Too hot a coil? Is this possible?

[LaGrasta]

I have had overheating trouble for a few years now. It occurs only at high speed of approximately 15 miles or more. Everything is new so I'm stumped as to what it could be. (I'm wondering if the water passages are blocked in the block even though I've hosed them out a million times.)

This post however, is in question to the coil. I'm running a hot 60v coil through 8mm wires, could this be too much on a freeway run?

 

[jahearne]

The only thing I can think of using a hot coil would be cross-fire or ionization inside the dist. cap. For your freeway overheating try advancing the timing a little bit too see if that helps and/or higher octane fuel.

I remember doing an experiment with my old Cyclone GT390 where if it was too far advanced it would overheat in the city, too much retart and overheat on the freeway.

 

[LaGrasta]

"I remember doing an experiment with my old Cyclone GT390 where if it was too far advanced it would overheat in the city, too much retart and overheat on the freeway."

Interesting, maybe I'll try some experimentation. The way it is now, there is no pinging.

 

[Lazy JW]

The hot coil won't cause any problem but you may well not be getting the actual advance under load that you think you are. Definitely try advancing the timing five degrees (whatever) and give it a whirl.
Joe

 

[JackFish]

Is it boiling over? What are the symptoms of the overheating?

 

[rbohm]

8) high speed overheating is usually caused by not enough timing advance, to lean a fuel mixture, or not enough air flowing through the engine compartment. i would work on the first two.

 

[The Plankster Prankster]

the other possible cause of high-speed overheating is a radiator that is clogged. it was the case in my LTD, installing the new radiator solved it. you said "everything's new" but i don't know what "everything" means.

 

[CobraSix]

Since it only happens at highway speeds, I don't suspect the coil.

Every time you've flushed the block, does more crud come out? If so, I suspect your radiator is junk. I flushed my block 5 times in a month prior to just replacing the radiator.

I'd double check time. Check the vacuum advance to make sure it actually is moving.

 

[LaGrasta]

Is it boiling over? What are the symptoms of the overheating?

NEW:
pump
aluminum radiator
stat
cap, with built-in thermometer
upper/lower hose
rebuilt head
in-line tranny cooler

After years of my stock gauge showing 1/4 readings, it now continues to rise to 1/2 and past. If I reach my freeway destination within about 15 miles, exiting the freeway and slowing through city streets, the gauge, using the electric fan lowers the gauge back to 1/4.
If I remain on the freeway past 15 miles, even the electric fan doesn't help lower the temp much if the ambient air is even slightly warm. My new thermometer cap confirms temps of about 230 at stock gauge 1/2 reading. Many a day in SoCal 100° I exiting the freeway with the electric fan running full blast and the heater on full blast as well.
In spite of being fairly slow and having a flat spot after idle, the car runs super, really super. I feel like I could drive to Phoenix and back if I didn't keep staring at the temp gauge!

 

[CobraSix]

I wonder if (like mentioned previously) your vacuum advance isn't working and you are running too retarded at highways speeds (all puns intended).

 

[LaGrasta]

I wonder if (like mentioned previously) your vacuum advance isn't working and you are running too retarded at highways speeds (all puns intended).

Sucking on the dizzy line moves the vacuum…

 

[mannella]

Just curious but why do you have electric fans? Fans are not needed at highway speeds and I'm wondering if they are restricting the air flow. At lower speeds they should kick in but not on the highway.

 

[66200i6]

Different parts of your discription confirm a couple of things. First, Your Temp indicator on your cap and dash gauge confirm the heat from your block is being transfered to the radiator, an important step. Second, the use of the fan during street use is able to remove the heat from your radiator, also good. The only thing left to review is that the advance is not enough at highway speeds and is creating more heat than the rad can remove and or the rad is blocked.

If your using ported advance, I would try using manifold vaccum advance instead which should give you a bit more advance on the highway. It sounds like the radiator is doing it's job.

Good luck, Ric.

 

[66200i6]

Wait! Cancel that! I keep thinking the ported advance is venturi vacuum. Most ported vacuum sources end up being the same as manifold just off idle.

I’m stumped,

 

[CobraSix]

On an outside line, is the mechanical advance working? Try taking a reading at 2k and 3k RPM.

 

[LaGrasta]

On an outside line, is the mechanical advance working? Try taking a reading at 2k and 3k RPM.

How do I do this, a reading of what?

 

[LaGrasta]

Just curious but why do you have electric fans? Fans are not needed at highway speeds and I'm wondering if they are restricting the air flow. At lower speeds they should kick in but not on the highway.

I see your point, but honestly, a hot rod aluminum radiator like I have should almost not even need a fan to keep my stock 170ci cool.

I run these because the radiator is too thick for the stock mechanical fan and in stop and go traffic, electric works much better than mechanical and this is when you need the most help in cooling, not at speed. (In most cases, that is). I ran a single pusher 16" for years and just swapped to a dual 12" pusher set-up. This made no change that I can tell.

 

[CobraSix]

Disconnect the vacuum advance, rev the engine to 2k and take a timing reading. You'll need a dial back timing light to do it.

Then to check that vacuum advance is coming in properly, use a small hand pump with a vacuum gauge connected to the vacuum advance with the engine at 2k. I forget off the top of my head what the max vacuum reading should be, but pull a vacuum to that and then measure total advance.

 

[LaGrasta]

Okay, let me gather up these tools (visit friends) and give it a shot. I'll report back over the weekend hopefully.

Let me ask this, if it doesn't measure correct, does it just need adjusted or does my dizzy need replaced?

 

[CobraSix]

Well, it may just be that a spring is stuck or is just worn out and broken. Hard to say. Springs are cheap enough. That's about the only thing that can go wrong with a dizzy.