Post by creative1 on Jun 29, 2004 12:31:52 GMT -5
this could turn out to be rather lengthy, but here goes...
first some specs
vehicle......'84 dodge d250 (orig. had 360 lean burn engine) weighing 4700 lbs w/gas tank 1/4 full
engine..... 440 smogger--- stock bore , stroke and compression (came out of a 1978 B350 van)
cam.......... comp cams 21-215-4...218*@.050 & .454" lift, 110* lobe sep, installed straight up (no adv or retard)
carb......... 750 cfm speed demon
intake....... edelbrock "performer 440"
exhaust.... 1 3/4" long tube headers into 3" collectors
ignition..... stock module...came in the vehicle (with the 360 lean burn engine)
trans........ 727 w/lockup converter stall about 1800-1900 rpm
diff...........3.54:1 dana 60 open diff
tires and wheels.... 16"wheels with 31" tall tires
fuel.......... normally 87 octane pump gas
distributor was tuned and phased by Don. i seem to have misplaced the tech sheet, but if i remember right, the dist was set up for 36* total advance (mech and initial... add the vac adv was around 52 or 54* total) all in by 3000 rpm. installed with 13* initial timing
carb was setup for this combo with the stock intake, also by Don.
now... the crux of the matter...
took the truck to test and tune a few times and was pleasnatly surprised when it made a 16.5 sec pass on its first (and my first too) ever pass. later that night, it ran a 15.1127 @ 91.78. i made no changes, except for the weight lost by gas burned.
went a couple of more times over a 6 week period and just ran the truck... upper 15's was all i could do. i am still trying to figure out a decent launch program. last friday, i put 15 gals of 91 octane in the tank, along with about 13 gal of 87 octane that was already there, took a 1/2" wrench and my timing light and went hunting street mustangs ( at the strip... lol)
leaving initial timing at 13*, i made 2 passes: a 16.37 and a 15.84 (87 and 88 mph respectivly). i then got out the wrench and timing light and started advancing the timing in 2* increments. adv the timing 2*, make a couple of passes...
by the end of the night, i had made 13 passes and 4 timing changes, ending with the initial timing set at 21* BTDC. during this, my et's dropped to a low of 15.3398 @89.23 mph. alas, i have been unable to reproduce the 15.113 sec run i made the first night. i have, however, made myself rather unpopular with some mustangs... lol.
now for the questions. what is happening with the timing here? or is any of this timing related at all? one reason that i only made the 4 changes is that i was getting worried about the advance i was putting in the truck. i should state here that the truck has NEVER pinged, even at the 21* figure. it has always started easily... 2nd time over compression and it is running... even at 16* f ambient temp. the engine does not kick back, although at the 13* ignition timing if i catch things just right during heat soak, it comes pretty close sometimes. the harmonic ballancer has not slipped, it was correct when i installed the cam, and it hasnt changed. i guess that i should also say that i took Don at his word on the dist, and judt dropped it in the engine with init timing set at 13*, and never did the 3000rpm thing. the truck seems to be much torquier now (timing at 21* on the 91 octane gas), when i am driving along at 20 mph in 2nd and floor it, it kicks down into 1st and the right rear wheel spins... not enough to lose all traction, but it makes a very audible squeal for about 100 feet or so.
i think that the truck can get to the 14.9's as is if i learn how to launch it, although it may take a suregrip to do it. cant get very aggressive with one wheel drive in a 5000 pound pickup... lol... and an 1800 rpm stall speed... tires just go up in smoke!
also, i am getting ready to put 87 octane gas back in the tank. should i move the timing back to 13*, or leave it where it is? again, the truck has not pinged once.
added after orig post:
as for the balancer, it is PERMANTLY marked... engraved at 18*, 36* and 52* both BTDC and ATDC (i wasnt patient enough to figure out which way to run the numbers... lol. it is a stock 440 cast crank damper, original to the engine.
just finished a timing check, at 3000 rpm. the timing is in fact set for 44* total mech and initial (within 1/2 a degree). i guess my timing like is like the truck... tempremental... lol.
also, just for kicks, the vacuum is a rock solid 15 3/4" at idle, and 20" at 3000 rpm, again with absolutely no flicker.
sorry about the length of this, but i felt that to get some good answers, i needed to provide as complete details as possible. more can be provided if needed.
