Screamin High EGT's 582

[t j]

Just to be sure on the needle clip. Full rich the clip would be in the bottom groove.

[LSaupe]

Quick update and more confusion I guess.

Tried the TC calibrator on the Westach EGT guage and even though the calibrator was putting out the correct mV it would stop working when connected to the instrument (not sure why yet). Tried a new instrument out of the box (though 20 years old) and... one side worked and the other was intermittant. Shut down and put back the old gauge and for some reason everything is now in line again. EGT's at about 1050-1100 across the range from 4K to 6K. Gave it a loop around the pattern and it behaved perfectly (no high EGT's). Inspected of the engine (through the exhaust ports and plug holes) and everything looks fine (no evidence of excessive EGT for any length of time). Actually appears to be running on the rich side.

I am hedging my bets right now on instrument error and will order a new EGT system (probes and gauge). Just odd that it would go off scale high and both needles together when it happened. The exhaust is also one area that has my interest (there was a great post in this at the Avidfox site). Never know if there was some sort of "visitor" that had taken up residence at some point. I will do a boro scope on the muffler to see if I see anything. I have had situations like that with the sleds but would lose high RPM power (though didn't have EGTs on those sleds). The kit was finished the exhaust pipe was elevated and protected from moisture, but not sealed off for about 25 years. Just now placed in service.

Thanks for all the feedback so far, this has been very valuable.

Larry

[LSaupe]

Just to be sure on the needle clip. Full rich the clip would be in the bottom groove.

Thanks for the back up TJ. Yep clip in the bottom groove (needle up as far as it can go).

[Av8r_Sed]

EGT's are definitely K type thermocouples.

[Dusty]

A plug reading is possibly the most accurate way to be sure of currect egt,
Straw brown is good.
A guy at our field calibrates westach gauges by hooking them up to a multimeter set on ohms? He looks for 800F,he splits the guage and bends the needles to both read the same.
These gauges are best left for trend/problem monitoring and if using a hacman
Sound like an odd problem you have?
1050-1100 es a good safe range as a randome cold day will see your egt's rise by at least 50F
If your egt's were 1400F you would have had a chance to review your glide approaches/ forced landings!
Remember your choke is another tool to be used
Crack the choke slightly in flight, your engine should load up and egt's drop
If you don't get a pronounced loading your engine may be lean
Mike stratman? Did an article years back on using the choke for tuning,
Well worth a read

[t j]

I chased uneven EGTs...one sometimes hitting 1300 for several years. I finally figured it was worn out parts in the carburetors. I removed my Arctic sparrow adjustable needles, bought all new jets, needles and pistons (slides).

You can't imagine how frustrated I was when the $200+ of new parts gave the same results.

I decided to order new gauge and a new exhaust manifold with the EGT ports and new probes. Another $450. Then very very disappointed when one side of the new gauge didn't work at all.

I called Spruce to get instructions to return the new gauge for a another. They said it was a warranty item and I needed to call Westach.

While on the phone with Westach about the no good new gauge I told him my old gauge problem of uneven temps. He said he could fix that and to send both gauges to him. In a week I got them back. No charge. Both work perfect. Temps are even and stay where they should for any given jetting, needle clip location.

I was telling my brother this story. He laughed and told me his story with Westach gauges on race cars. If it fails, don't buy a new one. Send the broke one in to be fixed. The new one will fail, the fixed ones will work.

[LSaupe]

T.J.; that is great. Thanks for posting.

[t j]

This photo I took yesterday. The one above was this summer. Notice the effect of the outside temperature on the EGT temp. Time to adjust the needle clips a notch richer.

[Olle1975]

Hi!

Was the pics taken in same high, if you fly higher the egt gets lower!?

In which notch did your needle-clip operates?

Olaf

[t j]

Hi!

Was the pics taken in same high, if you fly higher the egt gets lower!?

In which notch did your needle-clip operates?
Olaf

Olaf, I can't say for sure the altitude for the first photo with the lower EGTs. I'm positive the second photo with higher EGTs is not lower than the first and most likely about 1000 feet higher. The clip is in the top groove (full lean) in both photos. This is a 503 air cooled Rotax thus the cylinder Head temperature gauge too.

From the Westach instruction sheet:

This system is calibrated at 75 degrees F...
For cold junction temperature higher than 75 deg. the indicator will read one degree LOW for each degree above 75 deg.

For cold junction temperature lower than 75 deg. the indicator will read one degree HIGH for each deg. below 75 deg.

The cold junctions are located behind (cabin side) of the firewall so assuming the temp there is same as outside air temp:
Top photo: outside Air temp is 76 degrees F. so add one degree to the reading of 1100 = 1101 degrees.

Bottom photo: outside air temp is 43 degrees F so subtract 32 degrees from the reading of 1200 = 1168.

Did I do that correctly?