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PostPosted: June 7, 2017, 3:53 pm 
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Location: meadview arizona
the timing is not so critical if idling, small fprds will handle a lot of advance at idle right up to a point where the starter won't turn the motor over.

if its retarded there will be virtually no vacuum signal.

most street 302's can handle 20 degrees base timing and full vacuum at idle.

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PostPosted: July 18, 2017, 4:24 pm 
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Location: Frankfort, KY
Sorry for the super late reply! Still not driving it.

1. the aluminum heads, when fitting these were the head bolts new or the old ones, the new ones are torque to yeald and should be replaced if removed, they should also have special hardened washers under the head of the bolt.
No clue, previous owner built it. There are arp washers under the heads. I might find out if I have to change the headgaskets.

2. i need to see the inlet manifold you are using and the water pump, does the water pump have a elbow shaped hose from the top to the front of the inlet manifold next to the thermostat housing?
It does have an elbow.
https://photos.app.goo.gl/fArDWZ560JMDX4mB2
3. is the thermostat housing the highest point on the engine disregarding the carb and uncooled intake manifold?
Yes, I believe so.
https://photos.app.goo.gl/hy67gW6yh4QOSxKp1
4. are there any cooling pipes on the water pump other than the large port to the bottom of the radiator?
are there any water outlets on the inlet manifold adjacent to the thermostat housing?
I have a outlet going to the header tank from the intake, and on the water pump I have the thermostat bypass, and the inlet from the header tank's output.
5. does the engine sit in the car with a "nose up" attitude?
Yes, such that the carb sits at a level plane.
https://photos.app.goo.gl/Oc7b06IrV23VpoYF3
-------------------------------------------------------------------------------------------

now for the header tank

1. is it the highest point in the cooling system?
Yes. Notice behind the carb in this pic.
https://photos.app.goo.gl/1Y1Rf4ntJMlBm8fh2

2. does the pressure cap fit on the header tank or somewhere else in the system like the radiator?
It is on the header tank. The radiator "cap" is essentially sealed off.

3. how many quarts does the header tank hold?
Not much, probably 1.5? I wonder if I simply don't have enough coolant volume for a hopped up V8.
--------------------------------------------------------------------------------------------------------

radiator

1. core dimensions and thickness
https://smile.amazon.com/gp/product/B003OAWYWA/ref=oh_aui_search_detailpage?ie=UTF8&psc=1

Overall Size: 18.5” x 14.6” x 2.5” / Core Size: 13.78” x 14.09” / Rows: 3
Inlet & Outlet: 1.26” / Core Thickness: 1.2” / Tank Wall Thickness: 0.08”


2. what is it made of?
Aluminum

3. where are the tanks on the radiator?
On the top and bottom?

4. is the top hose spigot on the radiator above, level with or below the thermostat housing?
Below.
https://photos.app.goo.gl/56RTkt7dEGipvXLd2
------------------------------------------------------------------------------------------------------

other stuff to check

1. when you purchased the new water pump did you buy it for a fuel injected engine, was it the same as the one that came off the engine and how does it compare to say a 66 mustang with a 289?
The one I purchased was for the year of the car I believe, but was to rotate in the correct direction.

2. does the water pump have a "v" belt pulley or a serpentine pulley or is it a shorty pump?
It just wraps around the alternator, pump, and crank pulley.
https://photos.app.goo.gl/cSfSDqDQQG1zaGWV2

3. the block, is there any traces of water in the oil because the 302 blocks suffered from core shift worse than most other engines, is the block from Mexico or Dearbourn as the Mexican blocks are much better?
No traces of water, and i'm not sure where it was manufactured.

4. when they rebuilt the engine was it re bored and to what size as more than .030 over may have weakened the cylinder walls, usually on the back cylinders so you could have a pin hole in the cylinder which is sometimes exposed to above the rings and sometimes below the rings?
It was bored .030 from my understanding.

5. are you sure that the electric fan or fans are moving air in the right direction, if you have a pusher and a puller they must be wired oppositely.
I'm sure the puller is working, and I removed the additional puller. The radiator is sealed enough that paper will stick to the front grill.

6. is there a crossover passage at the rear of the inlet manifold or is it blanking off the water passages in the back of the heads?
I don't believe so, and the heads appear blanked off.

Any idea if maybe I simply don't have enough coolant volume? How much coolant does it take to cool a hopped up v8? I have more pics if any more might help.


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PostPosted: July 18, 2017, 5:52 pm 
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Location: Frankfort, KY
Regarding my total coolant capacity, I'd be lucky to have 8 quarts right now. Stock mustang used 14 quarts if i'm not mistaken.