thanks,
neil
first some specs
vehicle......'84 dodge d250 (orig. had 360 lean burn engine) weighing 4700 lbs w/gas tank 1/4 full
engine..... 440 smogger--- stock bore , stroke and compression (came out of a 1978 B350 van)
cam.......... comp cams 21-215-4...218*@.050 & .454" lift, 110* lobe sep, installed straight up (no adv or retard)
carb......... 750 cfm speed demon
intake....... edelbrock "performer 440"
exhaust.... 1 3/4" long tube headers into 3" collectors
ignition..... stock module...came in the vehicle (with the 360 lean burn engine)
trans........ 727 w/lockup converter stall about 1800-1900 rpm
diff...........3.54:1 dana 60 open diff
tires and wheels.... 16"wheels with 31" tall tires
fuel.......... normally 87 octane pump gas
distributor was tuned and phased by Don. i seem to have misplaced the tech sheet, but if i remember right, the dist was set up for 36* total advance (mech and initial... add the vac adv was around 52 or 54* total) all in by 3000 rpm. installed with 13* initial timing
carb was setup for this combo with the stock intake, also by Don.
now... the crux of the matter...
took the truck to test and tune a few times and was pleasnatly surprised when it made a 16.5 sec pass on its first (and my first too) ever pass. later that night, it ran a 15.1127 @ 91.78. i made no changes, except for the weight lost by gas burned.
went a couple of more times over a 6 week period and just ran the truck... upper 15's was all i could do. i am still trying to figure out a decent launch program. last friday, i put 15 gals of 91 octane in the tank, along with about 13 gal of 87 octane that was already there, took a 1/2" wrench and my timing light and went hunting street mustangs ( at the strip... lol)
leaving initial timing at 13*, i made 2 passes: a 16.37 and a 15.84 (87 and 88 mph respectivly). i then got out the wrench and timing light and started advancing the timing in 2* increments. adv the timing 2*, make a couple of passes...
by the end of the night, i had made 13 passes and 4 timing changes, ending with the initial timing set at 21* BTDC. during this, my et's dropped to a low of 15.3398 @89.23 mph. alas, i have been unable to reproduce the 15.113 sec run i made the first night. i have, however, made myself rather unpopular with some mustangs... lol.
now for the questions. what is happening with the timing here? or is any of this timing related at all? one reason that i only made the 4 changes is that i was getting worried about the advance i was putting in the truck. i should state here that the truck has NEVER pinged, even at the 21* figure. it has always started easily... 2nd time over compression and it is running... even at 16* f ambient temp. the engine does not kick back, although at the 13* ignition timing if i catch things just right during heat soak, it comes pretty close sometimes. the harmonic ballancer has not slipped, it was correct when i installed the cam, and it hasnt changed. i guess that i should also say that i took Don at his word on the dist, and judt dropped it in the engine with init timing set at 13*, and never did the 3000rpm thing. the truck seems to be much torquier now (timing at 21* on the 91 octane gas), when i am driving along at 20 mph in 2nd and floor it, it kicks down into 1st and the right rear wheel spins... not enough to lose all traction, but it makes a very audible squeal for about 100 feet or so.
i think that the truck can get to the 14.9's as is if i learn how to launch it, although it may take a suregrip to do it. cant get very aggressive with one wheel drive in a 5000 pound pickup... lol... and an 1800 rpm stall speed... tires just go up in smoke!
also, i am getting ready to put 87 octane gas back in the tank. should i move the timing back to 13*, or leave it where it is? again, the truck has not pinged once.
added after orig post:
as for the balancer, it is PERMANTLY marked... engraved at 18*, 36* and 52* both BTDC and ATDC (i wasnt patient enough to figure out which way to run the numbers... lol. it is a stock 440 cast crank damper, original to the engine.
just finished a timing check, at 3000 rpm. the timing is in fact set for 44* total mech and initial (within 1/2 a degree). i guess my timing like is like the truck... tempremental... lol.
also, just for kicks, the vacuum is a rock solid 15 3/4" at idle, and 20" at 3000 rpm, again with absolutely no flicker.
sorry about the length of this, but i felt that to get some good answers, i needed to provide as complete details as possible. more can be provided if needed.
thanks,
neil
