[Fot] TR coolant pressure/flow

[John Hasty]

I now have the car & can attest that it works well. Like Kas told us, though,
you need to take your time & make sure you he ALL the air out.

Sent from my iPhone

On Feb 8, 2013, at 4:45 PM, Larry Young <cartravel at pobox.com> wrote:

> Greg,
> I don't have an answer to your question regarding pressures, but I had a
similar arrangement in my TR3.  The Chevy style radiator is a great idea,
because it eliminates the worry of overheating. I cut off the radiator fill
cap and plugged it off, since it is unreachable anyway.   I put the expansion
tank in (from Pegasus I believe) so that I would have a way to fill it.  I
wanted to have water flowing thru the expansion tank to effectively increase
the volume of water in the system.  I went with the return to the suction side
of the pump with 1/8 inch pipe and small diameter hose to keep the flow rate
down.  I drilled and tapped the thermostat housing for a drain valve so I
could bleed all the air out.  It worked very well and was one of the best
upgrades I did to the car. Some would argue that you should have a cap to
regulate the pressure downstream from the thermostat, but I found that it
worked fine with something like a 7 lb cap on the expansion tank.  You would
think this would open up due to pumping pressure.  I think if I did it over
again, I'd just put a cap somewhere downstream from the thermostat and
eliminate the expansion tank.  I could probably find some photos if you'd like
to see them.
> Larry Young
>
> On 2/7/2013 9:08 PM, Greg & Alison Blake wrote:
>> Anyone out there every gauged coolant pressure on the TR block?  I'd love
to
>> see the results.
>>
>>
>> I am going through the process of adding a surge (expansion) tank on my
TR3
>> and I am starting to wonder if I am plumbing the return line in the
correct
>> spot.  I have installed the tank in the battery box with a line entering
the
>> top of the tank that originates at the heater port in the rear of the
head.
>> For the return line, off the bottom of the expansion tank, I have added a
>> welded fitting in my top radiator hose between the thermostat housing and
>> the radiator to accept the return line.  I use a cross flow Chevy style
>> radiator so I have a metal radiator pipe between the thermostat housing
and
>> the intake for the radiator.  I thought it would be better to introduce
the
>> hot coolant from the expansion tank back into the radiator vs dumping
>> directly back into suction side of the water pump via the return heater
>> port.  My thinking was that I should not introduce hot coolant into the
>> suction side of the pump and re circulate it back thru the block.  The way
I
>> have it plumbed (if it works), the hot coolant from the expansion tank
will
>> first go thru the radiator then into the pump and back thru the block.  I
am
>> guessing that downstream of the thermostat housing (I use a thermostat)
the
>> pressure will be lower than at the back of the block.
>>
>>
>> My questions are:
>>
>> Has anyone measured pressure between the thermostat housing and the
>> radiator?
>>
>> Has anyone measured pressure at the back of the head heater port?
>>
>> What is the difference?
>>
>> Am I going to get coolant to flow from my expansion tank back into the top
>> radiator hose or is the pressure higher in that top hose than the back of
>> the block?
>>
>> Would it be better to plumb the return line into the return heater port?
>>
>>
>> Thanks,
>>
>>
>> Greg
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