New radiator GT6?

[Clive]

3 hours ago, SpitFire6 said:

Hi,

 This radiator has no header tank. It would need an expansion vessel added to the system & then would be better than OEM.

Did you forget to add a link to your post (and assuming you didn't mean the GT6 rad on ebay had no header tank-it looks like a std GT6 rad to me, though no reason to doubt the uprated core)

[SpitFire6]

Hi,

 Did not realise there were other posts to different rads. Sorry.
I am referring to this one:
eBay item number:  264648618839
All alloy one. 

Cheers,

Iain.

[chrishawley]

At first glance it does does look like there are more hoses than are needed. The flow through the system is illustrated in Fig 1 attached. How it works in practice slightly mystifies me because the water pump is receiving, all at the same time, cold water from the bottom of the rad, hot water from the cylinder head, and partially cooled water on the return pipe from the back of the inlet manifold.

The thermostat housing is connected to the radiator twice; once via the fat hose and again via the narrower one to the neck. That's correct, although it seems plausible the the narrower one could be blanked off with no major loss of cooling.

That's the setup. Is there a Guru who knows why the setup is that way?

[Ian Foster]

Dave

The second small hose from the thermostat housing to the filler neck is specific to the GT6 and I believe is used on all models. The Vitesse and big saloons don't have it, but their rads are larger. I have always assumed that this was Triumphs response to making best use of the small frontal area of the radiator, with the cheapest possible 'fix' and was probably added during development. If blanked off you would be reducing the flow to the radiator. 

The overflow bottle, with a correctly functioning cap makes it a 'no loss system', ie what gets pushed out by expansion, gets pulled back under vacuum when the system cools down. A thermostat should always be used and general consensus seems to be that the standard 82C unit is the best all round although 74C and 88C stats are available.

If you have managed to find an up-rated core, then this is about as good as it gets without changing the radiator completely with all of the consequent modifications.

The shrouding at the front of the radiator is important and the original design can be improved upon a bit by extending the sides:-see pic.

Hope this helps.

Ian

[Clive]

I heard the extra hose was something to do with airlocks.

Lets put it this way, Triumph would not have added the extra hose with all the costs etc if it were not needed. Keep it! And as above, with the correct rad cap, the system should keep full using the expansion bottle. Same system as used on our rather newer MX5 and no doubt many other modern cars. Simple and effective, as long as the core has all the tubes clear etc it should work just fine. (if not there is a Golf radiator conversion that is well proved on a few cars. Cheap rads, uses a modern header tank which bleeds air from the system, and is very effective but clearly not original)

[NonMember]

Just a theory but...

The GT6 radiator has to sit quite low down due to the bonnet line - lower than the Vitesse one or any of the 4-cylinder cars. I wonder whether this was found to cause air lock problems, and the small hose to the filler neck aids the release of air locks to the filler? There's not really enough room to put the full-size top hose there.

Edit: And I see Clive beat me to it.

[Nigel Clark]

48 minutes ago, NonMember said:

Just a theory but...

The GT6 radiator has to sit quite low down due to the bonnet line - lower than the Vitesse one or any of the 4-cylinder cars. I wonder whether this was found to cause air lock problems, and the small hose to the filler neck aids the release of air locks to the filler? There's not really enough room to put the full-size top hose there.

Edit: And I see Clive beat me to it.

I also suspect the extra top hose is there to help rid the system of airlocks. It must have been quite a challenge for Triumph's engineer's to squeeze enough cooling capacity into the limited space under the front of the GT6 bonnet.

My experience of the GT6 radiator is that despite its small frontal area, it works well if there is sufficient air flow through the core. Anything that reduces air flow e.g. an obstruction to flow or removing the cowl, will lead to overheating.

