New thermostat installation

[Nigel]

I found a Gates inline bypass thermostat from Car Builders Solutions which was preferable to the inhead option. All 3 outlets are 32mm,so somewhat in between the original fitment.
I made up a right-angle solid piece reducer using 28/35 copper plumber fittings,including a hose rib at each end.
I had to source some random hoses from a local breakers.
The end result should work fine.

[rossocorsa]

Could you not get the original one?

[mangocrazy]

Nice work, and a very neat installation, but how does it improve on the in-head thermostat arrangement?

[WestonE]

Hi Nigel

An interesting solution. What was the temperature range on the CBS thermostat? Could you not get new hose solutions from CBS given the effort of strip and re-fit?

Well done

Eric

[rossocorsa]

Nice work, and a very neat installation, but how does it improve on the in-head thermostat arrangement?

I think GC is adamant that the in head stat is best it just doesn't offer as good warm up as the standard stat plus I realised that on the late cars the extra pipe to relieve head pressure means that the in head stat is partially bypassed. Can't do anything about that as the top pipe had already been modified wth the lower exit cut off

[mangocrazy]

Interesting - so not quite as cut and dried as I first thought. I think for my usage, with the car living in the south of France, an in-head thermostat (but the standard one, not a hot climate one) and with the bypass from cyl 4 to the top rail added would probably be the best solution. If needed, then it would be a simple matter to replace the standard stat with a hot climate one.

For large parts of the year in the S of F, 'warm-up' isn't normally a problem...

[squiglyzigly]

I expect some criticism for saying this but the GC in head thermostat is not acceptable for road use and I wouldn’t even use it on track for the reason below.

I’ve recently changed my Volumex to ‘in-head’ and feel it’s a very poor conversion.
There are a number of reasons for this, not least the slow warm up.

The head has a significant flow of water through the outlet at number 4 cylinder end of the head when the stat is closed. So one end of the head runs hot and the other cold until the stat opens. On some production engines this causes head gasket problems.
In winter the engine doesn’t even get off of the cold indicator if you use the heater which is barely luke warm.
When you stop at lights for long enough the engine warms up. Then you pull away and the flow through the rad via the open pipe at number 4 causes the temperature to plummet to cold again.
This is thermal shock as far as an engine is concerned and it’s bad in every way.

I’m currently changing both my cars away from the inhead  setup with one similar to the gates bypass setup (to keep the original look) and another with a top hose inline unit that I’m making up. The later will be simple to open up and change the stat to whatever temp is preferable. This will do away with all of the problems associated with in head stats.

[rossocorsa]

I expect some criticism for saying this but the GC in head thermostat is not acceptable for road use and I wouldn’t even use it on track for the reason below.

I’ve recently changed my Volumex to ‘in-head’ and feel it’s a very poor conversion.
There are a number of reasons for this, not least the slow warm up.

The head has a significant flow of water through the outlet at number 4 cylinder end of the head when the stat is closed. So one end of the head runs hot and the other cold until the stat opens. On some production engines this causes head gasket problems.
In winter the engine doesn’t even get off of the cold indicator if you use the heater which is barely luke warm.
When you stop at lights for long enough the engine warms up. Then you pull away and the flow through the rad via the open pipe at number 4 causes the temperature to plummet to cold again.
This is thermal shock as far as an engine is concerned and it’s bad in every way.

I’m currently changing both my cars away from the inhead  setup with one similar to the gates bypass setup (to keep the original look) and another with a top hose inline unit that I’m making up. The later will be simple to open up and change the stat to whatever temp is preferable. This will do away with all of the problems associated with in head stats.

Very much my thoughts but probably only applies to very late cars with the extra bypass pipe(mainly VXs) , GC refurbished my top pipe but cut off the small pipe to the standard stat as a matter of course so I'm kind of stuck! Unless I can get another top pipe and at the moment with more important things to do and the car in bits I've kind of lost all interest in it really! Are you thinking to put a stat in the rubber pipe from the top metal water pipe?

[mangocrazy]

Interesting stuff. So as I understand it, if you're running the VX top water rail (or one modified to VX spec) then connecting a thermostat housing in the flexible hose line to the radiator would be a suitable modification, ensuring that head temps are consistent across all 4 cylinders? The only problem would be locating a suitable freestanding thermostat housing, I suspect.

[squiglyzigly]

This is today’s work. A pair of thermostat housings from a Renault etc and thermostat. I fabricated the flange to allow the pair to be bolted together and now it’s ready to be fitted in-line between the top rail and the top radiator inlet.  Of the 2 smaller bleed pipes, 1 will be blanked and the other will go to the plastic expansion bottle via a t-piece where the small radiator bleed pipe originally fits.
I hope to fit a test this in the next few weeks while the weather is cold.

