Lycoming Engine Baffles

[H. Ivan Haecker]

I'm fabricating engine baffles for my O-360 and have a question about the area under the cylinders where the cooling air escapes. I am interested in knowing what spacing is used for this escaping air between the curved potion of the baffles and the fixed intra-cylinder baffle (between the cylinders).Engine installations that I have looked at vary considerably, even from cylinder to cylinder on the same engine. They mostly range from 2" to 3" for the portion that surrounds the head area of the cylinder and 1" to 2" for the portion that surrounds the barrel area One source told me it just doesn't matter, but it seems strange that there is a lot of variation among cylinders on the same engine. Does anyone know if there is some standard gap that Lycoming recommends or is it just up to the airframe manufacturer, i.e. us builders? Thanks.

Ivan Haecker . QB Patrol

[Bdflies]

Maybe not the answer you were looking for, but the Vans baffle kit sure is nice! It's really well engineered, fits perfectly and everything is included.
The lower opening, in the barrel area, looks to be about 3". Not real sure about the head area.

Bill

[H. Ivan Haecker]

Unfortunately for me, the Van's option may not be worth its cost. My Lycoming clone variant (ECI) has front mounted governor and tapered cylinder barrels, so significant modifying would be needed. Besides, their kit has the same issues I was referring to in my original post. Different exit openings under the heads and barrels from cylinder to cylinder. Maybe it's engineered to be that way on purpose. I certainly have no clue. Or maybe it just doesn't matter. Just seemed odd.

Ivan QB150 Patrol

[Ray Strickland]

Ivan,

Don’t be intimidated by building the baffles...there are few mysteries involved. Most Lycomings are very much the same, so take a good look at others and start snipping sheet metal. If you can do your own fabric work, you can make baffles that will work just fine. Two hints: make individual parts for the valve cover ends—some builders make the mistake of using one large piece for each side of the engine only to have cracks develop due to thermal movement of the cylinders. Also, make the vertical plates in front of the #1 and #2 cylinders adjustable or easily replaceable so that after a few flights you can re-work them based on cylinder head readings.

Ray Strickland
4-place planes built s/n 877