Another factor that contributes to the smaller radiator and the higher
pressure systems is the style of newer vehicles. I can't think of a
specific example at the moment, but most newer cars have only minimal
'grills' for air to get to the radiator. I think it was the mid 90's
Oldsmobiles that had an air intake under the front bumper, with no grill.
Thomas James Pokrefke, III
1970 MGB
pokrefke@netdoor.com
Audentes Fortuna Iuvat
On Wed, 20 Oct 1999, Bob Howard wrote:
> Chris,
> I suspect that 7 psi was MG's way of slow evolution. As late as the
> TDs, the systems were not pressurised at all. The TFs were the first to
> use pressurised systems. They retained the old radiator cap for
> appearance, and had the pressure cap under the bonnet.
> The lower the pressure, the less stress on the parts of the system,
> radiator, hoses, waterpump seals, gaskets, etc. If 7 psi suffices to
> keep the water/antifreeze mix from boiling at the temps the engine would
> be expected to generate, there would be no advantage to going to the
> higher system.
> Having said that, the reason that everyone uses higher pressures today
> is that heat flows from areas of greater concentration to those of
> lesser. What that means is that the hotter the radiator, the more heat
> per square inch will move to the cooling air. Thus one can use a smaller
> radiator running hotter than a smaller radiator running cooler to do the
> same job. Today, smaller means cheaper and lighter.
> What this means to the owner is something else.... Radiator on my '87
> S-10, running at 14 psi has been replaced twice, the second time at
> 130,000 miles. This may be great for GM's budget, but it's not good for
> mine. Radiator for my TD was in the shop for inspection during engine
> rebuild. THe shop said that it was in great shape and should be good for
> another 45 years or so. The TD's radiator is about the same size, though
> twice the weight, of the S-10's.
> Bob
>
> On Tue, 19 Oct 1999 08:31:23 -0700 Chris Attias <cattias@cats.ucsc.edu>
> writes:
> >Since we have been going for some time on cooling system and heater
> >threads, I thought I'd ask a question that has puzzled me for years...
> >
> >Early MGBs have 7 lb. (don't know what that works out to in metric
> >units) radiator caps. Most car cooling systems can run at twice that
> >pressure. This seems desireable, as it raises the coolant boiling
> >point. What is the weak link in an MGB cooling system that would
> >prevent you from running at a higher pressure? Radiator core? Brass
> >header tank metalurgy? Heater core? Heater valve? Head gasket??
> >Or is this a bad idea for other reasons?
> >Chris Attias
> >'64 MGB
> >'84 Alfa Romeo GTV-6
>
>
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