1966-67 HCS running hot & ignition timing

[66hcs-conv]

Hi all,

I've been concerned with our '66, 289, auto, running hot. Using one of the hand held temp gauges I get 215 after about an hour on the interstate driving 65-70 mph, and the outside temp was 90 degrees.

I've got a 180 t-stat (check with candy therm and a pan of water). 3 row radiator, 6 blade fan, mounted 1" away from radiator, and using a shroud. I've put the seal along the top of the front cross member (where the radiator mounts), trying to direct the air into the radiator instead of over the radiator mount (It's a 6 cyl thing). New 13 lb (tested) radiator cap. I installed a burp tank, but nothing ever goes into the tank.

I've eliminated everything I can think of, so now I am wondering about the timing and the distributor advance.

I disconnected the vacuum line at the distributor, retarded the timing to 0 and checked the centrifugal advance. It is correct at the spec for 2000 RPM, (10-12 degrees) BUT will go 18-19 degrees advance at 3500 RPM. With the vacuum connected I am getting close to the spec at 2000 RPM, but 40 + degrees at 3000 RPM.

Is it normal for the advance to go to those numbers at the higher RPM? Or should the timing stop advancing at the 2000 RPM mark?

Thanks for your help.

 

[Mosesatm]

That's way too low at 2,000rpm. It should be around 30-35 degrees at 3,000rpm.

Try 12 degrees at 650rpm with the vacuum hose unhooked and plugged, then see what it is at 3,000.

 

[66hcs-conv]

With vacuum advance disconnected, initial timing set at 12 degrees advance, and at 3000 RPM, I get 26 degrees advance.

With vacuum connected, and at 3000 RPM, the advance is well over 40 degrees. I'm guessing it is 46-48 degrees advanced. Seems way too much advance under those condition's.

 

[robert campbell]

As long as the engine does not "ping" or have signs of "detonation" do not worry about total advance. The more initial advance you dial in (12 degrees is a good start) the cooler the car will run, more horse power, and better gas mileage. Under full throttle the vacuum is at zero and then the vacuum advance is at zero.

The trick is to dial in as much initial advance as the engine will stand. sometimes the starter has trouble during a hot start. So that and pinging are the limiting factors. Most modern vacuum advances are adjustable by inserting an allen wrench in the tube with the hose removed. Clockwise turning increases the amount of advance and how quick it comes in. Counter clockwise turning reduces the amount of vacuum advance and makes it come in slower.

Retarding ignition timing creates heat, destroys power, and ruins gas mileage.

Rob

 

[Mosesatm]

With vacuum advance disconnected, initial timing set at 12 degrees advance, and at 3000 RPM, I get 26 degrees advance.

With vacuum connected, and at 3000 RPM, the advance is well over 40 degrees. I'm guessing it is 46-48 degrees advanced. Seems way too much advance under those condition's.

Play with it a little. Move the initial down to 6 degrees and see what happens. Like Rob said, as long as it doesn’t ping you’re good. I am surprised that it advances that far.

 

[66hcs-conv]

It doesn’t ping at all.

Is being advanced 46-48 with the vacuum connected too far? According to the shop manual I can take some of that out by adding or removing washers where the vacuum unit screws into. Might try that & see if it runs any cooler?

 

[robert campbell]

Do you have an original Ford vacuum advance? They are the only ones that you can adjust with shims. Again, if it does not ping do not worry about the total advance. Measuring timing in the garage with no load gives you a false reading of total advance with the vacuum advance plugged in. When driving with a load you have less vacuum and less advance.

Rob

 

[1968Cally]

Not sure what you mean by a hand held temperature gauge. Do you mean a "gun" where you point it at the engine, pull the trigger and it tells you the temp? If so, here are my comments/questions:
1) 215 is not real hot for a 289. 215 working it hard on a 90 degree day is not dangerously high.
2) Where are you pointing the gun? The thermostat housing should be the hottest spot.
3) Are you getting the temp with the engine still running or after you have shut it down? Temp will start to rise immediately after shutdown.
4) Are you using a $20 Amazon gun or a $250 professional one?

