| Author | Message | ||
     Chris Miller Grand Master Username: cjm51213 Post Number: 416 Registered: 5-2013 |
Hi Folks, I've been monitoring the discussion, "Early Shadow Viscous Fan Coupling", and it has been informative. It raises the question, how does it work? The design is "Cool Engine:Lo fan, Warm Engine:Hi fan", so without understanding how this thing works, it seems like the mechanics are exactly opposite, meaning when fluids get hot, they become less viscous reducing friction and reducing torque. Anybody have any explanations? Thanks for the help, Chris. | ||
| Paul Yorke Grand Master Username: paul_yorke Post Number: 1559 Registered: 6-2006 |
A Bi-metallic spring operates it. Regards, Paul. | ||
| Chris Miller Grand Master Username: cjm51213 Post Number: 417 Registered: 5-2013 |
Hi Paul, Ah, now, see? That makes sense! The "viscous" part is only when the spring releases so there is some non-zero friction turning the fan even at lo engine temperatures. Thanks for the help, Chris. | ||
| richard george yeaman Grand Master Username: richyrich Post Number: 536 Registered: 4-2012 |
Hi Chris on reading the workshop manual there isn't any information on how the viscous fan operates but from the little knowledge that I have it has a bi metal strip that triggers a clutch to engage when the water gets to a certain temperature and disengage when the reverse happens, All is well until it goes wrong hope this helps | ||
| richard george yeaman Grand Master Username: richyrich Post Number: 537 Registered: 4-2012 |
Hi Chris and Paul I was shaving and having lunch and answering your query I hadn't realised that Paul had answered it cheers. Richard. | ||
| Chris Miller Grand Master Username: cjm51213 Post Number: 418 Registered: 5-2013 |
Hi Richard, Have no fear. Two answers are better than zero answers. The operation of the device makes so much more sense with a more complete knowledge of the components. I was unaware of the bi-metallic spring and thought the entire behavior relied on the nature of the viscous fluid. Now, I have achieved enlightenment. Thanks for the help, Chris. | ||
| Robert Noel Reddington Grand Master Username: bob_uk Post Number: 1007 Registered: 5-2015 |
On tee one topics is a bit about refilling the coupling, using Toyota vicious coupling oil. The electric route has been discussed at length. So quick recap. Bearing in mind that Crewe are experts at cooling piston engines and and often refered to by others in the same game. Meaning that the vicious coupling works the best. The thermal controlled vicious is more effient than any other system. The thermal bit also varies a bit thus getting closer to the optimum running temp. It the car is being used in the market where the car was supplied then the cooling system as designed will be about as good it gets. Cars used out of the original areas maybe slightly different in the more extreme places. However they all have the same basic layout. Worth removing thermostat to check screws threads also when filling the bulk of the coolant can be directly poured in the stat hole. The stat elbow looks good in black gloss. | ||
| Robert Noel Reddington Grand Master Username: bob_uk Post Number: 1018 Registered: 5-2015 |
Forgot. The shadow cooling system is like a blue print for other makes with vicious couplings. Such as the Ford Cortina Mk 5. |
