Thorp Air Command - T18.net

That's what cured mine Lou..............Dan

Lou,

While our 0290 is basically a stocker, we have had high EGT issues and engine stumbling when EGT got above 1400 or more when we first flew the AC when we bought it over 10 years ago. Drilling out the jet helped, we checked the induction tube...nice an tight,wires fine. What we find interesting is that if you run full rich, full power on climb out that all EGT/CHT temps stay pretty even and engine just hums. But when you pull back to cruise if you go to 2300 to 2400 rpm that the EGT goes through the roof on number 3. We just power back to 2200, it cools, back with power, mixture and it settles down nice at 2350-2400 a little leaned out. Runs around 165-170MPH. Engine and AC nearing 1000 hours. Going to have a party soon to celebrate when she breaks 1000 hours...you all come! We have an expensive AI Monitor that is fine. Someone explained it is just the uneven fuel flow caused by resetting the butterfly on the carb. As u know we will be flying our new 180HP, injected Thorp soon, so we an compare the engines to see if this is really the case.

Happy landings!

Brent Schultz
N6CM
KAJO

After I installing a new exhaust system on my O290 the EGT on cylinder #3 will start to climb when I throttle back to a cruise setting 2350 rpm, all the other cylinders are normal, reducing rpm to 2200 and the temps come back to normal. WOT is not a problem even at altitude, 9500'. I did not have this problem with the old exhaust.

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Bruce Finney
N18JF T-18C #262
Yelm, WA USA

What are the differences in the two exhaust systems?

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http://www.dixiefriedfabrication.com/

We should compare notes! I still owe Chris a ride. I think I

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http://www.dixiefriedfabrication.com/

Come by the hanger and take Chris up. He is real good at checking and finding the problem.

Hey Lou,

What model/HP engine do you have?

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John Evens
Arvada, Colorado
T-18 N71JE (sold)
Kitfox 7 SS N27JE

Lyc. 0360 AIC (narrow deck) H.P. 180 With 9.5:1 comp. Cam timing bumped 1.5 degrees that

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http://www.dixiefriedfabrication.com/

They are both cross over systems, the old one had 2" tail pipes, the new one 1 3/4". There may be a difference in the length of the individual pipes before being joined together, I don't have the old one any more to do a direct comparison.

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Bruce Finney
N18JF T-18C #262
Yelm, WA USA