Oilburner
Adventurer
Hello all,
I’ve been slowly fine-tuning my engine conversion since I finished stuffing the 4D3 into my 80 series Land-Cruiser. So far it’s been excellent and more economical than the previous gasser, but I am trying to make sure it is running optimally.
Do any of you lads have experience setting the mechanical engine injection timing on the 4D3? When I got the engine, the pump was a dud and the engine was supplied with a replacement injection pump. I replaced the injection pump, making sure to line up all the marks, but when I started it up, the injection timing was badly retarded and it was smoking like an old Detroit diesel. So, I bumped the timing forward by cranking the pump over until I had about 1/8 inch between the marked lines on the pump and the intermediate housing, and the smoke cleared right up and it started running sweetly. It wasn’t until I removed the timing gear from the old pump that I observed that the bolt holes in the gear are slotted, allowing for adjustment at the gear, in addition to rotating the pump.
The timing procedure in the service manual is incomplete and not very accurate as it only references adjustments done by rotating the pump and assumes that the gear is phased correctly in reference to the injection pump shaft. The procedure consists of removing the front most RPM sensor and looking down at the reluctor ring, and observing the position of the ‘tooth’ that indicates TDC in reference to a mark. That’s all fine and dandy, but with this mark, the engine could very well still be 30 degrees off at the timing gear and lined up on the reluctor due to the slots, as the reluctor is “after” the timing gear.
I suspect that the gear position is likely set at the rebuilder and wasn’t in my case, and it looks like a specialized timing tool is necessary.
Right now, my options are to pull the timing cover off and observe the position of the slotted holes and compare to the old pump, but that’s not exactly super reliable as a measurement. I can continue to play with the timing by rotating the pump but it’s hard to time it by ear as I’ve never heard one run before this one.
I suspect that it is still retarded as the engine sounds too quiet, it builds boost lightning fast and seems quite "lazy". I can't describe it but my Cummins is the same when I back the timing right off.
Any ideas are welcome!
Cheers
I’ve been slowly fine-tuning my engine conversion since I finished stuffing the 4D3 into my 80 series Land-Cruiser. So far it’s been excellent and more economical than the previous gasser, but I am trying to make sure it is running optimally.
Do any of you lads have experience setting the mechanical engine injection timing on the 4D3? When I got the engine, the pump was a dud and the engine was supplied with a replacement injection pump. I replaced the injection pump, making sure to line up all the marks, but when I started it up, the injection timing was badly retarded and it was smoking like an old Detroit diesel. So, I bumped the timing forward by cranking the pump over until I had about 1/8 inch between the marked lines on the pump and the intermediate housing, and the smoke cleared right up and it started running sweetly. It wasn’t until I removed the timing gear from the old pump that I observed that the bolt holes in the gear are slotted, allowing for adjustment at the gear, in addition to rotating the pump.
The timing procedure in the service manual is incomplete and not very accurate as it only references adjustments done by rotating the pump and assumes that the gear is phased correctly in reference to the injection pump shaft. The procedure consists of removing the front most RPM sensor and looking down at the reluctor ring, and observing the position of the ‘tooth’ that indicates TDC in reference to a mark. That’s all fine and dandy, but with this mark, the engine could very well still be 30 degrees off at the timing gear and lined up on the reluctor due to the slots, as the reluctor is “after” the timing gear.
I suspect that the gear position is likely set at the rebuilder and wasn’t in my case, and it looks like a specialized timing tool is necessary.
Right now, my options are to pull the timing cover off and observe the position of the slotted holes and compare to the old pump, but that’s not exactly super reliable as a measurement. I can continue to play with the timing by rotating the pump but it’s hard to time it by ear as I’ve never heard one run before this one.
I suspect that it is still retarded as the engine sounds too quiet, it builds boost lightning fast and seems quite "lazy". I can't describe it but my Cummins is the same when I back the timing right off.
Any ideas are welcome!
Cheers