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PostPosted: August 26, 2017, 3:15 pm 
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Location: Frankfort, KY
Work trips finally calmed down enough for me to go do a leakdown test and compression test. Was expecting a head gasket issue and poor numbers on the leakdown, but got bizarrely good numbers. Very possible that cylinder 2 wasn't perfectly at tdc.

All tests done while the engine is cold
Leakdown Test
cylinder 1 90/85 - 5.5%
cylinder 2 90/77 - 14.4%
cylinder 3 90/87 - 3.3%
cylinder 4 90/85 - 5.5%
cylinder 5 90/86 - 4.4%
cylinder 6 90/85 - 5.5%
cylinder 7 90/83 - 7.7%
cylinder 8 90/85 - 5.5%

Compression Test
cylinder 1 160psi
cylinder 2 150psi
cylinder 3 155psi
cylinder 4 150psi
cylinder 5 150psi
cylinder 6 145psi
cylinder 7 150psi
cylinder 8 150psi


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PostPosted: August 28, 2017, 10:01 am 
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There's nothing wrong with those numbers.

Generally, by the time someone is concerned enough to run a leakdown or compression test, there's at least one dead hole...


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PostPosted: August 28, 2017, 11:20 am 
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Location: Frankfort, KY
Yeah, I was kind of hoping that the leakdown test would reveal the problem, but alas it has not. Next step is to test with more coolant volume to see if the issue is literally just one of "too little coolant capacity".


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PostPosted: August 28, 2017, 1:59 pm 
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Quote:
issue is literally just one of "too little coolant capacity".


It's horrible how much trouble you are having with this. I hope we really learn something here. My 302 is slowly getting ready to go in my frame now.

I don't think you're going to get a solution with more coolant. In your system you have a place coolant is heated and another place the coolant is chilled. Nothing is really helping to the coolant otherwise, it's just circulating or sitting around. If you had an old water heater sitting around and you plumbed that into the circuit, it wouldn't change anything, it would just be sitting there holding coolant. With that much extra water it wold take longer to heat up, but still you're going to get to the same place. If your problem was you wanted to add 10-20 seconds of cooling capacity for a straightway - then adding 1 or 2 gallons would mean something. I think you are in a drastic cooling issue territory though, so there must be a huge problem somewhere. You have a big motor but it only needs big cooling when it is putting out big power.

One thing I am wondering about is the change in volume we saw in that funnel as it warmed up. I still in the back of my mind am wondering about porosity in the head or somewhere that is letting a little combustion pressure get into the cooling. It would take very little per engine revolution to add up to a big problem over just a few minutes.

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PostPosted: August 28, 2017, 2:14 pm 
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Location: Frankfort, KY
Quote:
You have a big motor but it only needs big cooling when it is putting out big power.


Yeah, that makes a lot of sense. I guess when I say "add coolant capacity" I also mean "Add cooling ability". The idea was to possibly route in a second radiator (would have to be mounted in the back of the car due to space issues) and put two fans on it. I've tried every variation of fan on the front and it doesn't seem to do much. There are two things to keep in mind with this issue;

1. At speed, it stays cool. I can even do some fairly hard pulls, and it stays cool. Would this still occur if there were exhaust gases getting in?
2. The engine, though relatively freshly built, was in a car before mine, which had no cooling issues that i'm aware of. I converted it to carb and added a few auxillary things, but that is it. I had bought the car specifically for the transplant. I think i'm about a gallon down on coolant capacity compared to the stock 5.0, but what you're saying makes sense. It'd just slow the rise in temp unless i'm adding something more for the extra capacity to run through and cool.


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PostPosted: October 9, 2017, 9:37 pm 
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Location: Frankfort, KY
I had a spare radiator so I tried this to see if a bit more radiator might solve the problem. Long story short, I went about 14 minutes at idle (starting at 180) before it started to edge up past 190. Not sure how high it would have climbed, but this is also without a radiator cap and instead using the spillfree funnel. The pic is showing where I'm testing a second radiator in series. The fan on the second radiator was NOT hooked up at this point. Going to try a few more times while flushing the radiator, and then try with a cap to see what I can do. The goal is constant idling for an hour if I want. If this works, I'll probably try a drag radiator that I can tuck into the rear of the car (if there is room) and I'll try to mount a couple fans on it.
Image


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PostPosted: October 12, 2017, 11:28 am 
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Maybe your issue involves alack of air flow through your radiator while driving because there is higher pressure under your car so the air does not flow out of the engine compartment well?

Have you ever tried driving the car without the hood and nose on it? If that works then you could look into improving the air flow instead of trying to get another radiator installed. People have reported that louvres on top of the hood and exhaust scoops on the sides in front of the dash helped them with cooling.

