Griffth Radiator Upgrade
Discussion
Hello Everyone
I have a 1994 Griffth 500 and over the last two years it has started to run rather too hot for comfort.
Having trimmed the number plate slightly and repositioned it to allow better air flow it will now cool the car sufficiently to knock the fans off whilst in motion but is generally hovering at or just below the red mark on the temp gauge.
Having read a number of posts in this forum regarding recored or aluminium replacement rads for the Griff I am after some good advice on what would be my best option to replace or renovate my rad and who can do this for me.
My preference would be to replace with an aluminium rad however the Griffith bible (Steve Heath) advises that these rads would over-cool the Griff and leave it for at least some of the time running OUT of it's SWEET SPOT courtesy of the ECU.
Just to note I am 99% sure my thermostat is operating correctly and assume that the existing radiator is simply less efficient than it was AS NEW due to deterioration over time.
To summarise: - do I go for RE-CORING my current rad or go for a new ALUMINIUM replacement - and where would you go?
Thanks in advance for any suggestions!!
I have a 1994 Griffth 500 and over the last two years it has started to run rather too hot for comfort.
Having trimmed the number plate slightly and repositioned it to allow better air flow it will now cool the car sufficiently to knock the fans off whilst in motion but is generally hovering at or just below the red mark on the temp gauge.
Having read a number of posts in this forum regarding recored or aluminium replacement rads for the Griff I am after some good advice on what would be my best option to replace or renovate my rad and who can do this for me.
My preference would be to replace with an aluminium rad however the Griffith bible (Steve Heath) advises that these rads would over-cool the Griff and leave it for at least some of the time running OUT of it's SWEET SPOT courtesy of the ECU.
Just to note I am 99% sure my thermostat is operating correctly and assume that the existing radiator is simply less efficient than it was AS NEW due to deterioration over time.
To summarise: - do I go for RE-CORING my current rad or go for a new ALUMINIUM replacement - and where would you go?
Thanks in advance for any suggestions!!
The only way for an uprated radiator to overcool your engine under normal conditions is if the thermostat is missing/faulty. Many top stats leak slightly, and some people drill an extra 1/8" hole to aid bleeding, and these will allow a trickle of water through the radiator even when the stat is nominally closed. In extremely cold conditions when the engine is only working gently, this can be enough to overcool the engine. But if your engine is overcooled in normal conditions there is something wrong with your stat.
spend said:
There is a new fangled contraption called a thermostat which prevents overcooling (maybe it wasnt available in Old Testament times), you could try one, but you should inform your insurance company they may class it as a modification.
Spend - your sarcastic comment reference the thermostat shows your lack of understanding on the subject....
read through pages 140 to 142 of the TVR bible - 2nd edition
Quote pg 142 "Once the THERMOSTAT" is opened......This is important as it can prevent the ECU from adapting its settings to suit the car" Unquote
If you have anything useful to say I look forward to it!!
Thanks to all posters who have actually READ my message
Griff_500, as Spend and GreenV8S say, the thermostat should control the running temperature.
In a properly designed cooling system (...ok, ok, I know we are talking about TVR's!
), the radiator should always have excess heat transfer capacity.
Do you think your radiator somehow adapts and intelligently varies its own efficiency, depending upon whether you are out for a blast on the Yorkshire Moors on a crisp November morning, or speeding along an Autostrada in Southern Italy in the middle of Summer?
Thermostats will open as far as they need to to bring the coolant down to the correct temperature; if the radiator is dumping too much heat (as it should be at all times in a healthy cooling system), then the thermostat will run partially closed, so that the flow is restricted and the coolant temperature on the hot (engine) side is kept at the right level.
The only way a high-efficiency radiator will overcool your engine is if the wrong thermostat has been fitted, or it has been drilled out to increase bypass flow.
With due respect to Steve Heath, the problem with Bibles is some people believe every word in them, without question.
In answer to your original question, it will depend upon how much money you have to spend. A hgh-capacity alloy radiator is more efficient, looks better and is probably more reliable than a re-core, but costs several times as much.
