Augmenting Thermostat flow - Fiat Tipo 16v re-assembly

[Rich Ellingham]

Hello Guy, as you know I am wishing to increase flow through the thermostat in order to run the engine at a lower temperature on the circuit.

The Fiat parts catalogue does not seem to differentiate between any versions of the thermostat for the tipo there appear to be only one available. I suspect that may not have always been the case. The construction of the stat is of 2 parts the main cast body and the valve diaphragm/top hose exit. The 2 sections are bonded together with silicone sealant using some type of crimping of the housing to hold the 2 parts together.

The thermostat


The construction ( 180deg of the crimped join was drilled to disassemble - some of it broke away)


On removal of the diaphragm section you could see a blind 6 mm hole just above the valve, this drilling is into a cast section which makes it look intentional for some other use. I drilled this out to 6mm, and inserted an M7 x 1 thread to enable threaded rod to be inserted should the hole allow too much flow. I tested the opening of the stat and it appears absolutely fine.
Augmentation drilling

Made up from part of the casing - looks deliberate

Top hose end


My question now is how to re-assemble the two housings, The top hose section has a featureless face which will insert into the main body of the stat, I cannot re-crimp the housing as the aluminium housing is so brittle just removing it has cause large cracks. I have used Araldite 2014 before to block unneeded ports, and it is designed for aluminium bonding and gap filling. Data sheet https://www.huntsmanservice.com/WebFold ... 20_GB_.pdf
Do you thing looking at the pictures that the araldite will bond satisfactorily the 2 parts together considering the potential thrust there may be on the top hose section? (note : silicone has been cleaned up using a silicone eater product, all resin has now been removed) Or should I some how supplement the bonding with some additional 'keying' on the mating surfaces e.g. addition or a number of 2mm holes radially around the surface of the top hose section? Or should I look to an instant weld chemical to bond the surfaces rather than the araldite?
Suggested drillings on the mating faces to key the araldite (perhaps fewer then the picture would suggest)


Your help would be much appreciated

regards

[1NRO]

Devcon do suitable adhesives/sealants. A quick google finds them.

Nik

[Guy Croft]

Leaving aside the actual enquiry for a second (R.E. is a respected GC client and well-known to me, we had already talked about this).

Does no-one offer a low-temperature thermostat for this engine?! With all that's written on the web about '16 valvers' and 'Grales' and 'Evo this_and_that' has actually anyone given thought to this important item, ie: a low temperature thermostat (75 deg) or at least a versatile housing that accepts such a thing?

Because I have searched high and low for such and thing and not found it.

I know this site it read vastly more by non-members than members (x1000) so has no-one in the world except GC and Rich Ellingham given any thought to this? What about all these so-called tuning experts in Italy? Or do I again, have to develop this item on_my_own. I have (let me see) done 3 16v engines in so many years so I don't exactly thrill at the thought of developing a new product on that scale.

I despair, frankly.

GC

[1NRO]

Rumour has it the supply of thermostats is in short supply, maybe just until another batch is run but maybe someone will HAVE to develop a replacement.

A billet housing to suit the purpose won't be cheap thats for sure but might be the only way. Rich is on the right tracks it seems if he can find a stat that fits the origional housing and he manages to re-assemble. Am I right in thinking the origional is a 90 degree rating? The lower rated replacement isn't the problem thankfully just the housing to put it into.

Nik

[1NRO]

Having ratched round on the net I'd fancy the chances of Rich's bespoke drilling to do the job, keep us posted Rich please.

[Rich Ellingham]

So I have glued this thing together, but interestingly enough I removed the valve section very easily by compressing and releasing it. I know the element will start to respond at a certain temperature but this is opposed by the spring, I think it would be easy to change of adjsut the spring and reduce its resistance to the element. I wish I have kept my old thermostat to see if I can remove that section without the dissassmbly of the whole unit. There must be an alternative, and surely Fiat would either do something with that partial drilling or have a different element. The std EPER parts catalogue from Fiat does not seem to cover the hotter climates in Brazil. I may contact one of their Fiat clubs an try and see if they have a different part for the thermostat, Ichecked as hot a Cyprus and there was no differentiation in parts.

