Overheating 360 new engine

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Slappy

Slappy

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Hello guys I'm having an overheating issue. Little background info first. I was a master ASE tech for 30 years this one has me stumped. I have had this car at two separate shops also. Here are my engine specs for the cooling system. I have a champion 3 row radiator. March serp belt system, 180 deg t-stat, stock water pump, 2 12 inch electric cooling fans mounted diagonally, vintage air system, autometer pro comp ultralite gauge, also edelbrock aluminum rpm heads (6077). The engine has had a few different radiator caps. The current one is a stant 16lbs. Engine has less than 200 miles due to this issue. Forgot to mention this is an LA360.

First I will start with the shop experiences. First shop stated that my carb was running to rich and causing the overheat issue. I took it to another shop and they said the same thing and tried to work on the brand new out of the box holley carb. This just made it worse running. I went ahead and added a Holley sniper EFI set up on. What a difference in runability and power! Engine is still running hot. I have tried several different thermostats ranging from 160-195. 2 Different water pumps, 2 different electric fan setups. I had all the engine parts IE block and heads, crank ect checked at a local machine shop. Block was bored 30 over. Head gaskets have been tested chemically 3 times and all 3 times negative. The heads were not in the box but were new never used. But some small port work was done on them. This is why the machine shop checked them for me. One weird thing did happen. One of the freeze plugs on the left side of the engine blew out. Both times the engine was at a higher rev. I put a third plug in and it felt like it went in to easy so I JB welded it in. I know this method is not professional but aside from taking the engine out it was easier. No more issues with that plug. I should mention also that no oil or coolant appear to be mixing in the engine or radiator. I also had an oil analysis done and that turned out ok so far.

I decided today was the day to look deep into the issue. The starting coolant was 89f . I live in Florida. I went ahead and ran a suitable fan in front of the engine. The first temp check was gauge read 150f and my two infrared temp guns read 134F. At 180f both cooling fans came on and water was flowing well in the radiator. Next temp reading was 194f at the gauge and the gun read 184F. At this point I stuck in a thermometer directly in the coolant. I left the coolant thermometer in until 205F then I put the cap on. Temperature continued to rise on the gauge and on the gun until I shut the car down around 215F. I did notice that the exhaust temps engine running and engine off were all over the place. The two middle cylinders were as much as 100f difference than the end ones. This was true for both banks. The Left side was considerably hotter than the right side. To give you an example I have my MSD box mounted with an air flow gap under it on the inner fender well and it was 147f with the hood open. The master cylinder was 160F.

Not sure if the blowing out of the freeze plug was a sign. Bad Machine work?? EXhaust temps have me baffled as to why they are all over the place. I dont know if the engine block has some sort of flow issue. Heads issue?? I did order a cylinder leak down tester which will be my next task. I can watch the radiator for bubbles with it for head cracks ect. The car runs great accept to hot.
 
Do you have a fan shroud? Does it have proper airspace behind it, proper fan depth to shroud?

With your AC setup, is the main rad getting enough air flow to it?
 
cpearce said:
Do you have a fan shroud? Does it have proper airspace behind it, proper fan depth to shroud?

With your AC setup, is the main rad getting enough air flow to it?
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fans are mounted to the inside of the radiator. the fans have basically a shroud around them but thats it for a shroud. They are only a few inches from the engine but good air flow.
 
Normally one running hot at rest is air flow. Could be you don't have enough fan, OR it could be that radiator. There've been a couple different studies from testing that found a two row with at least 1" tubes cools better than a three row. Something about the three row having the flues crammed close together keeps the heat from shedding properly due in part to blocked air flow. I'm no thermodynamics engineer, but that's what the word is. Generally speaking, you need a minimum of close to if not more than 4,000 CFM to cool a hot rod engine. So if your fans are not close to that, that could be an issue. Also, are you using a high flow thermostat? If not, I highly suggest one. From your description though, I would look at air flow first.
 
Two thoughts come to mind:
Is the Sniper controlling the timing or do you have it manually set? If manually set, could be too much initial.
You have a March pulley system, but is it the right ratio? You should be at about 1.3:1, WP to crank.
 
RustyRatRod said:
Normally one running hot at rest is air flow. Could be you don't have enough fan, OR it could be that radiator. There've been a couple different studies from testing that found a two row with at least 1" tubes cools better than a three row. Something about the three row having the flues crammed close together keeps the heat from shedding properly due in part to blocked air flow. I'm no thermodynamics engineer, but that's what the word is. Generally speaking, you need a minimum of close to if not more than 4,000 CFM to cool a hot rod engine. So if your fans are not close to that, that could be an issue. Also, are you using a high flow thermostat? If not, I highly suggest one. From your description though, I would look at air flow first.
Click to expand...


