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Vans EGT CHT at tickover..... low RPM

W

WAM120RV

Well Known Member
Hi Guys

Having moved my 4 to the airfield I have started to follow Mahlons advice about ground runs prior to the first flight. However, I am not getting any temperature indication from the Vans EGT/CHT set up. I ran the engine about 2 years ago with just one cylinder hooked up and seem to remember I did not get any reading until the RPM got quite high.

I converted it to a 4 channel system now do not see any temp increase at low RPMs. I have checked the wiring it looks fine....maybe I am not revving high enough to raise the temps high enough to get onto the scale.

So, with Vans guages what EGT/CHT do you expect to see at tick over...... what sort of RPM would you expect to see the temps come up.
 
I just installed a new EI bar graph EGT/CHT UBG-16

I am scrambling to get a new speed mod in and I have not read the full set of manuals yet but at low rpm early in the ground run at least tha bars are flat and the digital readouts are low. I have a Lycoming O-360-A1A but it has recently installed high compression pistons with the same bore and stroke but several other mods internally and a lot of custom baffling in the lower cowl. At 2700 rpm, peak EGT on Cylinder #4 is less than 1200F and #2 is 1283F 1 and 3 peak somewhere in between. With the mixture richened to #2 at 1208F, WOT, manifold Pressure 28in, 2,750 ft MSL, CHTs were 1=337F, 2=326F, 3=343F, 4=326F, Surface temp. on the ATIS (Airport Terminal Information Service) was 34C and the altimeter was 30.01 in.Hg. My OAT (probably in error) read 36C at 2,750 MSL. I am still working on my own procedures for the engine so this is just a random snapshot but from what I have seen so far I don't think your experience is unusual.

Bob Axsom
 
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If you are having problems with the gauges reading anything, follow the test procedures that were supplied with each gauge.

On EGT you should have a reading within a few minutes of tick over. Cht will take longer to show on the gauge...... maybe 10 minutes.
 
Readings

Bob

Thanks this helps I am worried about running too hard or long at this stage of the break-in and getting things too hot....... heat is the enemy!! I will run it up to the next stage of what Mahlon suggests tomorrow. I too have modified the cooling system to a sealed plenum I hope your mods work out well for you.

Gasman, thanks the only thing that has changed from when they were definately working is a 4 way switch and probes on all cylinders. So, I dont suspect the guages....I am pretty sure now that I am not putting out enough power to get readings so will see what happens tomorrow.
 
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