[Tigers] Overheating

[e.coiner e.coiner]

Mayf,

You will get no flaming from me, but I am a believer in high flow water pumps.

Here is my Tigers's cooling saga.

I bought the car in fall of 2000.  Promptly started driving it work. (6 miles each way, no freeway, mostly parkway with speed limit of 45 or 50 mph.

The engine is a mild 260 with a ford 4v manifold and an edelbrock 500 cfm carb. ( I later had it dyno tuned 185 hp at the rear wheels)

Car would get up to around 215 in the 6 mile trip and when I shut the car off it would start percolating and puke a lot of coolant on the ground.

Car had a cheesy flex fan, original shroud, radiator and overflow tank.

Started looking for the mythical Maverick fan but the radiator was definitely tired.  I sent the radiator off to Tom Hall and they had it recored with their 3 row special. 

Reinstalled.  New radiator stopped the percolator action but it still ran up to 210. 

Found a maverick fan, Installed. No improvement.

Took the car on road trip to Mammoth mtn for a Tigers united.

Climbing Cajon pass the temp started rising, By the top it was 230 and blowing coolant.  Stopped let it cool and refilled with coolant and water.

It continued to push water and I had to stop every 100 or so miles and refill the radiator.

Took it to a shop in Mammoth and they found exhaust gas in the radiator.

Limped the car back to san Diego, pulled the heads. had them magnafluxed and found 1 cracked.  Ah HA!!!

Buy a matched set of 289 heads and get a valve job.

Reinstall. 

Car can idle for hours on end at 200 degrees, I even let it idle in the garage on a 103 day an it only went up to 205.

Take it out on the highway and the temp goes up to 210.  Go faster or climb a grade temp goes higher. Find a long 6 percent grade and the temp just keeps rising. Slow down and temps come down.  

Go back to idle and temps come DOWN!

As an aside, I know my temp gauge was accurate because I was correlating it with both an IR gun and a Type K thermocouple that I had mounted to a pipe fitting on the hot tank of the radiator.

Pulled the new radiator and had a shop check it see if it was clogged or anything  and it was clean.

So a this point my car has a new radiator, new hoses (spring in bottom hose) new radiator cap,  shroud, overflow tank and a maverick fan. It will idle with stable temps.  Will overheat on highway or climbing hills.

So.....  I replaced the stock water pump with an Edelbrock High flow pump.  Made that  ONE change.

Now the car runs 200 on the highway, climbing hills it just doesn't budge the temp gage. 

Car has been running like this for the past 14 years, never overheats.  I have even lost the habit of watching the temp gauge.

At the same time my car was overheating, a friend that vintage races a Shelby GT350 was experiencing overheating on the track. The track stewards were none to happy with the coolant he was dumping.

After hearing my saga, he replaced his water pump with an Edelbrock.  No other changes and his car stopped overheating on the track.

So I know that increasing the flow on the water pump fixed the overheating issues of two small block fords.

It also makes sense to my engineers brain.  The coolant system is a closed loop.  If the water is moving slow it picks up heat in the heads and gets really hot. Then it moves to the radiator where it drops a lot of temp because it spends a lot of time in radiator.

The temp gauge reads the temp as the water exits the engine.

Now speed up the flow. It gains less temp in the engine and drops less temp in the radiator so the hot and cold sides get closer together. But this works out because in a given period of time you flow more water so you are actually moving more heat at a lower delta T.

The heat carrying capacity of the water is Q= mdot* Cp* Thot-Tcold)  Cp is specific heat of water and mdot is the mass flow rate in pounds/hour or whatever.  More flow, more heat transfer and a lower hot side temp.  All good.

