Advice post engine build, engine runs hot at idle

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I am currently under the assumption that the Edelbrock heads require 10° less ignition advance than the OEM iron heads (until someone reports otherwise). So if the ignition is set up for 36° to 38° total advance, the static advance should be dialed out (retarded) by 10°.

Unless the overflow tank has been converted to a head tank, the top of one of the radiator's tanks needs a drain petcock screwed into it to serve as an air bleed. The factory air bleed doesn't function properly, Ford/De Tomaso tried about 3 different air bleed configurations, none of them ever worked. Wherever the factory air bleed connects to the coolant system needs to be disconnected and plugged. Manually bleed air from time to time or convert the overflow tank into a head tank. Either of those methods work.

Make sure there are no sections of radiator hose between the radiator outlet and the coolant pump inlet that could collapse due to vacuum. Gates green stripe hose, wire wrapped, (vacuum rated for 25” Hg) should be used between the radiator outlet and coolant pump inlet. Part number 24922 (1-3/8 inch - 35mm - ID hose) for most sections, and part number 24928 (1-3/4 inch - 44mm - ID hose) for the connection to the coolant pump. Those parts numbers are for 5 foot length sections of new hose.

Flow Kooler's coolant pump p.n. 1648 is designed to improve coolant flow at low rpm.

IPSCO sells a smaller diameter pulley for the coolant pump. This increases the speed of the coolant pump by about 10%. The "overdrive" pulley's part number is # IPS260-OD. Every Pantera should be equipped with one of these.

Since the radiator fans are DC, if the polarity of the connections is reversed, the fans will blow air in the wrong direction. So make sure the fans are blowing air in the proper direction.

I have seen the metal coolant tubes running below the car full of iron "chips, or rust. That could plug things up.

For your peace of mind, 93 octane fuel should be fine. Based on the mechanic's 10.4:1 static compression calculation, I calculate the intake valve closing at 68° ABDC (278° intake duration, 109° intake C/L), thus the dynamic compression is 8.09:1, which is just a little high for 91 octane.

There are a couple of issues I'd like to go over with the engine rebuild, not related to over-heating. I don't want to distract attention away from the subject of over-heating, so perhaps pose your request for comments about the engine build again at a later date, after the overheating is resolved.

Finally, Eric,I love the picture of you and your father in front of the Pantera. I would like to use it on the home page as the next picture of a member posed with his Pantera. Would that be OK?

-G

Our cars are very susceptible to retaining air in the cooling system.  Air pockets will cause a variety of problems including overheating at idle.  To diagnose this look inside the swirl tank the next morning after the car was up to temperature.  The water should be immediately at the top.  Otherwise there is air in system.  If the water is low, add more coolant and bring the car back up to temperature.  Then check it the next morning and repeat this until it is full.

Also, make sure the overflow tank is about half full.  If it is empty then it will keep pulling air into the system.

George-Many thanks for the response, I love all that you contribute towards the Pantera community. Absolutly you can post that photo. First memories for me was of that car and the birth of my younger sister.

Interesting comment on the Edlebrock heads, I didn’t realize they would require that much of an adjustment but that could point to my pinging, detonation, and possibly heating issues! i’m going to try retarding some next week.

The fluidyne radiator indeed has a drain petcock that I screwed in and open occasionally.  Factory air bleed hose from the overfill tank was removed and capped. I also use a coolant hand pump at the swirl tank to help pressurize the system and push air out.

I installed all gates green hoses with the exception of the hoses that enter and exit the radiator as I cound not find correct bend. Also do not have a gates green from the swirl tank top to the stainless line. I guess my question here would be at idle they shouldn’t collapse due to vacuum correct? (I am overheating stationary at idle).

The fans are indeed blowing in the right direction with both pulling air through. The stainless lines are clean and look new which I verified when I put the gates green on in July!

Just looked through the parts and a Milodon pump 16235 was put on with a 180 thermostat and water restrictor plate back in 2015. She also has the better sunpro guage showing 100-280.  I have not heard of the pump you mentioned nor the smaller diameter pully. This may be something to do!

Good to hear on the octane. Appreciate your input and good to know that she should be fine on 93. I’m guessing given what you shared about the aluminum heads that my timing is just off which is causing my stumbling and slight overheating.

@stevebuchanan posted:

Our cars are very susceptible to retaining air in the cooling system.  Air pockets will cause a variety of problems including overheating at idle.  To diagnose this look inside the swirl tank the next morning after the car was up to temperature.  The water should be immediately at the top.  Otherwise there is air in system.  If the water is low, add more coolant and bring the car back up to temperature.  Then check it the next morning and repeat this until it is full.

Also, make sure the overflow tank is about half full.  If it is empty then it will keep pulling air into the system.

Steve-Appreciate the response and have confirmed swirl tank is full with overflow about half!