I made a mistake the radiator is 2 row 1inch core. Im pretty sure but cant remember but the cooling fans are not that high of cfm. I have not used a high flow thermostat but the water seems to be flowing well at 180.
 
Professor Fate said:
Two thoughts come to mind:
Is the Sniper controlling the timing or do you have it manually set? If manually set, could be too much initial.
You have a March pulley system, but is it the right ratio? You should be at about 1.3:1, WP to crank.
Click to expand...
The timing is not controlled by the sniper set up. As far as the March system Im not sure. I just ordered the kit from them. I figured they would sell me the proper one. (Their i go thinking)
 
Slappy said:
I made a mistake the radiator is 2 row 1inch core. Im pretty sure but cant remember but the cooling fans are not that high of cfm. I have not used a high flow thermostat but the water seems to be flowing well at 180.
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Then you might can rule out the radiator. Have you tried DRIVING it down the road to see if the extra air flow might cool it down? 205 isn't over heating, but it's hotter than I like to run them.
 
RustyRatRod said:
Then you might can rule out the radiator. Have you tried DRIVING it down the road to see if the extra air flow might cool it down? 205 isn't over heating, but it's hotter than I like to run them.
Click to expand...

yes it just continues to climb. It has been as high as 220 and would keep climbing if I let it. I put a fan this morning in front of it and it made no difference.
 
Slappy said:
yes it just continues to climb. It has been as high as 220 and would keep climbing if I let it. I put a fan this morning in front of it and it made no difference.
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How much of a fan? A WalMart box fan? I also cannot stress enough about the high flow thermostat. While it may not cure your issue, I can tell you first hand on mine it made a big difference.
 
My money's on the fans, also put a 7 blade mechanical fan on it and add some timing for an easy test
 
Your fans are rotating in the correct direction ...... right?
Do this;
At idle and over 180*F
First check the temps of the water across the rad from where the coolant goes in to where it leaves, looking for about a 30 degree difference. If you get close to this; STOP! I'll bet you a box of dirty doghair that one of two things is wrong;
1) you have insufficient idle timing, (or waaay too much but that is near to impossible at Idle)
2) your rings are gapped too tight and or you need more skirt clearance.

As to #1,
if your timing is too retarded, the A/F mixture will not finish burning high enough up in the chamber, and will instead continue burning as the piston goes down. The blow-down heat now goes into the water jacket thru the cylinder walls, instead of out the exhaust system .
If you have headers; at idle,you should be seeing temps in the primaries of about 400*F +/- 50*, At 450, the mixture is still burning in the ports and head pipes, and heating up the heads now. At under 350, I'll guess she's running really rich.
So here is a test;
With the engine over 150, just advance the timing without regard to the numbers. As you add Idle-timing, the rpm will go up. Keep adding timing until the rpm no longer rises. If it goes over 1200rpm, put it back a bit. Now put a Timing-light on it and back it up 3 degrees. When the temp gets to 200, turn both fans on;
Now watch your temp gauges.
>Here's the deal, your engine, at idle, wants a ton of timing. By the rpm rising, she is telling you that she is making more Idle-Power. Since you did not adjust the AFR, this can only happen if more of the pressure produced by the expanding gasses, is being delivered to the crank at the optimum time, measured in crank-degrees.
Now, withe Idle Timing out of the way, and the rpm back to normal, the heat of combustion should be exiting at a normal temperature and your overheating issue should be gone.
Keep watching your temp gauges.
If the temp keeps rising, then Idle-Timing is NOT your problem.

Ok, so
With the fans on full-time, the coolant temp should drop back down to the thermostat setting. If it does not; check the following;
>the rotation of your two fans are both in the same direction, and
that the air is going in the right direction, from the front of the car to the engine side, and
>that the air is coming thru the rad, and
>is not able to shortcut back to the front side, and
>has an escape route under the car.
>That the lower hose is not sucked flat,
>That the thermostat is opening,
> that the coolant is circulating,

As to #2,
When all else fails to bring the issue to light;
you gotta consider that the engine itself may be creating internal friction, beyond the norm. That friction comes almost exclusively from the rings and skirts, with a portion added by the valve springs.
So go back to your build spec, and check those clearances. Then compare them to what the builders on FABO recommend, for the piston and ring types that you are using.

Happy HotRodding
 
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Oh and one more thing.......running too rich won't cause over heating. Running too lean can.
 
If your fans don’t move at least 3,000 cfm they’re not enough, I don’t care what kind of radiator you have. There are really expensive fans out there that don’t move enough cfm. The Ford Contour fans I run will flow 3,500 cfm on the low speed setting and 5,000 cfm on high speed, that’s the ballpark you need to be in for electric fans on the street. Less than that won’t keep up.

