will try it when I get back. | ||
| Hans E. Hansen (4re_gt4)
New member Username: 4re_gt4 Post Number: 8 Registered: 4-2002 |
Just a minor $.02 point. I'm new to this, as I only acquired my 'GT4 a few months ago. My car runs quite cool, slow to warm up, and then settling at about 180 or so (a little hard to tell because of the sparsity of markings). Highway or stop-and-go traffic. The needle moves very little. Rock solid. However... Today was the first warm day around here. Temp rock solid at 180, as normal. Turned on A/C, and temp went up to 200 or a little more. My naive conclusion: Perhaps the cooling system on these cars is a little marginal. The A/C was just enough to put it over the top. Your car may be within norms. | ||
| magoo (Magoo)
Advanced Member Username: Magoo Post Number: 2655 Registered: 2-2001 |
Burnell, Enjoy the time with your granddaughter. When you come back everthing will probably fall in place and you will correct the problem. | ||
| Bill Sebestyen (Bill308)
Junior Member Username: Bill308 Post Number: 193 Registered: 5-2001 |
Greg, This is interesting information. A couple of observations: 1. On the highway, you say you are getting 90C at the radiator inlet and 80C at the return. I don�t know what temperature your thermostat opens at, but mine is supposed to open at 85C, according to my OM. Your temperatures look consistent with a partially opened thermostat, where your radiator appears to be supplying all the necessary cooling capacity required for the run your made. The 10-degree delta is reasonable for this case. The cooling capacity of the radiator is probably not being taxed. 2. When sitting in the driveway, there is little cooling flow over the radiator. This reduced cooling flow is compensated by the engine not producing a lot of heat in the idle mode. In this case, the slightly higher temperatures and the 5-degree delta is also reasonable. The reduced heat input to the radiator is compensated by reduced heat rejection to the surrounding air. Your thermostat is probably fully open in this case, resulting in higher overall temperatures but a smaller delta. If one were to look at the overall process, you have coolant entering the radiator. Heat is rejected to the insides of the tubes. This heat flows from the tubes to the fins by conduction. From the fins, the heat is ultimately rejected to the ambient air. So, you have a convection-conduction-convection process occuring. The water wetter improves the forced convection from the coolant to the tubes. The intimacy of the tubes to the fins, controls the heat flow to the fins. Air flow improves the convection from the fins to the ambient air. The faster the air flows over the fins and the cooler it is, the better this convection process operates. This looks pretty good. I don't see any problems for these two cases. | ||
| joe saldana (Ironjoe)
Junior Member Username: Ironjoe Post Number: 51 Registered: 12-2001 |
custom alluminum radiator $350.00 2 row x 1 1/2 in.Perma-cool puller 2950 cfm fan $83.00 Evans npg no-water coolant $22.00 a gallon,hi volume thermostat 15.00 Gates greenstripe hose $4.00 a foot runnin fine at 180 degrees in july ...priceless.... | ||
| Burnell P. Curtis (Burnell)
New member Username: Burnell Post Number: 16 Registered: 4-2002 |
More data to confuse. The inlet temp was 90 C and 80 C on the freeway and 95 C and 90 C in the driveway and I suspect they would continue to rise in the driveway. I took the instruments off and put them on my Toyoto Camry and got almost the same readings in the driveway, ie 92 and 88. This work is over for 2 or more weeks because I am going to help care (play) with my granddaughter (2 years) while others take care of my new grandson. When I return I plan to remove the waterpump and check everything and put a smaller pulley on it unless I get some more excellent suggestions from youall. | ||
| Michael Fennell (Mfennell70)
New member Username: Mfennell70 Post Number: 45 Registered: 7-2001 |
This is possibly obvious and should have been checked by the radiator shop but what's the condition of the radiator fins? Are they able to conduct heat adequately? I've seen older radiators with the fins hardly in contact with the core at all thanks to corrosion. | ||
| Bill Sebestyen (Bill308)
Junior Member Username: Bill308 Post Number: 192 Registered: 5-2001 |
Greg, I've never measured my in/out temperature difference, but I'm surprised you're only measuring 10-11C. I would expect to see something close to double this, if the engine was completely up to temperature. I suspect you may have a radiator problem. What were the inlet and outlet temperatures when you measured this delta? If you still have the instrumentation in place, see if you can measure the temperatures when the fans just turn on. | ||
| Burnell P. Curtis (Burnell)
New member Username: Burnell Post Number: 15 Registered: 4-2002 |
I measured the temp of the returning water. It was 10 maybe 11 deg c difference between in and out when on the freeway at 64 mph. In the driveway it was about 5 c with both fans running. What have others measured? | ||
| magoo (Magoo)
Advanced Member Username: Magoo Post Number: 2651 Registered: 2-2001 |
