Yes that is possible. I am planning g a leakdown when I can coordinate the equipment with a buddy. I did verify lift of each valve and cam lob with a dial indicator. Once peak lift was reached, I walked the valve back down.to zero while looking for a sticky spot on the indicator which may indicate the valve was sticking. None were found during that test.Is it possible it's firing when the valves are off the seat.
as in valves not closing totally.
That's interesting. If I understand correctly, this would provide a site window to inspect the alignment of the rotor to the cap #1 firing position? If it was found to be off, how would it be corrected?It might be time to drill a big hole in a spare distributor cap and really check the phasing
The question is, where does the rotor point when the pole piece on the reluctor is lined up dead center with the pickup?
Ok try this, with the distributor advance locked at 32, MAKE the pole on the reluctor line up with the pickup dead nuts on center AND the rotor line up dead nuts on center on the number one terminal in the cap. You might have to remove the distributor to do this. Do NOT line them up at TDC put your balancer at 32 degrees btdc
Ever look down the carb while running at the rpm’s you say is starts chugging? Tried lowering the fuel pressure a little and run it?When I turned the engine over to do the compression test, gas was spaying out the remaining open plug holes onto the tops of the fenders.
Ever look down the carb while running at the rpm’s you say is starts chugging? Tried lowering the fuel pressure a little and
I’d run it to warm the engine up a little then turn off the pump and then bring up the revs to (where you had the chugging) and see what it does, before the bowls empty.I've ran pressures from 7 down to 4.5 while running the engine. It didn't make a change in performance. I have not looked down the carb when it starts to chug or pop out the exhaust. I did change carbs to one from a.running car with no change. I can say there is a lot of unburned fuel.
Adjust the total/full advance timing down to 28 degrees... then test drive it.Hey guys, I'm turning this mystery over to this forum after 2 weeks of troubleshooting with no change. I'll try to keep this brief and to the point and provide some details on the build.
340 block +.060, stock forged crank and rods with KB pistons, Oregon Cam solid 572/569. 252/[email protected] 106 lobe seperation. Howards oil thru lifters, EQ Magnum heads 1.6 Crane roller rockers. Edlebrock RPM Airgap with Holley 750 dpdf and 1 inch spacer. Ignition is all Mallory, HyFire VI 685, Coil and Comp SS distributor. Accel 8mm wires, Holley blue fuel pump regulated at 7psi. Hooker super comp headers. The car is intended for drag use only, running 93 octane currently.
Problem - at approximately 3000rpm and up, the engine chugs and struggles.
The following changes have been made with no improvement.
Carb rebuilt, jets 72 front and rear. Power valve at 450. Eventantually changed the carb to an 850 from a running car, no change.
Distributor set with 24* mech advance, springs changed to be all in at 2500rpm
Rechecked valve lash .016 Intake .018
Rechecked timing mark with piston stop. Off by 3* remarked with new degree tape.
Disconnected the tachometer.
Made sure the ignition box Rev limiter is set at 6500. Two step is not activated.
Checked firing order, cap and rotor condition.
Adjusted initial timing from 5 to 15 (29 to 39 all in) with no improvement.
Plugs indicate running rich.
I am more then willing to share any more information needed, in exchange for clues that solves this issue.