The current power level from a non bridgeported 13B
is 225 HP. I confirmed with two builders that best power is available with
more than 30 degrees of lead. That was 36 in one case. One says split the
timing events and the other says fire both at the same time. I looked at
another 13B before it was assembled and went on the dyno last Tuesday. It had
very mild bridge ports, very small. It has 259 HP. I will be doing the ports
on that one over again this fall. I had an idea about moving the inner edge
of the intake into the area where the outer oil control scraper runs and then
leave off the outer scraper. I was advised that you can do that and let the
outer scraper run over the open part of the port without affect other than a
little extra smoking at idle. Oil fuel mixture could be adjusted to account
for that. I was advised that the steel apex seals will survive up to 1700
degree EGTs with extra oiling. I placed a periphery port housing on a
bridgeported cast iron and noticed that the bridgeported engine would have
later intake closing than the periphery port engine. So if you wanted to, you
could run a smaller cross section periphery port to keep velocity high and
still run a later closing event. Might be good for a docile aircraft engine.
Just an idea. That C-130 was operating off of My aircraft carrier. USS
Forrestal, CVA 59. 1962-1963.
Lynn E. Hanover
Whata RPM's are these HP levels Lynn?