I am getting Lil' Mack in the shop next week to have a compression check and injector inspection/upgrade. I questioned the service manager at GCL Diesel about how he sets pump timing and mentioned the extensive talk about 1.25mm vs 1.35mm and the spill port technique on the TDR.
The last time I had my truck in to get the timing set, they gave me a worksheet with the timing reported in degrees of crank rotation BTDC. I noticed back then that a spot on the line going to #1 injector had been buffed of paint. So today I asked about how he got timing.
He told me about the spill port and how the pump has some dynamic clearances that will change the timing slightly while running from what you set and the important timing is when the injector needle is lifted from the seat. Which is true, if the injector is weak or strong in the internal tension, the pump will open the injector sooner/later than anticipated.
They have a pressure sensor that they clamp onto the outside of the injector line that senses when the injector opens to determine injector timing BTDC in degrees!!.
The shop report from Aug 95 was documented as follows. Mileage 181,524 IN Timing 5.4 @650 / Max speed 2800. OUT Timing 10.0 @650 / Max speed 3000. Aneroid screw up 1/2 turn. Boost IN 19 PSI / OUT 19 PSI.
I just found that this is an interesting way to check the injector pump timing and thought I would share it.
If the engine checks out for compression, the uprated injectors are going in!!. Funny thing is that they are cheaper than the stock ones.
around $599 CDN for the set. Not bad!
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Jason's Lil' Mack - 89 D250LE 2WD 5 Spd 3.55 Reg Cab. K&N,"tweaked pump", 3.5" Exst straight,E&M Custom seats. Bosch H4, PIAA 80W/80W HdLites. Bosch 100W Driving. Bosch 55W Fogs.
229,000 miles (366,000 Kms)
7550 Hrs.
Pump timing accuracy
Linear Mode
