WEmery7451@aol.com wrote:
>
> In a message dated 4/21/01 8:52:56 AM Pacific Daylight Time,
> kaskas@earthlink.net writes:
>
> << The reason to restrict the flow is to increase or maintain the BLOCK
> PRESSURE. The block pressure is what eliminates the areas of steam pockets
> in the cylinder head that when ignored result in blown head gaskets etc. >>
>
> Thanks for the information, Kas. I never did have all of the dots connected.
> In my early days, TR racers would shim their radiator caps with rubber
> O-rings (I assume that this activity was to keep the pressure up in the
> block.) It is anyone's guess as to how high the radiator pressures were
> going. After I suffered several DNF's from blowing off hoses and blowing out
> water pump packing, I eliminated the radiator cap shim and started to use the
> 15 psi cap. (Three TR-3 radiators filler necks were modifies to accommodate
> the short reach caps.)
>
> My first move now, I assume, is to look for a 25 psi radiator cap.
One of the considerations in doing the above should be the radiator
itself. The radiators we buy for heavy-duty diesels are only
pressure-tested to 28 psi. Wish I knew what the specs were for the
original Triumph radiators, but I don't. Nevertheless, I doubt they were
built for continuous service at 25 psi.
Moreover, from what Kas describes, if one got 25 psi in the total
system, it would be from steam pressure, rather than from water pressure
provided by the pump, which is the object of what he suggests
(increasing driven pulley size to slow down the pump below the
cavitation point--any restriction at the thermostat housing would be to
increase block pressure).
Also, what Kas seems to be saying is that block coolant pressure drops
with rpm due to cavitation of the pump. I would expect this from a
straight-vane pump such as Triumph used. Has anyone investigated use of
a scroll-vane pump or some other arrangement? Mere speculation, mind
you. Not necessarily encouraging yet another manufacturing project.
<smile>
Cheers, all.
--
Michael D. Porter
Roswell, NM (yes, _that_ Roswell)
[mailto:mporter@zianet.com]
`70 GT6+ (being refurbished, slowly)
`72 GT6 Mk. III (organ donor)
`72 GT6 Mk. III (daily driver)
`64 TR4 (awaiting intensive care)
`80 TR7 (3.8 liter Buick-powered)
`86 Nissan 300ZX (the minimal-maintenance road car)
`68 VW Type II Camper (Lancia twin-cam powered, but feeling its age....)
Remember: Math and alcohol do not mix... do not drink and derive.
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