Hej, hur kritiskt är det att grada in kammen (Melling 068 kam)? Ett "Cam degree kit"kostar ju en slant och kommer ju inte att användas allför ofta.
Vad gör man om värdena inte stämmer med specifikationerna?
//Peter

Visst kan det vara intressant att VETA hur kammen är funtat, men jag har aldrig "gradat in" kammarna som jag stoppat in i mina motorer.
Kanske jag hade gjort det om jag byggt en motor för endast racing?
För en bruks/standard motor är det knappast nödvändigt.

Mätte upp min 068-kam för nån månad sen och fick värden mycket nära det Melling anger (använder Summit´s double roller/true roller kamdrivning).

Från Melling´s hemsida:

Specs @ 0.50 Cam Lift
INT. Opens -7 BTC Closes 39 ABC Duration 212 Lift 1.5 Rockers .408 CL 113
EXH. Opens 50 BBC Closes -5 ATC Duration 225 Lift 1.5 Rockers .406 CL 118

Värdena inom parentes är det jag fick fram vid mätningen. Skiljer några grader när insug/avgas ventilen öppnar mot vad Melling anger, men är antagligen ett mätfel eftersom ICL och ECL stämmer.

(INT. Opens -11 BTC Closes 39 ABC Duration 208 Lift 1.65 Rockers .454 CL 113)
(EXH. Opens 48 BBC Closes -5 ATC Duration 223 Lift 1.65 Rockers .455 CL 118)

Ok, hoppar nog över det med tanke på vad utrustningen kostar, men det hade varit intressant att testa.
Burningbird, vad har du för bensinpump? Har den returanslutning?
Vad för pump (mekanisk) ska man köpa om man vill ha lite mer än standard, ska ha returanslutning.
Mvh Peter

En OEM-pump räcker mer än väl för normalt bruk, Pontiac gjorde miljoner bilar som funkade bra med "standard" pump.

hosjobo skrev:Ok, hoppar nog över det med tanke på vad utrustningen kostar, men det hade varit intressant att testa.
Burningbird, vad har du för bensinpump? Har den returanslutning?
Vad för pump (mekanisk) ska man köpa om man vill ha lite mer än standard, ska ha returanslutning.
Mvh Peter

Jag har en Tomahawkpump (80gph) med retur från Pacific Performance Racing. Kommer byta till en Carter M6907 (120gph) om jag monterar värre kam. http://m.summitracing.com/parts/crt-m6907" onclick="window.open(this.href);return false; Läsvärd artikel om mekaniska bränslepumpar till Pontiac: http://www.highperformancepontiac.com/t ... uel_pumps/" onclick="window.open(this.href);return false;

Burningbird skrev: Kommer byta till en Carter M6907 (120gph) om jag monterar värre kam.

Sån kör jag med...

zappafan skrev:

Burningbird skrev: Kommer byta till en Carter M6907 (120gph) om jag monterar värre kam.

Sån kör jag med...

Vilken dimension på bränsleledning har du? Förpump i tanken? Hoppas få ut ca 460hk ur 400an med bla. mer portning och en Crower mekankam (60311). Tänkte också montera ett 150-200hk NOS-system men med separat bränsletillförsel.

Nix har orginalstorlek på bränsleledningar, räcker nog en bit ändå ,den här går rätt okey med det iaf...



Strip Specs
Year/Model: ’70 LeMans
Race Weight With Driver: 3,650
Curb Weight: 3,400
Fuel Level When Weighed: 1⁄2 tank
Fuel: 93-octane
Engine: ’75 400
Cubic Inches Before/After: 400/406
Engine Built By: Owner


Induction System
Air Cleaner: None
Carburetor: 800-cfm Quadrajet
Jets: . . 0.068 primary (no primary metering rods), K hanger with DC secondary rods
Spacer Plate: 1-inch, home-made, wood
Intake Manifold: Edelbrock Performer RPM


Fuel System
Pump: Carter, set to 7 psi
Lines: Stock
Regulator: None


Heads
Casting: ’75 6X-6
Head Porting: Port-matched, angle-milled 0.085-in
Flow Numbers: Unknown
Valves: Ferrea stainless steel, 2.11/1.77-in


1971 Pontiac Gto 1970 Pontiac Lemans Engine


Bottom End
Pistons: Speed Pro forged, 0.102-in dome
Rings: Total Seal, file-to-fit, 5⁄64, 5⁄64, 3⁄16
Rods: Stock
Compression Ratio: 10.97:1
Crankshaft: Stock, 3.75-in stroke
Rotating Assembly Balanced: Yes


