Radiators

[Cottontop]

All,

I am in the process of installing a larger radiator in my V8 Healey. I was planning to use a 24" wide that I already have. It is a top down flow, hence is tall.

I started looking at cross flow aluminum radiators. They are not as tall as the tanks are on the ends.

One of our local houses had an double-pass radiator delivered which was not what they ordered from their supplier. The supplier just shipped them a new one. I can buy the double pass considerabley cheeper (about 1/2) than a straight cross flow.

Do any of you have any information or experience on how much better/worse a double pass is when compared to a side to side or a top down ?

It'd be a tight fit since it is 27" wide, but for the price I can get a radiator compressor or a space expander (grin).

Thanks in advance.

Tim

 

[Randy Forbes]

Comparing a single pass, like my 99 M Rdstr used to have, to the double pass that my 01 M Rdstr came with (and now fitted to my 99 also) there is a difference in efficiency.

My 99 is now supercharged, so the updated radiator was certainly desireable.

I'd like to see pictures of how yours turns out though, and where/what radiator you sourced for it.

 

[BUNDYRUM]

Hello Cottontop, when you refer to double pass I'm thinking your saying 2 rows. If so then anytime you can have more coolant available to use will mean you'll have better control of the heat. In some respects you can neve have too much coolant, as the temperature can always be managed by the thermostat.
All things being equal (which we know they are not) cross flow radiators are more efficient than top to bottom flow.
Ducting of the air is probably the most important issue to look at.
If you cannot get the air into and then out of the radiator then it doesn't
matter how much coolant you have it still isn't going to cool.
I'm sure someone from the "Nasty Boys" could give you some first hand knowledge.
I do know that even just an extra row radiator in a stock BN7 made all the differense in the world.

Best Regards,

bundyrum.

 

[GregW]

I can get a radiator compressor or a <span style="font-weight: bold">space expander</span> (grin).

You could do the Healey 4000 thing by cutting the car down the middle and adding 6".

 

[GregW]

... when you refer to double pass I'm thinking your saying 2 rows. If so then anytime you can have more coolant available to use will mean you'll have better control of the heat.

Hi Bundy,
I don't know if a double pass radiator would necessarily have more capacity. It could have a single pass that held a gallon, or 2 passes that hold a half gallon each.

 

[Cottontop]

when you refer to double pass I'm thinking your saying 2 rows.

Actually, a "Double Pass" radiator is usually the same height, width, and thickness as any other horizontal flow radiator.

What makes the double pass radiator unique is that the INLET and OUTLET are on the same end of the radiator and there is a baffle in the header tank between them, so that the hot incoming water will NOT mix with the cool outgoing water.

In operation, the incoming coolant makes a pass horizontally through the upper 1/2 of the radiator. When it gets to the other end, it turns around and comes back through the lower 1/2 of the radiator before going out of the outlet.

As the name implies, the coolant makes two passes through the radiator. Basically, instead of having one 20" X 20" radiator core, you have one 10" X 40" core. In theory, the longer the coolant is exposed to the airflow, the cooler it will become.

My question was "Does it really work that way?"

The reason that I want to install a bigger radiator is that right now, my car has the standard Healey radiator installed. In addition, I have an 9" X 18" Yamaha motorcycle radiator (fed & relieved by the heater hoses) mounted directly behind the 100-6 grille.

With NO thermostat, the baseline temperature runs about 190 at 60 MPH.

I am planning to add a hardtop and A/C. As a rule, adding A/C will elevate the coolant temperature by 15-20 Deg. That would result in a highway temp. of 205. WAY too hot for comfort in a Healey in Texas, even with A/C. The A/C will spend most of its time just trying to overcome the heat that it itself generated.

Tim

 

[BUNDYRUM]

Hello Tim, nice description.
I would call that a crossflow radaitor because the water flows across the radiator instead of up and down as the "normal" Healey one.

Crossflow radiators are generally more efficient.

How many rows of tubes are there in the new core you can get a hold of compared to the one you have?, or, does the new core actually hold more volume?.


It is your choice to run without a thermostat of course but it's there for a reason and that is to regulate the flow of coolant.

GregW, I originally thought of saying that if you cut the car down the center and widened it you would be able to fit a larger radiator but decided against it. I understand what you mean about the size and number of passes.

bundyrum.

