455 Bogs @ 3500 RPM - Please Help
June 6th, 2016, 12:10 PM
#1
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Join Date: May 2014
Posts: 19
455 Bogs @ 3500 RPM - Please Help
Hello everyone. I'm having an issue and any constructive advice would be greatly appreciated. The engine run great until the secondary's are opened.
Specs:
Specs:
Engine: 455, 1971 or 1972 (396021 F)
Carb: Edelbrock Performer Series Carburetor, 1413 2112, 800 CFM - Calibration Kit #1480
Pistons: L2323F .030, 07-194-11-A, Forged AL, +18.00cc, Bore: 4.125 in, 104.775mm (dish w/no valve reliefs)
Rockers: Guessing - Harland Sharp CSP-S5001 - Full Roller, Aluminum, 1.60 Ratio, 7/16” Stud
Current State:• Bored 0.030” over
Timing: According to Edelbrock – 14° initial, “Full In” 36-38° @ 3000 RPMCarb: Edelbrock Performer Series Carburetor, 1413 2112, 800 CFM - Calibration Kit #1480
• Current secondary jet size is 0.097”. (The original should have been 0.101”.)
Intake: Edelbrock Performer 2151 - Dual PlanePistons: L2323F .030, 07-194-11-A, Forged AL, +18.00cc, Bore: 4.125 in, 104.775mm (dish w/no valve reliefs)
Rockers: Guessing - Harland Sharp CSP-S5001 - Full Roller, Aluminum, 1.60 Ratio, 7/16” Stud
Setting Rocker Lash:
1. Starting with #1 cylinder, turn the engine over until the exhaust pushrod just begins to move up.
2. At this point, stop and adjust the intake valve on the same cylinder.
4. You are now able to repeat this procedure on the remaining cylinders.
Heads: Edelbrock Performer RPM1. Starting with #1 cylinder, turn the engine over until the exhaust pushrod just begins to move up.
2. At this point, stop and adjust the intake valve on the same cylinder.
a. Tighten the rocker until you can roll the pushrod between your thumb and forefinger with the slightest bit of resistance.
b. At this point tighten between an additional quarter to half of a turn.
3. You have now adjusted the #1 intake valve. You will now want to turn the engine over while watching the same intake pushrod that you just set, it will go full open and then begin to close. When it is almost closed, stop and adjust the exhaust rocker arm on that particular cylinder. By following this procedure, you are assured that both of the lifters are at the base circle of the cam and that there is no additional pre-load applied to them from cam lift at this point. b. At this point tighten between an additional quarter to half of a turn.
4. You are now able to repeat this procedure on the remaining cylinders.
o Springs: 150 LBS at the seat
o 305 LBS open @ .545" Lift
o .800 to Bind
o Chamber Volume 72cc, 10.27 Tol C.R. w/232.3 f .030 piston
CAM:o 305 LBS open @ .545" Lift
o .800 to Bind
o Chamber Volume 72cc, 10.27 Tol C.R. w/232.3 f .030 piston
Mondello Intake Exhaust Adv. Int/Exh Duration Intake @ 0.050 Exhaust @ 0.050 Lobe Separation RPM Range
JM-22-25 0.512 0.523 274°/280° 230° 236° 108° 1400-6000
JM-22-25 0.512 0.523 274°/280° 230° 236° 108° 1400-6000
• Timing: 14° initial and ~37° all in at 3300 RPM
• Plugs: 0.035”
• Secondary Jets: 0.097”
• HEI: 80KV
• Starts bogging at 3500 RPM
Troubleshooting Process in Chronological Order – Each step has made NO difference!• Plugs: 0.035”
• Secondary Jets: 0.097”
• HEI: 80KV
• Starts bogging at 3500 RPM
1. Changed the Edelbrock accelerator pump to the most aggressive (from the middle position)
2. Changed OEM ’77 HEI with 80KV HEI that is supposed to be curved for an olds 455.
3. Added a fuel regulator set to 6 PSI (it was at 12 PSI without regulator)
8. Sparkplug gap: Was at 0.025”, Now at 0.050”
9. Voltage at Distributor: 14.4V (even when rev’d)
10. At the Dyno (Stiegemeier’s, Bob and I worked on the engine)
12. Redone the backlash on all rockers. ¼ turn after zero lash. Some of the rockers may have been up to full turn past zero lash originally. I believe I have done the procedure properly.
