MG MGB and MGB GT Tech Talk
When talking to the guy whose 'B was next to mine at the All British Field Meet the other weekend he mentioned that I should get rid of the metal rad fan blade and replace it with plastic. 'Says that metal fatigue in cars this old has caused a blade to let go and do a good job of ripping up stuff in the engine compartment. Anybody heard/experienced this?
Seen a couple with the blade sticking through the hood, but it's never happened to me. I think I'd go with an electric fan instead
Yes I have. Both metal fatigue and the rivets letting go. Definitely worth inspecting VERY closely, especially around the rivets. And might be worth remembering before standing in the "line of fire" with a running engine!
I've seen the evidence of it on one early B and a big Healey. Yep, makes a miss.
I've been hearing the same thing.
How much more efficent are the electric fans and will the bolt in to the car without having to fabricate mounting brackets? Could someone suggest a good one please?
Thanks
Hey Paul, let me know if you go with the electric....I should go with one too. Perhaps we could get two at once? BTW how was "swinging the Bridge " last night??
Ross
Hey Ross,
Yes sure...just waiting for some comments from the folks on here.
Not one swing all night and none so far today the river is down about 2.5' compared to last week....I'm getting sleepy! Hope my relief shows up early!
What about other parts "letting go" from "metal fatigue"? Is it really an issue if subject parts are checked as part of regular maintanance?
A friends fan lost a blade recently, it tore up the radiator and dented the hood. A few months ago it was sand blasted, inspected and painted and we saw nothing wrong with it so you never know when it will let go!
Any fan blade that shows signs of being bent is scrap. Any looseness of rivets, or anything else suspicious is scrap. Not a bad idea to magnaflux them. Plastic is far better, electric better yet.
Any car with riveted pulleys is possible trouble - common on MGA cranks & some generator pulleys.
We had a guy killed at the local racetrack when a fan blade cut his throat.
FRM
If you take your metal fan off for any reason, it is always a good idea to inspect it for fatigue cracks and loose rivets. Seriously loose rivets probably cannot be simply reexpanded (hammered tight) to tighten as the holes or rivet shanks may be too worn or out-of-round to remain stable, even if "fixed". Fatigue cracks I have seen generally seem to start at the base of the blade, and altho they could be welded for repair, it is frankly not worth the effort.
My own opinion is that if you have either scenario, you are better off to replace the fan with a new one, a new plastic unit (if it will fit), or replace the engine driven fan with a 10" electric fan of the highest air flow capacity you can afford (measured in CFM ~ cubic feet delivered per minute). The electric fan takes no engine power and is not likely to ever throw a blade through your hood or on the street, like an engine powered fan may. Contrary to popular opinion, it is possible for many plastic fans to fatigue in a similar way to metal, depending on design and material. An electric fan offers the small protection of a shroud around their blades and if they were to come off, they would be deflected by that shroud.
This is the fan I would like to use for my MGB, I hope to run it in a puller setup - it's only 2.5" thick:
http://store.summitracing.com/partdetail.asp?autofilter=1&part=PRM%2D19010&N=700+400006+301218+4294775280+4294792704+115&autoview=sku
The clamp in probe is what I will also use:
http://store.summitracing.com/partdetail.asp?autofilter=1&part=PRM%2D19001&N=700+400006+309487+115&autoview=sku
This does 1250 cfm, pretty hard to beat for a 10" fan.
