Small mouth cooling

[Ben Freer]

No, please don't yawn! I know this has been discussed at length before - but we're all unique! (and yes I have reviewed previous posts first!)

 

My issue is not with effective cooling when moving. With a small mouthed TR3 this is not an issue (or hasn't been yet!). However we are planning a continental tour next June and I don't want overheating in traffic to spoil it!

 

The existing system is:

no mechanical fan, narrow pulley conversion, a tweaked engine with SS extractor manifold which exudes heat and a new alloy radiator with an electric "sucker" fan which is manually operated (oh and interesting alloy blocks raising the rear of the bonnet by 1/2" to let heat escape).

 

Under normal conditions (most recently the RBRR in very clement weather conditions) the engine probably runs cooler that it should ideally. But in traffic it rapidly becomes beastly! The fan will maintain the temperature gauge mid-way between "185" and "235" in the UK's mid-20's (Celsius - sorry mixing my units!) summers. I am less convinced how it will cope with higher temperatures, in queues in for example the Czech Republic and Germany.

 

The current electric fan is mounted on brackets on the tubular cross member very close to the matrix - 1/4". In this position it is in direct line with the grill mouth. However there is about 4" of "un-sucked" radiator above this. Should I reposition the fan to what after all must be the hottest part of the radiator - i.e. the top?

 

I am also planning to ceramic coat the manifold to reduce the engine bay temperature and reduce the fuel volatilisation.

 

Looking at the small mouth's built-in ducting there is still daylight either side of the radiator that could be blocked off.

Would further directing of airflow be of benefit in a stationary traffic situation?

Would shrouding behind the radiator to direct all the air through the fan be beneficial?

Would a pusher fan be better in traffic as it might huff the hot air through the engine bay and out through the raised bonnet?

 

 

Has anyone had any experience of this issue on a TR3?

[Guest]

Since it is not cooling at lower speed, I should look into the scaling of the radiator and the efficiency of the water pump.

[Ian Vincent]

Hi Ben,

 

My TR3a will start to heat up pretty quickly in traffic but the electric pusher fan mounted tight up against the front face of the rad is very effective at bringing the temp back down again. I would look at ways to increase the efficiency or effectiveness of your fan.

 

Rgds Ian

[McMuttley]

+1 with Ian and i have just 10" pushing !

[EdwinTiben]

My TR2 after restoration doesnt have any problems with heat, even in warm climate like italy and in traffic jam. climbing mountains, it will rise a bit but thats maximum 195.

 

I have an aluminium radiator, a tropical mechanical fan (2 blades extra) and i use an original bellows skirted thermostat. The modern thermostats just wont work unless you block off bypasses etc. I prefer the original setup which works fine.

 

Of course all of this depends on the flow in your engine. if all's blocked you are fighting against the symptons in stead of fixing the real problem.

[Lebro]

My pennyworth

A good electric fan (eg Revotech etc) should work well provided it is realy close to the rad.

Mine is a "sucker" fitted withing a couple of mm of the rad surface, and works very well.

 

Bob.

[iain]

Hi Ben

+1 for the Revotec and its purpose designed fixing kit. Very tight to the radiator and very efficient.

 

However, I would be checking the block for crud first, open the drain on the side of the block does coolant run out freely? If not its time for some serious descaling.

Then I would go to the pinned post under Technical and rule out all other potential causes.

Unfortunately for quite a few years my car would over heat at the slightest provocation. It was a combination of many small things in that list.

(Having just rebuilt the engine, with all tolerances checked and double checked, with a recondition rad, Revotec fan, properly timed cam, properly built distributor( mapped to the engine components by Dizzy Dr), mixtures set as good as I can get them, it runs at normal unless sat on the M5 in holiday traffic.....the fan easily copes with this. )

Check out all the easy stuff first. Crud in the block, thermostat type, bypass hose open/closed/restricted as appropriate. etc

 

Iain

[Alec Pringle]

" and i have just 10" pushing ! "

 

So modest these Yorkies, form an orderly queue please ladies . . . . .

 

Cheers

 

Alec

[TR24178]

Like Lebro I have a revotec fan close mounted very close to the ally rad, on my TR2, it has a thermostat but I have an override switch which I always pull in traffic or very hot weather or in the mountains, I have no faith in the thermostatic switch because its mounted at the bottom of the rad and in the damp the contacts (lucars) are always corroded but I just watch the gauge and switch on the fan when required, it works well never have to worry about overheating, done a lot of miles in France this summer with the temperature at 37 degrees!

 

 

Next time I have to remove the apron I think I will get a boss welded on the rad and move the thermostat to the top of the rad!!

 

Sounds like your fan is too far from the rad and is just recirculating the engine heat.

Edited October 20, 2016 by TR24178

[M. Pied Lourd]

Regarding your question about moving the fan higher on your radiator...especially with a puller style fan...in my experience, if the fan is mounted too high, it will pull hot air out of the rad and push it directly at the carbs...this may cause some fuel percolation issues among other things.

 

Cheers

Tush