Today I decided to start her from cold just to see how long she would take to hit 230. Started the car and for the first few minutes she sat around 2500 at fast idle. Finally she lands a hair below 1100 on idle. Took her just over 15 minutes of sitting in the (conditioned/75 degree) garage to slowly and consistently creep up to 230 at which point I cut it.

I don’t believe it to be air in the system as the temp very slowly and consistently rises, there is no up and down.

Also of note she does not run on. She cuts immediately when I turn her off. Both fans were very forcefully pulling extremely hot air from the Fluidyne radiator.

As George mentioned, the Ipsco water pump pulley will likely help.  It has a smaller diameter and thus it spins the pump faster.  It is only $89 and is easy to install.

Maybe pull the thermostat and double check that the water restrictor plate was actually installed.  If the original plate with the large hole is still there along with a Windsor thermostat then you will have reduced cooling.

So stupid questions here for you but:  Define what you mean by "the car Overheats?"  Is it puking fluid out the header tank?  Or is overheating your response to the gauge saying 230?

1.  You know your gauge to be accurate?  You know 230 is really 230?  Have you measured temps with an IR gun?  Is the gauge and sender correct for each other?

2.  Do you see the car warm up in temperature and see the gauge drop when the thermostat opens at the design temp, then gradually warm back up again and repeat until it gets pretty warm?  What thermostat is in the motor?  Are you sure?

3.  You have enough cooling fan capacity blowing over the rad and they are blowing the correct direction?  Clearly if the car runs at some temp on the freeway (what temp is that? when you are driving along at 60 mph?   then it would suggest your problem is not enough fan capacity at idle or your fans are not wired correctly nor getting enough voltage to spin then fast enough when idling.

4.  If you don't shut it off, how high does it get?  Let it run and see if the radiator cap discharges.  Does it?  It has been said if your cap is correct (16 lb cap) and it isn't discharging, then the car is not over heating.  Will it puke coolant if left idling?  try it and see.

Before buying pulleys and attempting to solve a problem, you need to figure out what the problem is.

Is it a gauge that you think implies overheating

Fans under capacity

Air in the system

???

⬆️⬆️⬆️ See above ⬆️ ⬆️⬆️

No stupid questions, searching for help and appreciate the guidance. Answers/thoughts below in bold:

@panterapatt posted:

So stupid questions here for you but:  Define what you mean by "the car Overheats?"  Is it puking fluid out the header tank?  Or is overheating your response to the gauge saying 230?

It’s a great question. I replaced out the lines with gates green and marine grade clamps and went for a drive when i first got her a few weeks back. After the drive and idling on the driveway for a while I noticed it was over 245/250 and immediately shut her off. I heard a hissing noises and fluid spilling out which was coming out the coolant tank. My father shared with me after that that he never let it go over 230. So I know it will puke out around at least 245, thus me keeping it at 230 to prevent “overheating”.

1.  You know your gauge to be accurate?  You know 230 is really 230?  Have you measured temps with an IR gun?  Is the gauge and sender correct for each other?

I have not measured with an IR and the guage is new. Its a great idea though. Where would you recommend taking the measurements with my IR gun at? This said we do know that 240+  on the guage causes it to boil over  

2.  Do you see the car warm up in temperature and see the gauge drop when the thermostat opens at the design temp, then gradually warm back up again and repeat until it gets pretty warm?  What thermostat is in the motor?  Are you sure?

i do, only a slight bit though. right around 185. I only see it really adjust down once before she continues a slow steady climb. The thermostat is a stant 180 degree part number 13468 . I am certain as my dad bought her new and kept all records.

3.  You have enough cooling fan capacity blowing over the rad and they are blowing the correct direction?  Clearly if the car runs at some temp on the freeway (what temp is that? when you are driving along at 60 mph?   then it would suggest your problem is not enough fan capacity at idle or your fans are not wired correctly nor getting enough voltage to spin then fast enough when idling.

correct. A massive amount of hot air is pulled from behind the rad. I could not imagine them pulling much more air!

On the freeway she runs a steady 175/180 at 60.

4.  If you don't shut it off, how high does it get?  Let it run and see if the radiator cap discharges.  Does it?  It has been said if your cap is correct (16 lb cap) and it isn't discharging, then the car is not over heating.  Will it puke coolant if left idling?  try it and see.

Good question and I do not know where she would peak. When she overheated and purged that first time i then bought the pressure tester and did the raising of the rear end trick to get air out. Air did come out. I have not gone above 230 as I do not want to damage the engine.

She did puke over idling following that first drive (showing 245/250).

Before buying pulleys and attempting to solve a problem, you need to figure out what the problem is.

Agreed. Love the questions to help me ID what the problem may in fact be. I have read over many forum posts prior to posting and still looking for the problem I am solving.

