Detonation? Plug read

[Built6spdMCSS]

Rattling would sound like labor knock, basically lower end to mid range knocking if you've ever heard it. Can do it all day with and standard vehicle, auto doesn't do it as much.

You wouldn't hear that up in the mid range to top end especially if you have loud exhaust. You'll notice sporadic power loss if you have detonation in that RPM range.

Tapered plug is this part, instead of the flat crush washer.

 

[Ernest]

Why GM recomends tapered plugs for aluminum(flat seat) heads when they are meant more for cast iron(tapered seat) heads is beyond me... i went along with the same mistake, but now use the proper flat gasket type plugs.

Pic 1 - tapered / Pic 2 - flat gasket

 

[Baker7888]

Thanks guys. Seems to be conflicting info … https://www.camaroz28.com/forums/lt.../taper-flat-seat-plugs-stock-95-heads-371931/

Every plug option on RA for 96 Camaro LT1 is tapered

 

[Ernest]

Aftermarket aluminum heads for sure only use the flat gasket type.

Heres a picture of my ZZ4 aluminum head(113) spark plug hole... lQQks like GM uses both style seats. GM calls for ac delco MR43LTS with the tapered seat, but i use the alternative ac delco FR5LS flat gasket seat. Slightly hotter plug, but it works much better for my engine IMO. You can see the taper just above the threads, then the flat area right above that.

 

[Built6spdMCSS]

Next time I pull a plug out of any of my stuff I'll have to see if the factory GM LS Heads are the same way.

 

[Baker7888]

Aftermarket aluminum heads for sure only use the flat gasket type.

Heres a picture of my ZZ4 aluminum head(113) spark plug hole... lQQks like GM uses both style seats. GM calls for ac delco MR43LTS with the tapered seat, but i use the alternative ac delco FR5LS flat gasket seat. Slightly hotter plug, but it works much better for my engine IMO. You can see the taper just above the threads, then the flat area right above that.

Hotter, interesting. I think colder, if anything, would be better for me, based on fear of detonation.

 

[Baker7888]

.

Ernest would you care to post a pic of your Malibu? Thing looks clean. Not to get off track …

 

[Ernest]

Ernest would you care to post a pic of your Malibu? Thing looks clean. Not to get off track …

Sure thing.

 

[Baker7888]

Sure thing.

Looks mint. I like the wheels!

 

[ELCAM]

For just a basic test all you need is a knock sensor, the pigtail for it and your volt ohm meter set on AC voltage.

Any sensor like that will work the only difference in them is a resistor that limits the output voltage.

Connect one lead of your meter to the pigtail and ground the other.

The voltage readings you get will increase as the vibration in the engine increases. See what voltages you get when in neutral and in first gear most of that is just noise that doesn't matter.

As you get higher voltages that's trouble. If it is really detonating the sensor is capable of like 50 volts but is limited by the resistor in the sensor. If I recall you have a 4 speed, climb a hill in too high a gear and lug the engine that should show you the "bad" voltage reading. Then you can keep advancing the timing and see where you get those same readings.

Play with it and I think you will get to understand what is damaging and what is just noise from all the parts doing their thing.