Burnell, Greg makes a good point there. Maybe it wasn't done correctly when the rad. was rodded. I would check to see if there is a big difference in temps. between the upper and lower rad. hoses. | ||
| Greg Rodgers (Joechristmas)
Member Username: Joechristmas Post Number: 253 Registered: 3-2001 |
To me is sounds like your radiator is partially clogged. I had the same problem on my Lotus. I had it rodded out and thought it was fine. It would start to run hot after I put the engine back in. I then pulled the rad. again and took it too another shop and they opened it up for me and it was still obstructed. The place I originally took it to didn't do a very good job. I then had it recored and my car runs incredibly cool. I would try just to be sure. | ||
| magoo (Magoo)
Advanced Member Username: Magoo Post Number: 2647 Registered: 2-2001 |
Burnell, I know you had the radiator rodded but what is the temp. differential between the upper radiator hose and the lower one. Have you actually taken these temps. after the engine reaches normal operating temps? Is there a great difference? | ||
| Burnell P. Curtis (Burnell)
New member Username: Burnell Post Number: 13 Registered: 4-2002 |
There is no "before" rebuild known to me. I bought the car disassembled and rebuilt everything. Since finishing the car, this overheating has haunted me. In the winter it is ok, but the summers in South Texas are brutal. The radiator was cleaned after about 1000 miles. I rebuilt the pump but do not remember checking the clearance. On my todo list but taking the pump out is somewhat of a chore. the car is hot at both ends. I did think that there was exhaust gas in the coolent and retorqued the heads and thought that did better. Seems to be less(no) gas now. Found the Redline and tried it with the hot water recycle plugged. WORKS BETTER. The temp got up to past the 0 in 90 deg(maybe 95) while around town and back down to between the 9 and 0 on the freeway. THAT IS MUCH BETTER THAN 105. The housing where the thermostat blocks the hot water recycle is definately corroded (erroded) and I need to reface it. I plan to next explore what the normal water temperature coming back from a radiator is. If the 308 is too cold or too hot then I will learn a lot. | ||
| Edward Gault (Irfgt)
Intermediate Member Username: Irfgt Post Number: 1183 Registered: 2-2001 |
If your radiator was cleaned before the overhaul it could have clogged while the car sat during the down time. I have seen this happen. Stuff that was normally washing around in the cooling system can harden when drained and sits idle. | ||
| Steve Magnusson (91tr)
Member Username: 91tr Post Number: 692 Registered: 1-2001 |
Burnell -- Can you clarify the description of the problem? Are you saying: 1. It ran "normal" for 1500 miles and has now suddenly changed in temp behavior, or 2. It's ran different temp-wise always after the rebuild? I think you're on the right strategy to confirm proper flow behavior first (perhaps another longshot would be to check the water pump impeller-to-housing spacing as shown in the WSM), but before doing anything too expensive, IMO, it might also be prudent to confirm no exhaust (CO) in the coolant (if you're fairly sure the flow stuff is all working decently and the temp doesn't come down somewhat at cruising speed compared to hot idle) -- just another thought... | ||
| Mark (Markg)
Junior Member Username: Markg Post Number: 178 Registered: 2-2001 |
www.redlineoil.com 800-624-7958 has list of local dealers or order from Automotion. Is your car hot at both ends, i.e. is the radiator as hot as the fill tank in engine compartment (if not, this might indicate a blockage or thermostat issue)? Do you notice a drop in temp if you open the heater valves? | ||
| Burnell P. Curtis (Burnell)
New member Username: Burnell Post Number: 11 Registered: 4-2002 |
I have not found a local source for Redline Water Wetter. Suggestions please. Has anyone tried putting a smaller pulley on the water pump to make it run faster and pump more. I know there are limits to this but maybe a small increase will help. I will inspect the hoses but they are new. | ||
| BretM (Bretm)
Intermediate Member Username: Bretm Post Number: 2447 Registered: 2-2001 |
I too bask in the fruits of water wetter. | ||
| magoo (Magoo)
Advanced Member Username: Magoo Post Number: 2608 Registered: 2-2001 |
Burnell, What Richard says is true about the Water Wetter. I used it in all my cars and like it very much. If you see an improvement that still doesn't answer why it is overheating does it? Another thing, Check all your hoses after driving for a while to see if any of them may be sucking shut and causing a restriction. | ||
| Burnell P. Curtis (Burnell)
New member Username: Burnell Post Number: 10 Registered: 4-2002 |
Next episode. Checked the timing and it was OK. I did rebuild the engine. Had forged pistons from JE made. Stock compression. Heads were milled a couple of thousands to flatten them. No cracks. Head gaskets were aftermarket from T. Rutlands. I think it is not possible to reverse the head gasket because of the positioning pins. One head was just off and there were no problems. Of course, there could be something in the engine that is obstruction flow but the only way to find it would be to take it apart. I am not there yet. I will try the Redline water wetter and see what happens. thanks all for the suggestions. Has anyone put different fans in a GT4, expecially on the back of the radiator? | ||
