A Radiator for your Morgan
by GoMoG Revisited in November 2023

Put simply, aluminum radiators dissipate heat more efficiently than traditional copper-brass radiators. Additionally, aluminum is the way the performance radiator world went or at least until recently, when plastic radiators with a variety of core types provided massive savings in cost to manufacturers. Plastic radiators should be, as you can imagine, a huge no-no for any car with a flexing chassis. Morgan however, chose this route in 2008 . My strongest recommendation is to swap them out for something better on arrival. The newer Morgans, fit with a plastic radiator, continue to report an ever growing rash of cooling issues (overheating) especially when the bhp is over 200.  Horsepower = heat and yet they seem fit the same rad to 4/4s (100 bhp) that they fit to Roadster 3.7s (280 bhp).

BRASS VS. ALUMINUM: RADIATOR THERMAL PROPERTIES

Around 25-30 years ago a big change happened across the auto and cooling industry, most auto-manufacturers switched from copper/brass radiators to aluminum radiators. Although some people speculate that this was done for a cost benefit reason, the primary reason for changing to aluminum radiator was simple; aluminum radiators are more efficient in terms of their thermal properties. Aluminum radiators dissipate heat better and more effectively than copper/brass radiators.

When comparing copper/brass radiators to aluminum radiators it’s important to first think about the materials used and their advantages and disadvantages. Although copper has better thermal conductivity than aluminum, copper is too soft to build a radiator from. Since copper is too soft for radiator construction, zinc is added to the copper to create the alloy brass. Brass has a much stronger structure and is suitable to build radiators. But there is a take away; the lost of efficient thermal conductivity.The alloy brass only has about ½ the thermal conductivity compared to aluminum (see the chart below).

Copper 406-430 Watts/Meters
Aluminum  353-390 Watts/Meters
Brass (copper & zinc) 109-125 Watts/Meters

Aside from the differences in the thermal properties of the different radiators, there are also some other important advantages gained when switching to aluminum radiators. The two primary factors to consider when evaluating why a aluminum radiator is more effective than older copper/brass radiators in regards to overall vehicle performance and cooling ability are:

Weight Reduction- Aluminum radiator are much lighter than brass radiators. Weight reduction is the single most all encompassing upgrade to any vehicle's performance. It improves acceleration, braking, and fuel economy.

Material Stability and Ruggedness- Aluminum is a much stronger and more durable material compared to brass. This allows aluminum radiator cores to feature larger, “skinner” tubes which allow a greater volume of coolant to enter the core and be cooled. The strength of an aluminum core and tubes also allows for greater cooling system pressure which can allow a smaller radiator to cool better.

In short, aluminum radiators mark a modern advancement in cooling. Not only does the material dissipate heat at close to double the rate compared to brass, but also reduced the overall weight of the vehicle and provides a stronger and more durable core and tube design. All these factors clearly lead to an overall increase in vehicle performance.


New Hope For Old and New Trad Morgans

I have recently looked at this area again after a decade, and I am saddened at what has transpired with the offerings. Once more, I am not likely to make friends with this one, but observation is inarguable and I hope I can encourage improve supply and discourage disappointment.

Morgan trad cooling is more much more than merely a swap to aluminum or a choice of more cores and fins. And this is not a one size fits all area. Each car must be diagnosed and individualized according to its model and owner usage. But there are some basics that have been discovered. The aftermarket does not follow them. They design Morgan rads, for a very unusual car, as if it is merely another no-name vehicle, something that even the Works began to realize twenty years ago. 

Experience, talent and an intimate knowledge of traditional Morgans expresses itself in MUCH better designs. My sadness referred to above is due to the fact that there has been no progress in this all-important area for some time. In fact, this area of the trads may have retrogressed. 

TRAD MORGAN RE-DESIGN NEED

This is an area where I have seen the creativity and expertise of Peter Mulberry, the wind tunnel observations of Rob Wells and the hit-or-miss experiences of the Factory combine. The area becomes vital as trad bhp (bhp=heat) has been climbing and the world warms. Two salient factors are observed making the classics unusual, different from other vehicles, even those with the same engine.

1. The first factor is that old trad rads are designed to be canted at the top rearwards. They welded on bracketry won't permit anything else without modifications. Yet Rob Wells observed that the same rads allow a substantial amount of the airflow, (entering the small entry in the cowl) to go over the rad rather than through it! Rob's diagram is found to the right. The MMC has confirmed this by example. Morgan Rads, trad or others, are installed at 90 degrees or near since 2008. 

2. The rads are designed with stock fins and cores. If the subject car has more power, they keep adding cores. This makes the likelihood of the rad acting as a dam rather than a cooling device even greater.

3. The earlier rads (for Triumph Plus 4s) do not provide for sufficient space for a adequate rad fan at the rear! Placing a fan in front of a radiator is a big cooling no-no. By using a more upright radiator with a tinner more modern core will allow for a proper rear mounted fan.

Review of the Trad Aluminium Radiator Market 2023

 RON DAVIS  

If you restrict you purchasing to the USA, this is a better option than Griffin. It goes by the name of Ron Davis Racing Products. RDR knows Morgan rads a bit better than any in the USA and has done many since the dear Bill Fink began using them. The joints on the rad are welded very well. I found the cooling ability of my Ron Davis rad better than my Griffin (tests back-to-back on the same day, roads and ambient temperatures). They can also flush mount a high powered SPAL fan if you so choose and I very much recommend that for the pre-2000 cars that can fit one. Many of cooling issues are caused by woefully inadequate fans the MMC used to use. SPAL became the MMC favorite in the late 1990s.

