<< You hit on a subject which can be a problem - coolant leakage through
 > thermal cycling. The only solution I can see is one Butch suggested i.e.
 > through the use of O rings. Although we haven't discussed this in any
 > detail, I have a suggestion for him to consider, when we get a chance to
 > discuss it.
 >
 > George (down under) >>

That is a comparison between bridge ported (Monster bridge port) and
periphery ported engines. There is no leaking problem. Both stock seal rings are
untouched. The port area just like the factory periphery port, the port area will
be filled and no coolant will be available to leak. The port is cooled buy
inducted mixture while running. As in carburetor ice. After shut down there will
be heating of the ported area from heat soak.

The kids are driving giant periphery ported engines on the streets of this
country every night to engage in tire smoking contests. There is no increased
wear from high RPM operation because there is no high rpm operation in aircraft
use. Even 7,500 RPM for takeoff is not high RPM. The 300 plus HP from a 12A
periphery port or 330 HP from a 13B is at over 10,000 RPM. That is high RPM
operation.

The bridge ported engine has much more intake duration and overlap than a
periphery port, and the kids drive Bridgeport engines to work every day. It is
hard as hell for me to drive the race car around slowly, with either port style.
With a 1.96:1 first gear. It goes 70 MPH in first gear. Jump in the car stick
in 3rd gear and drive to work and back. With a 3.26:1 stock first gear it is
no problem. It just has very little power at low RPM. You only use 40 HP to
get to work anyway so how would you know if it didn't have enough power down
low? My bridge port has 205 HP at 7,400 RPM. We don't use the engine at that low
an RPM.

If you could only get 200 plus HP out of a junk yard 13B with some pipe and
epoxy, would that not be worth the effort?

It took me one day to make a set of Pport housings and assemble the engine.
It is a good idea. It has been done. It works just fine. There is very little
new ground to cover here. Don't raise the top of the exhaust port at all. Keep
the intake open duration short and use a wide port to get the flow. It will
work so well you will not believe it. Even if you miss the tune up, get the
timing wrong, get the porting wrong, and get the runner length wrong, it will have
so much power it will scare the crap out of you.

I refer you to Tracy's first take off with the engine turning some real RPM
where it started to make some of it's potential power with the 2.85:1 box. That
is with a street port not a periphery port.

Not enough rudder? Almost ran off the runway? I like talk like that.
So no full throttle until rudder is effective. Put that on a nice placard
next to the throttle. Sounds like a P51-C.

Lynn E. Hanover

 
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