GT6 overheating

[GT6M]

Read wot I said, no what you did Col, !!!

two totally diff things,

60-70 MPH is pintln aboot,😉

[Nick Jones]

Can't say about my GT6 yet as with just over 500 miles on the engine,  I'd still be falling into the pootling about category, however, on hard runs through Europe in the Vitesse it's noticeable that if ambient temperatures go over the mid 20s and I try to maintain speeds over 80 mph, the temp goes up and keeps going up.  I usually just back off, and the temperature comes down again.  Not sure if I'm finding the limit of the radiator or the airflow through it (out from behind it most likely).

On track days I'm not seeing water temperature problems - oil temps though......... 60ºC to 135ºC in a 15 minute session - and still climbing fast!  Not seen above 120ºC on the road yet, but haven't had that gauge very long!

Nick

[NonMember]

4 hours ago, GT6M said:

them that say its no overheating, try driving at 5K plus for a few miles in top,

But hosses for courses, pintl,n an potter,n  aboot,   fine for ne shrould, ne oil cooler, an half fins missing / blocked off.

When we arrived at Bristol on the 2016 Round Britain, one of the other drivers described mine as "the very fast GT6". Like Colin, you can mark me down as "pintl,n an potter,n" if you wish.

[Colin Lindsay]

15 hours ago, GT6M said:

Read wot I said, no what you did Col, !!!

two totally diff things,

60-70 MPH is pintln aboot,😉

60-70 mph is what most of us do, max (I'm saying no more, walls have ears and roads have those speedy things...)

Most of us aren't building race cars so if the car doesn't overheat under normal road use, then I'm happy to say it doesn't overheat.

One of our local shows - Kilbroney - is a huge event that has really outgrown itself with too many cars for the facilities and getting in is nose-to-tail for two hours, usually in June. Quite a few cars end up at the roadside with their bonnets open, but the GT6 soldiers on, admittedly with the heater going full-tilt and all the windows open...  

 

[Clive]

27 minutes ago, Colin Lindsay said:

60-70 mph is what most of us do, max (I'm saying no more, walls have ears and roads have those speedy things...)

Most of us aren't building race cars so if the car doesn't overheat under normal road use, then I'm happy to say it doesn't overheat.

One of our local shows - Kilbroney - is a huge event that has really outgrown itself with too many cars for the facilities and getting in is nose-to-tail for two hours, usually in June. Quite a few cars end up at the roadside with their bonnets open, but the GT6 soldiers on, admittedly with the heater going full-tilt and all the windows open...  

 

Marcus makes a good point though. At (say) 3000rpm a GT6 may be making about  40bhp at the wheels?  And probably 80-100bhp of heat. But flat out a GT6 makes 100bhp, so will be needing to get rid of double (probably more) the amount of heat. So if a car is marginal at normal motorway speeds, it WILL overheat if driven harder. 

And in the queue, the radiator, unless blocked completely, is capable of getting rid of the heat, but the airflow isn't. (back to the everlasting argument, fixed or electric fan! (both could be a good idea I suppose)

My spitfire sits at normal temp, even at well over 100mph on the autobahn. (we sat at 105 for about 30 miles once, had some catching up to do) However, when coming to a standstill the temp shoots up briefly as all the heat has still to go but low airflow. The fan cuts in and deals with it, then only rarely cuts in when sitting at idle. I guess my 99p radiator is adequate! (ok, £9 postage, but it was brand new)

[Colin Lindsay]

42 minutes ago, clive said:

Marcus makes a good point though. At (say) 3000rpm a GT6 may be making about  40bhp at the wheels?  And probably 80-100bhp of heat. But flat out a GT6 makes 100bhp, so will be needing to get rid of double (probably more) the amount of heat. So if a car is marginal at normal motorway speeds, it WILL overheat if driven harder. 

True, but the point I'm making is that under normal road conditions there are more than a few cars that don't overheat. If you want to drive at 90 - 100mph everywhere then even my modern will show higher temperatures. How many GT6 owners do that even occasionally, or so much that they need to modify or upgrade their cars? A few, maybe more than a few, but not all. Do it if you need to, or want to, but at normal road speeds it's not an essential requirement and a well-maintained standard system is up to the job.

So yes I was nitpicking but you can't say that ALL GT6 overheat when you really mean that they overheat when driven to extremes. Someone has to stand up for the slowcoaches around here!

[Iain T]

Maybe a silly question but what are the optimum lower and upper water temperatures for efficient engine operation? 

I ask because I may fit an electric fan. 

Iain 

[JohnD]

That the radiator cap includes a pressure valve means that you can safely run it at or above the normal boiling point of water.   The addition of antifreeze will also raise the boiling point of the coolant.  The Internal Combustion Engine (or any engine) runs more efficiently at a higher temperature, so higher is better, but it's in a balance with practicality and cost.

     So 90-110C

[NonMember]

What John said. Modern cars with ECUs controlling the electric fans generally don't turn them on until the coolant is over 100C, normally 105C. Our cars may not be as efficient at removing the heat so you may need to set your threshold lower, and if you're sensing radiator temperature rather than in-engine coolant then reduce it to account for that, too.

[Clive]

2 hours ago, Colin Lindsay said:

True, but the point I'm making is that under normal road conditions there are more than a few cars that don't overheat. If you want to drive at 90 - 100mph everywhere then even my modern will show higher temperatures. How many GT6 owners do that even occasionally, or so much that they need to modify or upgrade their cars? A few, maybe more than a few, but not all. Do it if you need to, or want to, but at normal road speeds it's not an essential requirement and a well-maintained standard system is up to the job.

So yes I was nitpicking but you can't say that ALL GT6 overheat when you really mean that they overheat when driven to extremes. Someone has to stand up for the slowcoaches around here!

I was trying to say that many GT6's have cooling systems that are not enough for the engine. If there are overheating issues then the system probably needs proper attention, likely a recon rad (a tube that is blocked won't clear by flushing, as the water will just flow down the open tubes) and also a good clean out of the engine. But of course that rad is the bit that gets rid of the heat. 

Yes, most Triumph owners don't drive their cars hard/fast, but if there is an issue it really should be sorted. The overheating in traffic is an issue that I don't like, and more likely to affect many owners. Andy Cook did a bit about returning to a manual fan which helped, but in traffic, if hot, I wonder if it is enough as spinning so slowly. I guess the ideal is a speed controlled fan, so spins in traffic, and faster if the temperature rises.  And shuts off above 20mph. 

Just klicking ideas around, as I supervise a friends son welding up his MX5. Those have an awful lot in common with spitfires, though it has taken 17 years for the rear of the sills to rot.

[Pete Lewis]

and then theres the old nutshell is it actually running at a higher than normal temperature or the gauges are telling a fake story

on the old forum we had a member change and engine only to find it had a non stabilised sender unit fitted in a stabilised system 

easy to get carried away and ignore the simpluze 

Pete