You said you had march pulleys, whats the drive ratio on that water pump pulley? If you’re under driving the water pump too much it’s not gonna keep up. Most performance pulleys are under drive pulleys for more horsepower, they’re not made for cooling. You could have the “right” pulleys, but still have an under driven water pump. It’s all about application.

How many blades on your water pump? There are standard and high flow versions, they were designed for different pulley ratios.

The freeze plug blowing out it interesting. Might have a plugged passage in the block, although it could also just be a loose plug. I would suspect other issues first (like the fans not moving enough cfm). The cylinder temps will always be higher on the center two cylinders. If the right and left backs are different that could be a block machining deal, if it wasn’t square decked your compression ratio’s may actually vary side to side. Could also be a fuel issue, but if you’re TBI it shouldn’t be.
 
If he's running 205 plus, it's buildin up some pressure too. Also, @Slappy you should run as low PSI radiator cap as you can stand. Higher pressures are much harder on the cooling system and a higher PSI cap will not help it to run cooler.
 
Question about your serpanteen belt setup.

Does it run over the water pump pulley like a V belt setup or does the back side of the serp belt run over the WP pulley?

reason...

If the back side of the serp belt runs over the WP pulley you need a reverse rotation water pump. Might also need a reverse rotation front cover too.

Way back in the beginning of serp belts I put a 302 setup on a 351 W (Was not offered at the time ) I had to cobble together all the misc parts to get the rotation correct.


Lastly.

2 x 12" fans = 226 sq in of cooling

17" x 22" = 374 sq in of rad area

Only about 60% of the core has any amount of cooling (fan or driving speed)

The rest of the area is covered by shroud that I bet is about 1/2 inch from the back face of the rad core.

At idle you probably don't have enough air flow from the small fans.

At speed the shroud is blocking too much of the rad.

If it was me. I would ditch the electric fans, and shroud, put the stock mechanical fan back on and shroud (assuming the rotation is correct)

Also be sure the pulley diameters are correct. The water pump pulley should be the same size as the crank pulley give or take (OEM pulleys are 10% underdriven to 20% over driven AND the water pump vanes, etc are designed to match) from the factory the high performance / AC cooling water pump had fewer vanes but was over driven as compared to the stock cooling.

the factory engineers designed things the way they did on purpose. If s 383 or 440 can fit in a Dart and be propperly cooled with stock cooling system so can your 360
 
Slappy said:
The timing is not controlled by the sniper set up. As far as the March system Im not sure. I just ordered the kit from them. I figured they would sell me the proper one. (Their i go thinking)
Click to expand...
As a side note, the Sniper controlling the timing based on engine data from the sensors, is one of the huge benefits of the system, in addition to the F.I.. You may wish to have the Sniper control your timing in the future. Personally I wouldn't consider running one of those kits without using the timing feature.
 
Question about your serpanteen belt setup.

Does it run over the water pump pulley like a V belt setup or does the back side of the serp belt run over the WP pulley?

reason...

If the back side of the serp belt runs over the WP pulley you need a reverse rotation water pump. Might also need a reverse rotation front cover too.

Way back in the beginning of serp belts I put a 302 setup on a 351 W (Was not offered at the time ) I had to cobble together all the misc parts to get the rotation correct.


Lastly.

2 x 12" fans = 226 sq in of cooling

17" x 22" = 374 sq in of rad area

Only about 60% of the core has any amount of cooling (fan or driving speed)

The rest of the area is covered by shroud that I bet is about 1/2 inch from the back face of the rad core.

At idle you probably don't have enough air flow from the small fans.

At speed the shroud is blocking too much of the rad.

If it was me. I would ditch the electric fans, and shroud, put the stock mechanical fan back on and shroud (assuming the rotation is correct)

Also be sure the pulley diameters are correct. The water pump pulley should be the same size as the crank pulley give or take (OEM pulleys are 10% underdriven to 20% over driven AND the water pump vanes, etc are designed to match) from the factory the high performance / AC cooling water pump had fewer vanes but was over driven as compared to the stock cooling.

the factory engineers designed things the way they did on purpose. If a 383 or 440 can fit in a Dart and be propperly cooled with stock cooling system
 
wow thanks for the response, guys! I'm going to start working through all the suggestions tomorrow. I will also post some detailed photos of what i have. Thank you again to everyone.
 
Slappy said:
Does anyone know where I can purchase a 4000 cfm or greater fan?
Click to expand...
If I might suggest, get a factory clutch fan and proper shroud. I run one with stock water pump on my 550hp w2 408, no heating issues whatsoever. Although not sure if this can be done with serpentine system?????
 
cpearce said:
If I might suggest, get a factory clutch fan and proper shroud. I run one with stock water pump on my 550hp w2 408, no heating issues whatsoever. Although not sure if this can be done with serpentine system?????
Click to expand...
I wish I could but no room anymore. I will post pictures tomorrow.
 
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