Talk Morgan Forums Morgan Sports Cars Classic Morgans (pre-CX) radiator fan

Thanks everyone; I like the engineering-style approach.
I’m going to take measurements of the old fan.
It turns out the 30A fuse has indeed blown as well. That fuse sits by itself in the front engine bay. The power cables leading to the fan are also scorched.
Yes, it happened during a slow-speed section of a rally.
We shut the Morgan off and waited for it to cool down. I lost the rally.

To finish in first place ...first you must finish

Hope you get the new fan sorted Riri

Yes it´s a 12" fan.

From your image above and having 12 inch (305mm) blades with assumption the fan sucks cool air through the rad it looks like this one drawing 12.4 amps would fit from the current Spal range. Please check these dimensions though and accept that the later design, having blade protection and mounting on the periphery, may require you to re-engineer mounts.

Yes true, but he is a brave chap rallying his Plus 8 hey

Hi again riri,

It is as expected..and happily only melted/fused solid from the fuse and relay to the fan. They protected the fusebox and wiring from it. Sad nonetheless. I use a 40amp fuse with a SPAL 40 amp relay and along with their wiring. Your fusebox fuse merely covers the relay "trigger" for the SPAL relay. I can't figure why the fuse/relay didn't blow rather than fusing and melting the fan! We shall be more prudent with what you buy now. Stick with SPAL ancillaries rather than another setup. I have never had a SPAL system give me a problem on any Plus 8.

I gather you have not checked the engine compression yet. That can be done without starting the engine. It is your biggest worry. Unlikely, but it must be checked. You can do that yourself...even with an inexpensive pressure tester. https://www.gomog.com/allmorgan21.html#ENGINE. BTW, was the rear of the radiator core damaged from the heat?

And yes, engineering and experience should always set your priorities.

1[b]. the new fan should, ideally, fit the brackets you have.

2. have a depth or a smaller one that fits the space you have. You can use tape measure with the rad in the car or measure the depth of the fan once removed.

3. produce the most CFM (cubic feet of airflow) (aka M3/hours) you can find. I have picked a coup,e of possibilities out. The example posted is rather low cfm, IMHO. For example, my 12 inch SPALs pull well over 2300 cfm. Determine the part # of the melted one in the car. Then you can choose with wisdom and availability near you. I always take issues as an opportunity to improve Morgans.

Lorne

Hope you have sorted out your fan selection and fitting riri.. Whatever fan you have decided to use, perhaps best to check the manufacturers advice on the selection of an appropriate fuse.
I note that Richard advised that the fan in his post runs at 12.4 amps and if that fan might be selected a 30 amp fuse would perhaps risk creating a similar situation to the failure of fan and wiring you have already experienced..!

As gomog suggested it seems likely that the relay seems likely to have carried more current (amps) than it was designed to and may have damaged it`s internal contacts, thus a replacement relay suited to the replacement fan`s current and a modern relay with internal diode protection can help protect the relay`s internal switch contacts from burning in time.. using a relay that can carry more current than the fan requires is unlikely to cause a problem, thus a 30 amp relay should be fine, though once again the fan manufacturers advice is best followed..

Also perhaps worth thinking about is the possibility of wiring up a fan over-ride switch, which can be used to over-ride the radiator mounted temperature (otter) switch that switches the fan`s relay on and off..

The over-ride switch can act as a back up should the otter switch fail.

Hope you get it sorted out and avoided any engine damage riri.

Good post Luddite! The internet had had the same experience as I. For example,.https://forums.jag-lovers.com/t/fuse-rating-exceeding-manufacturers-specification/374193 Of course this is for the High-Output SPAL Fan (and SPAL) owners have found best. The smaller SPAL fans, mid-strength, can use 30amps and even, perhaps, less potent wires and relay: BTW, I have learned to use the lowest amperage I can in any task. If you're leery, merely try a lower amperage fuse while carrying a spare and also a more potent fuse as a precaution. In this way I went from 20s to 40s. .

Key point in your case is the strength of the relay as well. The standard SPAL fan relay is 40 amps as is the HELLA relay posted earlier. The HELLA (a very fine relay from Spain) is considerably less expensive as it can be purchased separately. However, the SPAL fan relays are sold as part of a complete kit with fuse holders and potent wiring which is safer decision for amateurs. BTW, I avoided a long length of odd heavy duty wiring by simply connecting the POWER into the relay from the nearby alternator. The relays "trigger" (my terminology), which is an earth to the.rad fan switch at the bottom of rad and/or a bypass at the dash...though in your case the last can be a toggle switch anywhere you can reach from your spot at the steering wheel.

Lorne

ADDENDUM: I had a later thought a researched it. I was thinking how I liked the HELLA design combining the fuse and the relay together in a compact whole. Then that concerned me. Research confirmed that the posted model has them melt together. If riri has one like it could explain what happened to him. Google it. "can a HELLA relay & fuse combination melt" It should not be used. Pity.