Spark Plug Question

BendRV-4 · #1 04-22-2010, 03:01 PM

I'm interested in getting feedback from anyone who has had experience with the Unison, now Tempest plugs. I have the common cowling clearance problem with the top plugs in my RV-4 and I know the Unison / Tempest plugs have the shorter shaft which will help my issue. Also, my 180 HP Lycoming seems to be prone to lead fouling even if I'm vigilant in ground leaning, etc. I have always run the Champion REM38E plugs in it. I have had one mechanic say that "upping" the number to a hotter plug such as the REM40E will help this. I'm considering switching out my plugs from the Champion REM38E to the Tempest UREM40E plugs. I'm curious if anyone else has tried this and what their results have been.

Mel · #2 04-22-2010, 03:10 PM

I've been running the Unison UREM-37BYs for several years now with no problems. I have 9.5:1 compression and use Decalin lead scavenger.
The -37BYs will help with the lead fouling problem.

BendRV-4 · #3 04-22-2010, 03:16 PM

Mel, Thanks for your input. I do have a new full set of UREM37BY plugs, but was hesitant to use them since they would be a "cooler" plug than the ones I'm running now (REM38E). That's why I was considering going to something with a "40" designation.

Ironflight · #4 04-22-2010, 04:20 PM

My Mattituck TMX-360 came stock with the 37BY's, and that's all I have run for 1100 hours - no leading fouling, and good performance. We also have no trouble with the 40's that are in Louise's "Genuine Lycoming" O-360. Oh well - stick with what works!

Paul

Mel · #5 04-22-2010, 05:54 PM

Quote:

Originally Posted by BendRV-4

Mel, Thanks for your input. I do have a new full set of UREM37BY plugs, but was hesitant to use them since they would be a "cooler" plug than the ones I'm running now (REM38E). That's why I was considering going to something with a "40" designation.

The -37BY is a cooler range because it is a "long reach" plug. It is "effectively" hotter.