What do you have as a grille in your nosecone?
I fitted pierced stainless sheet (1/4 inch dia holes and about 57% hole overall) and an 'MK' stainless steel logo.


Front, closer

Is it likely/possible/unlikely that this is impeding the airflow sufficiently to have caused my overheating grief? I'm thinking turbulent flow. Any fluid dynamicists out there?

Also, I have no vents in the bonnet or sidepanels but the gearbox/prop tunnel is open as is the bottom of the engine bay - so it should be well capable of losing the hot air.
Anyone have observations or experience on airflow issues?

I've cleaned up the block and head faces and there's no damage evident; used a suction doofah to get the water and a bit of sludge out of the water jacket and it's cleaner than many I've seen. So tomorrow the head goes back on...
Before getting the last of the water out, I twidded the water pump pulley and could see disturbance to the water, so assume that the pump is OK. Anyway it's only done 40-50 miles since I refitted it, and if it had been compromised I'd have fitted a new one...

Thanks guys,
John.

I cut two holes in the rear of my nose cone and three in the rear of the bonnet which dropped the coolant temperature and the under bonnet temperature considerably

Aha! Interesting, Mr Rusty. How big holes?

quote:

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Originally posted by rusty nuts
I cut two holes in the rear of my nose cone and three in the rear of the bonnet which dropped the coolant temperature and the under bonnet temperature considerably

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Approx six in long and two wide . Will try to post some pictures tomorrow if I can find the camara. Water Wetter will drop the coolant temperature , worth a try?

have you posted twice tonight, get rid of the mesh and keep the mk grill

There should be plenty getting through there. You dont want your red getting holed by a stone or something.
Just looked at your new rad pics. Its not still plumbed like that at the header tank end is it?

Yes, Alex, this thread and a similar one in 'Bodywork & Exterior'.
John.

quote:

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Originally posted by scoop
There should be plenty getting through there. You dont want your red getting holed by a stone or something.
Just looked at your new rad pics. Its not still plumbed like that at the header tank end is it?

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quote:

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Originally posted by rusty nuts
Approx six in long and two wide . Will try to post some pictures tomorrow if I can find the camara. Water Wetter will drop the coolant temperature , worth a try?

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The pipe work. You seem to have both pipes feeding into one from the over head shot.

quote:

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Originally posted by scoop
The pipe work. You seem to have both pipes feeding into one from the over head shot.

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Header, overflow, fusebox

If you want to get technical then buy a second hand Magnehelic pressure differential gauge and measure the presure in front and behind the radiator. Having lower pressure behind the radiator is more significant than the flow in to the nose cone. In practise you only need about 1/4 the frontal arear of the radiator (or intercooler) to feed sufficient air. Another tip is to block the gaps around the side of the radiator or fit a cowling to trap air in front.

The air under the car and down the tunnel is quite turbelent. Side exit vents do appear to be the best solution, preferable quite large ones. As mentioned previously this also lowers the under bonnet temps quite significantly.

I guess my car is quite a good example as I have an intercooler covering most of the front of the radiator. I use a small Polo rad and an oil cooler behind that for my Rotrex supercharger oil. I use a Sierra oil/water cooler as well so my coolant is doing quite a lot of work! So far no issues with cooling my engine on road and track.

[Edited on 30-5-09 by bimbleuk]

Ok mate. You have u2u

That's one full engine bay you've got there!
If you're dissipating the heat from that lot through a Polo rad then I should be having trouble getting a bog standard 2L pinto warm!
Good idea on the deltaP gauge - might make a locost one from plastic tubes.
John.

quote:

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Originally posted by bimbleuk
If you want to get technical then buy a second hand Magnehelic pressure differential gauge and measure the presure in front and behind the radiator. Having lower pressure behind the radiator is more significant than the flow in to the nose cone. In practise you only need about 1/4 the frontal arear of the radiator (or intercooler) to feed sufficient air. Another tip is to block the gaps around the side of the radiator or fit a cowling to trap air in front.

The air under the car and down the tunnel is quite turbelent. Side exit vents do appear to be the best solution, preferable quite large ones. As mentioned previously this also lowers the under bonnet temps quite significantly.

I guess my car is quite a good example as I have an intercooler covering most of the front of the radiator. I use a small Polo rad and an oil cooler behind that for my Rotrex supercharger oil. I use a Sierra oil/water cooler as well so my coolant is doing quite a lot of work! So far no issues with cooling my engine on road and track.

[Edited on 30-5-09 by bimbleuk]

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bimbleuk has the right idea.
Radiator exhaust is more important than intake. You need to have a lower pressure area behind the rad. Sealing the radiator so that all air has to pass through the core is also VERY important.

Your grille is not the problem.

C10CoryM:
Sounds as if you've found out the hard way!
My situation is possibly not helped by having foam rubber strip effectively sealing the trailing edge of the bonnet to the scuttle.
I feel a run with the bonnet off beckoning...!
John.

quote:

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Originally posted by C10CoryM
bimbleuk has the right idea.
Radiator exhaust is more important than intake. You need to have a lower pressure area behind the rad. Sealing the radiator so that all air has to pass through the core is also VERY important.

Your grille is not the problem.

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John , I put the vent holes in place as a precaution but did notice a large drop on the temperature gauge after doing so.