My 1967 d8h will not rev or accelerate the engine when the oil get hot after working for about two hours. I have change the oil pump, the nozzles, the turbo all to no avail. but when it cools down, it start working fine until the oil get hot again. some one help
If I remember correctly there is a function at governor that won't allow speeds above idle until normal oil pressure is reached. I would look there, is your oil pressure good at operating temp ?
My oil pressure gauge is good. I replace the oil pump with a new one when I thought the one I had is bad. But it can work a whole day with half throttle or more if you did not use the deceleration floor pedal, as soon as you touch the deceleration floor pedal, you have to wait for 10 to 20 minutes for it to pick up
Your gauge may be good but is the oil pressure on the gauge ok? Like Dpete said if its low on pressure it wont let you open your throttle the plunger will limit the throttle.
The pressure is ok. The funny thing is that we have 3 of these d8h and all have the same problem, some times we have to disconnect the floor deceleration pedal all together so we can use it like that . It usually starts when we have their engine rebuild.
the oil pressure gauge is good I have tested it with another gauge and they read the same pressure, but is there a bearing in the governor that may be bad? we have 3 of this d8h and all have the same problem after the engine has been done. we have to disconnect the floor deceleration pedal on the other two and keep the acceleration at half speed and they work good all day.
did you just buy another d8h on iron planet on the 30th?
Thes old girls had an oil filled servo inside the governor that the weights ran on. They would leak if worn after the oil got hot and thinned out. Same principle as hydraulic lifters in car engines. Not saying this is the problem, but i would look there first if it was my choice. Best of luck with it.
Still sounds like an oil pressure problem to me. You keep saying the gauge reads ok but what is the actual pressure? Should be 30 psi normal operating pressure with 90 psi maximum relief pressure when cold. Your info that the problem is when warm or when using the decelerator indicates you are not making adequate pressure at low rpm and the engine struggles to make adequate pressure....ok as long as you keep the rev's up but once it drops the limiter restricts the rack movement. There are a couple of adjustments that need checking....the "X" distance between the top of the governor housing and the upper bearing race on the governor shaft (affects maximum rack movement) and the decelerator rpm's need to be set at 200 rpm above low idle speed. Might also check the line and workings of the limiter. There is no servo involved.
My very thoughts O.M. I have found motors with low oil levels and oil pick up faults cause a lack of the " Black Smoke " but most always the fault is tied into the blood pressure being a bit crap, this throttle thing can also lead to no gears on the p/s when the trans pump is worn out, it all works great till the temp starts to set in then no gears after a press on the speed pedal,I have also had a sump full of water give a similar throttle responce to what this man is finding.