1970 Challenger 440 Heating Problems

[Orange Man]

Along with the two previous observations, I can see where the first owner looped the heater hose back into each other since there is no heater core. Could this also be a problem. I have a friend with a 360 in his 73 Challenger and he did the same thing. He is running an OEM radiator with a flexfan with no problems. He has no A/C either.

 

[sixpactogo]

I measured my water pump pulley and it is a 6" (5" 13/16") pulley. Is this an underdrive pulley? I could not find specs on the March pulleys. I don't know if these are March pulleys.

Yes, You have an underdrive system. The factory used a 7" crank pulley. (7.5"). If you could get that larger pulley, it would help with coolant movement. I was not aware they made the larger pulley. The idea behind the smaller crank pulley was supposedly less horsepower needed to run the belt system.
As to your question about eliminating the heater core, It would not be a noticeable change IMO and is not part of your problem. Sure, if you had the heater core and had the heater on full roar, it would maybe drop your engine temp a degree or so but not enough to notice.
I think your best bet at fixing your problem would be to ditch that front fan, get both puller fans to work together and maybe see if you can get a larger crank pulley as mentioned in post #16 or a high flow water pump.
That would be my starting point.

 

[plymouth67]

The real question on the pulleys from my stand point would be the relation in size between the crank pulley and the water pump pulley.

 

[i_taz]

My cars temp seems ok but can't help but wonder about the updated aftermarket head gaskets that replace the top holes with slits like the BBC but aren't even over the passage. Most of mine were blocked shut by rust or the teflon coating from the head gaskets sticking to the block. I read where that's to force coolant to the back cylinders but why then in '75 or so did the blocks came with a figure 8 hole design, seemingly doubling water flow thru those passages...?

 

[Orange Man]

Update on the heating problem. My friend, who owns a bare bones 73 Challenger with a 360 came to spend a couple of days to help me rebuild a barn wall that suffered wind damage. We got it done in one afternoon. The next day we spent trying to eliminate one variable on my 70. We manually changed the timing from 5* BTC to about 13* BTC. This was guess work because I don't have a timing tape around the dampner. The engine increased in RPMs so we manually reset the idle on the Sniper back to about 990 RPM. I have no clue how old the Optima red top is but it got real hard to start after that. I noticed the starter was getting sluggish and it is my understanding that there needs to be a full 12 volts for the Sniper. That being said we got it started and let it run about 25 minutes. The ambient temp was about 83*. Both fans came on unlike before. Temps stayed around 195 for about 25 minutes. I decided this morning to run it for an hour if it could stand it. I used my infrared thermometer to monitor temps on the water pump, hoses, and radiator. I won't bore you with all the data but it did not heat up fast like before. Before, by 30 minutes the radiator was boiling. At idle for one hour and revving it up ever so often, the dash gauge showed 205*, the Sniper readout showed 200*. I checked the iron water neck and it showed 195*+ or -. and so did the sensor. Both fans were running as they should. This was all encouraging. I did close the hood for a few minutes then opened it to check the temps and they had gone up. I guess because of the small grille there is not a lot of air going through unless you are driving down the road. Also, I have not removed the AC fan and not repositioned the power steering cooler. That is on the list. I want to get the temps to stay in the 190s.

I was cautiously optimistic so I let it sit for about 10 minutes. I checked the temp on the water pump and it was up to 210*. I started the car and noticed that the temps were not coming down so I checked the fans. The top one was on the bottom was not. I shut it off for a little while and started it back up and again the bottom fan did not come on and the temps started to rise again. The bottom one that is inline with the AC condenser fan that does not come on unless the AC is on. Anyway, I got to figure out why the bottom one doesn't come back on when the engine is still hot. When the engine is cold, the bottom fan comes on about 165* then the top fan comes on about 175* and they both stay on until the engine is shut off. I also notice that sometimes they both come on when the engine is hot and sometimes they don't.

This fan problem may be what happened and I was not noticing it because on my 36 mile trips I made before when the heating problem reared its head, I stopped for a few minutes both times at a convenient store. My guess is that the bottom fan did not come back on and the exacerbated the problem.

Yes, You have an underdrive system. The factory used a 7" crank pulley. (7.5"). If you could get that larger pulley, it would help with coolant movement. I was not aware they made the larger pulley. The idea behind the smaller crank pulley was supposedly less horsepower needed to run the belt system.
As to your question about eliminating the heater core, It would not be a noticeable change IMO and is not part of your problem. Sure, if you had the heater core and had the heater on full roar, it would maybe drop your engine temp a degree or so but not enough to notice.
I think your best bet at fixing your problem would be to ditch that front fan, get both puller fans to work together and maybe see if you can get a larger crank pulley as mentioned in post #16 or a high flow water pump.
That would be my starting point.

I am going to look into the pulley with March Performance. I am trying to eliminate variable at a time.

