Looking for advice
#1
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Looking for advice
Made some wide open runs Saturday on my stock 1997 502 Mag MPI running 7 Lbs. boost pro charger. Brought motor back to idle and it sounded sick. Stalled and I restarted once. Then stalled again. I was in the middle of the shipping channel so I attempted to restart again and broke starter. I figured it blew the head gaskets and Hydro-locked.
Pulled her in the barn today and sure enough 3 cylinders were full of water and the spark plugs were wet on the other 5. Whats my diagnosis? full rebuild? Get lucky and replace head gaskets? I know there is a good chance I bent something in the motor.
Pulled her in the barn today and sure enough 3 cylinders were full of water and the spark plugs were wet on the other 5. Whats my diagnosis? full rebuild? Get lucky and replace head gaskets? I know there is a good chance I bent something in the motor.
Last edited by hadleycat; 08-24-2014 at 12:12 PM.
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I think the smartest approach is to put plugs in and start her up. Look at pressure and listen for noises/missing. Also, do it with the belt off the charger so you can hear better.
You can run it for a minute/minute and a half without concern of lack of water.
If it sounds ok....then buy a top end gasket set with arp's and swap out the head gaskets. After resurfacing the heads, buying the gaskets, and installing the arp's......you'll be in under a grand and potentially back on the water next weekend.
If anything is amiss.....blow by, rattling, missing....knocking.....time for a rebuild. Either way, use studs on the heads.....
You can run it for a minute/minute and a half without concern of lack of water.
If it sounds ok....then buy a top end gasket set with arp's and swap out the head gaskets. After resurfacing the heads, buying the gaskets, and installing the arp's......you'll be in under a grand and potentially back on the water next weekend.
If anything is amiss.....blow by, rattling, missing....knocking.....time for a rebuild. Either way, use studs on the heads.....
#6
Made some wide open runs Saturday on my stock 1997 502 Mag MPI running 7 Lbs. boost pro charger. Brought motor back to idle and it sounded sick. Stalled and I restarted once. Then stalled again. I was in the middle of the shipping channel so I attempted to restart again and broke starter. I figured it blew the head gaskets and Hydro-locked.
Pulled her in the barn today and sure enough 3 cylinders were full of water and the spark plugs were wet on the other 5. Whats my diagnosis? full rebuild? Get lucky and replace head gaskets? I know there is a good chance I bent something in the motor.
Pulled her in the barn today and sure enough 3 cylinders were full of water and the spark plugs were wet on the other 5. Whats my diagnosis? full rebuild? Get lucky and replace head gaskets? I know there is a good chance I bent something in the motor.
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Pull it apart, unless you don't mind if it get's broken further.
I'm sure you'll find atleast a bent rod, or two, or three....and atleast one head not flat.
I'm sure you'll find atleast a bent rod, or two, or three....and atleast one head not flat.
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Yes it is the one with the Holley. I was doing some wide open runs to make sure the computer would learn the upper rpm ranges before I pulled my O2 sensor to run open loop. I haven't checked the data logs yet but believe this problem was caused by running 7 psi on stock motor. Water has been in cylinders for about 24 hours now. Starter is broken right now. I am purchasing a new starter tomorrow so I can turn the motor over and blow the water out of the cylinders.
Checked the intercooler and it was dry. I am surprised I have water in every cylinder. Boat does have flappers and the exhaust exits well above water line so I am sure it didn't come thru the tips.
Was running 86 mph trimmed out nicely before this happened. Didn't notice a problem till I slowly brought the motor down to idle after the run.
Judging by the dipstick there is no water in the pan.
Still debating my next move !
Checked the intercooler and it was dry. I am surprised I have water in every cylinder. Boat does have flappers and the exhaust exits well above water line so I am sure it didn't come thru the tips.
Was running 86 mph trimmed out nicely before this happened. Didn't notice a problem till I slowly brought the motor down to idle after the run.
Judging by the dipstick there is no water in the pan.
Still debating my next move !
Last edited by hadleycat; 08-24-2014 at 06:42 PM.
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Headgasket blew (or cyl head lifted) and water went in those cylinders. It's a common plenum intake, therefore other good cylinders (if there are some) pulled water from there.
Same deal when a motor breaks a valve. Sometimes the valve head ends up in another cylinder in the other bank.
Same deal when a motor breaks a valve. Sometimes the valve head ends up in another cylinder in the other bank.
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I am thinking I will rebuild over the winter. Upgrade motor to where it needs to be to stand up to the 7 lbs. of boost and possibly upgrade the cam. Any suggestions on builders.