8630 Injection Timing

KY Reed · Mar 3, 2023

Can anyone tell me what the factory injection timing degrees are for an 8630 and an 8650 on a 619 / 10.1? Thanks

Dieseltech · Mar 4, 2023

KY Reed · Mar 4, 2023

I am looking for injection pump timing degrees and not engine location at timing degrees. Number should be around 30* but am trying to double check. If engine is at tdc then I need to know at what degree the pump is when pinned. I am in need of increasing the timing for my application. Thanks

Dieseltech · Mar 4, 2023

The pump to engine timing is set at TDC, but the ACTUAL timing is more like 28-30 degrees BTDC. How it's done is on the test bench, number one cylinder is set to port closing, beginning of injection. The stand degree wheel is then used to turn the pump in normal rotation another 14 or 15 degrees per the spec sheet, and then the hub mark and tab mark are set to align. Only way to know the ACTUAL timing is per the spec sheet for the pump on each engine. Other make engines are doing the same thing now also. Years ago the port closing timing only was used to mark the drive hub, and the actual engine timing was used, not TDC. You NEED to set the pump mark to align at TDC engine with the number one cylinder, both valves closed. The number SIX valves will be rocking at that time to verify number one is on compression stroke.
The only Bosch inline P pump that did NOT use TDC timing that I recall was the JD 531 engine in the 6030, that one used actual timing BTDC.

ohiodick · Mar 4, 2023

if you need to know exactly what timing is set to you need a high pressure timing machine to set timing we still have the machine at the mack dealership. very seldom gets used only 2 of us know how to use it any more.

8630 Injection Timing

KY Reed

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Dieseltech

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KY Reed

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Dieseltech

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ohiodick

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