Recently had #2 cylinder get hot and freeze the rings and lose compression on a Zipper big bore on a 912ULS. Suspect ran lean from a brittle / bad o-ring as there was blue, fuel stains on the intake before the cylinder. After this I decided to add EGTs to the front cylinders to my Dynon (only had rear before). However there is what appear to be an excessive spread between the front to back, between 140-170F at 5,500 RPM and 180-200F at 5,800 RPM at WOT with a CS prop on the ground. Is this normal? What’s weird is the front are higher even though they are about an inch further from the exhaust flange (best I could do with the bends on the Just Aircraft exhaust).


#1 1503

#2 1447

#3 1360

#4 1276


#1 1541

#2 1480

#3 1360

#4 1284

  • Re: Front vs Rear EGTs

    by » 3 months ago

    Carbureted engine, correct?

    I think the fuel mix is always a bit different between the front and back cylinders.

  • Re: Front vs Rear EGTs

    by » 3 months ago

    It is carbureted and what I'm finding is a difference of 200-300F between front and back is not uncommon on these engines from others with EGTs with the best to hope for being 100F front to back. There are some tricks to get turn the carbs slightly or disrupt the flow through trial and error to get the difference to be closer that I'm going to try.

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