Jim-you would need to space that out much more to get close to the radiator. The clutch/fan setup is to get you only into the shroud opening. Somebody running hot might want to try the 6 blade fixed rascal that the '66 non A/C Rivs used-
If they didn't need electric fans when the car was built--it doesn't need them now. Fix the REAL problem(s).
Shurkey- Right on. John, personally I would run the timing according to the old formula 8-10 deg. for a single 4 engine. 12 deg. for a super cat. The lower the timing is the more it tends to run hot.
I`m trying to fix the REAL problem. As for the timing it was set incorrectly after the rebuild at 15 btdc and it heated up real bad and boiled out. I will try it around 8 degrees. I thought increasing it would make matters worse. John
John, Stock initial timing for the 65 Nailhead was 2 1/2*BTDC. That is with the vacuum advance disconnected and plugged. When you hook up the vacuum advance, the timing should increase to about 16-18* BTDC. The mechanical advance for the stock distributor is 13-17*@ 1400 RPM, and 28-32*@ 3900 RPM. At WOT, vacuum advance drops out and total timing should be 30-34*. At cruise the timing will be a combination of partial mechanical advance and vacuum advance for a total of around 36-40* In any case, the engine should run cooler with more advance especially at idle and low speed. If there is too much advance, it will detonate at WOT. Have you verified that the mechanical advance and vacuum advance are working correctly?
Larry. Thanks for that info. We did set the timing at 2 1/2 btdc with the hose off and plugged. I never did check those other readings. I also put a suction to the advance with the cap off and the advance unit was functioning. Could it be functioning improperly? Maybe I should replace it? John
The vacuum advance unit should be connected to manifold vacuum. When you disconnect it with engine running, you should notice a decrease in RPM, and there should be strong suction at the disconnected hose. When you reconnect the hose, RPM should increase. You will also see the timing mark move if you watch with a timing light. It either works or it doesn't.
Not usually , increased lead in the timing will help one run cooler. Later timing makes the flame burn further down in the cyl. , increasing the heat and cutting the power. I am wondering about the headgaskets. What is the history on them???
When the engine was rebuilt the head gaskets leaked externally. They were the thin metal ones. I thing the heads were torked incorrectly. The rebuilder then put on thicker composite ones. No leaks. I think there was an issue with heat before I had it. There was no thermostat. Maybe someone thought this would cool it. I ran it without for a short bit and it was still hot. I am going to try advancing the timing when the weather here warms up a bit. Thanks to everyone and keep the suggestions coming. John
Have you checked for exhaust gases in the radiator? Could be cracked a cracked head, cracked cylinder wall, or blown head gasket. Kurt
I have one other idea, that I dont think has been mentioned. There are 2 sizes of water pump pullys for a nail head. A larger one and a smaller one. I would think you would need the smaller to spin the pump and the fan faster. This would increase the water flow and the air flow at the same time. Cant hurt. You need the pullys from a 66 425 riv. with factory air.
I had a problem with my non A/C 401 overheating after extended idleing during hot weather. Would run at 180 running down the highway but wanted to overheat at idle. At the car craft national in 100 degree heat and stuck in traffic it went clear up to 225 before I could get it off the road and shut down. I replaced the 4 blade fan with a 7 blade clutch fan off a buick 350, replaced the thermostat with a 165 degree unit and replaced the water pump with a 5 blade pump for an A/C engine. It helped somewhat, took longer to overheat, but after 15 - 20 minutes idleing in a parade on a hot day in got hot again. I noticed if I raised the idle speed it would cool down. I got the smaller fan and balancer pulley's from an A/C car and put them on so the water pump would run faster at idle. It solved the problem.
Just last summer I tried a smaller pulley on the fan. It was from a 64 cat with ac. We figured the pump was turning 35% faster. No difference. I have also already tried the 5 blade pump. Keep the ideas coming guys. Thanks, John
About all that is left is a cracked head or block. Put a chemical sniffer on the cooling system and see if there is combustion gas in the system. a rad shop can do this for you for a small fee. Also run a good compression test, recording the numbers in order. A nail head is like any other engine, it is not normal for it to run hot. If it is then there is a reason why.
Hey John- just wondering if this problem was ever resolved- I'm chasing the same issue in my 62 Electra, though mine runs cool at idle, heats up to 215 under a load on the freeway. Flushed the engine and had the radiator re-cored, water pump seems fine as it turns water very well, initial timing at 12 with vacuum and mechanical advance both functioning, original AC car with correct shroud and pullys, fan and clutch seem fine-- worried about head gaskets at this point but havent had a chance to check yet-- not sure if the motor has been bored over or not, but does look like there was a rebuild at some point--- anyways will prob start a new thread if this one doesnt come back but I dont want to kick a dead horse. Let me know if you've had any luck thanks Paul
Hello Paul. No it`s never been resolved. From reading my previous posts you can see I have tried nearly everything. When I got the car, the engine was shot. When I had it rebuilt they said it had already been bored .030 and would have to go to .060 which we did. There was no thermostat so I think there was an issue with overheating previously. Perhaps there is a defect in the block or heads. Some say these engines run hotter than others. Remember, these cars originally came with idiot lights and the heat lamp would not come on until 245 degrees. John
Paul. Are you sure you have the original engine? Soon after they changed the timing from 12 before to 2 1/2 before. John
Definitely original numbers motor-- tested for exhaust in the coolant, headgaskets were fine, put on another original fan clutch- no change-- checked to see if dampener had slipped and altered timing mark- seems like its right and engine runs well. Car would run up to 220-230 as indicated by electric guage with probe in rear left water jacket port-- checked coolant temp at rad cap and it was runnin 200-210. Turns out the probe and guage were not matched or maybe not suitable for a generator car? Both are Stewart Warner but there must be a resistance issue or somthing. Switched back to old Stewart Warner mechanical guage-- temps down 10-20 degrees. I tried a non thermal fan just to see if pushing that extra air on the highway would make a difference-- also spaced the fan about an inch closer to radiator. I was skeptical because everyone says that the fan on the highway is irrelevant--not the case here! Power is down and the sound is ridiculous but the thing ran 170-180 all the way to Huntington Beach in 85-90 degree weather. Now I just need to find a happy medium in a proper thermal fan-- any suggestions? Thanks, Paul Also forgot to mention- I spoke with guy who seems to be in the know on nailheads and he suggested that at the factory, they would shoot for a temp range on the motor and anything that fell within the boundaries was sent down the line-- as would be indicated by the idiot lights from 110 to 245. Perhaps they ran up to 200 or so right off the lot?
