Hey everyone, I have been working on a little project for awhile now and have been running into some idle quality issues.
Here is what I have.
1970 318 with a 4 inch crank
Holley 670 Avenger Carb
Mopar distributor and electronic ignition
Edelbrock performer intake
Crane gold adjustable rockers
Comp XE268 cam
I pulled this engine this spring due to some seal leaks and just over all appearance issues. Noted in my "restoration" thread, I found many issues from the previous owner. After correcting all of them or most of them I am left with this idle issue.
Basically what happens is the engine shakes pretty badly when I first started it. I have corrected a lot of the shaking with timing (16 BTDC) and the idle mixture screws (2).
I have the idle set at about 700 RPM
I have worked with Rob
@RustyRatRod on this for a few days and we have gotten it close but to me something still seams incorrect.
I let the engine warm up, set timing to 16 BTDC (seems to be it's happy spot)
Set the idle mixture screws with a vacuum gauge.... (slight adjustments initially make the engine really shake, then it settles down) These adjustments seem very sensitive and affect the shaking a lot.
Setting the mixture screws with a vacuum gauge really seems to have very little affect on the amount of vacuum produced. I am getting around 13-15 on the gauge and it bounces between the two.
Initially we thought this was some sort of vacuum leak so I checked all of the hoses, disconnected all of the vacuum lines from the carb and plugged them. This has no affect on the idle quality so I feel like I can eliminate those issues other than maybe the pcv?
I have taken the intake manifold off (edelbrock performer) and resealed it with new printo seals (previously had the metal stamped seals)
New carb to intake gasket.
I checked the bottom of the carb with a straight edge to make sure it wasn't warped.
I have sprayed water around the intake and carb, also brake cleaner with no noticeable vacuum leaks.
Motor mounts are tight and do not appear to be broken.
One thing I have noticed also is I can cover the primaries completely with my hand and the engine continues to run. I can close the choke almost fully with little to no affect on the engine running. Once fully close it does kill the engine.
I have uploaded a video to show the shaking.
Let me know if anyone has any ideas on what to look for.
Thanks!
