6.2 injector pump timimg

[bob455]

I have a quick question on the 6.2 injector pumps I have a 85 suburban I recently changed injector pumps the original one was a C series light duty and the one I installed is a rebuilt J series heavy duty pump and the question I have is besides the increase in fuel do these two pumps have a different timing calibrations? for instance the original pump the timing marks were just about lined up with the pump just a hair to the right of the engine mark and the timing was 4 1/2 degrees with the new pump at that same location the timing was at 11 degrees I back off the timing quite a bit and brought the timing mark of the pump a tad to the left of the mark on the block there the intial timing is at 7 degrees I bring up the rpms to 2800 to 3000 and the pump advances to 11 degreees total like the other pump that I had originally on the engine it runs great its a lot more power but the question is can I get away with running the initial pump timing without any future problems ..like blowing head gaskets ? or possibly breaking a crankshaft?

[DmaxMaverick]

Welcome to the forums!

The difference in timing could be from several reasons, specifically a worn out old pump, and timing variations in an old valve timing set. Did you replace the timing set? If so, the measured timing can be very different, comparing new timing set and IP to old.

Damage that can occur from pump timing/fueling will be from excessive combustion temp (cracked pistons/valves, etc.), if the timing is too advanced. Head gaskets and the crank can fail from other causes, but not that, directly.

[bob455]

I havent changed the timing chain set with both pumps i.would figure the timing would jump alot if i had a sloppy chain i would think anyway a gas engine that would happen anyway the old pump really didnt have any time on it i had it rebuilt in the early 90s and shortly after that i put the truck away in the shop for a very long time and recently til about a year ago i started working on it i was figuring old gelled up diesel fuel in the pump so i was using clear kerosene with lucas injector cleaner to maybe clean the pump out..but i.decided to.get rid of.that california pump.and just put on a fresh heavy.duty.pump with rebuilt injectors.....i appriciate your input dmaxmaverick for now ill run it around for a little while and in a couple of weeks ill change the timing chain and gears it should have slack it does have 200k on the clock