On July 21, 1998, I solicited the views of the Triumphs list regarding
rust in the tank of a TR3A and an overheating problem that I couched in
terms of possible fuel starvation due to a missing vent line at the top
of the TR3's fuel tank. I received several responses to the separate
questions, and I appreciate the collective wisdom of the list.
The overheating was a primary concern, as the temp gauge would stay
around 185 unless the car was run aggressively, at which point it would
go up to about 230 and pretty much stay there. It was if the radiator
was not functioning once the foot was connected to the accelerator. I
am pleased to report the overheating has been cured, thanks to a great
extent to the persistence and follow-up of Jack Brooks of the list.
Jack questioned if a "proper" skirted thermostat was fitted and if the
by pass hose was fitted. I responded the thermostat was as supplied by
Moss, and had been recently been replaced by a 160 degree thermostat,
all with no lessening of the overheating. Jack was quick to re-state
his question, focusing on the skirted thermostat and the by pass hose,
suggesting that if a non-skirted thermostat was fitted, and the by pass
hose was as per stock, there could be a 30% or more coolant diversion
past the radiator. Jack further suggested that on his TR3, his remedy
had been to put a steel washer in the by pass hose to restrict the flow
of coolant through the hose.
I didn't like the idea of a steel washer just sitting in the by pass
hose, so this weekend I fashioned a restrictor out of 1" aluminum bar,
turning down one end to fit snugly in the lower fitting that the by pass
hose attaches to, and turning the other end to the size of the by pass
hose ID. I used a knurling attachment to give the top end of the
restrictor some grip on the ID of the by pass hose, and drilled a 3/16"
hole to allow some coolant to pass through the plug at all times.
I have run the car pretty hard since fitting the restrictor and am
pleased to say it seems to be doing the job intended. The car heats up
a little more quickly than before, but once it reaches operating
temperature, it levels out at just under 185 in hard running,
stoplights, stop and go traffic and slow running.
For anyone interested, the dimensions I used were .575 inches diameter
for the lower end, .890 inches diameter for the upper end. Overall
length was one inch, with the smaller diameter and larger diameter ends
roughly equal in length.
Thanks again for the input, and especially for the persistence of Jack
in correcting my oversights in reading and reacting to several of his
posts.
M. W. Jordan, Jr.
Marietta, GA
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