Type of Radiator

MightyBoy tech questions and answers.
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eris58
Posts: 19
Joined: Mon Nov 24, 2014 6:08 pm
Location: Wentworth Falls NSW

Hi all. just want to pick your brains. I have a Mighty boy with a F8b motor in it & manual gear box. I had a Auto F8b radiator in it as I was told once that they are bigger and give better cooling in traffic
.
Anyway my problem is I put the radiator in for an inspection as the top tank had a small leak at the front. He pulled the top tank off & said the core is about 60 - 80% blocked and should be replaced. I had noticed the temp only slightly higher when in traffic.

A quote for a new core is $510 all up (wtf).

without selling my arm and my dog I can't afford that at the moment.
Question. Is there another radiator that fits the mighty boy. I had a look at the forum and some have mentioned the MINI radiator.
Has anyone done this and What modifications need to be done.
Or will the standard 550cc Mighty boy radiators that we see on eBay sufficient
Thank you in advance. Cris
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Eamon
Posts: 83
Joined: Fri Apr 29, 2016 10:49 pm

The mini cooper radiator is probably your best bet, hell even i put one in when i was 16. you will need to do minimal modification (just some angle metal, measuring tape, few bolts and a drill) and your all set

the F5a radiator is probably fine if you only want to do small drives with the F8B but it might get a little toasty on the highway / stop and go traffic but dont take my word for it
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Brayden
Posts: 9101
Joined: Sun Apr 11, 2004 3:09 am
Location: Canberra ACT
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A standard F5A rad will work if you don't do a lot of stop-start driving in traffic. On open roads the air speed is enough to overcome the limitations of the single core.

If you're often in traffic then get a COPPER mini radiator, not the 4 core 'high flow' alloy units. Copper is a far better conductor of heat, making it a good heatsink when stationary. Plus the high flow rads allow coolant to pass through quickly, which reduces the time it has to cool in the radiator.
Be aware that a mini radiator doesn't have a fitting for the thermo fan switch, so you need to have one soldered in, or convert the drain plug to accept a switch. Some people keep the standard MB switch, but on the swaps I've done I use a more common switch to make replacements cheaper/easier.
F8B EFI turbo - Three pots and a snail.
User avatar
eris58
Posts: 19
Joined: Mon Nov 24, 2014 6:08 pm
Location: Wentworth Falls NSW

Thanks guys.
I picked up my Radiator from the guy. called over to a radiator supply and repair place who wanted to look at my old one.
he said its not to bad only 3 tubes are blocked not 60%
So I'm not sure what this other guy was on about. So I left it with him and if no good he'll order in a Mini cooper one for me and Transfer the switch over.
and better still if the old radiator is ok it'll cost me 200
Thank you all for your help. Cris
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