alloy radiators

Just got one of my MKII's on the road and during the recent hot weather the temp started get too hot for comfort. The engine is a mild Pinto and it does have the 2 litre radiator with a thermo fan.
Well to cut a long story short I went to a local radiator shop and they suggest I get it rebuilt with a three core centre using the original top and bottom tanks, as this has more cores and therefore more fins the cooling effect should be better.
A couple of questions I have are
Is $600 to do this job to expensive
Are there problems with Alloy radiators (as this builder says do not use them as they are prone to corrosion)

$70 for a inline fiter means never having to cut open your alloy radiator.

The mkI RS2000's use a radiator from a MKI (or maybe MKII) Cortina which is a great deal thicker.
 
Matt

Mk1 Lotus

$70 for a inline fiter means never having to cut open your alloy radiator.

 
Got an example of what you use??

Items to keep in mind.
1.  Copper is more efficient at heat transfer than Aluminium.
2.  Corrosion is much more common in Aluminium due to:  the alumium, cast iron block, coolant and the earthing of the  block produces a Galvanic Cell.  This causes the Aluminim to sacrificialy (as used on ships) protect the cast iron bloke, ie the radiator corrodes.  An electrical circuit is produced from the Aluminium through the coolant to the block and returns via the car body to the Aluminim.  The rate of corrosion of the Aluminium is inversly proportional to the resistivity of the coolant.  Ie distiilled water less corrosion  (less current, milliamps) tap water then coolants and finally if sea water (large currents, amps) was used, rapid corrosion.
3.  The solution to the Alumium corrosion problem is very simple.  (a) DO NOT link the radiator to metal work with a strap.  This will produce  corrosion.
                                                                                                        (b) Electrically insulate the radiator from the metalwork.  By useing plastic insulating blocks.
                                                                                                        (c) Only use distilled water ( corrosion inhibitors generally do not stop corrosion)
 
Aluminium radiators were installed in cars as they are lighter are cheaper.
 
I would stay with the copper radiator and do the following:  Check the condition of the cooling fins and core blockages.
                                                                                               If with spec:  Investigate why it is getting hot ( timing, fuel mixtures, thermostat, faulty head gasket  etc )
                                                                                               If nothing obvious  upgrade to a 3 row.  Shop around for prices, $400 max.
                                                                                               If stuffed, depending on price renew with 2 or 3 row.
 
If any boby requires further information on electrical insulation or insulating methods for an Aluminim radiator, they can contact me through the forum. Plastic insulating blocks approx $50 per car. 
 
Regards
John
Capri Spares

Do you have someone youd recommend John in the Brisbane area for this work?
 
Thanks,
Kieran