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Reading spark plugs

2K views 2 replies 3 participants last post by  larryblack 
#1 ·
I just pulled # 1 plug 400 SBC to read it, my problem is i have to drive down side street 25 MPH and then idle into garage. I don't think i am getting true reading off my plugs. I have aluminium heads, can i check a plug after full throttle run and then shut off car. Do i need to let engine cool off before i put plug back in?? If so do i just snug up plug in stead off tighting and stripping threads??

Thanks
Doug 66 Chevelle 406 SBC
 
#2 ·
Trying to read plugs on a street driven car is a bit of a chore. It is nearly impossible to get an accurate reading due to the varying driving conditions. If you are after a WOT reading that is a little easier. Just make a full throttle pass and shut off the engine and coast to a stop. Put the car in neutral or hold the clutch in as you slow down.

Vince
 
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