 

[Ed_K]

Hello Cottontop,
Have you considered updating your standard Healey radiator by having a local radiator shop install an modern, uprated core using your original tanks ?
I got twice the cooling capacity in the same space by doing that to my BJ8 last year. Doing that may add more capacity than you will need even when adding an AC.
Ed

 

[Cottontop]

Hi Ed,

Yes. The stock Healey radiator CORE measures 15" wide X 17" tall (255 sq. in.) and had 96 water tubes.

The "High Efficiency" Healey radiator that I PULLED OUT measures 15" wide X 17" tall (255 sq.in.), but has 144 water tubes. More tubes = more water, but less included fin area. There is a trade-off.

In addition to the Hi-E radiator I had a Yamaha motorcycle radiator (7.5" X 14", 28 water tubes) mounted immediately behind the Healey grille. This radiator was plumbed to the heater hoses.

My long held belief is that cooling a Healey is more about air flow than radiator capacity. I maintain that is why Healey went with fender vents and louvered hoods rather than a big radiator, although many times excessive radiator capacity can compensate for poor air flow.

Unlike the long slender I-6, most V8 Healeys have engines stretching from footwell to footwell. There is much less room for the hot radiator air to get out. Much of it just piles up on top of the engine.

In the past, I have documented a 20+ degree temperature drop by removing the hood/bonnet.

Along with a bigger radiator, I am making several changes in an attempt to get the hot air out of the engine bay.

Ed, thanks for your suggestions, but I've been there and done that and it still didn't work well enough to give me the result I wanted.

When all else fails try something else. I'm not out of ideas yet.

Tim

 

[Randy Forbes]

You said no thermostat.

In a lot of cars (MGB and BMW for certain), taking the thermostat out allows the coolant to flow too fast through the radiator, and as such, cannot transfer enough heat to the airstream.

At the very least, install a gutted thermostat, just so you have a restriction to slow the flow.

 

[Cottontop]

Randy,

It is amazing that in the last 15 minutes, I have had that exact discussuon with a Classic Mustang friend.

In my youth, I spent two summers working in a radiator shop. While that doesn't make me a cooling system expert, I learned that the ONLY 2 reasons that cars had thermostats were:

1) to rapidly bring the engine up to an efficient operatirng
temperature and

2) to quickly provide warm coolant so that heater would work faster.

I also learned that the only way to "baseline" a cooling system was to remove all restrictions. Only then could you determine how much real cooling "capacity' your system had.

Many stationary engines do not use thermostats.

For example, if you install a 190 thermostat, the system will never cool below 190. You cannot be assured that by adding an additional load, e.g. more HP demand (going up a mountain), adding A/C, or driving through Death Valley in August, your cooling system will provide adequate cooling.

I am not arguing with what you are saying, but for most circumstances, it doesn't make sense to me. IF there had to be some restriction in the coolant flow to keep the coolant in the radiator longer, why would there by high volume thermostats and high volume water pumps ?

If you pump MORE coolant through the same size hose, the fluid speed goes up. Then you need a thermostat or restrictor to slow it down. That doesn't make sense.

I was at a circle/dirt track supplier the other day and saw a bag of coolant line restrictor plates(metal plates with holes in them (aka. big washers). These color coded plates were designed to do just what you say. Slow the coolant flow.

The difference is that NONE of the plates had a hole over 1" and none of them are designed to provide a MINIMUM temperature.

A gutted thermostat for my engine would have a 1 1/2"-2" hole.

Back at the same time when I took the hood off, I also tried using long nose vice grips on the top hose to slow the coolant flow. Things NEVER got cooler, only hotter.

For measurement, I used a S-W bulb type temp. gauge and an IR pyrometer.

I've heard a LOT of people say what you are saying, but I've never seen any actual studies or any data that supports that.

I don't know... I've still got a lot to learn to get this temperature thing sorted out.

Thanks for your input.

Tim

 

[tiga2]

....Funny, I tried running with out the hood on my SBC and was disappointed how little difference it made, tho it was not a scientific study by any means. I plan to get my rad re-cored, not that I have to worry too much way out here in the "sticks"!

When I had a Pantera, notorious for overheating, re-coring made all the difference.

 

[Deleted member 8987]

I have some experience with restictors.
I run flathead V-8's.
Other than the Jag....

I use brass washers with 5/8" holes with no t-stats.
With twin pumps, and 4 hoses, you cannot get the coolant through the tubes at speed, lift the 4 pound cap, and in a couple of miles at 65 you empty the system out the overflow.

My 3/4 race 50 Merc in my Willys......when I rebuilt the water pumps, I cut off every other vane.
Helped.
Added restictors.
Helped.
(These are all old circle-track tricks....one other was to drill a handful of holes in the impeller).
Final fix was a new $500 wholesale (at the time) 5-row core.
Even with the bonnet off, it ran hot up until then.

