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RED DRAGON 1
10-23-2011, 05:57 PM
OK HERE GOES.I JUST PURCHASED 2 PROMAX 300s.I KNEW AHEAD ONE WAS BLOWN UP.PULLED IT APART TODAY AND HAS DAMAGE TO NUMBER 4 AND 5 CYLINDER,SLIGHT SCORING WORSE ON NUMBER 5.CRANK APPEARS TO BE GOOD NICE AND SMOOTH JOURNALS NUMBER 4 JOURNAL LOOKS TO HAVE GOTTON A LITTLE HOT{TINT OF PURPLE IN COLOR}.

WAS WONDERING WHAT MAY HAVE CAUSED THIS

MOTORS ARE SUPPOSEDLY PUTTING OUT 330HP AND HAVE MODS,JUST FROM WHAT I SEE IS ROD SLOTS,POPPET VALVE,I BELIEVE COMPUTER AND INJECTORS WERE DONE,PUSHED A 28 SKATER 111MPH FOR SURE BUT 2 OWNERS AGO SAID 124MPH

REBUILT 2.4s,not 3.0l but going to give it a whirl
245178245179245180
THANK YOU FOR ANY HELP
RED DRAGON 1
10-23-2011, 06:06 PM
more pics
87starflite
10-23-2011, 06:15 PM
looks like a lean condition that caused the piston to begin to melt and the rings are more than likely toast. did you have any compression on those two cylinders? i just blew up my 225 3.0, the number 4 leaned out and the ring over heated and motor locked up. cylinder walls and piston look very similar to your pics. i believe mine was due to a mix of bad fuel and the carb hanging up
RED DRAGON 1
10-23-2011, 06:23 PM
i believe number 5 was 60lbs not sure on 4
rev.ronnie
10-23-2011, 08:51 PM
Resleeve it while its apart and get rid of the compression relief notches. Ick.

Looks lean, pretty dry and colorless up top.
Euroski
10-23-2011, 09:07 PM
get rid of the compression relief notches.

Why?...
rev.ronnie
10-23-2011, 10:57 PM
Those notches are creepy. They go against everything I believe in.

I was pretty much kidding, they don't really hurt top end and only affect the real low rpm response, which is probably negligible.
Teddy G
10-29-2011, 03:24 PM
Compression on motors, when I checked it

STBD Motor----


118 124

120 125

123 127


PORT Motor----


116 121

118 125

121 60