But see the RDR Rad to the left and right. Note the thicknesses!

RDR service is very good. Expect to save 10-20% on a Griffin package after everything is factored in. They also weld the joints rather than epoxy them like Griffin. Like RDR and all current after market suppliers, RDR will not use a plug-in Otter switch but they can offer you a range of rad fan switches or make the threaded bung you wish. (Big engines see the BMWs above). Most US dealers use them..likely the typical knee-jerk reaction for a home-grown products.    

Two important codicils. 

 1. Like most aftermarket rads,  RDRs, especially those made for the bigger-engined Morgans, (Roadsters, and Plus 8s)  are unwisely designed. I will explain further on. And Roadsters, aside from the very early ones already fit with aluminum rads at the Factory, come with inadequate cooling directly from Malvern..much as the Plus 8s did. If driven as they should be (why on earth buy a sports car and drive it as tamely as possible?!!!) they boil over with stock MMC cooling. You COULD HAVE obtained adequate cooling from the MMC (when Peter Mulberry was still around to supply ) but only if you asked for a "performance upgrade" and then the right Peter Mulberry product would have been fit for a price. (sigh) 

REASON 2 RDR  decided to address that by installing a thicker core. I had the first of these on a Morgan. They had had success with that with other big motor cars. But trad Morgans have always had a problem with airflow through the rad..and most of the, prior to the plastic rads were canted at 30 degrees encouraging air to sadly go over the rads rather than through them. The thickness of the core determines the resistance the radiator puts up fighting airflow through it. The best race preparers in England have correctly noted to me (they have the results from professional airflow chambers) that this forces much of the air around and over the radiator..not helping in the cooling process at all. There are methods to address this (which I will explain in another article when I find the time) but the punchline is that RDR's super thick core for bigger engined Morgans, combined with Morgan dynamics creates a very poor result as well as making installation of both the rad and a better fan super difficult. I doubt RDR or the Morgan dealers selling them are aware of this, but there you have it. You can also obtain RDRs through Morgan Spares (aka Morgans of New England) and this will eliminate any fitting risk.

Mulfab increases the cooling by making their rads thinner..allowing more airflow THROUGH the rad and adding more capacity by lengthening it at the bottom. My guess is that if their thinner rads are made to Morgan size, they will cool much better than the originals, can be canted upright and allow the fitament of a rear fan (VERY DESIRABLE) on TR Plus 4s. Merely copying older radiators in aluminum is, IMHO, treading water. 

SUMMARY

Using my original Morgan Plus 8 (copper) rad as a starting point, my big Morgan engine was 5C degrees cooler under normal driving conditions and 9C cooler under stress conditions with the Griffin. The time it takes to cool from 108C (fan on temperature) to 88C (thermostat closure) was approximately 7 minutes at 60 mph. However, the Ron Davis Racing rad was 2C cooler than the Griffin under all conditions (tested on the same day, same car, same coolant on the same road). BUT the Mulberry beat the RDR by an additional 3C degrees in all conditions and cooled from 108 to 88 faster. To this one must add the effect of the better SPAL rad fan when NOT moving. However, the RDR did 2C better than the originally used on my first Morgan. (It is now on my former UK Plus 8.) All Morgan rads are a better option in this regard than Griffin. They are made with welded joints rather than epoxy ones (which eventually crack). It is has the same height and width of the original Morgan radiator by has a thicker core for more powerful Morgans (Plus 8s and Roadsters). Both Griffins and RDRs are generally more expensive than the more competitive UK market. (I exclude the current plastic radiators from the Morgan Motor Company which I cannot recommend, for reason given) though there are elements that can be learned from them.

WATCHPOINT: The late Bill Fink told me that the cooling ability of an aluminum radiator can be increased by painting it black and this could be an excellent idea for those of us in hotter climates. It would also make the radiator virtually indistinguishable from a Morgan trad original from the pre-plastic rad days.  I have kept mine unpainted and polished to a chrome finish. (vanity, vanity!) I have seen some people paint them..which makes them look like the old style  MMC rads.  

THE NEWER GENERATION OF TRAD ALUMINUM RADIATORS (November 2023)

Good new and bad news. :)

COST: The price of trad radiators has dropped a lot with the appearance of Made in China rads. There are a few of Chinese brands selling on ebay everywhere. However, there is also a new UK player who is selling trad radiators at double the earlier rad prices.  The new Mulfab, is holding steady at the prices we saw under its old ownership, (in the 500 quid range) but rads for models with air conditioning require a bit more. The "heavy duty" radiator for Plus 8s is now approximately 800£. Sadly, I can no longer recommend Mulfab as I once did. These prices do not include the radiator fan, the type of which is as important as the radiator itself.

The new UK player is a company called . Their product looks very good and is reported as such. It is priced at £1,135.77. I am unaware of the core size. However, it is merely a copy of the same old technology. Those ideas were/are dated. We can do better. 

The New CHINESE RADIATORS FOR MORGAN (very new)

I now have enough reports on these to recommended them, if only for their amazing price. Yes, they blindly follow the same old, same old designs. So far, scores have been installed with no more problems than we have seen with any other made-for-Morgan supplier. However, they are selling at less than 1/3 the price we have seen before them. They too are merely a copy of the same old technology. Those ideas were/are dated. We can do better. I am working on that as I write this. March 7, 2024.   

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