455, Iron Small valve heads. Using an NGK- UR5 gapped .045 (HEI SWAP) They all look similar, I don't see anything alarming/problematic. What say you plug whisperers? Silvery stuff is anti-sieze not munged up threads... Appreciate your responses......JIM
Also , what gap is best suited for an HEI swapped 71, 455? Book has between .040 to .060 for Later model HEI Equipped vehicles...I split the difference at .045 on the tight side...Jim
I know there is a way to read the color change on the ground electrode that denotes whether the plug is too hot or cold as far as timing. https://www.crankshaftcoalition.com/wiki/Reading_spark_plugs
I took a look at a few of the plugs I pulled. Both timing marks were where they were supposed to be. Threads showed no signs of overheating, plug is in correct temperature range. Thanks for the link. JIM
Of course if you read that linked article, they tell you for any of that to be accurate, the car has to be at WOT, and then immediately shut down. So what is the worth of that to a street car? Not much IMO. Even a race car? Weather changes, and the tune/jetting is no longer optimal.
Plugs light brown to light gray after being in the engine for a year? Not pitch black from oil or too much fuel? No silver speckling indicated possible detonation? No?, then you are good.
They have been in for only 1500 miles. I am racing next weekend in a Nostalgia Event , and had some new ones on the shelf , was going over the car, and figured what the heck, might as well. I have been watching for specks indicating detonation everytime I change plugs, and have not seen anything at all. Running 98 octane at the track as insurance . Jim
It's possible that racers read plugs after a WOT run because that is what they are testing for, WOT. Reading plugs may still be beneficial for street cars. There is a definable timing/heat band on the ground electrode. As far as tuning for weather/air density, at my level that only involves jetting secondaries up or down a jet size. Jim
Yes, but the engine has to be shut down immediately at the completion of a pass. That means you either read the plugs at the end of the track or you tow the car back to the pits and do it there. How many guys do that?
Never seen it done, so not many I assume...plugs be hot at end of track , thinking the tow back is the only option for plug reading racers! JIM Ps: I do have a BBQ/ Oven glove in my track toolbox for HOT stuff...
I've heard that too, but what about your steering and brakes? OMG, what about the power windows, it gets warm in there
Like I said, these are race cars. No power steering or brakes, or power windows for that matter. It doesn't make any sense for a street car IMO.
I do. If i want to check the plugs on my speedway car i shut it down at the end of the back straight on the slow down lap after a race and let the tractor tow me back to my pit, however I don't tell the guy on the tractor why I'm getting a tow
