The stroke of the plug end is 8mm. How far is that from the sealing face?

We can argue (or get confused) over anything !!!

 

Tommaso,

That seems to be an 8mm difference from cold setting to open. Is that the fully open length, or when it first opens at 82 degrees?

Paul

 

Oh dear, I'm having my dumb moment 🤦🏻‍♂️ yes, you're both right, and I'm wrong. I'll correct the post for future readers: the stroke or travel is 8mm

 

The valve starts moving @ 82°C but reaches it's full opening (or closing, depending on how you look at it) after a few seconds. So 8mm is the fully transgender, after a short while.

 

If the 8mm takes the two ends (i.e. plug to foot - not sure of the jargon?) far enough apart (was it 40mm?), I think you're OK?

 

I don't know ... Craig ?

 

The stat has to cover the red dimension of 40mm in post 129. From your photo, I think it does.

 

I don't know. Can't tell without measuring the space marked in red.

I'll have to ask my mechanic to measure the distance marked in red in the photo in post 129

However, in post 112 Craig mentions that the total height must be minimum 42mm, and stroke travel 6-7mm.

I'll post a photo when cold:

 

42mm is the distance you want, from the largest flange to end of foot. This is when fully hot. The cold and stroke measurements are simply a way to avoid having to measure a hot thermostat.

The 6 cylinder 4.2 EFI cars use the same thermostat as the V12, and I measured a 4.2 housing last night and it was 42mm.

 

This the the one I bought:


​​​​​​
36 mm when cold.
44 mm when hot.

Is it ok?

 

Yes.

 

Thanks you to all who helped me 🙏🏻

 

That will be perfect.

If I was wanting to keep a V12 cool, the things I would address in order are:
- Remove the radiator and make sure the fins are clean. The space between the AC condenser and the radiator can collect all sorts of leaves, grass, etc that block the radiator.
- Proper thermostats
- Proper fan clutch
- System bled completely

Then I would move on to smaller stuff, like making the sure the ignition timing is correct, fan shroud fits closely, aux fan working etc.

 

I don't claim experience or knowledge in this matter but, to me, this thermostat travel (or stoke) question seems paramount.

One could have the best radiator, fans, etc but if the valve only redirects 50% of the coolant flow to the radiator then, at best, one can expect only 50% of total efficiency 🤷🏻‍♂️

Correct me if I'm wrong, but this 42mm valve travel/stroke seems key to me.

For future reference, to close this thread, the thermostat valve tested here is this one: David Manners 82°C Thermostat Valve V12 series III GTS101

Thank you to all who helped (Craig, Doug, Greg, Grant, Peter, Paul etc ... I'm sure that I forgot someone, apologies)

Tommaso

 

It can be a bit of a chicken and egg situation. In many cases 50% capacity is sufficient, such as in cold weather with the heater on full. If the radiator is blocked and all the coolant goes to a radiator that is 90% blocked, you still don't have sufficient heat shedding ability. 50% of the coolant going to a perfect radiator is still a better system than a blocked radiator.

Of course, it's best to have both systems working properly.

 

As usual, you're correct 🤷🏻‍♂️

 

I am now looking for the larger alternator DAC5224 for my twin SPAL electric fans.

• SNG Barratt and Simply Performance do not carry it.
• Jack Weston @ DM told me that they do not carry the 115 AMP, I found these on their website: https://jagspares.co.uk/alternator-1...-5-3-dac5224-3 are these compatible or are they overkill?
• I also found these: https://www.autodoc.co.uk/car-parts/oem/dac5224

I would appreciate advice on which to buy!

No, for some reason mine is a 75AMP but, remember, mine has many many miles so it could have been replaced.

 

115 Amp? That's giving around 2 horsepower in old money! The fans night hit that running at maximum, but that's only a brief peak demand. Most of the time, it must be much less. And the battery is there to deal with intermittent peaks. I would be inclined to see how things go with the 75 Amp alternator. If you see the battery is suffering, upgrade; otherwise stick with the 75 Amp.

 

Thank you Peter. My mechanic recently tested the alternator, and discovered that it requires servicing. Overhauls are not that cheap and, hence my idea to upgrade it.

 

Update: has anyone installed the DM alternators on that link? DM suggests that I may need to make some adaptations. Can anyone help me with these?