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Old 02-26-2018, 08:42 PM
rvdave rvdave is offline
Join Date: Jun 2005
Posts: 339
Default Spark plug temp

Wondering if spark plug temp range has any effect on running lop? I’ve just tweaked my afp injectors but get a hesitation/miss before I get to where i think I should able to get lower fuel flow.
Dave Ford
Cadillac, Mi

Last edited by rvdave : 02-26-2018 at 08:47 PM.
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Old 02-27-2018, 08:56 AM
Carl Froehlich's Avatar
Carl Froehlich Carl Froehlich is offline
Join Date: Dec 2007
Location: Dogwood Airpark (VA42)
Posts: 1,777

Iíve had good success with the standard BR8ES plugs on the 8A (pMags) running LOP. The RV-10 is unfortunately still running mags (will Brad ever have the six cylinder pMag out??) and standard Tempest plugs. Even so, after balancing injectors LOP ops are smooth even when way below practical LOP fuel flow.

That said, I did have problems before I replaced the orginal Champion plugs with Tempest. 8 of the 12 Champion plugs tested bad after 300 hours (high center electrode resistance). The new plugs made a big difference.

If you are having problems running LOP and are sure your plugs are clean and in good shape, recommend you look at the other usual suspects before messing with plug heat values.

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Old 02-27-2018, 11:11 AM
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Raymo Raymo is offline
Join Date: Nov 2014
Location: Richmond Hill, GA (KLHW)
Posts: 1,802

My understanding is that the plug temp range can help avoid fouling; running LOP also helps here so temp range is not likely related. Plug temp has to do with heat dissipation, not spark.
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Old 03-03-2018, 09:06 PM
lr172 lr172 is offline
Join Date: Oct 2013
Location: Schaumburg, IL
Posts: 3,326

Plug temp too hot and it can cause pre-ignition. Temp too cold and deposits on the electrodes don't get burned off. Plug temp will not cause poor engine running unless the deposit build up becomes great enough to prevent the plug from firing. This is unrelated to mixture levels.

RV-6A / IO-320, Flying as of 8/2015
RV-10 in progress

Last edited by lr172 : 03-03-2018 at 09:10 PM.
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