Terry,
Not sure where your friends family in Australia finds "throw away" PI
units - I wish I could find them! Like everywhere else they are getting
scarce here as well. The units are usually sourced from PI sedans, not
the TR range. They *are* different. The sedan is heavier and runs more
fuel through the unit than is required for a TR - this results in a
fairly rich mixture. In addition to what's already been said, you will
need change the springs within the metering unit to TR5/6 spec and have
the unit recalibrated to suit your application. There are "shops" here
that have bench test calibration units that can set up to what you need.
Let me know if you're interested in names and addresses? I've had my
unit recalibrated to suit an uprated cam profile (a bit more savage than
the standard TR5 unit) and to give me an additional 3cc of fuel at zero
vacuum - gives a better accelerator response without loosing too much
in economy at the top end. You will need to have a baffle in your fuel
tank - not all carb (USA) cars were fitted with these and without it,
your pump may cavitate, sucking air into the system causing much
heart-ache when you need to bleed the air out. Also figure on
reconditioned injectors and these are NOT cheap. These will have the
tips reground and new springs fitted to ensure the crack pressure is
right (around 40 psi). I'd seriously consider an alternative to the
Lucas fuel pump - these have a tendency to overhead also causing air
into the system and yet another bleed. I run a Bosch pump and have had
no problems (about 10 years of running).
Generally, once set up the Lucas PI system is reliable and provides for
some serious horsepower. The beauty of the system is you can run a
really lumpy cam and still have it idle at around 6-800 rpm - try doing
that with carbies! Happy to help out further if needed. All the best,
John Mc
'71 TR6 PI
'76 Dolomite 1850
'76 Dolomite Sprint
"Fast is First"
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