MOST RV's do not cool properly.. There Iv'e said it... Depending on where you live most RV's do not cool adequately.. Ya we douse them with 100LL or climb at high speeds or reduced power and deal with it... The problem is that the Van's baffles do not allow the lower aft one fourth of the rear cylinders to get any or enough air... Also to a lesser extent the front lower one fourth of the front cylinders are not doing much better... Some have tried to add exit air which will
help a little just because the rest of the cylinder gets a little more air but does not
solve the problem...
Take the time and go look at the baffles on an old 60's Cherokee and you will see that they addressed those areas way back then... An instructor and student can beat up on one of those all day long without getting hot.... Ya they have a larger
opening but also going much slower so not much pressure..
The RV's need a duct down the back side of the right baffle and forward under the lower fin area of at least 1.5 square inches and the existing wrap removed from just below midpoint of the cylinder... Also the it needs a duct down the inboard side of the oil cooler and then forward under the fin area. Also 1.5 square inches and the wrap removed... Then holes cut in the baffles above to admit air into the
ducts of at least 2 square inches..
The front cylinders need almost 1 square inch down to below the midpoint of the cylinder and into the wrap..
For your information, I have built 7 RV's of different models, have around
1000 hrs in them, and have been around big bore Lycomings almost since they were first introduced.:: without divulging my age!!!!
It is a lot of work but these engines are expensive and we are kind of relying on them to stay healthy... I have seen 25 to 30 degrees F. decrease in head temps
help a little just because the rest of the cylinder gets a little more air but does not
solve the problem...
Take the time and go look at the baffles on an old 60's Cherokee and you will see that they addressed those areas way back then... An instructor and student can beat up on one of those all day long without getting hot.... Ya they have a larger
opening but also going much slower so not much pressure..
The RV's need a duct down the back side of the right baffle and forward under the lower fin area of at least 1.5 square inches and the existing wrap removed from just below midpoint of the cylinder... Also the it needs a duct down the inboard side of the oil cooler and then forward under the fin area. Also 1.5 square inches and the wrap removed... Then holes cut in the baffles above to admit air into the
ducts of at least 2 square inches..
The front cylinders need almost 1 square inch down to below the midpoint of the cylinder and into the wrap..
For your information, I have built 7 RV's of different models, have around
1000 hrs in them, and have been around big bore Lycomings almost since they were first introduced.:: without divulging my age!!!!
It is a lot of work but these engines are expensive and we are kind of relying on them to stay healthy... I have seen 25 to 30 degrees F. decrease in head temps