30dodgeboy
New User
Need some help with a Lucas CAV pump, DPS model 8523A110A (97HP). It's on a 268T engine (also called BSD444T). I think this engine and pump is also used in Ford 7610/7710 trackors and 755 backhoes.
This engine is in a piece of forestry equipment that was recently purchased not running condition. Engine had a blown head gasket (poor workmanship issue) and a spun rod bearing on #2. I overhauled the engine but now that it is running its power is low. When adding load, the engine sounds as if the throttle was reduced, and there is no smoke or haze out the exhaust. I checked the timing (used my MAC pulse timing adapter) and advanced it from where it was at (12) to 18 degrees BTDC, but that made no difference. I want to say it needs more fuel. I have confirmed that the fuel is fresh, there is good flow from the electric lift pump, replaced both fuel filters, and confirmed it has a constant stream of fuel return flow back to the tank. Again, no difference - the engine runs smoothly, but is certainly down on power.
After researching Lucas CAV pumps, I checked the cylindrical screen within the pump at its back end near the vane pump, and all is well there with the screen and the regulating piston and springs. Under the rear cover, the pump vanes and cam ring look new. I saw 'DELPHI' on the cam ring making me think that this pump was replaced and is newer than the 1995-ish engine.
Removing the top cover from the pump I can see that it is very clean inside there as well, suggesting the pump is fresh. Even the top gasket looks new (no staining on outside edges). All looks well with the governor spring up top.
Whomever was working on this machine before had done a LOT of horrible work, and I wouldn't be surprised if the fuel line connections on the pump were somehow messed up. The fuel supply from the filters connects to the back of the pump near the injector line connections, and is also teed to a second connection at the top cover. There is also a connection on the top cover to supply fuel up to the intake manifold flame heater, but that is not operational yet on this machine. The return line is at the front end of the top cover and has a ball-spring regulator to hold some pressure in the pump - much like the overflow valve used with Bosch inline pumps. I followed that passage through the top cover to a drilled passage in the pump body near the drive end. It seems as if this arrangement (no return connection at the top cover)would trap air in the top housing, unless the flame heater gets used a bunch, but then again I think the fuel going to the injectors and timing advance mechanism all comes from the connection at the back of the pump. Earlier pumps had no connections to the top cover, so maybe I'm just overthinking it?
Can anyone supply a few pics of correct fuel line connections?
Thanks in advance.
This engine is in a piece of forestry equipment that was recently purchased not running condition. Engine had a blown head gasket (poor workmanship issue) and a spun rod bearing on #2. I overhauled the engine but now that it is running its power is low. When adding load, the engine sounds as if the throttle was reduced, and there is no smoke or haze out the exhaust. I checked the timing (used my MAC pulse timing adapter) and advanced it from where it was at (12) to 18 degrees BTDC, but that made no difference. I want to say it needs more fuel. I have confirmed that the fuel is fresh, there is good flow from the electric lift pump, replaced both fuel filters, and confirmed it has a constant stream of fuel return flow back to the tank. Again, no difference - the engine runs smoothly, but is certainly down on power.
After researching Lucas CAV pumps, I checked the cylindrical screen within the pump at its back end near the vane pump, and all is well there with the screen and the regulating piston and springs. Under the rear cover, the pump vanes and cam ring look new. I saw 'DELPHI' on the cam ring making me think that this pump was replaced and is newer than the 1995-ish engine.
Removing the top cover from the pump I can see that it is very clean inside there as well, suggesting the pump is fresh. Even the top gasket looks new (no staining on outside edges). All looks well with the governor spring up top.
Whomever was working on this machine before had done a LOT of horrible work, and I wouldn't be surprised if the fuel line connections on the pump were somehow messed up. The fuel supply from the filters connects to the back of the pump near the injector line connections, and is also teed to a second connection at the top cover. There is also a connection on the top cover to supply fuel up to the intake manifold flame heater, but that is not operational yet on this machine. The return line is at the front end of the top cover and has a ball-spring regulator to hold some pressure in the pump - much like the overflow valve used with Bosch inline pumps. I followed that passage through the top cover to a drilled passage in the pump body near the drive end. It seems as if this arrangement (no return connection at the top cover)would trap air in the top housing, unless the flame heater gets used a bunch, but then again I think the fuel going to the injectors and timing advance mechanism all comes from the connection at the back of the pump. Earlier pumps had no connections to the top cover, so maybe I'm just overthinking it?
Can anyone supply a few pics of correct fuel line connections?
Thanks in advance.
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