Nigel

[Pete Lewis]

yes air bleed  the smaller hose increases the flow velocity and expells any bubbles into the header

dont know if triumph were one of the first to do this but its just normal on any modern over the past  god few   years 

the flow thro the manifold and its tortuous route back to the pump is the bypass to aid circulation when the stat is closed or the pump would just cavitate 

its called a pump  but its more a circulator rather than a Pump it needs a constant and equal flow and return  same as a central heating pump

pump is a simple  description but its recognised by us all    

pete

 

[Dave the tram]

Thanks all. Fascinating. The interesting thing is I only got into this because my radiator leaks slightly from various places. Despite having no cowls or shields of any kind and no extra top hose, It never overheats no matter how I drive it. This includes hammering it through the hills of the Peak District, some very hot weather drives and occasional long hard drives like a recent trip to Suffolk in 30 degree weather, 200miles, almost non stop each way. Ok the gauge creeps up a bit if after a long hard drive if I then sit then stationary or crawling for a long time, but without an electric fan It would be doing well not to. Otherwise it sits bang in the middle.
 

Still, probably makes sense to fit the extra hose when the recon radiator arrives, which has extra core, but no plan to fit cowl.

Ha, just had another look and I can’t see anywhere for the second top hose to go, that’s why it’s blanked off at the radiator. I guess I must have a non- standard thermostat housing. Also, my overflow pipe feeds into the tapered bottom of the expansion bottle, which seems a good  idea.

Another question, what exactly is meant by the ‘extra core’ and how do they do this? You’d think the radiator would already have all the cores it could fit.

cheers

Dave

[NonMember]

32 minutes ago, Dave the tram said:

Ha, just had another look and I can’t see anywhere for the second top hose to go, that’s why it’s blanked off at the radiator. I guess I must have a non- standard thermostat housing.

You probably have a Vitesse / 2000 or even Herald thermostat housing, not the GT6 one. The main pipe is a different shape on all, so without a photo it's just a guess, but the GT6 one is the only one with the extra pipe. I could have a root around to see what the spare housing I have is - it came attached to a 6-cylinder pump housing and I vaguely recall it not being a Vitesse one (the pump housing was to replace a cracked one on the Vitesse).

[Colin Lindsay]

3 hours ago, Ian Foster said:

The second small hose from the thermostat housing to the filler neck is specific to the GT6 and I believe is used on all models.

Mk1 doesn't use it; it may have been an upgrade to later models after deficiencies were found in the early setup but on my Mk1 there's only two pipes to the rad and two to the thermostat housing.

1 hour ago, Dave the tram said:

Another question, what exactly is meant by the ‘extra core’ and how do they do this? You’d think the radiator would already have all the cores it could fit.

cheers

Dave

Original cores on early cars of the period sometimes only have one pipe running from top to bottom; other versions have two thinner ones where you have fit two pipes fitted into the depth originally occupied by one. Modern cores using more modern manufacturing techniques are more efficient so I had mine upgraded to three pipes; effectively you've got three banks of pipes running top to bottom so more surface area for cooling. I found this diagram on the Net which helps illustrate:

[Pete Lewis]

gt6 thermo hsg  https://www.canleyclassics.com/?catalogue=triumph-gt6-mkiii&diagram=triumph-gt6-mkiii-water-pump-thermostat-temperature-transmitter

[Dave the tram]

 

All that helps greatly, cheers. It’s so good to keep increasing your knowledge of new bits of the car that you’d never needed to tamper with before. Thanks all for the schematics, links etc.i might as well do it right, so if anyone does have a spare housing to sell let me know, otherwise I’ll buy a new one from Canleys along with hoses. (I must also check again the boxes of old bits that came with the car!)

Although I said my car never overheats, ie the gauge says the right thing, I guess that doesn’t mean everything isn’t getting a bit hotter than it might. The fuel evaporation was easily solved with a bit of lagging, but the oil certainly gets hot on those long runs. Might consider an oil cooler one day. Oil pressure about 65 when cool, but when fully hot it’s 25-30 at 2-3k revs, and If very hot only 10 at tick over. Probably the engine getting a bit tired, but first I’ll try better oil at next change.

Note the worn top hose due to lack of bonnet clearance. I also learnt that if you don’t turn that jubilee clip out of the way, the screw bit puts an extra mini bulge in the bonnet!

