Converting a Sprite for a Crossflow Radiator
By Mike Harlan
Originally printed in the Austin-Healey Magazine, February 1998
This article is reprinted from PDLJMPR Web Magazine with kind permission of Les Myer
Last year I converted my Bugeye from a downflow to a crossflow radiator to improve the cooling situation, since I was marginal on cooling with a built 1098cc motor. The procedure below is what I did for the conversion. Steps might vary for a non-Bugeye, but should be fundamentally the same.
First, I bought a radiator shroud from a 1275 Spridget with a cross-flow radiator. You need to be very careful here, as some 1275 Sprites were downflow, and the Midget 1500 is a totally different design! I got my shroud used from Faspec, Inc. in Portland, Oregon, along with a lot of other bits listed below for about $65. I have since seen that someone, Vicky Brit 1 believe, sells them new.
It would have saved a lot of work in cleaning, straightening, and painting, but certainly would be more expensive. I also got the lower crossover tube, which runs below the radiator in front of the steering rack. These are also available new if used can't be found. An overflow tank is needed, as it is the source of filling the system rather than the radiator itself. The overflow tank is brass, soused is OK.
The new parts I purchased were the radiator, all hoses (upper, lower, crossover, and overflow), and the radiator cap. Why bother with old, unknown parts which may or may not work? Mini Mania cut me an EXTRAORDINARY deal for all that stuff, plus a 6-bladed plastic fan. The conversion itself is simple, once you have the right parts.
Simply remove the old radiator and hoses.
Bolt the crossover tube to the steering rack mounting bolts, making sure the ends of the tube are tilted forward.
Install the lower radiator hose between the crossover tube and the engine.
Install the plastic fan.
Install the radiator into the shroud (Note — only use the bolts supplied or you will destroy the radiator!).
Next, bolt in the new radiator shroud where the old radiator was mounted. Make sure shroud is as low as possible in the mounts.
Install the crossover hose, which goes between the bottom of the radiator and the crossover tube.
Install the upper radiator hose. On 948 and 1098 engines this requires turning the thermostat housing 1/3 turn to align with the hose. The 1275 engines (which have the thermostat clocked differently), there is a specific housing which must be used. These are readily available.
Finally you have to install the overflow tank/radiator cap assembly This needs to be mounted as high as possible to ensure air won't be trapped in the system when you fill. 1 tried to mount this to the fender well braces, but it was not high enough, so I had to move it to the inner fender well above the left shock.
One additional note on the tank is that it is mounted by means of a metal strap with bolts on each end which wraps around the tank. This part could be fabricated, but is best purchased used from your friendly parts supplier. That's it! The conversion was easy and made a significant reduction in water temperature on my car. It was definitely worth the money and effort for me!
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