Camshaft
Brand: Ultradyne hydraulic flat-tappet
Duration at 0.050: 236-/242-deg
Duration Advertised: N/A
Lift with Specified Rocker Arms: 0.538-/0.546-in
Lobe Separation Angle: 110 deg
Installed Position: -4 deg
Rocker Arms: Harland Sharp, 1.5:1


Ignition
Distributor: GM HEI
Amplifier: None
Coil: Pertronix
Wires: MSD 8mm
Spark Plugs: Bosch
Total Timing: 36-deg
Rpm That Total Timing is Reached: 2,800


Exhaust
Headers: Hedman
Primaries: 1.75-in
Collectors: 3.00-in
Exhaust Pipes: None
Mufflers: None
Crossover: None


Drivetrain
Transmission: Turbo 400
Converter: TCI 9-in, 3,600-stall
Shifter: B&M Pro Stick
Rear: Chevy 12-bolt
Rear Gear Ratio: 4.33
Spool: Moser
Axles: Moser, 33-spline


Chassis and Suspension
Brakes F/R: Stock Drum
Wheels F/R: 15x3.5, 15x8
Tires F/R: MT ET Fronts/ Goodyear 28x9x15
Tire Pressure F/R: 45 psi / 15 psi
Suspension Front
Springs: Stock replacement
Shocks: Competition Engineering 90/10
Control Arms: Stock
Stabilizer Bar: None
Other Features: None
Suspension Rear
Springs: Moroso Trick
Shocks: Competition Engineering single-adjustable, set on full soft
Control Arms: Stock upper w/no-hop bars, boxed lower
Stabilizer Bar: Stock
Other Features: None
Chassis Mods: None


The Rest
Interior Mods: Auto Meter tachometer, Summit gauges
Exterior Mods: None
Safety Mods: Driveshaft loop, fuel-cut off, rear battery disconnect
Color: Sierra Yellow/ Tan vinyl top
Launch Technique: Footbrake to 2,500-3,300 rpm
Best 1/8-mile ET/MPH Prior to Event: 7.33/99.62
Best 1/4-mile ET/MPH Prior to Event: 11.79/114.21


1971 Pontiac Gto 1970 Pontiac Lemans Ed Deel


Ed Deel


Ed, a 56-year-old supervisor, has been racing off and on for 40 years. His LeMans was a gift from his son in 2001. His favorite moment in it was “winning Modified class at the Ames Performance Tri-Power Pontiac Nationals in 2007.” Though this is his only Pontiac, he previously owned an ’04 Grand Prix GTP.



Strip Tuning Log

Run/Tuning Launch RPM Shift Point 60-ft. 1/8-mile 1/4-mile
1. 36-deg timing, all in at 3,200 rpm, 0.068 primary jets, rear shocks set to medium soft, 17 psi in rear tires 2,500 5,400 1.62 7.50/90.76 11.86/111.45
Best Pass Corrected 11.60/113.97
2. 16 psi in rear tires 4,000 5,400 1.66 7.64/89.36 12.06/109.90
3. Rear shocks set to full soft, 16.5 psi in rear tires 2,200 5,400 1.62 7.60/88.35 12.06/109.19
4. 17 psi in rear tires 2,500 5,400 1.60 7.53/89.60 11.96/109.85
5. Lowered all-in to 2,900 rpm, 15 psi in rear tires 2,000 5,400 1.67 7.62/88.62 12.04/110.17
Run Notes: 1) Hooked ok; 2) Bad wheelspin; 3) Hooked ok; 4) Hooked good; 5) Bad wheelspin.



Conclusion


Both of our Shootout participants came to the track to evaluate recent changes they’ve made to their Pontiacs.

Mike learned that his A-body reacted favorably to the diet, and the front skinnies alone shaved 0.1 second off his e.t.

Ed learned that his new smaller-width Goodyears, full-soft rear shock settings, and new launch rpms did not help his performance. He’s going to go back to a wider tire, stiffer shock settings, and his old launch technique.

Like the racers in this Shootout, you may want to evaluate the effect new speed parts have on your e.t’s. Maybe you’ll find they produce better performance, like Mike did; maybe you’ll decide you’re better off with what you had, like Ed learned. No matter your results, we’re sure the cars and combos detailed in this story will give you plenty of ideas for your project.