Technical Running hot at idle

So I have a problem with the engine getting hot at idle
Havent had a chance to drive the car on the road yet, its situated on my parents land, but seems like it warms up pretty quick, and just sitting there idling the temp gauge goes up into the red. I always switch it off before it has a chance to boil. I have flushed the radiator through, it has a 160 thermostat which I checked that it opens by putting it in a pot of water on the stove. The water pump was new around 2013 when the engine was rebuilt, and radiator re cored at the same time. Pump isnt making any odd noises or leaking anywhere that I can see, i've replaced all the heater hoses,, no leaks there or at the heater. The heater works and blasts out hot air. I have the timing set to 7* btdc, which is showing 28* at 2,500 rpm, the vaccuum advance is connected to manifold vaccuum, the ported side of the carb is blanked off. I had some issues a while back with a flat spot off idle but have sorted that now. Its a 364 Nailhead, overbored to 0.40, stock cam, now using a 500 cfm AVS2 carb and an HEI distributor. It runs and drives ok, has plenty of grunt and shifts like shit off a stick in the short space I have to test it. I read that if the timing isnt advanced enough it will cause the engine to run hot, by how much does timing need to be retarded in order to cause a hot running engine? Having read the 401's need to be set at 2 1/2 * btdc when connected to manifold vaccuum, does this also apply to the 364's? Playing with the timing yesterday, I advanced it ( turning distributor clockwise) to get the 2 on the timing mark, and this seems to slow the engine down way too much, I know this will speed up somewhat when hooking the vacuum back to manifold, but it didnt sound right. Even 5* seems a little off. The one thing I forgot to do was to slow the idle down to around 400 rpm when setting the initial, not sure how important this is, but disconected and plugged the vacuum line anyway, which seemed to drop the engine speed down a lot. Vacuum gauge is reading high when idling, so quite happy with the timing/carb set up. I guess my question is, having set initial at 7-8* with the vacuum hooked to manifold, is this now going to add too much timing at inital and cause the temprature rise? The other thing I need to question is if I have air in the cooling system, and how to bleed it. I have the correct ratio of coolant in the water, the water is always at the same level, its not losing any. The top hose does feel like its empty and very soft and squishy, running the engine with the rad cap off, doesnt look like the water is moving, yet if it wasnt, then the water in the rad would stay cold wouldnt it? The radiator has the factory shroud, and the fan is the large aluminium type, lots of blades, havent counted how many but look razor sharp. No AC on the car.. The fan blades are just about sitting in the opening of the shroud, but are quite a distance from the rad. I made an extra covering bolted onto the shroud to create more of a tunnel thinking this would help, but it hasnt at all..so I have removed it for now. I guess I could try a different temp gauge to check that the issue isnt with that. Both top and bottom radiator hoses feel hot. Feeling the front of the rad , the top feels hotter than the bottom, but the bottom is still quite warm. I am thinking maybe its not drawing enough air through the rad, but its had this same set up for the past 30 years without any issue before.

 

Try more initial
12ish maybe more ,
Some engines like 18 deg
Experiment , maybe 700 rpms also.
Initial timing is one thing & total is another,
A "total " limiter might be required

 

Clutch type fan or not?

 

Nailheads do not like a lot of advance. Seven degrees initial should be fine if the timing marks are correct. I also run manifold vacuum to my vacuum advance so you do get a lot at idle which makes it idle smoother. How hot is hot? Have you checked the temperature with a mechanical gauge? Does it push coolant out the overflow?

My nailhead will get warm enough at an extended idle to kick on my electric fan. I think I have it set to 215 degrees. That puts my 50 Ford temp gauge a shade above 1/2 scale (no numbers). When the fan comes on the temp drops. The fan never comes on going down the road.

On your engine driven fan, the blades should be not quite 1/2 way inside the shroud.

 

I wojuld put a good mechanical gauge on it and see what the numbers really are. Have you checked the heat riser valve? If it is stuck closed or partially closed it will cause the engine to run hot.

 

I don't think tuning is the problem. It's more basic to the cooling system. You can't see a river flowing past the cap? That's it right there. You have a coolant flow problem. I don't know why, cuz you said the radiator was flushed and recored and everything. I would look for an obstruction. A mouse or something that got in the radiator when it was sitting around open? Flush it backwards upside down. And then when you flush it right side up, block the tube at the bottom, fill the radiator and unblock the lower tube. It should drain instantly, like in two or three seconds.

 

Nailheads run warmer, 364s not as much. Make sure the radiator is not partially plugged with rust, especially after a rebuild.

 

Or your water pump simply isn't working. But I doubt that. Pulley bolted to the water pump? LOL had to ask.

 

First time I drove it after the rebuild that valve was stuck closed, and the car overheated after about 45 minutes of driving.. i didnt know about the valve and it got hot a couple more times and then I figured it out and removed the whole thing.

 

Yeah this is my next line of investigation I think. I'll remove the bottom hose and see how it drains. Maybe the water pump inlet is blocked too. Nope, no churning or river flowing past the cap, water just sits there. If I rev the engine it looks like the water level drops ever so slightly, then rises back up on deceleration

 

Heres a screen shot of the engine running. You can see where the blades are positioned in relation to the shroud. Its not boiling or pushing coolant out the overflow or anything, but then as soon as the gauge starts going into the red I shut the engine down. Ideally it should be sat around 80c on the gauge which is 176F but its pushing past 100 which is over 212f . It could be a false reading on the gauge, but the fact the water doesnt seem to have much movement makes me think that the gauge is accurate. I do have a mechanical replacement that I bought new, that has that bulb censor with the curly steel wire, like the original guess its mercury opperated..i could try fitting that, the sensor is plugged into the rear of the driver side cylinder head at the mo, I was unable to get the plug out of the front passenger side and locate it there. If the water isnt flowing through the rad though, how is it still getting hot? Surely if its not going around the engine the water wouldnt be getting hot?