I tested the element and it opens at 90 degrees far too warm for what we want. The dyno will prove out if the 6mm hole is too much, if it is I will drain and thread/bond some aluminium rod and re-drill a small by pass. Incidentally using some more interesting hose plumbing on the NA unit the turbo thermostat with its extra outlet for the Turbo core could be used with a valve as a variable thermostat by-pass.

Regards

[Rob Bakker]

Richard,

I've looked at one of those units I have lying around in the shop and my thoughts would be braking them up the way you did.
I would make acollar out of aluminum and weld it to the housing.
After that try to clamp it in a lathe en make some sort of V-band connector for it to join the 2 halves together again with
o-ring sealing.
Doing so you can replace the termostat whenever you wish.
Hope of being some sort of help.

Rob

[dfom]

So I have glued this thing together, but interestingly enough I removed the valve section very easily by compressing and releasing it. I know the element will start to respond at a certain temperature but this is opposed by the spring, I think it would be easy to change of adjsut the spring and reduce its resistance to the element. I wish I have kept my old thermostat to see if I can remove that section without the dissassmbly of the whole unit. There must be an alternative, and surely Fiat would either do something with that partial drilling or have a different element. The std EPER parts catalogue from Fiat does not seem to cover the hotter climates in Brazil. I may contact one of their Fiat clubs an try and see if they have a different part for the thermostat, Ichecked as hot a Cyprus and there was no differentiation in parts.

I tested the element and it opens at 90 degrees far too warm for what we want. The dyno will prove out if the 6mm hole is too much, if it is I will drain and thread/bond some aluminium rod and re-drill a small by pass. Incidentally using some more interesting hose plumbing on the NA unit the turbo thermostat with its extra outlet for the Turbo core could be used with a valve as a variable thermostat by-pass.

Regards

Rich,

Hy, I´m from Brazil I have two thermostats housing very silimar to the one you showed (i´ll post pictures soon). About our thermo opening temperature.
Opening at 83 Celcius. My 16V tempra rarelly goes over 90 degrees, usually it´s around 80 degrees in free running, but it´s with it´s original power.
In fact the thermo opens só that the flow is enough to keep temperature almost constant at 80C.

Another way we found here to reduce the temperature for our stock car is the use of an lower temperature fan switch placed right after coolant output from thermostat. We use diesel Fiat Ducato engine switch. Another interesting thing we have here are two poweful fans and a big radiator as a stock item, i will post picures for you.

The placing of the switch and it´s temperature grade really changes the temperature behavior of the engine. With that, plus the fact of the lower opening temperature, give-me a pretty good temperature engine. I don´t know if i helped, hope so. I´ll try do dissassemble my Themo bodies to show you.

Fiat still suplying this 83 C thermo here. May i post the OE Code?
Daniel Melo - Brazil.

[Rich Ellingham]

Please do, pictures and part number, do you have access to a Brazilian specificmarket parts catalogue?

Many thanks

Rich

[Guy Croft]

Big rad, OK.

I get this asked/stated a lot. Additional fans for cooling underway/load are an absolute no-no.

If the rad won't supply enough cooling capacity with the forward airstream - sort it out!

GC

[dfom]

Please do, pictures and part number, do you have access to a Brazilian specificmarket parts catalogue?

Many thanks

Rich

The pictures.

Thermostat - Tempra 16V Brazil

P4060156.JPG (38.8 KiB) Viewed 18293 times

Thermostat - Tempra 16V Brazil

P4060155.JPG (35.72 KiB) Viewed 18293 times

Thermostat

P4060153.JPG (42.74 KiB) Viewed 18289 times

Thermostat

P4060152.JPG (37.83 KiB) Viewed 18291 times

Our thermo look like the same. This thermo is an old one i had bough at a junk yard for experiments. Based on your pictures i´ve opened and removed the themostatic element (it is stuck on the always open poisition). I´ve read a thermostatic catalog from MTE-THONSON and found that the thermostatic element for Mercedez C 140(420, 500 SEC) (i don´t know what car or truck is this) look like very close to our element. Temperature for mercedez is 80C.

