SA22C 12A Possible rear rotor has no combustion?
 

Hi folks. Been trying to resolve several issues with the car recently. SCCA Improved Touring A 12A stock port with modified Nikki carb and dual MSD 6AL ignition. Had major flooding issues with the Nikki carb which I was able to track down to a sliver of teflon tape that was jammed in one of the float needle seats. I had foolishly used teflon tape when I redid the entire fuel system (new Holley Fuel Pump, 2 fuel filters, Holley Pressure regulator with bypass and new stainless steel braided supply and return hoses) but have since gotten rid of any traces and used joint compound instead. Anyway the carb flooded badly several days ago but I've since managed to get the car running again. I've also replaced the plugs and installed new plug wires. Car runs poorly under load and hesitate during a short 15 min test drive around the block.. When I pulled the new plugs out, the front leading and trailing plugs looked good and were obviously firing. The rear leading and trailing plugs looked spotless and clean with a slight smell of gas on them but they didn't look like they were even firing. For the record, the car was running well before the entire teflon tape sliver/carb flooding fiasco. Could the rear rotor seals be buggered up and stuck from the flooding? Any ideas? I need to get the car running as I am supposed to be attending driver's school in three weeks. Thanks for any help.

Did you change the oil after your flooding episode?

Changing the oil and filter is a HUGE MUST once you have had flooding issues. The oil will be contaminated by gas and should be replaced right away.

If you are concerned about a compression issue, you should perform a compression test.

A hesitation can be caused typically by a lack of fuel or a lack of spark. Are you using NGK BR8EQ-14 spark plugs?

I suspect a carb issue however. When is the last time you rebuilt the carb?

1st thing you should check is to be certain you have spark at both rotor’s plugs. It should be blue in color.
Are you running leading ignition only?

Is it possible you may have dislodged any MSD wiring while replacing coil wires? Do you have DFI ignition?
Remove/examine/ohm test each coil wire and if still running spark thru dist. cap, test all the wires for resistance. What kind of wires are you using?

Remove all plugs and put them back into their respective wires and lay onto top of engine to ground them,have someone crank engine over for about 30 seconds while you watch for presence/color/consistency of spark. If you have equally good spark at all plugs,do a compression test on engine to verify/rule out mechanical faults in engine.
All rotor faces should show even compression and both rotors should show same relative compression.

If you have lack of spark or poor quality of spark,investigate the part of system that is inoperative.
Test each coil for resistance on both primary/secondary side. What kind of coils are you using?Compare results with other known good coil. Switch coils and see if problem switches to other rotor. You can do the plugs on top of engine for ground/crank engine to check spark.
If so you identified a defective coil,replace it.If not the problem,inspect wiring from distributor pick up coils to MSD boxes for being dislodged or damaged. If wiring is determined to be ok,test for signal/voltage from each pick up coil.

If you had a healthy engine prior to flooding issues.i would not think the engine to be physically damaged unless a foreign object made its way into the engine while carb was apart/off.

Sounds like you lost ignition on the rear rotor somehow. Flooding would not cause a difference. Are you sure the leading ignition is working? I ask because the symptom remind me of when you lose leading and only trailing is firing.

you said it ran poorly, how did it idle? i also think the carburetor may be the source of your issue.

have you confirmed the "no-fire" situation at the rear plugs, or is this just based on the way the plugs looked?

you mentioned changing the plugs and wires, well how old are the cap and rotor?

what plugs are you using?

maybe evacuate the chamber, re-oil it, then try a compression test to see where you're starting and also to eliminate (or discover) that as a potential issue.

I assume the shutter valve has been removed, and therefore isn't stuck closed?