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View Full Version : c and j injection pumps, what's the difference?


johnhanging
08-11-2003, 21:16
How much difference is there between a DB2-4126 C/lh6 injection pump and a j/ll4? Are they interchangeable?
britannic
08-11-2003, 22:16
An inj. pump for a "C" engine will flow a bit less fuel at WOT/2000rpm than the "J" (47.5-51.5cc/minute). The "C" pump is designed for economy, so if power is your goal, go with the "J", otherwise enjoy the frugal fuel usage of the "C" pump.
johnhanging
08-12-2003, 13:02
So no timing problems, eh? I like the notion of less power/better fuel mileage. Thanks for the response.
britannic
08-12-2003, 14:45
There will be a less aggressive timing advance, but static timing won't be an issue. Also, to realize the best economy, the "C" heads would need to be used. If you have "J" heads, get the "J" pump, you won't regret it.
johnhanging
08-14-2003, 07:43
I've got the "J" code heads, as far as I know (casting #14077162). I'm in the process of rebuilding an engine out of my suburban. Actually the engine that was in there is headed to the bone yard. Anyway, I took the old pump in and had it rebuilt, and $480 later I finally look at the model number on it, and discovered it was for the "C" code engine. Can a "C" be converted into a "J"? Or am I stuck??
johnhanging
08-14-2003, 08:02
I've got the "J" code heads, as far as I know (casting #14077162). I'm in the process of rebuilding an engine out of my suburban. Actually the engine that was in there is headed to the bone yard. Anyway, I took the old pump in and had it rebuilt, and $480 later I finally look at the model number on it, and discovered it was for the "C" code engine. Can a "C" be converted into a "J"? Or am I stuck?? :confused:
britannic
08-14-2003, 08:20
A "C" code can easily be converted into a "J" by having it recalibrated. Tim Wagner at www.cleaninjectors.com (http://www.cleaninjectors.com) has a great IP service, he converted my "J" pump into a 4911 for under $200.00 plus shipping.
johnhanging
08-14-2003, 13:25
Thanks! I'll check into what the local guy can do first. I had asked them to set it up as a J, but what's said and what's on paper are two different things. Thanks again!