Is it a gauge that you think implies overheating

Dont believe show. Read 245/250 and puked coolant.

Fans under capacity

dont believe so, moves massive amounts of air, that said i have not (do not know how to) tested.

Air in the system

Dont think so . Many drives. petcock on rad opened, followed by swirl tank and (many times over) the coolant pressure tester to help purge air. Nothing more coming out….

???

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It's the coolant pump!

The Milodon pump, like the Weiand pump, is designed to operate without a thermostat. The recirc passage of the Milodon coolant pump is not drilled out. So until the thermostat opens up a bit, there is no coolant flow through the engine.

Not good for the engine.

You have two three choices
(1) remove the thermostat
(2) remove the pump & drill the passage open.
(3) while the pump is off, replace it with the Flow Kooler pump.

Also, the Stant 13468 thermostat is nothing like the original thermostat. The original thermostat, made by Robertshaw, has been sold by many companies, always identified by the number 333. I would strongly suggest replacing the Stant 13468 thermostat too.

Need two bits of info for the picture caption:
Your father's name
The chassis number

-G

First time I have heard anybody say the Weiand water pump does not require ANY thermostat. I’ve always heard that it works just fine with the Windsor thermostat as well as a Cleveland thermostat.

But no thermostat?

🤷‍♂️🤷‍♂️🤷‍♂️

Larry

I was wondering if the thermostat was not a high flow style which would cause lower flow, especially at idle. Anyone know?

I did some searching and found multiple images of 13468 and it is standard flow, with the “hat” but not a high flow.

Larry

I think job 1 is to replace the water pump with a FlowKooler or Edelbrock and install the Robert Shaw style high flow thermostat and make sure the proper brass plate is under the thermostat.

@George P posted:

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It's the coolant pump!

The Milodon pump, like the Weiand pump, is designed to operate without a thermostat. The recirc passage of the Milodon coolant pump is not drilled out. So until the thermostat opens up a bit, there is no coolant flow through the engine.

Not good for the engine.

You have two three choices
(1) remove the thermostat
(2) remove the pump & drill the passage open.
(3) while the pump is off, replace it with the Flow Kooler pump.

Also, the Stant 13468 thermostat is nothing like the original thermostat. The original thermostat, made by Robertshaw, has been sold by many companies, always identified by the number 333. I would strongly suggest replacing the Stant 13468 thermostat too.

Need two bits of info for the picture caption:
Your father's name
The chassis number

-G

Awesome! I know he had replaced these (pump and thermostat) upon recommendation prior to engine build. Also had the plate put on.

I’m guessing the pump itself would not be causing the issue of continuing to slowly rise up till 230+ at idle given once the thermostat opens it should stop the recirc challenge as it will fully flow to rad, etc, correct?

It does, however, seem that the thermostat would be an issue at idle or while running, and could be a series contributor to my problem. I did not realize the Stant 13468 was not high flow. I want to look for any Windsor based thermostat with a 333 in it, correct?

Father is Steve Bruce and chassis is 7084

The Windsor thermostat is not correct. Here is a picture of the correct thermostat and bypass plate. (Credit to MJ for his picture).

As George pointed out, the pump you have installed is incorrect too. All of the parts were designed to work together as a system. We know you have the wrong pump and the wrong thermostat. What we do not know is if the bypass plate was replaced. There is a bypass plate out there that essentially seals off the bypass port.

Here is the link to the proper thermostat but it looks like they are on back order.

Track Boss Thermostat

Summit Racing shows them in stock and for a Cleveland but their picture does not show the bottom of the thermostat to confirm the "hat" is actually there.

Summit Racing

None of this matters if you do not have the correct water pump. The FlowKooler and Edelbrock have an enclosed impeller designed to move more gpm. They also have the bypass port designed to work with the thermostat and bypass plate.

FlowKooler Water Pump

Edelbrock Water Pump

“Wrong” Water pump and/or thermostat and/or thermostat rating and/or radiator air bleed and/or block-off plate and/or surge tank/overflow tank piping configuration, …..

All are commonly seen as the likely culprits for a Pantera cooling system that has, or is suspected of having, “overheating” issues.

I present my following true experience:

when I purchased 2511 it had a Weiand  water pump with no after-purchase bypass hole drilled, a Windsor thermostat, and a bypass plate with a totally blocked opening, water pump pulley was OEM, Meriah pusher fans, top of aftermarket Ron Davis radiator had a fitting connected with piping to the small surge tank in the engine bay. Both tanks were unmodified as well as the under car piping.

how did I deal with all of the anticipated “overheating” problems?

there weren’t any.

I drove 2511 with that system for well over 40,000 miles, and I live in the very-hot-Summer California Central Valley.

Moral of the story? ……

YMMV

Larry