>> Edited by Martin_S on Monday 25th April 14:00
In a properly designed cooling system (...ok, ok, I know we are talking about TVR's!
), the radiator should always have excess heat transfer capacity. Do you think your radiator somehow adapts and intelligently varies its own efficiency, depending upon whether you are out for a blast on the Yorkshire Moors on a crisp November morning, or speeding along an Autostrada in Southern Italy in the middle of Summer?
Thermostats will open as far as they need to to bring the coolant down to the correct temperature; if the radiator is dumping too much heat (as it should be at all times in a healthy cooling system), then the thermostat will run partially closed, so that the flow is restricted and the coolant temperature on the hot (engine) side is kept at the right level.
The only way a high-efficiency radiator will overcool your engine is if the wrong thermostat has been fitted, or it has been drilled out to increase bypass flow.
With due respect to Steve Heath, the problem with Bibles is some people believe every word in them, without question.
In answer to your original question, it will depend upon how much money you have to spend. A hgh-capacity alloy radiator is more efficient, looks better and is probably more reliable than a re-core, but costs several times as much.
>> Edited by Martin_S on Monday 25th April 14:00
Just another point to this ...
I ripped off the lip spoiler for the 3rd time on Sunday leaving Mallory park ... the car runs 20-12 degrees hotter cruising on the motorway without it than it does when it is fitted ...
I always rip it of in field at British or foreign circuits and now have 3 occasions of running with out it to compare. Definitely has a significant effect on my car's running temp.
My dad makes mine up for me, they are 900mm long, 65mm with with a 25 degree bend put in 25mm from the rear edge. All held on place with 4 self tappers ... Aircraft gradr ally
Mine currently is sitting at 95 on the gauge when queuing to go anywhere, concerning as since the rebuild it runs hotter than ever, more power + more heat.
Steve new pressure gizmo helped finding one small leak, but that's all, could be gauge or could be coolant issue. I want an ally rad ...
I ripped off the lip spoiler for the 3rd time on Sunday leaving Mallory park ... the car runs 20-12 degrees hotter cruising on the motorway without it than it does when it is fitted ...
I always rip it of in field at British or foreign circuits and now have 3 occasions of running with out it to compare. Definitely has a significant effect on my car's running temp.
My dad makes mine up for me, they are 900mm long, 65mm with with a 25 degree bend put in 25mm from the rear edge. All held on place with 4 self tappers ... Aircraft gradr ally
Mine currently is sitting at 95 on the gauge when queuing to go anywhere, concerning as since the rebuild it runs hotter than ever, more power + more heat.
Steve new pressure gizmo helped finding one small leak, but that's all, could be gauge or could be coolant issue. I want an ally rad ...
Ahem... Trouble is with any religious doc, it can be open to interpretation....
Actually what I said in the bible is that the alloy rads also provide superior air flow and this air flow can lead to a lower running temperature because of the increased flow irrespective of what thermostat is installed and that it may be beneficial to block the air flow off to reduce this effect. This usually happens at temps when the stat should be shut anyway but the affect of the air flow and possible bleed through means that the car is over cooled. It does suggest that an upgrade to a three core rad make sense but questions whether the additional expence of a competition ally rad is really justified for a standard car.
As for the thermostat controlling the overall temperature. Yes in principle but in practice often very different due to various plumbing changes, bypass fittings and thermostat holes that provide some bleed through. As a result, its degree of control is quite variable. Some cars do it more than others.
Do a search and there are a lot of references to owners claiming that their new rad means they never see over 60/70/80 degrees which means that the car is running out of that sweet spot. Not good.
Actually what I said in the bible is that the alloy rads also provide superior air flow and this air flow can lead to a lower running temperature because of the increased flow irrespective of what thermostat is installed and that it may be beneficial to block the air flow off to reduce this effect. This usually happens at temps when the stat should be shut anyway but the affect of the air flow and possible bleed through means that the car is over cooled. It does suggest that an upgrade to a three core rad make sense but questions whether the additional expence of a competition ally rad is really justified for a standard car.
