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I am testing an
'88, 13B, non turbo engine that I rebuilt according to Tracy Crook's manual
(Aviator's Guide to Mazda Rotary Conversions). I did the rebuild, many
years ago, before Tracy sold his rebuild kits, and it's my
first rotary that I rebuilt. I purchased my rebuild kit
from Dave Atkins. I am running it with Tracy's EC2 (purchased
in '02), and I wired the harness as per his plans. I
fabricated my own intake manifold. Presently, the motor is installed in an
'86 Mazda RX-7 car. I am using the transmission (i.e., most of the
drivetrain) from the car, to put a load on the engine (i.e., wheels are off
the ground). The fuel pump, fuel tank, battery,
tach, coolant temp gauge, exhaust, starter, is, stock, from the
car. I have an external oil pressure gauge, oil temp.
gauge, ammeter, voltmeter, vacuum gauge, air/fuel gauge, circuit breakers,
and toggle switches. I didn't want to spend any more money (i.e.,
purchasing Tracy's RD-1B, EM3, prop. etc.) on the
engine until I knew the engine was running adequately, and, therefore, I am
using the car as the test bed. The engine starts fairly easy up
here in B.C., Canada, on cold winter days, and I have been running it, off
and on, since late spring of '07. One of the problems/issues I am
trying to deal with is a random, intermittent noise from the engine, when the
engine is running cold. The noise sounds like a coin on edge
being tapped against some metal, such as a fender of a car. After
the engine warms up, and I run it up to 3000 - 6000 RPMs I don't hear the
noise. The engine hasn't used any oil, and I have run approximately
40 gallons of gas through it. At very high RMPs (5000 to
6000) I have placed the transmission into neutral because I have been
concerned about damaging the transmission/drive train. As a result
of running the engine with no load (i.e., transmission in neutral) on it, at
high RPM's, my plugs have fouled and stopped working or produced a weak
spark. Tracy has warned me that his EC2 was designed to run with a
propeller load, and my plugs will foul, if I don't run it with a
load. My question is regarding the noise that I hear. Has
anyone experienced such a noise? I have noticed the engine
missing sporadically at low RPM's with a load on it, and the fuel/air mixture
gauge showing five to six LEDS. Can a miss, detonation, bad
timing, fouled plug(s) etc cause such a noise? My timing is very
close to 23 degrees BTDC. When I turn the engine
over manually (i.e., with socket and ratchet) the engine feels like it has good
compression, and doesn't make any strange noises, such as, anything broken or
loose inside. I may tear the engine apart to inspect the
inside, later this year.
Thanks,
Tom
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