Can it be done?
04-25-2008, 02:05 PM
#1
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Can it be done? I've got a 98 Z28 and a problem. A little history for you, my LS1 was replaced a few years ago and the insurance company gave me a new used one with 24k miles on it. Sounded like hell.
Three years later I'm tired of it and I'm looking for solutions to fix it because I think its getting worse and really killing my performance.
To describe the sound: its like a whining noise, not like a super charger, lower pitch and more grinding.
A few years ago I saw an episode of HorsePower TV and they had a similar problem with a 99SS. They said it was the bearings on the Crankshaft. Of course they have a ton of money and time so they rebuilt the engine.
I don't, so the question is, is this my problem (the main bearings)?
And can they be replaced without taking the engine out of the car?
Maybe taking the oil pan off and then the crank out from under the car?
Thanks for you input. I'll try to figure out how to post a video of the sound.
Three years later I'm tired of it and I'm looking for solutions to fix it because I think its getting worse and really killing my performance.
To describe the sound: its like a whining noise, not like a super charger, lower pitch and more grinding.
A few years ago I saw an episode of HorsePower TV and they had a similar problem with a 99SS. They said it was the bearings on the Crankshaft. Of course they have a ton of money and time so they rebuilt the engine.
I don't, so the question is, is this my problem (the main bearings)?
And can they be replaced without taking the engine out of the car?
Maybe taking the oil pan off and then the crank out from under the car?
Thanks for you input. I'll try to figure out how to post a video of the sound.
04-25-2008, 02:10 PM
#2
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If this noise has been around for awhile, I doubt it is bearings. Perhaps pulley related.
No you cannot just drop a crank, you have to yank the motor out for a shortblock rebuild.
No you cannot just drop a crank, you have to yank the motor out for a shortblock rebuild.
Last edited by PREDATOR-Z; 04-25-2008 at 10:30 PM.
04-25-2008, 02:32 PM
#3
WoW if you have a bearing problem usually the oil pressure will drop and the car will be making a hell of a noise.
First thing you need to do is a compression test to make sure the cylinders are all in good shape. Then do a leakdown test. Those 2 things right there should tell you the shape the motor is in.
First thing you need to do is a compression test to make sure the cylinders are all in good shape. Then do a leakdown test. Those 2 things right there should tell you the shape the motor is in.
04-25-2008, 02:36 PM
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"leakdown test" ? not sure what that is.
Is pulling the spark plugs and turning over the engine the best way to check for compression?
Keep in mind the engine runs fine, never had a problem with it other than the sound of it.
Is pulling the spark plugs and turning over the engine the best way to check for compression?
Keep in mind the engine runs fine, never had a problem with it other than the sound of it.
04-25-2008, 02:41 PM
#5
Well if it sounds like that then there is a problem & it's not running just fine. A healty motor will run smooth & not make those sounds.
If it is bad cam bearings you need to get that addressed soon. I bet if you took the motor apart the stock cam is gonna be chewed up on the lobes & lifter rollers chewed up too at least. From how you explain the sound it seems like the damage was already done to the motor before it was installed.
If it is bad cam bearings you need to get that addressed soon. I bet if you took the motor apart the stock cam is gonna be chewed up on the lobes & lifter rollers chewed up too at least. From how you explain the sound it seems like the damage was already done to the motor before it was installed.
04-25-2008, 02:54 PM
#6
A leak down test is almost the same as a compression test in that it tells you how well your engine’s cylinders are sealing. But instead of measuring pressure, it measures pressure loss.
ya you need to remove the spark plugs. Then turn crankshaft so that each piston is at top dead center as each cylinder is tested.
then thread a pressure guage into the cylinder your testing and put in about 80psi of air into the cylinder.
If you see the guage moving pretty quickly then you've got issues. But if your only losing a lil bit (normal) then your fine.
A leak down test is alot quicker than a compression test. If you hear air coming out of the exhaust during this, that means there is a leaky exhaust valve. Air coming out of the throttle body means a leaky intake valve. Air coming out of the PCV valve fitting would tell you the rings and/or cylinders are worn.
ya you need to remove the spark plugs. Then turn crankshaft so that each piston is at top dead center as each cylinder is tested.
then thread a pressure guage into the cylinder your testing and put in about 80psi of air into the cylinder.
If you see the guage moving pretty quickly then you've got issues. But if your only losing a lil bit (normal) then your fine.
A leak down test is alot quicker than a compression test. If you hear air coming out of the exhaust during this, that means there is a leaky exhaust valve. Air coming out of the throttle body means a leaky intake valve. Air coming out of the PCV valve fitting would tell you the rings and/or cylinders are worn.