Cooling Tips for Cylinder #6

[ethand]

My #6 CHT is a good 10 -15 degrees higher than any of the other 5 cylinders. The EGT is in line with the others.

Thoughts on opportunities to assist with airflow?

I improved the sealing on the oil door and made some improvements to the baffles and that helped a bit but looking for more. I also looked in the area and sealed a bit more on the inboard rear with RTV to force the air over the cylinder.

My oil temp is running about 180 so I may try to block a bit of the flow to the cooler and see if that helps.

Other thoughts?

Thanks
E

[Robin8er]

10-15 degrees isn't bad at all. But I had the same issue with the cylinder by the oil cooler. I blocked off part of the pilot cooler and it brought the temp on that cylinder down about 15 degrees. It also helped bring my oil temp up. My oil temp was running around 175-180.

[BobTurner]

Forget the absolute egt number. How far is the egt from peak egt (assuming rich of peak), and what is that value for the other cylinders? E.g., is #6 running 50 F rich of peak while all other cylinders are 100 F rich of peak?

[lr172]

where is the #2 CHT? If it is on the low end of your range, you can try increasing the height of the #2 air dam. That should increase #2 and lower #4 and #6.

Larry

[paul330]

http://www.vansairforce.com/communit...d.php?t=143064

[douglassmt]

Originally Posted by BobTurner

Forget the absolute egt number. How far is the egt from peak egt (assuming rich of peak), and what is that value for the other cylinders? E.g., is #6 running 50 F rich of peak while all other cylinders are 100 F rich of peak?

He said CHT, not EGT

[douglassmt]

Originally Posted by ethand

My #6 CHT is a good 10 -15 degrees higher than any of the other 5 cylinders. The EGT is in line with the others.

Thoughts on opportunities to assist with airflow?

I improved the sealing on the oil door and made some improvements to the baffles and that helped a bit but looking for more. I also looked in the area and sealed a bit more on the inboard rear with RTV to force the air over the cylinder.

My oil temp is running about 180 so I may try to block a bit of the flow to the cooler and see if that helps.

Other thoughts?

Thanks
E

If you have a stock build you're losing some cooling air on #6 to the oil cooler. Seal it all up the best you can, maybe get a butterfly valve for the oil cooler, and you'll be fine. 10-15 deg higher is nothing unless you are over 380-400.

[BobTurner]

Originally Posted by douglassmt

He said CHT, not EGT

He said ?the egt is in line with the others?. My comment was that you want to know how far from peak egt you are, on each cylinder. Having absolute egt readings is not the same. If #6 is running 50F rich of peak and all the others are 100 rich, you?d expect #6 cht to be higher.

[lr172]

Originally Posted by BobTurner

He said ‘the egt is in line with the others’. My comment was that you want to know how far from peak egt you are, on each cylinder. Having absolute egt readings is not the same. If #6 is running 50F rich of peak and all the others are 100 rich, you’d expect #6 cht to be higher.

It was my understanding that peak CHT is at max power mixture (80-100 ROP) and will slowly fall as you go leaner, to around peak EGT and then drop more rapidly as you go leaner still. Similarly, CHT will also fall from it's peak if you go richer from max power. This assumes, of course, that ambient and ignition timing remain the same.

so, if #6 is 100 ROP and all others were at peak, I would expect #6 CHT to be a bit higher. The Lyc charts show a relatively small change in CHT between 250 ROP and peak.

Larry