An Aluminum Radiator for your Morgan
by Lorne M. Goldman Revisited in May 2020

This article is not written to convince the reader of the virtues aluminum radiators. Other articles should have done so already and if you are reading this you  have been convinced. As simply put as possible, aluminum radiators dissipate heat more efficiently than traditional copper-brass radiators for two primary reasons:

 1) Copper-brass radiators must be soldered together. Solder is a very poor thermal conductor and inhibits the ability of the fins to pull heat out of the tubes. (Although aluminum does not dissipate heat as well as copper-brass).

 2) Modern aluminum radiator designs incorporate wider tubes with smaller cross sections. This design allows for more contact area per cubic inch of coolant, and allows the radiator to cool substantially better than older designs using narrow tubes with larger cross sections.

3) Aluminum is much much (2) lighter and capable of enduring the constant flexing of the tradiaional Morgans. 

4.) The newer Morgans, fit with a plastic radiator, have reported an evergrowing rash of cooling issues (overheating) especially when the bhp climbs over 200.  More horsepower means more heat and they fit the same rad to 4/4s (100 bhp) that they fit to Roadster 3.7s (280 bhp). Sad. 

I am NOT trying to suggest that an aluminum radiator is a substitute for proper maintenance. Morgans are constructed in a fashion that makes the cockpit vulnerable to excess engine heat because of the proximity to the motor and the "funneling" of the heat through the gearbox cover. However, this heat may have important messages for you. High temperatures can indicate poor timing, too lean an air/fuel mixture, a bad coolant, radiator or cooling system blockage, faulty water pump, bad combustion, poor lubrication, a lousy rad fan, a malfunctioning sensor, a bad thermostat, an imprudent camshaft selection and many other items that should be looked into.

The Best of the Best  - MULFAB  - UK

Mulberry Fabrications, formerly Peter Mulberry, a bespoke UK Morgan community supplier, has the ultimate cooling solutions for any Morgan. Peter Mulberry designed and Mulfab makes aluminum rads for all classic (trad)  Morgan models and all types of usage. For some, the rads are longer (10cm), but they are also have less depth, allowing easy fitting of rad fans, no clearance issue and more airflow (as there is less resistance for the the air to flow through the rad rather than over it.  Mulfab's knowledge of the marque makes sending them your rad unnecessary. That makes the shipping cost reasonable anywhere in the world as it is a one way trip for one rad rather than a one way for one and return trip for your old rad as it is with Griffin and Ron Davis. Even without that saving, these rads are the least expensive anywhere in the world...which is delightful as they are the best.  Lastly, MY tests of these rad on the same car, same day, same roads shows it to run the coolest and any of the aftermarket suppliers. No question. 


 I originally purchased a GRIFFIN radiator in 1995.  My first aluminium radiator. They had an excellent reputation for many years...but read on...

Their ordering procedure is call up GRIFFIN (they are in South Carolina) and deal with one of their representatives and receive an order number. Then you send your old radiator to them. This can be a problem as you don't want to part with the old radiator and it increases the new rad price by the shipping costs for the old rad there and return (another $300-$400). On the other hand, the possibility of mistakes DO disappear if they have your old rad as a model..

After your old radiator arrives, you speak with a technical person at GRIFFIN and indicate your motor, its characteristics and horsepower. This allows him to properly order the amount of tubing (cooling ability) you will need. I asked for mine to be shaped exactly like my old rad saving for it to be a 1/4 inch less deep to allow for an easier installation for the high powered rad fan I have. They also WOULD NOT drill holes to provide for the Otter rad fan switch. They simply did not trust it. Instead they gave me a standard 22 mm threaded hole in the same place and I simply fitted the standard Rover rad fan switch. You can also use a BMW (14mm)

Parts nos still available (2021)

61311364272  = 90C (when temperature here or below fan OFF) - 95C (when temperature here of above fan ON) (gold body and white top)

61311364273   = 95C (when temperature here or below fan OFF) - 102C (when temperature here of above fan ON) switch (gold body and red top)

  With Griffin,  expect a five week turn around (less for your old radiator they use a template). From 1996-2000, surprisingly, at least for those on the North American continent, the price for the Griffin rad itself was cheaper than the then new copper Morgan radiator at $550 US (no longer available) when Morgan radiators ranged from 320 pounds ($600US) for a 4/4, to 450 pounds ($812US) for an EFI Plus 8 EFI rad.  Of course, to all of these prices you must add transport, taxes etc.

HOWEVER, sadly in 2000, Griffin almost doubled their prices on Morgan  rads...amongst others they make. They are now sold at $1000 to which you still have to add the transport of your old radiator for a model. Upon inquiry, I was told that radiator has not been improved or otherwise changed outside of price. As well, Griffin used epoxy rather than welded the joints. Eventually those joint fail as expoxy and aluminium do not expand and contract by the same amount and eventually that forces the joints to fail. (I HAVE BEEN TOLD THAT MANY TIMES, however, it never happened to me with my Griffin in 20 years.)


There is a fine competitor for Griffin in the USA with a great reputation, going by the name of Ron Davis Racing Products. RDR knows Morgan rads better than any in the USA and has done many. The joints on the rad are welded very 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.  Much of the cooling issues are caused by inadequate fans used prior to that date.

See the RDR Rad to the left and right. Note the thicknesses!

Their 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.... MUCH better than Griffin (see the Griffin comments who has been known to use epoxy in those key places. They too will not use a plug-in Otter swtich but they can offer you a range of rad fan switches or make the threaded fitting you wish. (Big engines see the BMWs above). Most US dealers use them..llikely a knee-jerk reaction for a home-grown product.  BUT, bless their hearts, if you wish, they can order from Mulfab as easily as you can.  

Two important codicils. 

1. The RDRs for made for the bigger-engined Morgans are unwisely designed. And these are most often the Morgans that need better cooling the most. The 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 buy a sports car and drive it as tamely as possible?) they boil over with stock cooling. You CAN get adequate cooling fro the MMC (they use Mulfab as well) if you ask for a "performance upgrade" at the cost of the Mulfab. RDR (I was there when they did it) decided to address that by installing a thicker core. I had the first of these. They have had success with that with other cars.  But trad Morgans have always had a problem with airflow through the it is canted at 30 degrees. The thickness of the core determines the resistance the radiator the allow 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. Mulfab increases the cooling by making their rads thinner..allowing more airflow THROUGH the rad and adding more capcity by lengthening the rad at the bottom (not really visible)

2. RDR rads cost more than Mulfabs..even in the USA. 


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 3 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. 

WATCHPOINT: Bill Fink told me that the cooling ability of an aluminium 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 newer plastic rads.