Chuck---I'll toss in a few ideas of what may be going on here. I'll
limit these ideas only to the changes you've made.
a) The cam may not be timed correctly.
b) The valve springs may not be strong enough to keep the valves
from floating with the S-9.
Be sure there is no coil binding when the valves are
(supposed to be) wide open.
c) The throttle linkage may not be allowing the trips to go to
wide open.
d) Usually not a problem with the dual point system, but
check that the points gaps are not set too wide. The 36 deg.
total advance should be OK. (The recommended total
advance of 28 deg. is mostly to stay out of detonation)
e) If you really have three lb. of fuel pressure, this should be
more than enough.
Is the 5,000 rpm limit in all (lower) gears?
Dick Taylor
From:
triosan@gmail.com(Chuck Arnold) Date: Sat,
I have a problem with my engine -- it get to about 5000 rpm and will go
no
further -- it kinda "Floats".
Here is the back ground: Engine made 7000 rpm in my TR6 with a Kent D9
cam, 12:1 compression, electromotive crank fired trigger, triple webers
and a header. HP was about 165 at the wheels at 5800.
Put the engine in my TR250 and made these three changes:
1. Kastner S9 cam grind [yielding about 1/2 lift at the valve. Cam lobe
center of about 104 degrees and duration of 320 degrees.
2. Mallory dual point distributor
3. Mallory [I think] return style pressure regulator set at it lowest
level yielding 3 lbs pressure.
I am not knowledgeable enough to know what is causing the problem. I
have not changed the valve springs, but have uprated ones from when I
had the head built a few years ago. I think I read somewhere that with
this much duration and lift I should probably limit total ignition
advance to 28 degrees -- it is now about 36 total [12 static, 24
mechanical].
So, I am looking for ideas, from changing cam timing, changing valve
springs, limiting advance, to increasing fuel pressure or????
thanks in advance,
--
Chuck Arnold
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