 

[robert campbell]

I feel that a properly tuned small block Ford should basically operate at the thermostat heat as stamped on the unit. When these cars were new in the 1960's most came with a 195 degree thermostat. Not sure if hot areas received a 180 thermostat or not. These cars were daily drivers and expected to perform in cold temperatures and warm up quickly. Now these cars are garage kept and driven in nicer weather. I never install a 195 thermostat in any of these cars. I worked as a radiator and heater journeyman in the early 1970's when these cars were very new.

By design the thermostat is supposed to keep the car at a constant hot temperature. Winter or summer. The radiator was sized based on the engine and other equipment to hold the temperature the same in the summer as the winter. I feel that 215 is to hot for these engines and if you had a stock gauge it would be buried. An owner experiencing a buried gauge would quickly get off the road.

Years ago I solved Amy's car "Satan" that she experienced second degree burns from removing a hot radiator cap. Her fix was basically engine timing that was far to retarded. She also had the dual diaphragm vacuum advance that by design retards the timing as an emission control attempt by the big three. A retarded engine more completely burned the gas, but performance, heat, and mileage also suffered. I plug the hose to the opening closest to the dizzy cap. This removes the retard feature of this vacuum advance. If the owner will let me I install a more modern single diaphragm vacuum advance that is adjustable. This allow me to recurve the dizzy for optimal performance. I never did understand the fact that the big three retarded engines to more complexly burn the gas, but the car got worse mileage. seems to me that worse gas mileage would cause more pollution.

Basically said, a properly tuned 289 in good condition should always stay at the heat of the thermostat. I check every thermostat I install with a candy thermometer also. Now if you are pulling a boat up a mountain pass you will exceed the factory design of the cooling system. That or a dirty cooling system will cause excessive heat.

Rob

 

[1968Cally]

I feel that a properly tuned small block Ford should basically operate at the thermostat heat as stamped on the unit. When these cars were new in the 1960's most came with a 195 degree thermostat. Not sure if hot areas received a 180 thermostat or not. These cars were daily drivers and expected to perform in cold temperatures and warm up quickly. Now these cars are garage kept and driven in nicer weather. I never install a 195 thermostat in any of these cars. I worked as a radiator and heater journeyman in the early 1970's when these cars were very new.

By design the thermostat is supposed to keep the car at a constant hot temperature. Winter or summer. The radiator was sized based on the engine and other equipment to hold the temperature the same in the summer as the winter. I feel that 215 is to hot for these engines and if you had a stock gauge it would be buried. An owner experiencing a buried gauge would quickly get off the road.

Years ago I solved Amy's car "Satan" that she experienced second degree burns from removing a hot radiator cap. Her fix was basically engine timing that was far to retarded. She also had the dual diaphragm vacuum advance that by design retards the timing as an emission control attempt by the big three. A retarded engine more completely burned the gas, but performance, heat, and mileage also suffered. I plug the hose to the opening closest to the dizzy cap. This removes the retard feature of this vacuum advance. If the owner will let me I install a more modern single diaphragm vacuum advance that is adjustable. This allow me to recurve the dizzy for optimal performance. I never did understand the fact that the big three retarded engines to more complexly burn the gas, but the car got worse mileage. seems to me that worse gas mileage would cause more pollution.

Basically said, a properly tuned 289 in good condition should always stay at the heat of the thermostat. I check every thermostat I install with a candy thermometer also. Now if you are pulling a boat up a mountain pass you will exceed the factory design of the cooling system. That or a dirty cooling system will cause excessive heat.

Rob

Rob, While agree with most of what you say, I have read multiple articles that state Ford engine engineers found that the late 60's V8s were the most efficient and produced lower harmful emissions at the higher temps and that 205-215 were okay on a hot day. That is why in the mid sixties most stock thermostats began to move fro 180* to 195* The fords were actually calibrated to 192* This was done mainly to help achieve the evolving emission standards.

A thermostat only controls the minimum temperature an engine runs at and how fast it will reach that minimum. Assuming the system is in good shape (brand new car) then engine load and ambient air temperature will determine it's upper operating temp. If you live in a hot area such as Atlanta, you may be tempted to put in a 180* thermostat. On a hot summer day though, it will not really matter as the engine will run significantly hotter than 180* So now when you get to a January day that is sunny and dry in the 30's when you take an early morning spin, engine will run at 180* which is not optimal. So, why not go with the 195* year round?

 

[robert campbell]

Back in he day when they were daily drivers and brand new standard bore I would agree. Now a days most cars see 70's and above when they are driven. I am the exception to that up here in the Seattle area. My cars are driven on any dry day.