| Paul Newman (Newman)
Junior Member Username: Newman Post Number: 149 Registered: 12-2001 |
Burnell, You said you restored the car. Im assuming the engine was in a million pieces then? Assuming everything is working correctly like fans and circulation from the pump, is it possible there is a head gasket concern, such as installed upside down, obstructing passages from the head to block? Are they factory gaskets? Is compression ratio stock? Do you have an improperly stamped gasket? Ive seen these problems on other makes and models right from the dealer with factory parts. Could a head have a crack? There are so many possibilities. | ||
| Richard Stephens (Dino2400)
Junior Member Username: Dino2400 Post Number: 62 Registered: 10-2001 |
Since winter is over and you don't need anti-freeze protection, you could flush out the glycol mixture and go straight water with a bottle of Redline Water Wetter. You'll run cooler with just water and with the Water Wetter you'll run cooler still. Will drop your operating temps by 10-20 degrees F. Assuming your system is 15psi, boiling point will be 250F with water and water wetter instead of 265F with 50% glycol/water mix. So take that into consideration but if aren't having boiling problems and just want to run cooler, the Water Wetter is great stuff. (If you use AC a lot they recommend running 20% glycol anyway because the heater core might freeze). | ||
| Mark (Markg)
Junior Member Username: Markg Post Number: 174 Registered: 2-2001 |
Try this guy's site: http://members.tripod.com/~ferrari308gt4/ferrari.6.html long article on his Gt/4 over-heat issues | ||
| Burnell P. Curtis (Burnell)
New member Username: Burnell Post Number: 9 Registered: 4-2002 |
Another chapter. I vented my thermostat housing. A large quantity of air is released but it made no difference to the overheating. I next removed the thermostat and plugged the recycle return with a freeze plug. There is now no chance for recirculation. It made no difference. My last duty is to check the timing. Is it set on 6 deg, or 10 deg, or 16deg. | ||
| F-J'87EuroTR (Ferrarijoe)
Junior Member Username: Ferrarijoe Post Number: 114 Registered: 5-2001 |
Burnell, Try here for an explanation for the Hayden fans. http://www.haydenauto.com/products.html | ||
| Burnell P. Curtis (Burnell)
New member Username: Burnell Post Number: 7 Registered: 4-2002 |
Thanks for the comments. I will check the thickness before I drill and tap. What are Hayden fans? I have original four blade non shrouded fans that appear to work correctly, ie high speed and good air flow but more would be better. | ||
| Edward Gault (Irfgt)
Intermediate Member Username: Irfgt Post Number: 1159 Registered: 2-2001 |
I am not sure what your problem is but it seems to me that the air would have purged its self out by now. I have drained my system several times and even after overhauling the engine, I simply filled the engine through the coolant tank and have never had to get any air out and have not had any cooling problems. My temp gauge always stays just barely to the left of the 195 degree mark and when in traffic climbs to 195 and then the fans turn on and it never goes any higher. The fans run a long time though. If I had the Hayden fans it would lower the temp faster I am sure. | ||
| '75 308 GT4 (Peter)
Intermediate Member Username: Peter Post Number: 1815 Registered: 12-2000 |
Be careful Burnell about drilling into the GT4 housing, I'm not sure its thick enough to tap (if I remember correctly, the later 308's housing had additional material to have a sufficiant amount of threads). It would be best to locate and purchase a later housing (#105165-housing, 16042940-vent bolt, 10260060-washer). | ||
| Paul Newman (Newman)
Junior Member Username: Newman Post Number: 144 Registered: 12-2001 |
One other thing to keep in mind with the coolant is strength. If it is mixed too strong like more than 70% then it can overheat or run hotter than normal. This even causes emission test failures in late model cars if you can believe it. It increases NOX due to higher combustion temps. Just a thought. | ||
| Burnell P. Curtis (Burnell)
New member Username: Burnell Post Number: 6 Registered: 4-2002 |
I will drill and tap the thermo housing to vent it. I am going to check the timing again. Last time it was set on 10 deg at idle. After rereading the manual I think it should be set on 16 deg at 1100 rpm. It only has one set of points. The thermo has been changed with no effect. It came from T Rutlands in a Ferrari box. Brand unknown to me. Has anyone had any experience with leaking by the lower part of the thermostat due to corrosion of the base? That would cause bypass and lower cooling efficiency. | ||
| '75 308 GT4 (Peter)
Intermediate Member Username: Peter Post Number: 1810 Registered: 12-2000 |
Steve, my Motorad thermostat has this drilled-hole modification (about 2mm dia in my case). My car has gotten really hot in grid-locked traffic (around 105*C or so) and no ill affects afterwards when the traffic cleared (temp came right back down to 90*C). | ||
