John,

#2 was also my hottest cylinder.  First I installed the concave insert that was listed in one of the on-line articles that allows the air to flow around the shallow fins on the oil cooler side of #2 (is that what you are calling the “hat box”?).  However, even with the concave insert, #2 was still my hottest.  At that point I remembered that my engine, which I got from a salvage of Adam aircraft inventory, came with a piece of baffling for the oil box that had a scoop installed inside the oil box that directed air around to the lower right side of the cylinder.  The scoop was ¾” deep at the top and flush at the bottom, and about 3” wide (the width of the long fins on the cylinder).  I moved this scoop from the discarded Adam baffling piece onto the Lancair oil box (the hole was nearly the same size as the previous concave shaped part I had installed before).  Not only did this solve my #2 CHT problem (it is now one of my coolest cylinders), but it did not noticeably affect oil temps.  A win-win.

Hello all,

In April I asked some questions about this issue of  managing the cooling flow for #2 cylinder and there was a prolific and enlightening response that helped a lot.  The most common piece of advice was to build what was termed a “hat box” in the forward wall of the oil cooler box to allow more air around the back and bottom of this cylinder.

Someone posted a photo of that fix and it was excellent.  Now I’m ready to go to work on this project and I’ve searched my data bases in different computers for that photo for a couple of hours to no avail.  I’m hoping that whoever was kind enough to post that picture will resend.

Thanks in advance.

Regards,

John Barrett, CEO

Leading Edge Composites

PO Box 428

Port Hadlock, WA 98339

www.carbinge.com