Originally posted by kpierre
I have the rex 421p m.rossi tune aac and the engine runs fine. I have about 15 tanks thur it. Since i drag race how long should i expect engine to last. What will be some of the signs of the engine wearing out. Also can i change p/s to abc? I feel like i just wasted my money. What would be an equal replacement?
Just like what A-Rass said, no worries about you wasting your
money on a 421P... It's a good motor.
On an ideal environment, signs of wearing down is when the
motor looses power. And the general reaction of people when
this happens is to keep leaning it out in order to keep up the
power. And ofcourse, by doing so, it reaches a point when it will
just blow up. Another sign is that the motor is getting harder to
tune and wont keep a good steady idle.
Another sign, which I do not believe applies to the AAC motors,
is the feel of loss of compression when turning the flywheel over
(even when its cold and has a glow plug on it). I say this about
the AAC because my 421P felt like it had almost no compression
since about the 8th or 9th tank of fuel. But it kept steady like that
until now (one gallon and a half).
Physically, rod play is one sign of wear too.
If you feel like you prefer to go with the ABC, yes you can just
drop in an ABC replacement Piston and Liner on your 421P and
it should be like having a 321P. But you may need to likewise
change the head button.
Hope this helps...