| Bill Sebestyen (Bill308)
Junior Member Username: Bill308 Post Number: 177 Registered: 5-2001 |
Good point Magoo. It'd be a good thing to alternately put a timing light on both the 1-cylinder and 5-cylinder wires and check for both initial advance at idle and also confirm that the advance mechanisms are in synch and operating properly. | ||
| magoo (Magoo)
Advanced Member Username: Magoo Post Number: 2543 Registered: 2-2001 |
Burnell, Is your timing set accurately? An engine tends to overheat if your timing is retarded too much. It sounds like you have covered all the basis. What else? | ||
| Steve Magnusson (91tr)
Member Username: 91tr Post Number: 681 Registered: 1-2001 |
Burnell -- you might consider getting a later thermostat housing that has the bleed port or trying to add one to your existing housing (all of the later cars have this). One trick I've seen is adding a small hole (like 1~1.5mm diameter) in the flat sheetmetal portion of the thermostat itself (if it doesn't have one already) to be sort of a permanent small "leak" to give a path for any entrapped air to reach the bleed port even when the thermostat is closed. For an experiment, you might try to do some "bleeding" at one of the upper hose connections between the head crossover pipe and the water pump by loosening the hose clamp and sticking a small diameter rod under the top of the hose to see what comes out -- just a thought... | ||
| 1975GT4Don (1975gt4don)
Junior Member Username: 1975gt4don Post Number: 52 Registered: 1-2002 |
....could also be a sticking or defective thermostat. There are two different types that can be used in the gt4. The savara brand and I forget the name of the other brand. Try changing your thermostat. Good idea to change it whenever your replace a water pump. | ||
| Bill Sebestyen (Bill308)
Junior Member Username: Bill308 Post Number: 174 Registered: 5-2001 |
Your measurement of 100-105C seems like a pretty normal water/antifreeze temperature for a preasurized (12.8 psi) system. The high limit for opening of the thermostat on my 308 is 85C and the max permitted temperature is 110-115C, according to my owners manual. Remember, thermocouple measurement systems are not the most accurate devices in the world (+/- 3C) unless specially calibrated. You could check your meter on the stove, by measuring the temperature of boiling (distilled preferred) water and see how it compares to 100C. This would be a good check of your meter. | ||
| Burnell P. Curtis (Burnell)
New member Username: Burnell Post Number: 5 Registered: 4-2002 |
Thanks for the comments. I have bled that radiator until I am blue in the face (and red fingers). My thermostat housing does not have a vent. The radiator was opened up by a radiator shop and rodded out. He was impressed that it had two plates in it that made it circulate the water up and down. I checked the temp by sticking thermocouple wires between the thermo housing and the hose and then retightening the hose. Hot is 100 to 105 C. Do you think that is hot? More suggestions are needed. Thanks again. | ||
| Ken (Allyn)
Member Username: Allyn Post Number: 354 Registered: 10-2001 |
As a cooling system/Lucas Prince Of Darkness veteren, I suggest it's air in the system as mentioned, or the gauge itself. But you said you checked the water temp; I'm curious how you did that in a pressurized system? Another thought: my radiator has a weak metal plate right between the intake and outflow. This frequently gets bent/corroded so the water doesn't circulate through the radiator itself like it should. Only careful inspection will reveal this. Are you sure the water is circulating inside like it should? | ||
| TomD (Tifosi)
Member Username: Tifosi Post Number: 556 Registered: 9-2001 |
Magoo Congrats on becoming an F1 vet | ||
| magoo (Magoo)
Advanced Member Username: Magoo Post Number: 2536 Registered: 2-2001 |
Burnell,When you say hot what do you mean. Boiling over or what temp. Harry is right about the air in the sytem and your bleeders at the radiator and the thermostat housing should be bled to remove the air. Another thing is how did you clean the radiator? If you did not have the tubes rodded that could be your problem by restricting coolant flow. | ||
| Harald Dichtl (Harry)
New member Username: Harry Post Number: 7 Registered: 3-2002 |
Maybe air in the cooling system. Lift the front end of the car up and open the valve at the radiator. | ||
| Burnell P. Curtis (Burnell)
New member Username: Burnell Post Number: 4 Registered: 4-2002 |
My 75 308 GT4 has 1500 miles on a complete restoration and now it is getting hot. I have had the radiator cleaned (not dirty). I have built a front air dram to force more air. I have moved the horns out of the way. The fans are coming on at the proper temperature and are blowing in the correct direction. I changed the thermostat. I checked the water temperature to confirm it is hot and it is. The water pump had a new bearing 1500 miles ago and spins freely now. All hoses are new and the cap is new. I believe the timing is correct but am going to recheck. My experience is that when a water pump is spinning with the proper resistance, it is ok. Is this true with this car? the car has no air pumps. Any suggestions for other areas to look into? |