About the Brazilian OE code: 50009966

I´ve replaced my thermo last year and there was a priting on it ( 83 ºC) (and it behaves like that!)

About the fans,

My car is with it´s stock power and is for daily use, not a competition car at all ! The problem here in Brazil is that the original temperature for starting the fans is 100 for slow speed and 110 for fast speed. Some places here in brazil usually reaches 38 even 40 ºC. An engine at 110 degrees and 40 ambient temperature is not a good thing! In city use, in a short acelleration, engine temperature easily goes over 120 C, not necessary to mention that an OE head gasket simple do not cope with this. This is another fault from Fiat, import a car from europe and do not test on Brazil high temperatures.

The problem wasn´t the thermo switch rate choosen by Fiat (93C and 97C). But the fact that it was located at the radiator output. As the radiator is a big one, fans do not need to be kept on for too long for cooling the switch and turning it off. So originally the fans switch off too fast. The net effect is that not enough heat is exchanged and engine temperature start to goes higher and higher. Even in idle speed !

Marea also suffer from this. Fiat even released an KIT for Tempra to positon the thermo switch on the radiator input (not output).
On the first MAREAs imported from italy this problems persisted. Later, Fiat switched the hose, so that thermoswitch be located before radiator.

So, it´s been found that starting the fans at 90 (slow) and 100 (fast) solved the problem for city use, temperatures never goes higher than 100 C. At road (Over 100Km per hour) fans simple do not start.

Bye

Daniel Melo - Brazil

[Rich Ellingham]

Excellent, it looks the same. I have brand new one here, I will see if the element will come out without dissasembly, then we can see if there's the chance of retro fitting the UK one, otherwie I'll be trying to source a brazilian one.

I will look up the supplier you mention.

Rich

[dfom]

Rich,

The code i´ve posted is the Fiat OE CODE (just to make things clears).
About the supplier i´ve quoted, MTE THOMSON, it´s a large supplier for our local market, not sure if it is international.
Their catalog may be downloaded at internet, just google "mte thomson catalogo fotos dos produtos pdf" and you will find it.

The thermo i´ve said in the previous post (mercedez one) is number 283 in catalog.
I´m not sure about it´s dimensions. As you will see it´s rated for 80C (probably for diesel engine).

I´ll go at a local store to check it´s real size or to find another compatible one.
I thing it´s not possible to remove the original thermo from its housing without braking one of the "arms" that support it. If it were just a little bit rotated, the arm would clear the way for mounting and unmounting the thermo...

Bye
Daniel Melo - Brazil

[dfom]

Rich,

I could not resist trying to find a way for closing the housing. I´ve made some holes for screws with a small drill, take a look.

P4060152.JPG (37.53 KiB) Viewed 18228 times

P4060153.JPG (49.58 KiB) Viewed 18231 times

P4060155.JPG (47.92 KiB) Viewed 18220 times

P4060156.JPG (71.77 KiB) Viewed 18219 times

The holes don´t get into the housing, but very close to internal walls, indeed! I think this is an easy way for closing it. The only problem i found is at upper corner, were there is not much space for drilling. But i think a good positioned set of screws would close enough good. I´ve drew this suggested layout:

placment.gif (2.08 KiB) Viewed 18216 times

The blue circles are holes for screws. The purple line indicates were it´s hard do drill. One way to drill in this region is first drilling the housing them, with a small paper circle, mark the corresponding drills and transfer the positioning in the back of the hose connector and drill in the back of it.

I think this would be enough strong. And would allow easy inspection inside the housing in the future.

Bye

Daniel Melo - Brazil

[dfom]

Rich,

I dissassembled the element. Take a look.

Tempra 16V Brazil - Thermostat elemet dissassembled

P4070193.JPG (53.27 KiB) Viewed 18165 times

Today i went to a local shop and found one thermostat with (visualy) the same core.
My idea is to buy this one, dissassemble and mount out thermo spring, plates over a new core.

Bye
Daniel Melo - Brazil