[Fot] Racing a TR3 A Type Overdrive

[Catpusher at aol.com]

Racing a TR3 A Type Overdrive  
Please see what you can find in the archives. 
For many years the TR3 was one of a very few cars  not allowed alternate 
gearbox ratios in SCCA E Production. Using second gear  overdrive was 
essential with a full race motor to bridge the gap between  2nd and 3rd. I spent 
thousands of hours studying and  modifying the OD. Running a pressure gauge 
during events is necessary, as is not  allowing it to leak on the driver. The 
gauge will show when the solenoid is out  of adjustment, and most critically, 
when there is a running pressure drop. If  the accumulator piston does not 
reach the blow off holes, that oil no longer  gets to several parts. The 
specks for the accumulator bore are very tight, and  honing to remove the steel 
piston ring scratches will only work a few times. The  TR4A IRS/TR6 piston, 
sleeve, and spring provide a much lower volume and  pressure, but a 
replaceable sleeve is a good idea. Much research about piston  displacement and 
pressure pointed me towards a Jaguar sedan assembly that was  NLS, but JRT, 
with the help of a UK Jaguar club, provided a few sets of piston  and sleeves, 
and I also located the matching springs. I did find it necessary to  run an 
oil cooling system with an electric pump and MGC auto gearbox cooler, all  
set low enough that it would not flow back into the gearbox during the early  
laps before the pump was turned on. Keep in mind that I was running slicks 
and  often ran where the track temps were high. 
TR Regards, Hardy