Vic Babyak Solves Cooling Issues With Creative Baffling Design

Vic Babyak and his RV-8A.

Vic Babyak built a beautiful RV-8A 18 years ago and has flown it over 2000 hours since then from his home base in Punta Gorda, Florida. If you have been to Sun ‘n Fun in years past, you probably have seen and appreciated his Navy trainer orange and white paint scheme. After years of faithful service, Vic’s O-360 Lycoming engine whispered that it was time for an overhaul. Vic chose the central Florida stalwart engine shop, JB Engine Service to do the job.

When the brand spanking newly overhauled Lyc was reinstalled in N848VB, Vic flew it hard to break it in and was rewarded with a smooth and cool running powerplant. Even running in the notorious Florida temps, his oil temperature gauge registered 190-195°F. However, something new popped up on his engine instruments. His cylinder head temperatures on the right side of the engine, cylinders 1 and 3 where running about 30°F hotter than the left bank cylinders 2 and 4. Vic had not seen such a spread before.

The path of the oil drops from the oil pressure regulator fitting to the forward and middle of the engine.

At this point, Vic Babyak decided that the term “Experimental” really meant something. He pulled the top cowling to investigate and noted faint oil leakage from the oil pressure regulator valve located on the top of the right side of the engine. The micro leak from this valve had nothing to do with CHTs, but the faint trace of small droplets from the point of the leak traced in an odd path. Rather than flowing to the back of the baffling, as would be expected, they traced forward and towards the centerline of the engine. Vic followed his instinct, that told him to force the airflow from the top of the engine down between the 1 and 3 cylinders. He fabricated a simple baffle wall down the centerline of the engine (right at the case split) to accomplish that goal.

CHTs after the fix.

It worked like a charm. The right side CHT readings are almost identical to the right side. For a couple of dollars worth of left over .035 aluminum and baffle seal, the engine is perfectly temperature balanced. Vic’s 8A is on display in front of Hangar B at the JB engines tent.

The fix, an engine centerline baffle.



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