Dave

 

[NonMember]

That looks like a 4-cylinder thermostat housing. The proper one takes the big pipe from the back and routes it lower down to avoid the hose rubbing issue.

[Colin Lindsay]

56 minutes ago, Dave the tram said:

if anyone does have a spare housing to sell let me know, otherwise I’ll buy a new one from Canleys along with hoses. (I must also check again the boxes of old bits that came with the car!)

https://www.ebay.co.uk/itm/Triumph-GT6-Thermostat-Housing/164330374886?hash=item2642da86e6:g:desAAOSwETBeXXCh

Might help, unless it's too crusty to have a good seal on the hoses and you really want a new one? 

[Pete Lewis]

yes a one size fits all convoluted hose will lead to chaffing 

Pete

[Nigel Clark]

23 minutes ago, Pete Lewis said:

yes a one size fits all convoluted hose will lead to chaffing 

Pete

The convoluted top hose is correct for a GT6.

With a genuine GT6 thermostat housing, the top hose run is short and straight. The convolution is necessary to absorb engine vibration, not as a bodge to get around a curve.

Nigel

[Nigel Clark]

Here's how the GT6 Mk3 thermostat housing and top hoses should look.

Nigel

[Pete Lewis]

 Yes Nigel  ,  thats better   nice progressive convolutions   Daves is a much deeper "get you out the sh1t"  convoluted hose  presumable due to the wrong stat hsg, entry angles 

and its stopped being darn hot and its also stopped raining     happy days to come  

will you make duxford  for old times sake  ??? 

Pete

 

[Nigel Clark]

By the way, the hoses in that photo are Club Shop silicone, over 10 years old and still in fine condition.

Pete, I hope to get to Duxford but my elderly spaniel is a bit poorly and always very anxious when I'm not around. At this stage of his life, his needs may have to take priority. The things we do for our animals!

Nigel

[Dave the tram]

Indeed. My English Shepherd Finn is only 3 but gives us many worries. He pays great attention when I’m taking things apart. I often think ‘ if only he could speak better, I bet he can remember where all these bits go back!’
 

And your engine bay looks all together tidier than mine, I must make more effort, although mine would not cope well with those un-lagged copper fuel pipes in a heatwave. 
 

Thanks for the link Colin, but I think for an extra £20 I’ll get a new one without the corrosion.

Cheers, Dave

 

[Nigel Clark]

Dave,

Good to see Finn enjoying life with a Triumph, he's a big chap.

Jasper (my spaniel) is a working cocker that doesn't work. He's a rescue that's been absolutely devoted to me since we gave him a home just over 6 years ago. He's supposed to be 11-12 years old but recently has suddenly seemed a lot older and has developed a debilitating balance problem. The vet says it may clear up temporarily but there will be recurrences.

Here he is, enjoying the TR6 a few years ago.

Apologies for the thread drift!

Nigel

[Pete Lewis]

your trying to lead us astray 

and on the vapourising ideas  its probably something else rather than vapour  .

 

Pete

[Dave the tram]

No, Finn is only big border collie size, it’s the wide angle lens effect. Great thing about the GT6 of course. He fits nicely on the back seat, harness clipped in, even if I have a months supermarket shopping in the back. With the seat down even my racing bike fits in with quick release wheels off. I’ve had the bike in with full camping gear as well.

A new MX5 coupe might look pretty in a modern sort of way, but it won’t do any of those things, as wont most modern sports cars until you get to something bigger and fancy.

Hope Casper goes on ok Nigel, he looks a thoughtful, calm sort of dog.

Back to the hot weather etc. I’m 99% certain it’s vapour lock I had Pete.

Dave

[NonMember]

13 hours ago, Dave the tram said:

A new MX5 coupe might look pretty in a modern sort of way, but it won’t do any of those things, as wont most modern sports cars until you get to something bigger and fancy.

A friend of mine used to drive the really unpopular Porsche - 944, was it? Anyway, he chose it because he could fit a double bass in the back.