Hurt motor diagnostics.
09-27-2009, 06:55 PM
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Hurt motor diagnostics. Im done racing for the year and the motor is hurt. I wont be able to pull it and take it apart for a few weeks so i started diagnosing it in the car, just for fun.
Its a carburated 5.3 with a edelbrock dual plane (divider cut down), holley 750 street HP and a TR220-114. Motor has 70k on it.
-The cooling system smells terrible, burnt/exhaust smelling.
-I did a compression test, all cylinders were between 165 and 175.
-Some of the spark plugs were perfect, some where very rich and one was completely fouled and actually wet.
-I havn't done a leak down test, but might try to before i yank the motor.
The compression test threw me for a loop, i was expecting a very hurt cylinder, i guess it was nice to see they were all good though. I would suspect a leak down test will reveal the problem though. The motor has fresh head gaskets about half way through the season, so i highly doubt its a head gasket.
The block or head might be cracked, i forgot to turn my water pump on one pass, i turned it on down the return road and shot cold water through a 265 degree motor.
The oil was never milky and it always had awesome oil pressure so i know water wasn't getting into the crankcase. However, every time i changed my oil there was large amounts of 'fuzz' on the drainplug...more than there should be. I wont know where that came from untill i tear the short block apart.
Lastly, maybe someone can shed some light on the spark plugs all being different....i dont have a clue on that one.
Funny thing is, last pass i made on the motor was the best pass ever, in the same condition as the motor sits now. Got any input?
Its a carburated 5.3 with a edelbrock dual plane (divider cut down), holley 750 street HP and a TR220-114. Motor has 70k on it.
-The cooling system smells terrible, burnt/exhaust smelling.
-I did a compression test, all cylinders were between 165 and 175.
-Some of the spark plugs were perfect, some where very rich and one was completely fouled and actually wet.
-I havn't done a leak down test, but might try to before i yank the motor.
The compression test threw me for a loop, i was expecting a very hurt cylinder, i guess it was nice to see they were all good though. I would suspect a leak down test will reveal the problem though. The motor has fresh head gaskets about half way through the season, so i highly doubt its a head gasket.
The block or head might be cracked, i forgot to turn my water pump on one pass, i turned it on down the return road and shot cold water through a 265 degree motor.
The oil was never milky and it always had awesome oil pressure so i know water wasn't getting into the crankcase. However, every time i changed my oil there was large amounts of 'fuzz' on the drainplug...more than there should be. I wont know where that came from untill i tear the short block apart.
Lastly, maybe someone can shed some light on the spark plugs all being different....i dont have a clue on that one.
Funny thing is, last pass i made on the motor was the best pass ever, in the same condition as the motor sits now. Got any input?