Regards,

Erich


> On April 22, 2018 at 1:20 PM Larry Mayfield via Tigers <tigers at autox.team.net> wrote:
> 
> 
>     I am always amazed by overheating issues.  Mainly because there are so many ex0lanations and fixes as there are members of the various lists! Heck, I am one of them lol, and I have and have my thoughts as well.  Where I am coming from is the overheating event itself and the causes and maybe not so much the fixes.  I know my car, now a box stock OEM 260 that came in the car when manufactured along with the header tank and stock radiator. Over the years the cooling system has remained the same despite several serious motor upgrades over the years which have been uprooted and morphed back to the 260. It has never been opened! 
> 
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>     Now one of my engines was a 5 bolt 289 that had heads made into hipo heads long ago, in the later part of the 60’s.  Got the whole treatment, cast iron suckers. Screw in studs after modifying the head stud bosses by shortening them  (space needed for the screw in stud wrench flats) and then ported for flow. 11 + CSR pop up pistons;  forged, Jahns as I recall.  Small combustion chambers in the heads.  0.030 bore, 0.010 under crank mains, “hipo” crank which means a good inspection.  I had the pleasure of a Holman and Moody rep chatting with me at a Drag Race in Santa Maria CA. He was impressed by the rpm capability and the fact that with my gearing I could pull the front wheel off of the track on launch.  I sure that was fairly common back then. I drove that engine as a daily driver for a couple of years, out to VAFB, up to Paso Robles, San Luis Obispo and all around Santa Maria. Before that, I once drove the Tiger to Hollywood and to the Playboy Club on a week end night. WOW. What an experience that was: more people than should be allowed to congregate in one place at one time. TRAFFIC, can you say. Movement measure in inches for a good long while. I once surrendered a forward move when a heavy revolver came out of a passenger window of a car full of gentlemen who wanted to get in front of me. Certainly so, no problem, lol.  The important part of this is that so far, and I have owned this car since 1967, January, and I have not yet had an unexplained overheating issue. Not once, not with any engine put into the car.
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>     I think that some of the issues are due to poor maintenance, poor driving habits, and mismatched components and missing pieces.  Yes, there are known factors that come into play when and engine is being assembled, such as those mentioned by Bugz.  Things like piston clearances, ring gaps, thin cylinder walls.  We usually mitigate those during design of an engine and then during assembly making all the necessary checks.  The engine guy most often makes good engines. Where some of the problems arise come from mismatched bits and pieces.  Coupled with mismatched power expectations. What?  Sure, how many of us have lusted after the super spiffy high output engines making north of 400 or more hp in our little cars?  When we do that , we seldom consider our driving habits and whether or not this is a daily driver. Even a high output engine in safe in a daily driver because of a number of factors.  Daily traffic is the pits for getting up to speed so the excess power the engine has simply does not come into play. We generally sedately accelerate at a small rate to match traffic speeds. And guess what, you really do not use more hp to get that from your high HP gee whiz engine than the old 260 produced doing the same job at the same loads. HP is HP and it takes a certain amount of gasoline to make that HP, no more. Yeah, we all find the occasion to stomp on it and we accelerate a bit more than we should or need to but not often. We can pass a bit faster on the freeways but most of the time we sedately motor down the road with our friends in the other lanes.  So why do we overheat? Well consider that our vehicles are old and that over time things have been removed or left off or changed to accommodate changing driver wants and styles. In this thread I have heard notions of higher flow rates and higher pressures in the systems, and bigger or smaller radiators or missing header tanks. SO lets reason out what happens when we take a stock system designed to use a radiator that came on a car with a small low output engine. Higher flow means a few things and one is that the coolant flow is thought to flow faster though the engine carrying away heat better, but is it?  It could, but that stock radiator may not be up to the higher flow rate and so all that excess water flow goes into pump cavitation because you cannot push the water fast enough through the straw of the radiator. And older radiators are even worse for flow. So, while your mileage may vary, it is likely that you just spent money for the honor of owning a high flow pump.  Further, most on our cars have had plumbing changes made.  Header tanks seem to be removed way too often. But those suckers play an really important role. One is that they are a source of extra cooling water. And the manner and location in the system permits the radiator to be as full as it can be if you keep the tank topped off.  Next is finding a replacement radiator for your car or mine for that matter. Are the tanks the same size as OEM? Is the surface area the same how about then number of rows and  fin spacing? I expect that an  Alpine rad will fit but it is not adequate for flow or hp needs.  Put a high flow water pump on that and nothing improves.  And new car radiators are smaller because they want the engine to be more efficient. Thermodynamics says that hotter is better for efficiency. So with the mostly aluminum engines and the ability of that material to shed heat like a banshee they can use very thin radiators.  Other issues crop up as well, as I personally ascribe to. Instrumentation.  Can drive you bonkers trying to get sorted out. Old gages, old sensors, old wiring, old voltage regulators can make your life and expectations miserable.   My temp gage and fuel gages worked but were not correct.  I actually had two issues: a poor voltage regulator and I had removes and cleaned the gage faces and put in new o-ring gaskets between glass and instrument case. I  miss clocked them just a tiny bit. That permitted the connection post on one to short out on the case. Just enough for faulty readings.
> 
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>     So where is al tis going? Well only to cautionary notes. Look carefully at your expectations before, during and after any modifications and make sure that the bits and pieces you have installed or want to install are compatible in size and capability. Make notes of everything that the errant system does and what the conditions are that might have cause the issue: like oh yeah, I had my foot into it for 10 miles and golly gee it overheated with my small pump and radiator. Well, yeah.  Sh*t does happen and sometimes it can be a full on bugger to sort out. I think a lot of the issues are coolant quantity issues. A cup of water is not as effect as a swing pool of water so make sure the radiator is full to the top.  And for goodness sakes, when asking for help, on any issue, give every bit of information you can on the bits and pieces and conditions and ambient conditions that you can remember and dig up right up front. In the past I have seen some like , “my motor quit running as I was just driving down the road. What’s wrong with it?” And this group is the most helpful of any I have ever seen, so a round of applause to the key  knowledge folk who help to keep our LBC running happily.
> 
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>     Now back out to the shop to do some welding on my radio telescope mount.
> 
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>     Flame wars on, ok to shoot the messenger (me), etc.
> 
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>     Mayf
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>     _________________________
>     drmayf
>     Worlds Fastest Sunbeam, period.
>     204.913 mph flying mile average speed
>     210.779 mph exit (not top)  speed
> 
>      
> 
 

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