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The fuel distributors with the small plugs on the injector attachment bungs (both cast iron and the aluminum version) were designed to make the very low speed fuel delivery the same for all the cylinders. The early fuel distributors (without these plugs) do this job by changing the shims under the springs (which is a real pain in the butt, extremely time consuming, and which is why you should never mix the springs and shims from one position to another, inside the fuel distributor.)
Any of the fuel distributors take extremely accurate volume measuring equipment to adjust the low speed fuel distribution (which is why most "rebuilders" will not accept a fuel distributor that has been taken apart as a core.....they don't want a core that has had the springs or shims moved around.)
13-14 when just cruising. At really low rpms with no pedal, like at 1,500 RPMs, it will get to 14.5 but not past. If I punch it it moves to 14 for an instant then comes back to 13 almost immediately, and keeps getting richer as boost and rpms continue to climb, hitting about 12 before I shift
I like the sounds of that! How is the exhaust at the tail[pipe? Smooth at idle? Not huffing any more? Yes - drive those spark plugs for a few 100 miles and pull top check coloring. You mighta found the culprit.
I like the sounds of that! How is the exhaust at the tail[pipe? Smooth at idle? Not huffing any more? Yes - drive those spark plugs for a few 100 miles and pull top check coloring. You mighta found the culprit.
Yes, I don't hear that popping at the the tailpipe anymore and the car is just much smoother. Before it wasn't as smooth under light throttle but would seem pretty good under boost at high RPMs - with the boost power masked the missing or maybe at higher RPMs, those plugs would fire.
In any case, I'll check them again in a couple hundred miles and see how things look on all 8 plugs.
What's the rebuild cost if I wanted to send you that other distributor ?
Finally had a chance to get the supercharger belt tensioner assembly over to my machine shop. I had him elongate the bolt attachment slots as far as he could without going all the way through and had him notch the corner a bit deeper. The corner notch goes around one of the bolts on the supercharger mounting plate when the tensioner is pushed close to the max.
You can see in the pictures where the old washer marks in the powdercoat were and how the tensioner can now move a good bit further. I installed it tonight and if the roads are dry at some point this weekend, will take it out and see if the slippage problem is resolved.
By the way, the car still seems to be running well since swapping the fuel distributor to my old one. I still need to pull the plugs in 6 and 8 to confirm my belief that the engine issue has been resolved and I might need to go just a hair richer in the mixture screw when I do that.
Pulled the plugs today for the first time after swapping the fuel distributor. Dramatically different. Car has been running on all 8 and none of them are completely black, shiny, or fuzzy. Have a brand new set of BR8ES plugs in now gapped at. 025 because of the supercharger.
Coloring of 8 still isn't as good as the others, but the plugs I put into 6 and 8 last time were previously pulled good ones from other cylinders so I could see if I was on the right track before putting brand new ones in again, only to have them foul in 20 miles. I'll pull 8 again (and maybe 3) in a few hundred miles and check the coloring. I have a couple hundred miles on this set in the pics. All the ones except 6 and 8 were new when they went into those cylinders.
Based on what I see here, I think the fuel distributor was the primary culprit to all my runnability issues and constant fouling of 2 of the plugs since installing this motor last May.
Going to change the oil to get the Seafoam treatment out of it that I was using to free a stuck lifter (if I had that) and desludge the bottom end of the motor.
AFR gauge also was going a little lean in rare circumstances so moved the mixture screw a bit clockwise while I had things apart. We'll see how that goes.
Still had some belt slippage at full boost after the tensioner mod and figure it was because I couldn't get the belt tight enough as I still had space left in the new slots.
Remedied that today with more leverage on the tensioner.
Now the belt no longer turns 90 degrees on the long run. Hope that takes care of it.
12-16-2019, 08:54 PM