14. Put 0.097” jets in – Bogs exactly like before!
2. Changed OEM ’77 HEI with 80KV HEI that is supposed to be curved for an olds 455.
3. Added a fuel regulator set to 6 PSI (it was at 12 PSI without regulator)
a. Ran a fuel pressure gauge from the carb to the interior, it never dropped at WOT
4. Timing:a. Advanced timing to the point where it very hard to start
b. Incrementally retarded timing the point where it backfires at WOT
c. Tried vacuum advance connected to the Port side and Manifold side
5. Disconnected the Vacuum advance:b. Incrementally retarded timing the point where it backfires at WOT
c. Tried vacuum advance connected to the Port side and Manifold side
a. Tried to increase and decrease the timing with the vacuum advance disconnected (See #4)
6. Changed from the Edelbrock to the Holley – The Holley acted EXACTLY like the Edelbrock.a. Switched back to and I’m now running the Edelbrock again
7. Gas Tank – Blew the “sock” off of the end8. Sparkplug gap: Was at 0.025”, Now at 0.050”
9. Voltage at Distributor: 14.4V (even when rev’d)
10. At the Dyno (Stiegemeier’s, Bob and I worked on the engine)
a. Checked timing (was measured at 32° at WOT)
i. I checked at the timing is about 14° initial and ~37° all in at 3300 RPM
1. Should be 36-38° all in about 3000 RPM.
b. We found the engine was very rich when bogging
i. Reduced jet size from 0.101” to 0.083” – Didn’t make a difference
ii. Reduced jet size to 0.080” – Didn’t make a difference
iii. Changed the primary jets to 0.083” – The engine bogged (lean) on just the primaries
ii. Reduced jet size to 0.080” – Didn’t make a difference
iii. Changed the primary jets to 0.083” – The engine bogged (lean) on just the primaries
1. Changed the primaries back to original.
c. Before the secondary’s open, the AFR appears good.
d. Re-Gapped the plugs at 0.035”
d. Re-Gapped the plugs at 0.035”
Conclusion: I think the rocker lash is not set properly thus when the oil pressure is at maximum the hydraulic lifters are now allowing the valves to close all the way. When bogging, it appears there is a mist back flowing from the carb.
11. Changed the Edelbrock accelerator pump to the middle position12. Redone the backlash on all rockers. ¼ turn after zero lash. Some of the rockers may have been up to full turn past zero lash originally. I believe I have done the procedure properly.
a. Still running the 0.080” jets
b. The engine appears to try to open up and then acted like it went lean.
13. Put 0.108” jets back in – Bogs exactly like before!b. The engine appears to try to open up and then acted like it went lean.
14. Put 0.097” jets in – Bogs exactly like before!
Last edited by Bitburner; June 6th, 2016 at 12:19 PM.
June 7th, 2016, 01:00 AM
#4
Registered User
Join Date: Nov 2015
Location: So. Ca.
Posts: 651
Assuming you've checked the throttle linkage opening fully with someone sitting in the car with their foot to the floor while another person outside verifying the throttle blades are fully open (engine off of course). Can you test with and without the exhaust connected? Good luck
June 7th, 2016, 08:27 AM
#5
Registered User
Join Date: Jun 2010
Location: Rogues Island, USA
Posts: 3,613
Are you running an air cleaner?
If not put one on and tell us what happens.
If yes is the lid close to the top of the carb. A 3 inch tall filter would be minimum with a 4 inch element preferred.
If not put one on and tell us what happens.
If yes is the lid close to the top of the carb. A 3 inch tall filter would be minimum with a 4 inch element preferred.
June 7th, 2016, 08:55 AM
#6
CH3NO2 LEARN IT BURN IT
Join Date: Jul 2010
Location: Land of Taxes
Posts: 4,841
How do the plugs read? That 1400 performer series carb is very tune-able. Call the tech line and have them send you the tuning curve scatter plot charts pdf. This will help you zero in on the right rod, jet and spring combos for that condition. You may need additional rods jets n springs not offered in the 1480 kit should you require something outside the range in the scatter plot. Ebrock will help. I just did one with a flat spot. All gone now.
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