Amici, beware of having the only radiator cap be on a neck welded onto the
t-stat housing. You need for the Radiator cap to be on the Low pressure
side of the water pump which is immediately after the T-stat housing
(either T-stat restriction or restriction caused at outlet of T-stat
housing reduces pressure downstream from it). The block itself has over 30
psi of pressure when the water pump spins up regardless of cap pressure
rating. I would think that the heater hose hole in the head would be high
pressure, but maybe the size of the hole in the head in combination with
the size of the low pressure return to the pump restricts flow enough for
that to work. On uncle jack's car, the block pressure overcame any
pressure cap we put on the t-stat housing until we plugged up the overflow
hole completely (making it an extremely high pressure rating). We still
use the Radiator cap on the Radiator for pressure relief to the overflow
bottle. Took us a bit to figure out why we were pushing all of the water
out... Having a radiator cap on the T-stat housing sure makes filling the
system a breeze, though.
- Tony Drews
At 08:16 AM 7/12/2005, Larry Young wrote:
>Joe,
>I installed a commodity Chevy radiator in the smallest size available ( I
>think it was a Tru-Kool from Speedway Motors for less than $150). It
>almost fills the space between the fenders. Cut off the filler neck and
>have a patch welded over the hole. I also had some tabs welded near the
>top on the sides, in order to attach stays. Fabricate some simple brackets
>to move the bottom of the radiator forward. I fill through a Canton
>expansion tank mounted on the firewall (from Pegasus and others). The
>expansion tank is plumbed the same as the original heater (take off from
>rear of block, return to pump). If I were to do it again, I'd dispense
>with the expansion tank and have a filler neck welded onto the thermostat
>housing. Find radiator hoses by looking through the picture book at the
>parts store. The biggest problem was finding some tubing in 1 3/8 inch size.
>
>This is one of the best things I've ever done to my TR3. Even with 95
>degree temperatures in Oklahoma, there are no worries about overheating -
>one less distraction.
>Larry Young
>
>
>Joe Boruch wrote:
>
>>I put in a new Oil Temp gauge for my race at NHIS this past weekend and
>>was surprised to see the temps going to 260 during the race. The old
>>gauge was 25+ years old. Not sure if it was the old gauge or the new one
>>that is the issue or if the temps are really that high. On the cool down
>>lap it did, however come down to 200. In previous years 220 was about as
>>high as it would go. Water temp was 210. I took the screen off of the
>>back of my grill and water dropped to 200 and oil peaked at 240, so the
>>extra air helped (it was also a 20 deg. hotter day after removing the screen).
>>
>>I already have 2 oil coolers, but am using a stock looking/size TR3
>>aluminum radiator. I would like to change over to a wider crossflow
>>radiator and since I am racing SCCA so the rules allow it. Does anyone
>>know of an off-the-shelf (i.e. not too expensive) crossflow aluminum
>>radiator that will work in a TR3? I understand that some hose rerouting
>>will be needed. Joe(B)
>>
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