Quote:
Originally Posted by gtofreek
….I pulled the distributor when I got the engine back from dyno. I checked the busing which was fine and I restabbed the distributor BUT had no way of setting the timing. That is why I wrote on a piece of tape on the carb plate that the timing needs to be reset. It was only close enough to get the engine to start and run.
You need to get the idle RPM up and not down at 400-500 RPM. That's just ridiculously slow for an engine with this much cam in it. I only hear the knock at this really low idle. Pick the idle up, set the timing as I wrote on the tape, and disconnect the vacuum advance for the distributor and plug the vacuum port on the carb., then see if the noise is still present. I bet it won't be there.
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Ok, this makes a lot of sense, there was a discrepancy of whether the timing was set and ready for starting as shipped.
Sorry I haven't posted, biggest reason was I was unable to get in until tonight.
When I visited Thursday, first thing I did was pop the driver's valve cover, turned the engine over by hand, watched the #1 intake open, close, then brought the balancer zero mark up to the 12 on the timing cover. Then popped the distributor cap, and viewed the orientation of the rotor. It was half way between the #1 post and the #8 post, so I would say it was around 15-20 degrees advanced or more.
So I squared the rotor with the #1 post, put the cap back on, removed the IGN 12v wire from the + coil side, and ran a wire directly to the batt. Attached the timing light, and to get it ready to start.
Then I checked the carb, made sure the idle speed screw was about a half a turn or so from where the butterflies were closed, checking the screw I could see where it was lifting off the arm, made it to where it just touched, and added the half or so turn.
Then I went on to the idle mix screws, found all were different, one was like an 1/8 or less from being closed, one was about a turn and a 1/4, the rest were in between. I set them all to 3/4 of a turn.
It ran slightly rough when it initially started, but smoothed out some with a little run time. It was idling a little high, but it idled, revved freely, but still had an occasional miss. Let it reach operating temp, checked water temp and oil psi, it was fully warmed up, @ 185 degrees, had about 45-50 psi at idle, and to me, the knock was much less pronounced, and really felt it was only the typical crower rocker sewing machine type noise.
Joe mentioned it was idling high, so I turned it down some, which later he said after checking was about 1050. (I was not there for that). We shut it off, and for grins, we put the original IGN wire back on the coil +, and started it again. We didn't let it run long that time, but it appeared to not be affected by the original wire. I did notice though that there was a wire spliced into it, and I commented that it should be a dedicated wire, and to consider correcting that.
Since it still had an occasional miss, I suggested if it continued to have that miss, to change out the plugs, and if it still missed, to change out the wires. Also mentioned that it of course will require some additional tuning, idle mix, advance curve, etc, once he has the miss taken care of.
I was satisfied with the results, and felt the original 'knock' had subsided, but due to the high idle, he felt the results were inconclusive. Since we didn't have a tach, I suggested he have it checked before making any other changes, and if it was high, turn the idle speed to 850-950, due to the size of cam.
Joe, maybe for comparison purposes, post the vid of that day? That may help if others can chime in and determine if it was just drowned out or masked by the idle speed.
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