As for the thermostat controlling the overall temperature. Yes in principle but in practice often very different due to various plumbing changes, bypass fittings and thermostat holes that provide some bleed through. As a result, its degree of control is quite variable. Some cars do it more than others.
Do a search and there are a lot of references to owners claiming that their new rad means they never see over 60/70/80 degrees which means that the car is running out of that sweet spot. Not good.
Scuse me old chap, you are obviously a true believer, so who am I to question your Faith in the good book?
However, I for one would take the advice of the heretical Pete & Joo before the gospel text. Even if I know nada...
One thing I do know though, is that Power to weight ratio and handling balance is much improved by a good diet :-))))) and you dont have to buy so many bags of spuds to the corner weighting :-)))))))))))
Dave
However, I for one would take the advice of the heretical Pete & Joo before the gospel text. Even if I know nada...
One thing I do know though, is that Power to weight ratio and handling balance is much improved by a good diet :-))))) and you dont have to buy so many bags of spuds to the corner weighting :-)))))))))))
Dave
Well your choice but I tried to put forward the pros and cons in the bible because whether we like it or not, cooling in these cars is not straightforward.
Let's look at the over cooling is always caused by a faulty stuck open stat. Yes it is in many cases but equally there are many reports/experiences of owners experienceing overcooling when moving only to find that the car warms up stationary. If the stat is operating correctly, then that shouldn't happen as it will prevent any coolant getting to the radiator. It will be shut like a good stat should be. So there must be other factors involved.
There are as blocking off the air flow to the rad stops this little problem and the car warms up even on the move. If there is some leakage there will be a cooling effect. There is also a cooling affect casued by air flow coming through the rad onto the engine (and temp sensors). These will cause over cooling or at least symptoms of it.
So in this case, the fundamentalist claim of the thermostat sets the temperature is actually not bourne out in reality.
Let's look at another. Does the car run at 74 deg when a 74 deg stat is fitted? Not really but it does usually mean that the car doesn't overheat because there is additional time to get coolant going through the radiator before the temperature starts to get too high. There is a huge time factor involved.
Similarly if the car's average temp is 85-90 why does fitting a 88 or even a 92 deg stat cause so many cars to overheat?
So while I do agree that the stat is an important temp control component and needs to be the right one to ensure no problems, I don't subscribe to the point of view that it is the only thing that does though as it is a very dynamic and complex system.
Let's look at the over cooling is always caused by a faulty stuck open stat. Yes it is in many cases but equally there are many reports/experiences of owners experienceing overcooling when moving only to find that the car warms up stationary. If the stat is operating correctly, then that shouldn't happen as it will prevent any coolant getting to the radiator. It will be shut like a good stat should be. So there must be other factors involved.
There are as blocking off the air flow to the rad stops this little problem and the car warms up even on the move. If there is some leakage there will be a cooling effect. There is also a cooling affect casued by air flow coming through the rad onto the engine (and temp sensors). These will cause over cooling or at least symptoms of it.
So in this case, the fundamentalist claim of the thermostat sets the temperature is actually not bourne out in reality.
Let's look at another. Does the car run at 74 deg when a 74 deg stat is fitted? Not really but it does usually mean that the car doesn't overheat because there is additional time to get coolant going through the radiator before the temperature starts to get too high. There is a huge time factor involved.
Similarly if the car's average temp is 85-90 why does fitting a 88 or even a 92 deg stat cause so many cars to overheat?
So while I do agree that the stat is an important temp control component and needs to be the right one to ensure no problems, I don't subscribe to the point of view that it is the only thing that does though as it is a very dynamic and complex system.
Getting back to the origional question....
I suspect that your rad and cooling system is getting pretty old and way pasts its best. The choice is to either get a recore with a 3 core system or spend 2 -3 times the amount on an alloy rad. Ignoring all the religous wars...a good rad in a well maintained system should be fine. Get a three core if you want a bit more capacity - shouldn't cost you any more but will be considerably less than an alloy one.
I suspect that your rad and cooling system is getting pretty old and way pasts its best. The choice is to either get a recore with a 3 core system or spend 2 -3 times the amount on an alloy rad. Ignoring all the religous wars...a good rad in a well maintained system should be fine. Get a three core if you want a bit more capacity - shouldn't cost you any more but will be considerably less than an alloy one.
