[TR] TR4 Fuel Delivery Issue & Mod

staffel staffel at comcast.net
Mon Aug 10 21:43:35 MDT 2020


Several years ago on an evening  club drive in the Catoctin Mts of Maryland my TR4 developed running/ hesitation issues. Then it got dark & started to rain. Could not drive the car steady over 45mph. Typical fuel flow clogging issue symptoms. Fortunately we made it into Fredericksburg and a Motel.Next morning, still raining,  the issue was apparent: in the bottom of the Glass fuel bowl- a pile of 'rust dust'.  Cleaned the bowl & nursed the car home 30 miles, but it kept dying. Fortunately a Jag club friend came by and got his trailer & towed me home.Further examination determined sediment also in the CD carbs fuel bowls. So much for the fuel pump 'screen' being 'effective'.Also examination of the fuel pump (original) revealed a weak diaphragm, so while working on the carbs, ordered a new pump from TRF. A few months later got everything back together.  The engine started right up & ran fine. But no matter how I tried to seal the threads on fuel feed of the original  curved pipe inlet 'nut' to the new pump ( pipe dope, teflon tape, rtv) the leak wouldn't stop. Magnifying glass exam of the original Triumph  Male pipe 'nut' and the female threaded bore of the new TRF pump revealed a slight thread mismatch - Chinese machining. It was not Metric either. So after talking with TRF, I decided to forget the mechanical pump and install an electric pump, ala Jaguar V12s & Jensen Healey / GTs (Lotus 907).Well, I installed a couple of  different new electric  pumps  adjacent to the mechanical pump.They would never 'self prime'. Now, returning to the project. I removed the mechanical pump, & DRAINED the tank of the old fuel. It seems that the gravity feed when the tank is less than 1/2 full requires the elec pump to be very low ( like the original input height of the original pump, to receive fuel. So I am redetailing the frame (cleaning & new paint) and securing the new fuel line, inline glass Filter & elec pump  right on the frame. This allows the steel feed line from the tank ( after Dremel Tool cutting) to match the new location of the electric pump.Next will be modifying a new copper fuel line ( semblance of originality) to meet the elec pump feed right behind & adjacent to the Water pump. The original copper pipe mated to the back of the mechanical pump , ran up and forward along the engine at the cylinder head level to the front of the engine & then across to the carburetor feeds.Finally hope this resolves the fuel delivery issue.I  wanted to share a warning about the TRF pump supplier manufacturing glitch. So others can not waste years getting their TRs back to Roadworthy status.Obviously not going to drive a car with weeping fuel near a hot engine. At least on the TR4 & 6s, ( unlike Jaguar 6s ( have 2) or V12s ( have 3), Jensen GTs ( have 3) ; the exhaust Manifolds are on the opposite side of the engine. Sherman D Taffel Columbia MD and Goldvein VA 65 TR4 CT 50054L( per VTR the last known TR4 produced & shipped to USA)Sent via the Samsung Galaxy S10, an AT&T 5G Evolution capable smartphoneSent via the Samsung Galaxy S10, an AT&T 5G Evolution capable smartphone
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