It would be harder to plumb but the radiators will work best if they are in parallel, not in series. If they are in series the fluid is cooler in the 2nd radiator and so doesn't lose heat as well. If they are in parallel, they both get high temp fluid and it spends twice as long in the radiator, so works better.

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PostPosted: October 12, 2017, 1:01 pm 
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You can do some tuft testing of the nose cone to locate areas of low pressure and reverse flow. The idea is to maximize the pressure differential across the radiator. Feeding incoming air straight to the radiator is about as good as it can be, but if that same air isn't able to leave, it could cause what you're seeing.

Look at pictures of 1950-60s race cars. Some of them have really small radiator inlets yet they worked fine. The inlet ducting gradually expanded to match the radiator face, forming a diffuser, trading air speed for pressure. Where to exit the air depends what's accessible and realistic. In my mid-engine car I routed the exiting air out the sides to between the chassis and front wheels. The thinking is that the air flowing between the wheels and chassis get squeezed, raising the velocity and lowering the pressure. It means that the faster the car goes, the better the cooling, which is exactly what happens.

While I haven't kept up with this entire thread, if the problem is at idle and not at speed, that implies the issue is too little airflow and/or too little coolant flow. You have an electric fan, but as above, the air going through has to be able to get out. Check other obvious things, like confirming that the fan turning the right direction. Though a stretch, also confirm that the mechanical water pump is being turned the right direction. This isn't as silly as it sounds, especially if various engine accessories were removed and the belt rerouted. It's not hard to end up turning it the wrong direction.

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PostPosted: October 12, 2017, 1:27 pm 
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KB58 wrote:
While I haven't kept up with this entire thread, if the problem is at idle and not at speed, that implies the issue is too little airflow and/or too little coolant flow. You have an electric fan, but as above, the air blow/pulled through has to be able to get out. Check other obvious things, like is the fan turning the right direction. Though a stretch, confirm that the mechanical water pump is being turned the right direction. This isn't as silly as it sounds, especially if various accessories were removed and the belt rerouted. It's not hard to end up turning it the wrong direction.


This is indeed my problem. At 55mph, i'm fine. At low/no-speed I'm having issues. I've tried everything I could think;
1. leakdown test - numbers were fine
2. new radiator that was possibly too thick - thought it might be causing more of an airflow issue
3. dual fans on the thick radiator - a pusher AND a puller to ensure that air is moving through fine, though admittedly would hurt at speed
4. Bought a "name brand" radiator - worked better
5. Bought an oil cooler in case that was contributing to overall slow rise in temp.
6. Have tested dual radiators - in series due to inability to reliably provide identical parallel setups.

These 6 things aren't the limit to what has been tried, just what has been laborious. Number 6 is still being tested, but I think it is going to be successful. If the test today is successful, I'll be running coolant hardlines to the back of the car to a second radiator in series. It adds total coolant volume, dissipates it a little, and more. I'll probably be removing the auxillary heater cores that were added as aux cooling. I think they probably pose more threat to having air in the system than anything.


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PostPosted: October 12, 2017, 1:34 pm 
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Okay, I skimmed through the thread.

You mentioned that you replaced the water pump but I didn't see where you confirmed that it's rotating the correct direction.

A later owner of one of my cars added an electric water pump to improve cooling while sitting still, and it worked. What he apparently didn't notice was that it ran oddly at-speed and melted the engine. Seems he wired up the pump to move coolant the opposite direction than the engine's mechanical pump was trying to drive it! The result was that at low speed, the higher flow of the electric pump won out and the engine stayed cool. At high speed, the mechanical pump won out and the engine stayed cool. BUT, as some magic middle speed, the two applied equal and opposite force and the net cooling flow in the engine was zero!

I know you aren't running an electric pump but my point is: assume nothing and be suspicious of everything.

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Last edited by KB58 on October 12, 2017, 1:39 pm, edited 1 time in total.

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PostPosted: October 12, 2017, 1:37 pm 
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eh3civic wrote:
...I'll be running coolant hardlines to the back of the car to a second radiator in series...

No. Radiators work by the difference in inlet and outlet coolant temp so you need to maximize that. Run them in parallel - though I still think a second radiator isn't necessary.

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Last edited by KB58 on October 12, 2017, 1:42 pm, edited 1 time in total.

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PostPosted: October 12, 2017, 1:41 pm 
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If you suspect a head gasket problem, kits are available for testing for the presence of carbon dioxide in the coolant. Google 'combustion leak tester'. Most of the large chains carry them. Usually about $35.

You can also remove the rocker arms and use an air fitting to apply air to the spark plug hole, while looking for bubbles in the coolant. This is how we checked 3.8L Fords during the infamous head gasket recall. It was almost always #4 cylinder that pulled the fire ring of the head gasket into the cylinder.

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