jbiscuit
07-19-2007, 09:52 AM
I've had the urge lately to see what I can do with my tune on the Biscuit so the last couple nights I have been out in the garage wrenching. I wasn't REAL happy with the tune so I figured let's see what I can do with it.
Here is what I am working with:
.030 over 327
double hump heads with port matched intake
mild cam (specs unknown)
crane rockers/ springs
Eddy performer intake
holley 750 double pumper
Eddy mech. fuel pump
MSD 6al box
MSD 85551 mech. advance distributor
external coil
headers
Eddy high volume aluminum water pump
First I swapped out that oil last week from 10W30 to the 20W50 racing oil....good first step. The motor loves this stuff....highly recommended for older V8's. Next I swapped plugs. The motor had 1° hotter plugs when I got it so I swapped these out with standard heat range Champions. Car runs better all around. Next: New Taylor 8mm Spiro Pro Wires.
Car has had a slight...and I mean slight stumble off idle since I bought it. I noticed the motor was running a hair lean both at idle (a lil too lean) so I thought fattening up the carb a hair would eliminate the stumble. No dice. Again with just a lil more fuel at idle, it runs/starts better so its still an improvement. Plugs look good too as far as A/F. Secondaries are coming in nicely, no bog no nothing.
Next I tackle the distributor. Mechanical advance is pretty straightforward. Upon getting in there to tune it, I notice the thing is RIGHT on the ragged edge with too much timing. Just a BIT of advance makes the thing break up. SO what if I have TOO much initial I think? What if I back it off a hair? So I do and MAN what a difference. It was at 12° inital and now its at like 9. What a huge difference this adjustment makes. Idle is better/smoother, the off-idle stumble is gone too which is nice and the car makes a LOT more power. A quick test drive confirms this. Pulls all the way through the RPM range.
I'm no expert at tuning these things but its nice to see instant results when you make an adjustment. All it takes is some time and patience.
Here is what I am working with:
.030 over 327
double hump heads with port matched intake
mild cam (specs unknown)
crane rockers/ springs
Eddy performer intake
holley 750 double pumper
Eddy mech. fuel pump
MSD 6al box
MSD 85551 mech. advance distributor
external coil
headers
Eddy high volume aluminum water pump
First I swapped out that oil last week from 10W30 to the 20W50 racing oil....good first step. The motor loves this stuff....highly recommended for older V8's. Next I swapped plugs. The motor had 1° hotter plugs when I got it so I swapped these out with standard heat range Champions. Car runs better all around. Next: New Taylor 8mm Spiro Pro Wires.
Car has had a slight...and I mean slight stumble off idle since I bought it. I noticed the motor was running a hair lean both at idle (a lil too lean) so I thought fattening up the carb a hair would eliminate the stumble. No dice. Again with just a lil more fuel at idle, it runs/starts better so its still an improvement. Plugs look good too as far as A/F. Secondaries are coming in nicely, no bog no nothing.
Next I tackle the distributor. Mechanical advance is pretty straightforward. Upon getting in there to tune it, I notice the thing is RIGHT on the ragged edge with too much timing. Just a BIT of advance makes the thing break up. SO what if I have TOO much initial I think? What if I back it off a hair? So I do and MAN what a difference. It was at 12° inital and now its at like 9. What a huge difference this adjustment makes. Idle is better/smoother, the off-idle stumble is gone too which is nice and the car makes a LOT more power. A quick test drive confirms this. Pulls all the way through the RPM range.
I'm no expert at tuning these things but its nice to see instant results when you make an adjustment. All it takes is some time and patience.