Another thing on the timing was that I noticed the Sniper handheld monitor did not show timing. I show NA. I have an MSD Pro Billet 8546 and it is supposed to run with a CD box. My friend and I looked all over the car and cannot find one. All that I read says it absolutely needs the CD box. Is this another problem?

Thank you all. Baby steps but I am getting there. I have to because I promised two young ladies I would deliver them to their prom in the Challenger.

 

[MoparCarGuy]

I looked up the 8546 distributor and it definitely says you need an MSD ignition control to use it. There has to be some kind of box somewhere.
The Sniper EFI is best matched to a Holley Hyperspark distributor that is locked out for timing and enables the EFI to control your timing. Your Sniper display would then be able to display your ignition timing.
Timing control is one of the best features of the Sniper EFI systems.

 

[Orange Man]

I looked up the 8546 distributor and it definitely says you need an MSD ignition control to use it. There has to be some kind of box somewhere.
The Sniper EFI is best matched to a Holley Hyperspark distributor that is locked out for timing and enables the EFI to control your timing. Your Sniper display would then be able to display your ignition timing.
Timing control is one of the best features of the Sniper EFI systems.

You are correct. I finally found it. It was mounted under the drivers seat and I just did not see it. I found it accidentily by putting my hand under the seat looking for something else.

 

[MoparCarGuy]

You are correct. I finally found it. It was mounted under the drivers seat and I just did not see it. I found it accidentily by putting my hand under the seat looking for something else.

Great place for it. Cooler and dry!

 

[Orange Man]

Update on the heating problem. My friend, who owns a bare bones 73 Challenger with a 360 came to spend a couple of days to help me rebuild a barn wall that suffered wind damage. We got it done in one afternoon. The next day we spent trying to eliminate one variable on my 70. We manually changed the timing from 5* BTC to about 13* BTC. This was guess work because I don't have a timing tape around the dampner. The engine increased in RPMs so we manually reset the idle on the Sniper back to about 990 RPM. I have no clue how old the Optima red top is but it got real hard to start after that. I noticed the starter was getting sluggish and it is my understanding that there needs to be a full 12 volts for the Sniper. That being said we got it started and let it run about 25 minutes. The ambient temp was about 83*. Both fans came on unlike before. Temps stayed around 195 for about 25 minutes. I decided this morning to run it for an hour if it could stand it. I used my infrared thermometer to monitor temps on the water pump, hoses, and radiator. I won't bore you with all the data but it did not heat up fast like before. Before, by 30 minutes the radiator was boiling. At idle for one hour and revving it up ever so often, the dash gauge showed 205*, the Sniper readout showed 200*. I checked the iron water neck and it showed 195*+ or -. and so did the sensor. Both fans were running as they should. This was all encouraging. I did close the hood for a few minutes then opened it to check the temps and they had gone up. I guess because of the small grille there is not a lot of air going through unless you are driving down the road. Also, I have not removed the AC fan and not repositioned the power steering cooler. That is on the list. I want to get the temps to stay in the 190s.

I was cautiously optimistic so I let it sit for about 10 minutes. I checked the temp on the water pump and it was up to 210*. I started the car and noticed that the temps were not coming down so I checked the fans. The top one was on the bottom was not. I shut it off for a little while and started it back up and again the bottom fan did not come on and the temps started to rise again. The bottom one that is inline with the AC condenser fan that does not come on unless the AC is on. Anyway, I got to figure out why the bottom one doesn't come back on when the engine is still hot. When the engine is cold, the bottom fan comes on about 165* then the top fan comes on about 175* and they both stay on until the engine is shut off. I also notice that sometimes they both come on when the engine is hot and sometimes they don't.

This fan problem may be what happened and I was not noticing it because on my 36 mile trips I made before when the heating problem reared its head, I stopped for a few minutes both times at a convenient store. My guess is that the bottom fan did not come back on and the exacerbated the problem.

I am going to look into the pulley with March Performance. I am trying to eliminate variable at a time.

Another thing on the timing was that I noticed the Sniper handheld monitor did not show timing. I show NA. I have an MSD Pro Billet 8546 and it is supposed to run with a CD box. My friend and I looked all over the car and cannot find one. All that I read says it absolutely needs the CD box. Is this another problem?

Thank you all. Baby steps but I am getting there. I have to because I promised two young ladies I would deliver them to their prom in the Challenger.

Update on this issue. We found that one of the fan relays was intermittent. Both would work on the first start up but if you shut it down and cranked it back up, the bottom fan would not work. We replaced the relay and wired both fans to come on at the same time instead of different temperatures. I also installed an override switch under the dash. We also removed the AC condenser fan which was pulling instead of pushing air. It was fighting the upper radiator fan. I will try running it that way for a while. I relocated the power steering oil cooler away from the radiator to see if that helps.