I have an ally rad,2nd one !! I also have a 88 water stat, but of course i have much greater fan control to keep it there, 88 in winter and summer. I must admit i was not sure of the under reading on a cold day, as i knew it wasnt being over cooled. I swapped to the spare temperature guage sender, now it doesnt.
shpub said:
Well your choice but I tried to put forward the pros and cons in the bible because whether we like it or not, cooling in these cars is not straightforward.
Let's look at the over cooling is always caused by a faulty stuck open stat. Yes it is in many cases but equally there are many reports/experiences of owners experienceing overcooling when moving only to find that the car warms up stationary. If the stat is operating correctly, then that shouldn't happen as it will prevent any coolant getting to the radiator. It will be shut like a good stat should be. So there must be other factors involved.
There are as blocking off the air flow to the rad stops this little problem and the car warms up even on the move. If there is some leakage there will be a cooling effect. There is also a cooling affect casued by air flow coming through the rad onto the engine (and temp sensors). These will cause over cooling or at least symptoms of it.
So in this case, the fundamentalist claim of the thermostat sets the temperature is actually not bourne out in reality.
Let's look at another. Does the car run at 74 deg when a 74 deg stat is fitted? Not really but it does usually mean that the car doesn't overheat because there is additional time to get coolant going through the radiator before the temperature starts to get too high. There is a huge time factor involved.
Similarly if the car's average temp is 85-90 why does fitting a 88 or even a 92 deg stat cause so many cars to overheat?
So while I do agree that the stat is an important temp control component and needs to be the right one to ensure no problems, I don't subscribe to the point of view that it is the only thing that does though as it is a very dynamic and complex system.
Fair comments.
The problem is, the cooling system on the TVR is very marginal.
In an ideal world, the radiator on a car should have plenty of reserve heat transfer capacity. Fit an 88 degree thermostat (for example) and the temperature should sit at bang on 88 degrees, all day, no matter what the running conditions.
Because the standard rad in the Griffith is really inadequate for the job, it needs good airflow (either from vehicle movement or fans) to keep the temperature in check. Even with the thermostat full open, the temperature will gradually creep up in traffic until the fans cut in to give more airflow.
As a 'quick fix' TVR obviously reacted to this problem by fitting a lower-than-optimum running temperature thermostat (74 degree) to early cars to give this inadequate cooling system a bit more leeway. They obviously re-appraised the situation with 500's and decided that a slightly higher temperature thermostat coupled with twin fans would give a better compromise.
The fact remains, you really can't have too much cooling capacity: if a super-efficient alloy radiator means that the engine now runs at a consistent 74 degrees on a 74 degree stat, then change the thermostat for a hotter one!
It is unlikely that you will ever find a radiator efficient enough to keep the operating temperature at thermostat level even in heavy traffic (ie. with negligible airflow over the rad), without assistance from the fans, but providing a suitable thermostat is fitted the better the radiator's heat transfer capability, the more stable the running temperature will be.
Thermostats don't react instantaneously, so sudden increase in airflow can cause brief periods of overcooling, while the thermostat adjusts itself, but not enough to worry about in most cases. Conversely, the gauge on my car will often head rapidly toward 100 degrees for a few seconds as it warms up, before the stat has chance to open - but only for a few seconds; it never reaches boiling point, and once the stat has opened, the car runs at a fairly consistent 85 - 90 degrees and never overheats.
Remember that there is enough thermal mass in the cylinder heads and block to damp out these variations to a great extent, anyway - just because your coolant temperature drops by 10 degrees for a few seconds as the airflow and coolant circulation increases on acceleration doesn't mean that the temperature of the intake charge or combustion chamber drops by the same amount.
Some people worry about these temperature variations causing cyclic expansion, with consequent risks to head gaskets and so forth. I'd say they need to get a sense of perspective: a ten degree difference between 18 deg. C and 28 deg. C is the difference between a comfortably warmsummer's day and a comfortably hotsummer's day - it really isn't enough to create critical stresses in an engine block that is designed for an operating range of sub-zero start-up to 90 degree-plus running temperatures. And, as stated, a 10 degree difference in transitional coolant temperature translates to a lot less variation in temperature of the metal.
