Yesterday my engine shut off (apparently electrical) after a relatively mild curb-ride at Summit Point (T7). I was able cycle the power off, then on, then restart. Any thoughts? FWIW curb was on the left.

Let me know what you find. This cost me a shot at a good runoffs run this year.
Check the relays up by the battery and make certain they are "floating" and can't bang against anything easily.

Check your master shutoff switch. I've had a few go bad; hit a bump, and motor shuts off.

Michael Hausknecht (NE#60)

M.Hausknecht wrote:Check your master shutoff switch. I've had a few go bad; hit a bump, and motor shuts off.

Michael Hausknecht (NE#60)

Thanks. Will do that and report back.

PS: Spark plug gap: 0.054"?

Greg -
You may also want to check that your relay contacts are clean and tight.

Try running the car and tap on the relays. if it bobbles change them. This is still not a guarantee fix. I would then do a wiggle test on all the wires. Pay close attention to the wires behind and by alternator.
Reach back there and move them wires around real good, move them back a forth. Also by the ground to engine block area. Do this while the car is running. If it is a wire you should find it by doing this. After you do this and if you dont find it do it again. Tony SEI Motorsports

If you tap on the relays with a screwdriver they will cut out, period. We tried three different ones on mine and a solid tap made the motor cut out every time.

Racer X wrote:If you tap on the relays with a screwdriver they will cut out, period. We tried three different ones on mine and a solid tap made the motor cut out every time.

Just so we are having a clear discussion, my glitch was not a hiccup or a miss; but rather a complete, sudden shut down, and I was able to restart on the go by toggling power off and on. Given your description, I assume you had the same general symptom. Does messing with the relays do that?

I should add that the morning of the race, one of the wire leads into my alternator had broken off. The car could start and run, but it was not charging. I got that fixed (temporarily) and the car ran fine and charged for the rest of the day. Running volts were 13-14 and steady. It seems to me if that lead came off again, the result would have been no-charge, but the car would still run. So it must be something else.

Yes I have had some do that also, but not all. When I was talking about wire going up to master by alternator. Just to make sure power wires are not grounding. This would most likely cause car to bobble not die. One time at Sebring only turn 17 the car would shut off, cycle switch and it would fire right up and go. Found grond wire where it bolts to engine block by oil filter, will be a few ground wires there. Thats how they are on our cars. one was loose in the terminal. Found it doing a wiggle test, but did not find it the first 10 times missing around changing parts. I have all our cars where they do not bobble when tapping on relays. Also had a problem a moroso car would shut off on bumps. Mike Davies came over smacked the relays and no cut off said they seem fine keep looking. still cut off on track. Just before the race I said I'm going to change the relays because nothing else was working. Problem went away so like most people I felt like problem sloved. Just trying to give you some of my past experiences. Tony

If your altenator dies for whatever reason, the battery discarges. At some voltage the ECU will automatically shut-off the engine to protect it.
Just want to clarify a point from above.