[squiglyzigly]

Assembled

[squiglyzigly]

This is the intended installation position

[squiglyzigly]

I think the problem is very much the same for early cars as it is for late cars with the modified top water rail.

On early cars the head will still have varying temps end to end and warm up issues because the thermostat is still only controlling the temperature at one end. 

I have found a suitable (not tested or proven yet) bypass thermostat for under £15 that will fit in the original location and should operate exactly as the original. 

Don’t be put off by the slightly smaller body. Inside the original stat there is a lot of casting blocking flow. I expect the replacement to flow equally well. 

[WestonE]

Very Interesting. I have an in head stat and h section link on my Montecarlo and the temperature is stable and the warm up time reasonable for an older car. I also run the water pump faster by using the Beta Crank Pulley with the Monte WP Pulley. I did try a lot of different stat temperature ranges. I will need to check but think I used 82 in the end to keep the car in a sensible and safe range. Of course the 037 Supercharger creates a lot of power and heat and the alloy radiator is on a long run.

I have built an in head conversion for my tuned FI VX but have the bits to convert back minus a better (lower) temp range stat. The later pass through on the top rail I will be using because without it there will be a high chance of head damage/ blown head gasket given even standard early cars blow head gaskets far to easily.   

I am using head studs and a Cometic MLS gasket I commissioned along with a custom alloy radiator with a thicker core. NB this is far from a standard VX.

I look forward to following this thread because I cannot test my set up yet in a Beta and a better external stat might be just what is needed.

Eric     

[Nigel]

Greetings all,
I was reluctant to go the in-head route as i'd never done that and also the in-line method makes for easier changing and fault-finding.

Alan,I looked for an original part but didn't find one before the CBS unit came up!

Mango, I wouldn't think it's an improvement,just closer to what Lancia was thinking back then. Maybe a quicker warm-up?

Eric, it's rated at 87 degs,no range mentioned. From your comments, this may be a bit high? Yes,hoses maybe.
As with many things,it's not necessarily the final version!

Squigly,I do like your idea...that's 'right up my street' out-the-box thinking!


The radiator has been re-cored and there's a new water pump in there.
I'm hoping for a cooling system fill this weekend,leak check and start up.
I'll be back....

Thanks to all for the encouragement so far. This HPE is never going to be a pristine example, but it's intended to be a
reliable and usable car.

Nigel

[mangocrazy]

Apologies if I've got the wrong end of the stick here, but wouldn't using the existing setup as fitted to carb engines (no in-head stat, standard branch off top water rail to OE stat) but with the VX takeoff to the head spigot near cylinder 4, do effectively the same job? You'd lose the ability to run a hot climate thermostat, but would benefit from consistent temperatures across the cylinder head water jacket.

Or am I missing something?

[rossocorsa]

Apologies if I've got the wrong end of the stick here, but wouldn't using the existing setup as fitted to carb engines (no in-head stat, standard branch off top water rail to OE stat) but with the VX takeoff to the head spigot near cylinder 4, do effectively the same job? You'd lose the ability to run a hot climate thermostat, but would benefit from consistent temperatures across the cylinder head water jacket.

Or am I missing something?

Unless GC has chopped one outlet off your top rail 

[mangocrazy]

Unless GC has chopped one outlet off your top rail 

Yes, that would certainly put a crimp in any such plans... 

[squiglyzigly]

Apologies if I've got the wrong end of the stick here, but wouldn't using the existing setup as fitted to carb engines (no in-head stat, standard branch off top water rail to OE stat) but with the VX takeoff to the head spigot near cylinder 4, do effectively the same job? You'd lose the ability to run a hot climate thermostat, but would benefit from consistent temperatures across the cylinder head water jacket.

Or am I missing something?

Yes that is an ideal factory setup. But as you say, no adjustability with different temp stats.

[mangocrazy]

Apologies if I've got the wrong end of the stick here, but wouldn't using the existing setup as fitted to carb engines (no in-head stat, standard branch off top water rail to OE stat) but with the VX takeoff to the head spigot near cylinder 4, do effectively the same job? You'd lose the ability to run a hot climate thermostat, but would benefit from consistent temperatures across the cylinder head water jacket.

Or am I missing something?

Yes that is an ideal factory setup. But as you say, no adjustability with different temp stats.

Thanks for that confirmation. So in an ideal world we'd be able to find a replacement for the OE stat housing that can be dismantled to change the thermostat element... ? I'd be surprised if something of that nature didn't exist, although I doubt that tracking it down would be simple. You might get lucky and find a cast item that fits the bill, but I suspect it's more likely that it would need to be machined from billet (and expensive).