Fitting Leven engine cooling kit

[donatien]

New toys arrived from Leven today only ordered yesterday so that's very good service. They even threw in the steering wheel screw set FOC.

The engine cooling kit has a new thermostat. Looking in my bible (1st edition sorry Steve, promise I'll upgrade) there is no mention of how to get this baby out. Leven suggested taking off the belt and then moving the alternator to get easy access but is that necessary? Haven't looked yet cos it's too dark but other threads seem to suggest it's held in by 2 13mm bolts under/in front of the plenum.

Any need to drain the system to get it out and then bleed afterwards?

Hoping to fit all the other aluminium goodies tomorrow too - should look good with the brushed alloy dash.

Dave

Just read the stampings on the side, the thermo is 74 and otter 92 - aren't these standard parts anyway?


>>> Edited by donatien on Friday 7th February 18:57

[apcouldwell]

My Griff had a 74 degree stat which failed during the summer so I removed it. When I took the car for a service at a TVR delear they noticed the stat was missing and fitted an 82 degree stat.
I have since bought the mod wise duel speed fan kit and have set the two temps at 80 and 90 degrees. The only problem is that the stat doesn't open till 82 degrees so the fans are on half speed driving down the motorway in winter.
Next job is to either remove the stat or fit another 74 degree one.
Long winded answer but not sure what was actually fitted at factory just that TVR dealer fitted an 82 degree stat. Otter switch normally triggers at 90 degrees.


>> Edited by apcouldwell on Friday 7th February 19:55

[donatien]

Well that is my point. I already have a 92 kick in otter (if it worked) and a 74 stat. My problem was a stuck otter switch (stuck open - always on). I seem to have got the same stuff that TVR fit, or at least put in my Griff when it was last at the factory.

So if Leven say 92 fan and 74 stat in what way is it different from what I have? It's the same other than a bottle of red fluid.

Dave

[greenv8s]

apcouldwell said:
I have since bought the mod wise duel speed fan kit and have set the two temps at 80 and 90 degrees. The only problem is that the stat doesn't open till 82 degrees so the fans are on half speed driving down the motorway in winter.

That seems wrong to me, for two reasons. First, the temperature sensors should be in the bottom hose so they sense the return flow from the radiator - that will give far better temperature control (and completely solve this problem, by the way). Secondly, if you decide to keep the sensors where they are for whatever reason, why not simply knock the lower switch up a few degrees to allow the fans to go off when you're cruising? It can't be good for them to run continuously.

[shpub]

It is either 74 or 82 depending on when the car was made, and what spec fans were used etc etc etc.

Steve

[apcouldwell]

Fair point with setting the lower switch at 84 degrees but the main reason I bought the kit is so I could set a low first stage cooling fan so hopefully it would take a long time to reach 90 degrees or not reach it at all. With an 82 degree stat I have a temperature "window" of 6 degrees (stat 82, first switch 84, second switch 90).By the time the fans come on at half speed at 84 the temperature is rising quickly towards 90 and they won't have time to create a cooling effect before the temperature reaches the second switching point.

My ideal would be normal running 70-75,first switch 80 and second switch 88 with the otter as backup.

As you mentioned i do have the sensors in the top hose (inlet to radiator) as I wanted to monitor the temperature of the coolent entering the radiator and not the "cooled" coolent entering the engine.

I will set the lower switch at 84 until I decide what to do with the thermostat.

Would you suggest putting the sensors on the bottom hose?

Alan

[greenv8s]

apcouldwell said:
As you mentioned i do have the sensors in the top hose (inlet to radiator) as I wanted to monitor the temperature of the coolent entering the radiator and not the "cooled" coolent entering the engine.

I will set the lower switch at 84 until I decide what to do with the thermostat.

Would you suggest putting the sensors on the bottom hose?

Alan

You should definitely put them in the bottom hose. The point of the fan is to increase the air flow through the rad when the forward motion of the car isn't enough on its own. So you want them to switch on when there isn't enough air flow. The bottom hose temperature is a very good indication of whether there is enough air flow. The top hose temperature is a very poor indication because it only shows the overall engine temperature rising as it gradually starts to overheat.

With the temperature sensors in the bottom hose you will need to set them slightly cooler, and you can afford to set them further apart, giving you better control over the temperature. I would suggest half speed at 60 and full speed at 70 as a good starting point.

Cheers,
Peter Humphries (and a green V8S)

[donatien]

OK, thanks for the discussion guys, I do bow to the gods.

Now - how to get the thermostat out with minimum effort and minimum coolant loss! Given that I really only wanted to replace a shagged otter, but thought it was worth throwing in the whole Leven kit.

Which....

It does say 74 thermo and 92 otter. Just what I think I already had.

[shpub]

Also be aware that all these bits have sensors in different locations and the temperature may not be consistent. And add to that bypass and bleed effects (I would drill some holes in the stat BTW to allow some bleed through) and it can be very difficult to get scientific about this, especially as there is a lot of variation in what is going on.

[shpub]

[With an 82 degree stat I have a temperature "window" of 6 degrees (stat 82, first switch 84, second switch 90).By the time the fans come on at half speed at 84 the temperature is rising quickly towards 90 and they won't have time to create a cooling effect before the temperature reaches the second switching point.

The stat starts to open about 4-6 degrees before its opening temp and there is also likley to be (or not) depending on the car, some bypass flow as well (holes in stats usually but not always) so the whole system is nowhere as near as definitive as you state.

I would also refrain from setting targets like 70-75 for normal running as you won't get those in Summer without then compromising the ability to get them in winter. The engine temp will vary from 70 to 90 and that is fine.

[david beer]

As Peter has said the sensors are better off on the outlet from the rad. That way they almost trigger relative to speed, above 70mph all is ok, below 55mph half speed fans and full speed fans if thats not enough. Of course the weather will have an effect on this. Alan, i will send an LED so you can see when the half speeds are on, just plug it in.

>> Edited by david beer on Saturday 8th February 17:20

[apcouldwell]

Thanks for the info guys.

David: I already have an LED mounted on the steering column cover which I fitted when I mounted an overide switch. The LED is connected straight off the fan plugs so it illuminates when the fans come on at half speed. Obviously I can't tell when they come on at full speed. The only problem I have found with this is that when I am travelling at speed I think the airflow rotates the fans as the LED will glow. This only happens above about 40 mph. When the fans do turn on then the LED is bright so it is not so much of a problem.

[david beer]

The fact that the fans spin when moving was very useful for testing the air ram i have. It was possible to see at what road speed air was finaly going through the rad.

[greenv8s]

david beer said: The fact that the fans spin when moving was very useful for testing the air ram i have. It was possible to see at what road speed air was finaly going through the rad.

The 'fan whirling' LED gives you a rough idea whether or not you have a lot of air flow, but if you want to know how much air flow there is, the best way to do this is by measuring the air and water temperatures going into/out of the radiator.

[david beer]

Quite right Peter. I also had digi temp guages on both hoses but they took a while to show the "effect". The fans "whiring" was quite quick to shown when the fans spun. Oh i had fun for four days, just riding around.