The aluminium ones have a solid piece of land where they bolt onto the spindle. They are far less prone to buckle. It is a more reliable method of construction used on a number of induatrial cooling unit designs. If you bolt a standard fan onto the spindle (off the engine) you can bend it out of shape. I've swapped 3 and I'm still having issues. And since I can't really balance a steel one without spending more than the aluminium one costs, then I think the aluminium one is the way forward!
Technical Faulty Fan/Impotent Impeller
- Thread starter fiat500
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Technical Faulty Fan/Impotent Impeller
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I am struggling with the fan coming slightly loose on the boss which fits over the alternator shaft. It's not the nut slackening off but a poor clamping grip from the cone-shaped disc.
Tony Vitesse has rightly set me on-track to replace the flexible (fabric?) washers. But being a lazy beggar I decided that I'm just doing the one side that is accessible with the fan still fitted. We don't have exotic materials such as cork this far North, so I'm trying some damp-proof membrane...I have enough of that to equip all the Fiat 500's in the world.
I was tinkering with a spare set of the grip-cones as a template for the flexible washers and found that it had one of the elusive, steel spacers fitted. I'm now starting to wonder if the spacers might be intended to help prevent the central part of the mounting boss from grounding and preventing the two halves from properly gripping the centre of the fan. I'll certainly be using this in combination with my custom-washer.
Tony Vitesse has rightly set me on-track to replace the flexible (fabric?) washers. But being a lazy beggar I decided that I'm just doing the one side that is accessible with the fan still fitted. We don't have exotic materials such as cork this far North, so I'm trying some damp-proof membrane...I have enough of that to equip all the Fiat 500's in the world.
I was tinkering with a spare set of the grip-cones as a template for the flexible washers and found that it had one of the elusive, steel spacers fitted. I'm now starting to wonder if the spacers might be intended to help prevent the central part of the mounting boss from grounding and preventing the two halves from properly gripping the centre of the fan. I'll certainly be using this in combination with my custom-washer.
I was tinkering with a spare set of the grip-cones as a template for the flexible washers and found that it had one of the elusive, steel spacers fitted. I'm now starting to wonder if the spacers might be intended to help prevent the central part of the mounting boss from grounding and preventing the two halves from properly gripping the centre of the fan. I'll certainly be using this in combination with my custom-washer.
I was just trying to remember what order they go on to the generator shaft? The bit on the left is the cone that goes in the air intake end isn’t it? The woodruff key bit is on the alternator side. I’m pretty sure I had my #posh , #southern , #expensive , #home made, #cork gasket on the woodruff key piece. Remind me which side does the spacer go on?
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....all correct. I think there's meant to be what Axel Gerstl (Suvvern prices...1 Euro 20 each) calls "rubber pad" each side, touching the fan. In this example it looks like the steel shim washer was outboard of the one on the cone side. They could fit either side.
I've always thought they were positioned in a way to space the fan away if it was catching the cowling. But if that was the case I would expect them to be thicker, although there may be thicker versions. In reality they would only serve that function on the side nearest to the alternator.
I measured the length of the boss and the depth of the housing that it goes into and there's just enough clearance that they don't ground on each other even without the impeller sandwiched between. So my theory that maybe this conflict was preventing the fan being tightly gripped is wrong if my assembled engine is the same.. But to be safe I'm still going to pack the setup on my engne with this spare spacer as a precaution.
PS. My plastic washer needs a bigger hole.
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Yeah I always remember that I would mount it in the tin work and spin it and the stock fan allowed you a certain amount of flexibility to bend it as necessary, if it was catching the tinwork at all.
My rule of thumb with shims on the 500, as they seem to appear all over the shop! Is whatever you take out when dismantling, put back the same amount as before but I would council the thought of others?
My rule of thumb with shims on the 500, as they seem to appear all over the shop! Is whatever you take out when dismantling, put back the same amount as before but I would council the thought of others?
