Help with thread size???

Can any of the more techy types out there help with this one.....
Next to the thermostat housing on the manifold of my 2000 Berlina (which is of course the same as the rest of the carb. engined 105 series Alfas ) there's a brass screw-in plug for venting the upper galleries of the engine when filling the radiator with coolant. It would be a perfect place to screw in a thermal switch for my electric cooling fan conversion . Does anyone know the thread size of this orifice so that I can source a switch of the same thread to fit into it????

Not sure what thread it is, but I do know the breather nut is reverse threaded, so that might upset your plans. You can get alloy inserts to put in the top hose which will then take a standard radiator switch such as
X-eng

Cheer's Rick , The thread is a normal r/h one but i'm not sure if its metric or some kind of old pipe thread like BSP. The top hose on the Berlina isn't very long so i shyed away from the insert idea that you had suggested previously because of the lack of length in the hose and partly due to being a bit scrooge-like when it comes to buying bits I think I can do without. There's no great urgency to this, so i'll keep tinkering 'till I come up with a solution .

What state is your radiator in? You could always hang on until it needs recoring and then ask them to put a switch boss into the radiator for you. That would look very discrete.

The alternative and super cheap method is to have a switch on/under your dash and when the fan is needed, you switch it on manually. I ran this on my Westfield for years without bother. Helps concentrate the mind!

I've got a spare rad and had considered that idea, it could be a good 'un.
Concentrate the mind? i'm gonna need all the concentrating I can get at the end of June as i'm off to Spa Italia, Belgium, in the Berlina
I'll keep you posted on progress.

I've had Fiats and Lancias with electric fans, and there has been more than one occasion when I had wished I'd added an override switch, so I'm with Rick's Alfas on this.
Wrecked a waterpump once on a Beta Spyder because the thermostatic switch didn't cut in after a bit of a set to with an MX5 on the way down to Weymouth. It was worth it though.........

Thermostatic switch and manual overide switch . Easy to wire in , plenty of twin and earth you can have
Whats the electric fan off originally ?

Originally Posted by FORZA2000

Thermostatic switch and manual overide switch . Easy to wire in , plenty of twin and earth you can have
Whats the electric fan off originally ?

Hey Al, is yours back on the road yet ?
The fan i've used is the A/C fan from an '06 Astra CDTi, it fits just nice (sideways/90 degrees round from its original fitting) in-between the rad and lower front panel .
Do ya think the twin and earth will blend in nice with the original factory wiring?

Unfortunatly not back on the road yet , sad that a certain "DARLING" has thrown a spanner in the works with his tax the over taxed policy .
Can you do some pics of the fan , not that im sad or owt but have been considering this mod , the ideas on the backburner for a bit . Finding a suitable fan and mountings seems a bit of a mountain to climb at mo.
Im sure the twin and earth will work well but you'll have to change the fusebox to a rewirable wylex unit and mark it up incorrectly its the attention to detail that sets it apart

Update on progress to date, I think (not 100%) the thread size i'm after is M14x1.50.
Rick, what (if known) temp does your fan cut in at? there are several different switches available of this thread size and they have different temp ratings.
I'm led to believe that some 2.0 Alfettas had lecky cooling fans, can anyone confirm this? or, does anyone know if they did, then what temp should the fan come in on these cars?
Forza, I got some piccies, i'll get round to uploading them when i got a bit more time and the jobs done .

Yes, I'm pretty sure the Alfetta's had electric fans. I've got an Alfetta Haynes manual at home so I'll look and see what that says. Incidentally it's worth looking out for an Alfetta Haynes manual as the engine overhaul chapter is far better than anything you can find for the 105 and it is the same lump.

I employed a deeply scientific method for deciding when my fan kicked in.

I ran the engine up to normal temp (bang on halfway on my dial) and as it crept slightly over, that's where I made the fan come in!! Clever eh? Unfortunately I can't give you a specific value on that as my switch is adjustable but you need to make sure your fans are kicking in a good way above your thermostat opening value as you don't want the two fighting each other.

Me again. The Haynes manual for Alfettas says the switch is from 82 to 92. Now what it doesn't clarify is if this is a choice or the range it works from i.e. it comes on at 92 and goes off at 82. The Alfetta switch is mounted in the bottom of the radiator, just above the bottom hose.

Don't you think you would miss the bleed valve? Do you have a bleed valve on top of your waterpump too?

Er, dunno, i'll have a quick look tomoz, if I get chance. Off to Newquay for a stag weekend early friday morning, so not much Alfa action for this weekend or into the following week (away with the family). Will keep you posted, thanks for the temp range Rick.
Have a nice easter!

Hi Green Berlina,

I may have come into this late and perhaps you've sorted out your thread issue but for future reference, you can get a set of thread gauges which are similar to feeler gauges in appearance but instead of incremental changes in thickness, each gauge has teeth that (relief) fit the thread. Just pick the one that fits the thread correctly and the gauge will tell you the pitch. I recently bought a cheapie tap and die set and found one inside (yippee!!). Turned out it was useful the day I bought Alfie (my 116 GTV) to repair the busted thread on the seat back retainer hex bolt which had been mauled by some ham-fisted incompetent slack jaw in an earlier attempt to refit it. Good luck with your project.

Chris

Now you mention it, i've seen/used such a thing that was in a snap-on tap and die set we used to have in the stores at work 'till some light finger wotsit took it some years ago . i'll look out for such a tool for future use, as it may well come in handy .