The car has become hard starting again. I think it is a Air Fuel Ratio problem at start up. It takes 3 to 4 tries to start it. I bought a new Everstart AGM battery to replace the Optima and it seems to be holding up where the Optima would start to lose the cold cranking amps by the 4th start try.

The wife and I took it for a 30 mile reliability run last Thursday to see what the temps were going to run on the engine. Ambient air temp was 80 degrees. The temps were slower in coming up and stayed at 180* for a while then started to climb very slowly. By the time we got to the place we buy ice cream the gauge was showing 205*. We got back in the car and it fired right up but the temps climbed to 211* then came back down to 205* on the 2 mile drive back home. I kept it at idle when I got home and it stayed around 207* while I was resetting the idle. I don't know why the idle goes back up after it is driven a while.

I know many say that as long as it stays below 220* it is ok. I still feel nervous at that because the Texas heat is coming in another month and I am sure the engine temps will go up.

I tried to find a larger pulley from March as someone suggested. They got back to me and they do not make a 7" pulley for they system. My next step is to put a spring in the lower radiator hose to eliminate the possible problem of a hose collapse during driving. I don't know if the water pump is a standard or high flow. I am suspecting a standard and may need to go to that in the future.

I am also beginning to suspect the radiator. There is no name brand on it. It is a two row aluminum. My question on this is why does the return water from the bottom of the radiator returning to the water pump hot (180-195*)? The water pump housing is already at 200* as the water goes back into it. Is this normal? I have used my infrared thermometer and the radiator is showing 150-165 mid radiator then the bottom of the radiator is way hotter going back to the water pump. ???

I really want to enjoy this car but I am spending more time trying to figure out this heating problem instead of driving. I guess if I had restored this car with the mods it has on it, I would understand it better. Frustrating. I keep telling myself it is a hobby and not to get frustrated. I just want to get in the car and take it to church or go get groceries without worrying about the heating problem. Thank you all for your patience.

 

[Ricks72Chlgr440]

Update on this issue. We found that one of the fan relays was intermittent. Both would work on the first start up but if you shut it down and cranked it back up, the bottom fan would not work. We replaced the relay and wired both fans to come on at the same time instead of different temperatures. I also installed an override switch under the dash. We also removed the AC condenser fan which was pulling instead of pushing air. It was fighting the upper radiator fan. I will try running it that way for a while. I relocated the power steering oil cooler away from the radiator to see if that helps.

The car has become hard starting again. I think it is a Air Fuel Ratio problem at start up. It takes 3 to 4 tries to start it. I bought a new Everstart AGM battery to replace the Optima and it seems to be holding up where the Optima would start to lose the cold cranking amps by the 4th start try.

The wife and I took it for a 30 mile reliability run last Thursday to see what the temps were going to run on the engine. Ambient air temp was 80 degrees. The temps were slower in coming up and stayed at 180* for a while then started to climb very slowly. By the time we got to the place we buy ice cream the gauge was showing 205*. We got back in the car and it fired right up but the temps climbed to 211* then came back down to 205* on the 2 mile drive back home. I kept it at idle when I got home and it stayed around 207* while I was resetting the idle. I don't know why the idle goes back up after it is driven a while.

I know many say that as long as it stays below 220* it is ok. I still feel nervous at that because the Texas heat is coming in another month and I am sure the engine temps will go up.

I tried to find a larger pulley from March as someone suggested. They got back to me and they do not make a 7" pulley for they system. My next step is to put a spring in the lower radiator hose to eliminate the possible problem of a hose collapse during driving. I don't know if the water pump is a standard or high flow. I am suspecting a standard and may need to go to that in the future.

I am also beginning to suspect the radiator. There is no name brand on it. It is a two row aluminum. My question on this is why does the return water from the bottom of the radiator returning to the water pump hot (180-195*)? The water pump housing is already at 200* as the water goes back into it. Is this normal? I have used my infrared thermometer and the radiator is showing 150-165 mid radiator then the bottom of the radiator is way hotter going back to the water pump. ???

I really want to enjoy this car but I am spending more time trying to figure out this heating problem instead of driving. I guess if I had restored this car with the mods it has on it, I would understand it better. Frustrating. I keep telling myself it is a hobby and not to get frustrated. I just want to get in the car and take it to church or go get groceries without worrying about the heating problem. Thank you all for your patience.

Sure sounds like the radiator is not doing its job. There should be no "cold spot" like you're seeing. Hot coolant should flow evenly through the tubes. I took my 440 Challenger out the other day when it was in the low 80's. Temp stayed around 180-185 while driving 60. When I drove 75 on the highway it went to 190-195, then came back down as I went slower. I use a 160 high flow thermostat, Bekool water pump, and ECP radiator with dual fans. I did end up putting on a coolant recovery tank and recovery radiator cap.

 

[Challenger RTA]

I would remove the thermostat. Then with the radiator cap off. Observe the flow in the radiator. It should be a steam of a quick flow. Be careful. don't rev it to much. it will blow out everywhere.