I agree that the cooling on a Griffith is a complex and dynamic system, but only because it is juggling the marginal capability of the radiator against equally marginal airflow (from the fans, when stationary) and trying to compensate by using a thermostat that opens earlier than it would otherwise need to.
If you can substantially improve the efficiency of the biggest factor in the equation - the radiator - then a more suitable thermostat can be fitted an a more stable system achieved as a result.
I haven't seen all the problems Steve mentions so I can't really comment on them, but what I will say is that with the cooling system design on these cars, all the water flowing through the radiator comes through the stat. Talk about bypasses and so on is a red herring. The stat is designed to control the flow through the radiator, and if it is fitted and working correctly, it will do. However, they routinely leak a bit which means they can allow a trickle of water through - in freezing conditions when the engine is working gently, this can be enough to overcool it. From this point of view I don't see an uprated radiator as a problem.
However, one factor that is often overlooked is that these cars have a fixed and very restrictive bypass, and this means that there's very little flow round the engine other than what goes through the radiator. If the flow is inadequate and the engine is worked hard, the average engine temperature may be fine but there can be severe localised overheating in the heads. An uprated radiator will achieve the same cooling for lower water flow which paradoxically means the heads have less protection. This is more likely to be a problem if you have an uprated radiator and then drive the car hard in the winter.
Many modern production cars have a switched bypass which allows unrestricte flow when the stat is closed, and then shuts down when the stat opens. This gives you adequate water flow under all conditions. I have a system like this on the V8S, and I understand Cerberas etc use a similar system.
However, one factor that is often overlooked is that these cars have a fixed and very restrictive bypass, and this means that there's very little flow round the engine other than what goes through the radiator. If the flow is inadequate and the engine is worked hard, the average engine temperature may be fine but there can be severe localised overheating in the heads. An uprated radiator will achieve the same cooling for lower water flow which paradoxically means the heads have less protection. This is more likely to be a problem if you have an uprated radiator and then drive the car hard in the winter.
Many modern production cars have a switched bypass which allows unrestricte flow when the stat is closed, and then shuts down when the stat opens. This gives you adequate water flow under all conditions. I have a system like this on the V8S, and I understand Cerberas etc use a similar system.
There has been a lot of knowledgeable people getting involved in this discussion, and I have found it very interesting, but no-one has mentioned the role of the Otter switch especially a lower temperature switch which according to the Bible can be fitted as a simple method of bringing the fans on a little earlier and in doing so help reduce heat soak before it becomes a problem.
>> Edited by Dutchone on Tuesday 26th April 08:16
>> Edited by Dutchone on Tuesday 26th April 08:17
>> Edited by Dutchone on Tuesday 26th April 08:16
>> Edited by Dutchone on Tuesday 26th April 08:17
Mine ran hot,i fitted a 4 row 140 core rad this helped
a little
The best mod was to make up a 4 simple alloy plates
self tapped to body and about 1/4 to 1/2 from rad,mastic this space and then all the air goes through the rad,even at slow speeds and not around the rad.
Painted black you cant see plates
martyn
a little
The best mod was to make up a 4 simple alloy plates
self tapped to body and about 1/4 to 1/2 from rad,mastic this space and then all the air goes through the rad,even at slow speeds and not around the rad.
Painted black you cant see plates
martyn
I agree about the "seal" around the rad, did my last rad and have to do my new ally rad this weekend. Of course it has very little effect below around 50 mph, thats when the fans need to start if you want to prevent temp rise. An earlier otter is "ok" but an adjustable stat on the outlet of the rad is sooo much quicker.
It doesn't really matter whether a bit of air leaks round the radiator when you're moving. However, it's very important that at low speed when the fans are on, hot air from the back of the radiator can't nip back round to the front for another go. Dropping the total amount of air flowing through the rad has relatively little impact on the amount of cooling, raising the average temperature of the air has a huge effect.
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