 

Nice fuel filter. Once you have your cooling issue fixed, lose that thing.
I am watching your thread with interest, no one like cooling problems.

 

You might have air pockets in the block. Did you burp the system to remove airpockets?

 

Could the thermostat be in upside down resulting in no flow? I don’t mean to question your abilities, just thinking about possible causes. Good luck

 

That isn't disrespectful, we have seen guys do that on here. I have also seen fans installed backassward. Reverse rotation pumps and heat trapped under the hood with no escape at an idle and the guy a few years back that left a red rag in his radiator inlet/outlets to keep the mice out while it was out of the car and forgot to pull the rag out. Add to that timing issues and tight bearings. The OP has to keep checking them off the list.

I am battling a slight heat issue myself, so this is quite timely and informative.

 

I originally thought you said your problem was only at idle. However, it appears you haven't driven it on the road so it could well be a restricted radiator. You still need to verify your engine temperature with a known good gauge or at least an infrared temp gun. You can use a temp gun to see if the radiator is working, ie. is it uniformally hot at the top and cooler at the bottom.

 

Oh thats a really old photo from 2013 , it looks like this now. Got a holley regulator too, an electric pump and a big filter between the tank and pump

 

Oh yes thats possible as I completely drained the system when replacing the heater hoses. How do I burp it?

 

Its a good question, but no, dont think so..it would be really hard to put in the other way up as it wouldnt really fit. I will double check this anyway, as I want to check the water cross over pipe isnt blocked, but quite sure the thermostat is opperating as the water would likely stay cold in the rad otherwise.

 

I have got an infa red temp gun that I bought for my pizza oven, i'll see what its reading . Thanks

 

Oh thats cool, ( unlike my car ) i wasnt offended. Every day is a school day

 

I should mention that this is happening at idle with the hood open the whole time, when its not even that hot of a day.

 

No just a standard fan . It has no AC. Its a 58 Buick Special, didnt come with the upgrades. No P/S either.

 

https://youtube.com/shorts/ZKiWl-yV-Kg?si=TCPJe8rNDNkt-IOA

Heres a little video a made a few weeks ago, although when I gunned it there and had to brake quite hard to avoid going through the gates and into the road, the engine did stall. Think thats a completeltly seperate issue though,

 

Like mention, there are a few things to go back & check ,
Flow of Rad , Fill with water , pull lower hose , should empty pretty fast , like less then 5 sec.
Burp , crack heater hose while running .
Or
Drain coolant down , Block & Rad,
With out T -Stat & upper hose ,@ T Stat open hole one intake , fill
Block slowly , cup , bottle repeat until block fills to T -Stat location , Let set
Few mints , leave should drop , fill as needed , then install T stat ,upper hose
Fill Rad slow .
Or jack Vehicle up high in front Like 16 -24 inch fill Rad slow , so air can escape.
Like Y blender is Hight to bleed brakes .
Or
Use a Coolant Vac down & refill tool.
Many Newer Vehicles uses tool.

Timing , I have not worked on a Nail since like 1980, Seen in post Nail H's
Do not like Initial timing ,
I have had F-Hs in pass , I believe
Initial by the book was 4ish Btdc ,
The F -H I worked on Like 12 degs btdc .
I can say almost every 4 stroke engine I have worked on be for 1993 ish like more initial Timing over spec of Book .

Verify your temp gauge reading ,
Like Most Timing above ,
You move the Temp sensor around to different locations you will get different Temp readings , The father back on the block / heads you will get higher temps reading .
Not so much on pre early F-Hs with outlet in top center of Head .
& on Chevy 1st Gen V8's
Passenger side hotter than driver side coolant temps.

 

You mentioned the radiator was recorded 12 years ago. If the coolant level dropped below any of the rows of tubes in the radiator, they may have clogged with deposits. I pulled a perfectly good 4 core copper/brass radiator that cooled a bored, high compression engine for over twenty years without issue to do an engine swap. I left some coolant in it but not filled. The car was down 6 mos. Once back on the road the car heated up to 200 degrees at idle. Never got over 170 on the hottest days in traffic before. And yes, new water pump and thermostat. I flushed it too. Made no difference. I had to get the radiator boiled/rodded?? out. Now I only use distilled water and coolant. It's back to normal temps

 

When it's hot and idling, cool the radiator with water hose and see if the engine cools right down. This will show how fast the water pump is moving the coolant. If it cools down but takes awhile, the flow is restricted.
I replaced a 18", 6 blade flex fan, with a 17", 6 blade steel fan and solved a hot idle issue I was having. The smaller solid fan moves twice the air the flex fan did.

 

This is a great idea. Thanks..i'll give it a try

 

Virtually ALL the persistent overheating problems I've had over the course of my 50+ plus years of dinkin' with cars has been radiator blockage. Of course I've had few that have been coolant loss through a leaking core plug or water pump. But those were obvious, and an easy fix it and it was done.
Although, I was helping a friend out with the initial start on a fresh 360 AMC (Jeep) with brand new radiator, along with everything else. It got up past 200 within 5 minutes. After checking over everything multiple times, he pulled off the brand new water pump, and the impeller just fell off. It was a nice slip fit onto the shaft!
Not saying that's it, but weird things happen!