Running hot issue, BBc

[GRTfast]

What timing curve are you running? Vacuum advance?

If the timing is too retarded at idle and during cruising, it will dump a ton of heat into the exhaust port and make the car run hot.

Heats up the exhaust port and the cylinder walls also.

yup. Any heat that isn't being converted to work has to go somewhere.

[F-BIRD'88]

Truth. Truth

[67 Nova]

Change to a 120cc open chamber head will drop cr to 10.6:1 for street pump gas.

That might be where this is going. Will pull the restrictor out and change to 50/50 coolant/water and new hi flow t stat.

As for timing curve? That will have to look back into. Not sure off top of my head.

Thanks

[67 Nova]

What timing curve are you running? Vacuum advance?

If the timing is too retarded at idle and during cruising, it will dump a ton of heat into the exhaust port and make the car run hot.

Timing is locked at 32. This is the first time since the 90's I'm running an actual distributor in a motor again. ALL my other deals had crank triggers and MSD boxes. So no timing with them. Recall my buddy who built my motor and help set up my FIRST performance BBc (396/375 ++++) back in 1996 did this for me. Then first night out, when hot, car would like to start, very hard. I called him the next day and first thing he said was "car doesn't like to start HOT does it"? Went on to explain full timing with crank trigger and why he "rolls" the motor on his dragster over BEFORE tuning on the box. So I have had a box/ignition power in every car since then, INCLUDING this one.

So maybe need to get ahold of Petronix, as I'm using a Ignitor III distributor and coil, and get some insight and the parts that I HAD from them to put some sort of curve into this and not locking it out.

Hope to be able to load pictures later today or tomorrow.

[GRTfast]

What timing curve are you running? Vacuum advance?

If the timing is too retarded at idle and during cruising, it will dump a ton of heat into the exhaust port and make the car run hot.

Timing is locked at 32. This is the first time since the 90's I'm running an actual distributor in a motor again. ALL my other deals had crank triggers and MSD boxes. So no timing with them. Recall my buddy who built my motor and help set up my FIRST performance BBc (396/375 ++++) back in 1996 did this for me. Then first night out, when hot, car would like to start, very hard. I called him the next day and first thing he said was "car doesn't like to start HOT does it"? Went on to explain full timing with crank trigger and why he "rolls" the motor on his dragster over BEFORE tuning on the box. So I have had a box/ignition power in every car since then, INCLUDING this one.

So maybe need to get ahold of Petronix, as I'm using a Ignitor III distributor and coil, and get some insight and the parts that I HAD from them to put some sort of curve into this and not locking it out.

Hope to be able to load pictures later today or tomorrow.

I think you will find that a vacuum advance that allows 10-12 degrees of advance will cool things down at idle and cruising. I currently have a curve in my HEI that is about 30 initial, and is all in at 39 degrees around 3500 rpm. I also have a vacuum advance that adds about 8 degrees. This results in an idle advance of 40 degrees, and a highway cruising advance of 45 ish degrees depending on the speed. If I disconnection the vacuum advance, the car runs hotter, and will run-on after I turn the key off because the exhaust valve is hot enough to keep firing the mixture.

[F-BIRD'88]

You can keep the locked diz but should add vacuum advance too. About 10-12 at high vacuum pt cruise.
What you really need to address is the excessive CR.
And the water flow, air flow issues.

[MadBill]

Change to a 120cc open chamber head will drop cr to 10.6:1 for street pump gas.

That might be where this is going. Will pull the restrictor out and change to 50/50 coolant/water and new hi flow t stat.

As for timing curve? That will have to look back into. Not sure off top of my head.

Thanks

Keep in mind that a 50-50 antifreeze mix has ~ 20% lower specific heat than straight water...

[67 Nova]

Sorry couldn't get pictures. Trans guy was leaving for his grandson birth. But on the hoist it does look like lower rad hose needs "attention". NO SPRING and sitting cold it probably 12% reductions in size at the bend.

Like I said, it's a alum 2 core that seems to flow well when it's running. My concern is car heats up fairly fast stilling. Then I figure it should cool once I'm moving. IT'S NOT. Just keeps climbing in temp.

If I sit and idle say to 180/190, then move the car, keeps climbing to 210 even with airflow thru rad. It's like my other car with electric fan. At idle with fan off she heats up, but soon as fan turns on it cools well.

I have messed with a vac advance or timing curve in 30 yrs. Guess it's time to get back to the basics...........

THANK YOU ALL

John

[67 Nova]

Ok update:

After pulling everything out, changing water pumps and going thru whatever I could, found that the NEW Autometer electric Pro Comp ultra lite water temp gauge had a faulty sending unit?

Changed sending unit and out for a ride yesterday, 10 mins never got more then maybe 185. Now have a 180 hi-flow state in there too. Wasn't super hot yesterday out. Temp outside was about 85 deg. I can live with this temp.

Thanks to all for there inputs.

John

[lewy-d]

thank you for the follow up.
how did you determine the sending unit was faulty?

[67 Nova]

Actually, after changing a bunch of stuff on the front of motor, getting hi flow t-stat and car still heating up, I was lost???? So the gauge is new, but from one of my other cars since the other car is not ready for the road yet. Just a temporay install to get around for a bit bit before I install the Dakota dash.

Anyway, I went to work on the car the one day, and notice that the gauge jumped when I was about to start the car? Went from below 100 degs to about 115/120, just below the 125 line. So since the car wasn't stated in a week, I opened the rad and put in a digital thermometer to get water temp. Powered up the car, NOT RUNNING. Gauge was 115/120, water in rad 73.6. Looked on-line and seen others with sending unit problems, so for a couple bucks I ordered one.

Now on powering up, stayed under 100.

1 thing done and fixed......