Some interesting observations

[Don Coatney]

On all of the long road trips I have been on this and last summer my car engine temperature has been consistent at around 180-190 on the highway running at speed. In town it pushes 195-200 if sitting in traffic for extended periods of time. About 3 weeks ago I drove to a cruise in about 25 miles away. When I arrived at the cruise in my engine temperature was pushing 210. I parked and raised the hood. A few moments later my radiator expelled about a quart of coolant out the overflow tube. I have not added any coolant to my radiator for a couple of years. Last evening I drove to the Boro Friday night cruise in about 7 miles from home. My engine temperature was elevated when I arrived but it did not expel any fluid.

So today I did some diagnostics. I suspected that my engine-cooling jacket was plugged up or I had blown a head gasket. First thing I did was pull and inspect the dipstick. He oil was clean and did not show any signs of water. I last changed the oil prior to driving to Detroit. Next I did a compression check with the engine cold. All cylinders were 105-115 dry and 110-120 wet and the plugs all looked good. I then started the engine and let it come up to temperature. Observing the coolant through the radiator cap spout showed no signs of oil, the coolant had a slight green tint (not brown) and was circulating well. There was no sign of compression bubbles and the circulation increased when I raced the engine. There were a few brown rust flakes floating on the top of the coolant but no red flags went up. The temperature was running around 190 and I confirmed this with a hand held thermometer. I let it run for a half-hour or so as I scratched my head. I was ready to start flushing the radiator and the engine cooling jacket when I elected to check one last thing.

I connected my ignition timing light to see if my timing was still set at 5 degrees advance where I had last set it last summer prior to driving to Tulsa. I was very surprised to find it at 12 degrees advance. The distributor snug down bolt was still tight. I re-set the timing to 5 degrees advance and within a few minutes my engine temperature had dropped 180. My electric cooling fan began to cycle on and off and it is set to come on at 185-190 and go off at about 180. I think engine timing was my problem. I did not pull the distributor and inspect the points but I suspect the gap has changed and that is why my timing changed. I expect to receive a spare dual point distributor soon as James Douglas is setting one up on his distributor machine for me. When it arrives I will install it and then replace the points in my distributor and use it as a spare.

[JerseyHarold]

It could be that the rubbing-block on the points wore down and affected the dwell, which in turn changed the timing. They used to have a little capsule of grease packed with aftermarket points to prevent that kind of wear.

[Normspeed]

Good description of the diagnostics to go through for a hot running motor too. It would be interesting to know how the gap/dwell on the points reads now as opposed to when you last set them.

[Don Coatney]

I did a road test this evening to the same cruise in where I first noticed the problem. She ran cool as a cuke.

[De Soto Frank]

Did you notice any "pinging" on hard pulls ?

[Don Coatney]

Did you notice any "pinging" on hard pulls ?

Not this time. A couple years back when I had the timing advanced way too much it sounded like I had marbles boucing around inside the crankcase on hard up hill pulls.

[Olddaddy]

Nice bit of diagnostic work there Don. I know it's in the posts somewhere, but did you ever put down on paper your cooling fan system? I know you worked out a lot of details to get it working just right. I'd like to take advantage of your knowledge if you have.

[Don Coatney]

Charley;

I am using a JC Whitney fan (about 90 bucks) and a Hayden #3647

controller. I bought this controller from O-Rileys for about 40 bucks.

It was the only one I found that had the lower heat ranges required

for our engines. I had some issues with the first controller and Hayden

sent me a replacement after a short phone call. Good people to work

with.

[Johnny S]

Don, where is the sensor for the controller placed? Is it just sensing the temperature of the engine compartment or is it actually sensing the engine temperature more directly?

[Don Coatney]

Don, where is the sensor for the controller placed? Is it just sensing the temperature of the engine compartment or is it actually sensing the engine temperature more directly?

Johnny;

Sensing the temperature of the under hood air would not be of any value.

The temperature probe is inserted in a radiator fin near where the hot engine

water returns to the radiator top left of the first picture. I also used a heat

transfer coumpound on the probe for more accurate readings.

[Johnny S]

Thanks Don .... good photo and explanation. Makes a lot of sense.

[blueskies]

Don-

Sounds like a good thing you had overheating symptoms... I think the timing on my engine was the cause of my bad wrist pin bushing. I too never heard any sort of pinging during the time it was too far advanced.

Pete

[Don Coatney]

Don-

Sounds like a good thing you had overheating symptoms... I think the timing on my engine was the cause of my bad wrist pin bushing. I too never heard any sort of pinging during the time it was too far advanced.

Pete

I hear what you are saying Pete. I will now make a habit of checking timing prior to hitting the road for any long trip. And I will carry my timing light with me.

[blueskies]

I hear what you are saying Pete. I will now make a habit of checking timing prior to hitting the road for any long trip. And I will carry my timing light with me.

If only I knew then what I know now...

Pete

[Olddaddy]

Thanks Don for the info, I've learned a great deal from your experience and from others on this board. I may know enough to finish my car if I wait long enough.

And Pete, if we knew then what we know now, well now would be very different........from now.

[blueskies]

...And Pete, if we knew then what we know now, well now would be very different........from now.

:DPrecisely:D

Pete

[Bob Riding]

Don; Where you using an NOS distributor? How long had it been since you had done a tuneup?

Bob

[Don Coatney]

Don; Where you using an NOS distributor? How long had it been since you had done a tuneup?

Bob

Bob;

My distributor was last looked at sometime last year before I drove my car to Tulsa, Oklahoma about fifteen thousand miles or so ago. Not a NOS distributor. I subscribe to the "if it aint broke dont fix it" line of thinking.

[Frank Elder]

Dear don,

If it aint broke.....I also love that line of thought. That being said what are the advantages of a dual point over single and why should'nt I just go with a pertronix? If I can afford it!

FRANKIE47

[Don Coatney]

Dear don,

If it aint broke.....I also love that line of thought. That being said what are the advantages of a dual point over single and why should'nt I just go with a pertronix? If I can afford it!

FRANKIE47

A dual point distributor increases the dwell as there is an overlap in the time the points remain open. Increased dwell equates to a longer coil saturation time and a longer coil saturation time equates to a hotter spark. If there is a point failure with my dual point setup I can remove one set of points and continue driving until proper repairs can be made.

If a pertronix unit fails yoiu are dead in the water unless you carry a spare pertronix unit. Also I dont believe the pertronix unit offer any increased dwell time.

[Frank Elder]

Awesome answer! I know I dont want to buy 2 units and a dual has a built in fix. Will research further.

Thank you very much,Frankie