One of my friends at K2W6 has a Revmaster 2300 VW in a Sonex with 70 hours on the tach. Number 3 cylinder was not making power. After much trouble shooting and consultation with Revmaster, he took off the heads. The exhaust valve pushrod was bent. The valve pushrods are aluminum tubes with steel ends attached. Here is a picture of the ends of #3 pushrods: https://s3.amazonaws.com/expercraft/sidwood/11538091485584b594a9258.jpg He also found a crack in the head casting between the intake and exhaust valve seats for both #3 and #4 cylinders. https://s3.amazonaws.com/expercraft/sidwood/20674664685584b594b55a3.jpg The crack does not show up to well in the picture. Machining breakout at the head bolt holes is shown in the picture; the upper right hole breakout goes down to the cylinder seal area. Exhaust gas blow-by is apparent.
VW and particularly Revmaster users should be aware there may be some systemic issues with these increased displacement engines. Sid Wood Tri-gear KR-2 N6242 Mechanicsville, MD, USA
