"not strong enough"
Phil, I'm not sure how to answer. There are destinct versions of VW, the
type1/3 and the type 2/4, and within these are verious cranks. I have no
knowledge of how the revmaster crank is different. As to the cost of a
crank, I paid $100 for the core engine, $75 fuel to bring it home, $50 to
have it polished, I still have to pay to have it drilled and the keyway
enlarged, and then there is the time that I have invested. I'd bet I'll see
$ 300 before it is installed, and that is for a used part. So, I expect
that $550 for a new part is not unreasonable. I do know that all of the
Revmaster engines that I have seen are of the type 1/3 variety. In the
aftermarket arena with all the hype and claims is hard to tell who is
Forging what. When you get into stroked cranks, the rod journal size is
reduced to create additional displacement. Decreasing the overlap between
the main and rod journals has to decrease the strength of the crank. The
main bearing journal diameter of the type 1/3 is 54.97 mm, where the type 4
main journals are 59.97 mm. That being said, the type 4 crank is the
strongest of the VW's. Some aftermarket suppliers have added counter
weights to the cranks. This is a needed addition for high rpm engines.
Most of the mechanics that I have talked to say this is un-necessary under
5000 RPM.
Not many KR's talk about engine failure on a regular basis. I have only
heard of one type 4 crank failure, and that was in Diehl's KR. Even then as
the story goes, he did not know it had failed until after flight, and after
shutdown. I have heard of type 1/3 failures and I can't remember enouogh to
speak of the details. I will suggest that perhaps they were stroked cranks
with small journals. So, I have gone out of my way to find an original
crank which has a stroke of 71 mm to combine with 103 mm pistons for a
displacement of 2366.
After discussions with Ron Slender, I'm sure he would have what could
possibly be some interesting comments about your question.
