Phil Bennett Posted May 28, 2019 Share Posted May 28, 2019 Hello, Wonder if anyone out there can offer any views / comments on my 'problem' ? I have a 1970 R719 with the ENDT864 twin turbo V8 fitted, all pretty original. Understand that engine should deliver around 300hp, but was not Macks finest and had 'issues'... My Problem: Thought not used for everyday haulage (just shows), if I pull a ballasted 20' container (32 tons), I struggle to get much 'get up and go' over 35mph. As if the 300 hp is just not there. On a slight downhill road, it can (and will) do 50 mph. But a slight incline, not really. Compression fine. Injectors fine (clean exhaust), fresh diesel, filters and replaced fuel lines. Fuel pump pressure as per Mack manual. Checking the Turbo boost pressures (no gauges fitted, but have added aftermarket to be able to check) only give (under load pulling 32 ton) Mack Max RPM = 2300 1600rpm – 1800rpm = 2 to 4 psi. Best PSI reading is just about 5psi when accelerating up to 2000rpm. Am I expecting too much in the way of 'performance' from a truck of this age / era / horsepower ? Thanks Phil Quote Link to comment Share on other sites More sharing options...
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