74M35A2
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So upon reading other forums where the Cummins 8.3L is used extensively (RV motorhomes), it appears that most of them recommend the injection pump timing be advanced to about 16 degrees to greatly improve mileage, and other mods will take a much better hold.
It seems as if our MW injection pumps have oblong mounting holes, which would tend to allow some adjustment in injection timing. The pump itself appears to be very similar in layout to the more common Bosch P7100, but with a different governor.
So question becomes, has anybody advanced the injection timing on their M939 series 8.3L? If so, how did you do it, and what were the results? Did you do it by measure (#1 injection plunger height as measured via dial indicator after removing delivery valve)? I'm looking to do it via this method, but don't want to spend $500 in Miller tools to do it once. I do see P7100 injection timing tool kits on eBay for about $175 range, and can probably get the injection timing table for an 8.3 from any local Cummins dealer. I have not studied it close enough yet, but it appears there is a front access port cover to pull and re-index the injection pump gear (as done on the P7100 equipped 5.9L's in Dodge Ram trucks), if necessary.
Thanks in advance.
It seems as if our MW injection pumps have oblong mounting holes, which would tend to allow some adjustment in injection timing. The pump itself appears to be very similar in layout to the more common Bosch P7100, but with a different governor.
So question becomes, has anybody advanced the injection timing on their M939 series 8.3L? If so, how did you do it, and what were the results? Did you do it by measure (#1 injection plunger height as measured via dial indicator after removing delivery valve)? I'm looking to do it via this method, but don't want to spend $500 in Miller tools to do it once. I do see P7100 injection timing tool kits on eBay for about $175 range, and can probably get the injection timing table for an 8.3 from any local Cummins dealer. I have not studied it close enough yet, but it appears there is a front access port cover to pull and re-index the injection pump gear (as done on the P7100 equipped 5.9L's in Dodge Ram trucks), if necessary.
Thanks in advance.