I had one of my flatheads empty itself at 65 just past Sepulvida going up towards the Grapevine in about 1965 with no thermostats.

Heat, rapidly, for the heater and for proper operation, yes, but oh, boy, have I seen the need for restriction.

Thermostats, when open, have a hole, but also a plate to disrupt the flow.
A whole lot smaller hole than without a thermostat.

My Mark Two had no thermostat.
No heat, poor engine performance, and tended to get hot.
Thermostat fixed all of the above.

 

[RonMacPherson]

Smokey Yunick, when he used to write for Circle Track, did an article about this type of thing,i.e. no thermostat and restricting the flow to slow the coolant to transfer heat. I remember he said that he obtained better heat transfer when there was a restrictor, i.e. large washer with hole in the middle. Might see if you can research some of his data, either Circle Track, or Smokey Yunick.

 

[Randy Forbes]

I do know this, take the thermostat out of a 74-1/2 MGBGT in Southern Louisiana (Breaux Bridge, to be exact) and you won't get five (5) miles without it overheating.

No firsthand experience with the BMW, but some other cars with superchargers have tried it; yep, overheated in short order. This is bad when you have an aluminum head.

Your results may vary.

 

[BUNDYRUM]

Hello Cottontop,

Some of this may just be useless facts and information.

It appears your "High Efficiency" radiator core has 6 rows of tubes compared to the original that has 4.

I have to agree that sometimes more is not enough.

If the rows of tubes are arranged directly one behind the other then it could be argued that the first row of tubes will get the full force of the cooling air and each of the successive rows will get less and less of the cooling air.

BN1/2 Healeys had radiators with 5 staggerred rows of tubes, 6 cylinder Healeys had 4 inline rows of tubes.

After I bouht my BN7 in 1985 and going through a summer in San Jose where it boiled everyday it took me a long time before I realised the radiator was smaller in it than in my BN1.

I tried fitting an electric fan but that did nothing.

After I fitted a 5 row radiator the problems disappeared.

I have a thermostat fitted and would never run without one, I tried it once and the engine ran hot.

In the winter I remove the fan otherwise the engine runs too cool.

You can see the conclusion I made with just this new radiator core fitted.

Yes you do need airflow I agree.

Hot air still likes to go upwards in spite of what you want it to do.

I don't think that Healeys ever had both the fender vents as well as the louvered hood. In fact I remember Geoff Healey saying that the two contradicted each other. You either have one or the other.

The fender vents were there mainly for the exhaust heat to get out especially when headers were fitted.

The "Works" cars had a shroud in behind the grille to direct all the air from the grille opening through the radiator.
Even today a lot of racecars have this same feature in one form or another.

Maybe this is what you should look at at least for while you are moving.

The 6 cylinder cars are the only ones that used this and even though it could have been executed a little better than what it was it was at least a try in the right direction.

Yes they also used this shroud as a pick up point for the air to the carbs.

Another item to look at is the air coming out of the radiator and how that gets directed. I know some people have made a shroud around the outside edge of the rear of the radiator and they say it works(what it does I don't know).

Im glad to hear you haven't given up and are still open to ideas.

Regards,

Peter.

 

[RonMacPherson]

Grey cells just reactivated a long unused neural connection.

Stewart radiators or Stewart cooling systems... one or the other, had a very informative website explaining cooling systems and radiators in depth awhile back. I know it was around three years ago I looked at it.

 

[Cottontop]

Thanks Ron,

It is https://www.stewartcomponents.com/

What a co-inky-dink... Back when I worked college summers in the radiator shop, the owner's name was Frank Stewart.

Tim

 

[Cottontop]

WOW ! Did I learn a LOT !

Everyone interested in this thread should go to https://www.stewartcomponents.com
and read about Stewart Components and what they do.

THEN, start reading their 5 Tech Tips HERE -
https://www.stewartcomponents.com/tech_tips/Tech_Tips_1.htm

At the end of each tip there is a link to the next tip.

Largely because they support my thinking and what I have been saying,
I found Tech Tips 3 & 4 especially valuable.

THESE 10 FAQ's are a MUST READ too.
https://www.stewartcomponents.com/Stewart_faq.htm

Thanks again Ron for pointing me/us there.

Tim

Boy ! Am I going to show this to my Mustang buddies.

 

[RonMacPherson]

Glad to help, that's why I come to this forum. To pass on information.