The difference of 15 degrees in my experience helps these cars stay below the 200 mark most times. It is a little cushion, but it helps. Again if the cooling system (radiator fan and shroud) will not hold at the thermostats rated degrees then you have problems.

To support your thinking the cooling system should hold the car at 195 any time in the year. Winter or Summer. If it does not then again a problem exists. The 180 is a cushion for .030 or more over motors and a possible less than optimum cooling system.

Rob

 

[1968Cally]

You are fortunate to be able to drive all year round. In Chicago, Wile the roads may be dry in the winter, there is salt residue all over them. Four years ago when I had a '55 Chevy, we had heavy rains around New Years. Washed all the salt off the road and then not a flake of snow for six weeks. I got the car out several times during that period and it was nice cruising with the heater on full blast. She ran real well also.

You are also lucky that Seattle does not have that many horribly hot days. But, a lot of rainy days. No place is perfect, I guess.

 

[Mosesatm]

Spokane is perfect!!!

 

[1968Cally]

Well, the Chicago area is perfect also except for the weather. Oh, and high taxes. Oh, and the high housing prices. Oh, and the state so very deep in debt. Oh, and one last thing - corrupt politicians.

What the hell am I doing here?

 

[franklinair]

Nope. Sorry folks. I've bee to ALL the places mentioned, but you can't beat the mountains of western North Carolina.:wink:

Neil

 

[1968Cally]

Nope. Sorry folks. I've bee to ALL the places mentioned, but you can't beat the mountains of western North Carolina.:wink:

Neil

I agree with you Neil 100%. Four seasons but non of them harsh. In 2011 we bought a lot in a mountain community in Mills River outside of Asheville. We had plans for a house and had a builder but got cold feet about leaving our only child back in Chicago with no other family. I have been meaning to call a realtor to list the lot.

At least it was a good dream. We still go down in the fall and do the parkway. Heaven on earth

 

[66hcs-conv]

Meanwhile back to the subject of this thread/post - what ever this is.

I put washers in the vacuum unit, per the shop manual, and got the timing to stop advancing past 40 degrees at 3500 rpm. The OEM damper is only marked to 40 degrees and after doing a little measuring I think the timing was advancing to 50 degrees before I put the washers in. The advancing is very close to what the shop manual says it should be, maybe advanced a little past spec.

While I didn't use the heat gun, the heat gauge shows a little cooler. And before when I stopped at a light, the heat would go up, and not come back down. Now the temp goes up, but once I start to move, the temp goes down.

Also forgot to mention that I am at 5,000 feet elevation. Don't know if that makes any difference or not.

I know 215 is not considered hot by some folks, but I do not like it that hot.

Thanks for all your advice

 

[1968Cally]

Sounds good. How does it behave at say, 75-80* ambient temperature? At 5,000 feet altitude, do you get that many 90* days?

 

[robert campbell]

Meanwhile back to the subject of this thread/post - what ever this is.

I put washers in the vacuum unit, per the shop manual, and got the timing to stop advancing past 40 degrees at 3500 rpm. The OEM damper is only marked to 40 degrees and after doing a little measuring I think the timing was advancing to 50 degrees before I put the washers in. The advancing is very close to what the shop manual says it should be, maybe advanced a little past spec.

While I didn't use the heat gun, the heat gauge shows a little cooler. And before when I stopped at a light, the heat would go up, and not come back down. Now the temp goes up, but once I start to move, the temp goes down.

Also forgot to mention that I am at 5,000 feet elevation. Don't know if that makes any difference or not.

I know 215 is not considered hot by some folks, but I do not like it that hot.

Thanks for all your advice

So what is your initial timing set at now. I have a jar full of springs and washers for the factory vacuum advance units. What you have done now is you have increased the spring load pressure on the diaphragm so it comes in slower than before. This is fun tuning talk for me. I learn as we all learn!

Rob

 

[66hcs-conv]

So what is your initial timing set at now. I have a jar full of springs and washers for the factory vacuum advance units. What you have done now is you have increased the spring load pressure on the diaphragm so it comes in slower than before. This is fun tuning talk for me. I learn as we all learn!

Rob

The initial timing is set at 12 degrees advance, without the vacuum line plugged in.

Thanks, Dave