TJS93xj
NAXJA Forum User
- Location
- Rogue River, Oregon
Recently finished up the rebuild of a 4.0. Stock rebuild with the exception of a Borla header, 2.5" cat back/flowmaster, air tube/K&N, and a Crane cam P/N 753901, (260 deg. intake/272 deg. exhaust duration).
Upon the initial start up it didn't want to start, backfiring through the exhaust etc. Did some research and figured that with the aftermarket cam i needed to index the dist. Used the indexing info found on the Strokers website but still no start. Did some more research and found another site that talked about indexing but instead of the rotor leading the the #1 plugwire pickup by .020 @ TDC it showed the rotor lagging the #1 pickup by .020. Tried that and voila it started and ran. Any info on the discrepancies between the 2? Has anyone used the indexing info off the strokers website with good results?
It seems to run really well on flat ground when up at speed (2000-2500 rpm range) but there are still some things that make me think something is still not right.
1. At start up it catches on the 2nd crank and idles fine for about 25-30 seconds then begins to stumble and miss, almost like pulling plugwires one at a time. After 30-45 seconds of this it clears out and idles fine. When warmed up it starts and idles fine with no stumbling.
2. When climbing moderate grades at freeway speeds there seems to be a loss of manifold vaccum, ie. the a/c defaults to the defroster vents until I top out over the grade. And when climbing these same grades it seems like it dosent have the low end grunt it should. On flat ground it will go from 60-80 while passing with a good seat of the pants feel, but off the line (1000-2000 rpm) it feels sluggish.
I guess I'm wondering if the problems are centered around the dist. indexing, or if the cam I chose is too much cam for the engine,or is there something else that I am totally missing/not thinking about.
Any info, ideas, insights, money for a stroker, etc. would be great.
Tim
Upon the initial start up it didn't want to start, backfiring through the exhaust etc. Did some research and figured that with the aftermarket cam i needed to index the dist. Used the indexing info found on the Strokers website but still no start. Did some more research and found another site that talked about indexing but instead of the rotor leading the the #1 plugwire pickup by .020 @ TDC it showed the rotor lagging the #1 pickup by .020. Tried that and voila it started and ran. Any info on the discrepancies between the 2? Has anyone used the indexing info off the strokers website with good results?
It seems to run really well on flat ground when up at speed (2000-2500 rpm range) but there are still some things that make me think something is still not right.
1. At start up it catches on the 2nd crank and idles fine for about 25-30 seconds then begins to stumble and miss, almost like pulling plugwires one at a time. After 30-45 seconds of this it clears out and idles fine. When warmed up it starts and idles fine with no stumbling.
2. When climbing moderate grades at freeway speeds there seems to be a loss of manifold vaccum, ie. the a/c defaults to the defroster vents until I top out over the grade. And when climbing these same grades it seems like it dosent have the low end grunt it should. On flat ground it will go from 60-80 while passing with a good seat of the pants feel, but off the line (1000-2000 rpm) it feels sluggish.
I guess I'm wondering if the problems are centered around the dist. indexing, or if the cam I chose is too much cam for the engine,or is there something else that I am totally missing/not thinking about.
Any info, ideas, insights, money for a stroker, etc. would be great.
Tim