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My thought would be that you are correct in saying that. But when fitting; replacement parts the use of extra or fewer or different sized shims can be essential or improve things. I found that; particularly to be there case with the gearbox.
Sorry to side bar, but can someone explain "over cooling" an engine to me? About to start a performance 650 build and I'd like to know as much as possible. TIA
the hobbler
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All engines have an optimum running temperature---too cold and you require fuel enrichment and will get an accelerated rate of engine wear---too hot and you run the risk of it seizing!
'Over cooling'means exactly what "it says on the can"---the engine is being run at a lower than optimum temperature. Living where you do, I think that you would have to work hard to 'over-cool' the engine.
The 500/126 engine has the fan speed fixed with regard to engine speed due to it being driven by a belt from the crank-shaft pulley. The driving that you are doing can effect the running temperature of the engine---I find that my engine (a tuned 652cc engine with a 3-1/2 litre aluminium sump) actually runs cooler than at a steady 60mph than when it is being driven in traffic---the temperature being greatly affected by the amount air being blown over the ally sump.
'Over cooling'means exactly what "it says on the can"---the engine is being run at a lower than optimum temperature. Living where you do, I think that you would have to work hard to 'over-cool' the engine.
The 500/126 engine has the fan speed fixed with regard to engine speed due to it being driven by a belt from the crank-shaft pulley. The driving that you are doing can effect the running temperature of the engine---I find that my engine (a tuned 652cc engine with a 3-1/2 litre aluminium sump) actually runs cooler than at a steady 60mph than when it is being driven in traffic---the temperature being greatly affected by the amount air being blown over the ally sump.
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In myp
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?????!!!!!!
Bigvtwin996
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Faulty keyboard and brain. [emoji6] I was going to say that in my humble experience, admittedly with a feeble 652 engine and the sub-zero temperatures of Scotland, it is possible to overcool the engine. That would primarily be by omitting the thermostat. I think people don't always realise that the engine doesn't just get up to to working temperature and stay there. As Tom observes, it can drop as the terrain or ground speed changes. You actually want the engine pretty hot, so a good stat will maintain that and avoid overcooling. I don't see why that won't also apply to tuned engines.
I assumed you were X with a member over something
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I've removed the securing-nut for the impeller again...it was really secure because I originally used threadlock and it fought me to the end :bang:. It turned out that I do have a rubber washer fitted and in theory, everything should be fine. But I find that I can rotate the fan on the shaft by about 5 degrees when loose. There should be no significant movement as it sits on a boss which is tailored to fit the central hole. So this means that either the centre of the fan or the boss or both are worn.
Next step; order a new one....:bang::bang::bang:
Next step; order a new one....:bang::bang::bang:
lazylobster
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What fan you going for Peter! Original or the Alu unit ?
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Don't tell anyone, (especially Bigvtwin996)
, but I have chosen the aluminium version.The primary reason is that it seems to have a more substantial central fitting area whch will avoid this problem in future; but I am also told that I will have the benefit of increased air-flow and consequently better cooling and, presumably, heating.
I've done quite a few miles with the worn impeller
and it had already done an unknown number of miles on another engine. It will be interesting to find out how it compares with regards to noise, balance and the actual cooling function.***THIS IS NOT A MODIFICATION*** ..(just a service upgrade).
lazylobster
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I won’t tell a soul
Will you be able to do a before and after airflow measurement?
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Will you be able to do a before and after airflow measurement?
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***THIS IS NOT A MODIFICATION*** ..(just a service upgrade).
Doesn’t this apply to anything and everything?
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Good question. I haven't seen any stats on this but only anecdotal evidence. I will give some thought as to how I could give a scientific report on airflow improvement. :shrug:
lazylobster
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Only way I know is via a cfm meter. Seen on amazoooon for less than 20 notes.
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I was think more along the lines of an A4 sheet of paper flapping in the wind.......:idea:
