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How to Avoid Hydrolocking

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  #1  
Old 11-12-2012, 01:39 AM
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How to Avoid Hydrolocking

Any advice would be appreciated.

I removed the driver's side glow plugs and injectors and put new o-rings and coppers on the injectors and reinstalled them. Then I tried to suck out the fuel and oil which had glugged into the primarily #8 cylinder and got no oil out.

Then I used a bump switch to push the oil out the glow plug holes and got no oil out of them. Then I did a compression test on the driver's side cylinders and installed new Motorcraft glow plugs.

I have not spun the engine since and it has been about three weeks since I did the compression test.

Tomorrow I am completing my hutch mod and reinstalling the fuel tank.

Did spinning the engine without the glow plugs in, force the oil and fuel out the exhaust valves?

Should I do something else to prevent hydrolocking before starting the engine?

Your advice will be greatly appreciated.

Tim
 
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Old 11-12-2012, 05:29 AM
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Suction on cylinders and following up with spinning the motor with gp's out you should be ok.
 
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Old 11-12-2012, 06:57 AM
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I would repeat purging the system at the last minute, or crank the engine by hand a few revolutions to be sure it'll turn... but I'm not the expert here.
 
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Old 11-12-2012, 07:33 AM
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Originally Posted by Tugly
crank the engine by hand a few revolutions
This is all ya need to do. IF there was still some liquid in there, you'll be able to push it past the rings (slowly) without doing any damage.

And Rich, you are rapidly becoming an expert!! Graduating the school of hard knocks counts! (Stinky is earning his name...)
 
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Old 11-12-2012, 09:30 AM
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Originally Posted by Tim Hodgson
Any advice would be appreciated.

I removed the driver's side glow plugs and injectors and put new o-rings and coppers on the injectors and reinstalled them. Then I tried to suck out the fuel and oil which had glugged into the primarily #8 cylinder and got no oil out.

Then I used a bump switch to push the oil out the glow plug holes and got no oil out of them. Then I did a compression test on the driver's side cylinders and installed new Motorcraft glow plugs.
If the engine sat for for a day or more between the time you pulled the injectors and used your bump switch then most of the fluid may have leaked past the cylinder rings into the crankcase. If you did a compression test after re-installing the injectors then hydrolocking the engine isn't a concern.

As previously mentioned....turning the engine over by hand is the best/safest thing you can do whenever you are concerned about hydrolocking. I always rotate the engine by hand whenever changing injectors. Once I get 3 or 4 good revolutions, then I usually place the valve covers loosely on the heads and crank over the engine with the glow plugs removed. That usually does the trick.
 
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Old 11-12-2012, 12:55 PM
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FYI:

I got this idea from Dan (kwikkordead).

When changing injectors it is best to pull #7 and #8 first. Since the block is lower in the rear this allows almost all the fuel and oil to drain into those two cylinders. The other six cylinders get only a small trace of fluids in them. It's easier to deal with the fluids in just two cylinders rather than all eight.

It also helps if cylinder #7 and #8 are at BDC when you pull the injector. It will help contain the fuel and oil in the cylinder and not let it overflow back onto the head and drain into the crankcase. If either is at or close to TDC the fuel contaminated oil will oveflow out the GP hole and/or injector bore. I change the oil after an injector swap but just the same I try to keep the crankcase oil from being contaminated with fuel.
 
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Old 11-12-2012, 09:23 PM
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Old 11-14-2012, 12:47 PM
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Originally Posted by Riffraff Performance
Good link Clay. And it does say;

NOTE: Remove the aft injector from each head first. This will keep most of the fuel and oil that remains in the head limited to those two cylinders. You will evacuate them before you re‐install the injectors.
 
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Old 11-14-2012, 01:08 PM
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Originally Posted by PaysonPSD
Good link Clay. And it does say;

NOTE: Remove the aft injector from each head first. This will keep most of the fuel and oil that remains in the head limited to those two cylinders. You will evacuate them before you re‐install the injectors.
Here's the deal. I did that. And I heard the glug, glug, glug of the oil entering cylinder #8. But then, with the injectors out and the glow plugs out, I spun the engine with my bump ("remote starter") switch until the fine mist (of fuel/oil) coming out of #8 stopped.

Then I put my injectors with new o-rings and coppers back in.

Then I used my bump switch and did my compression test. And no fine mist came out.

Then I tried my Bill Hewitt inspired HPOP oil changing vacuum device and stuck the vacuum tube through each glow plug all the way until it bottomed out and vacuumed all of the driver's side cylinders and . . . got absolutely nothing to come up.
 
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Old 11-14-2012, 01:55 PM
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Tim,

If you are still worried about hydrolocking get a 24MM socket and the longest breaker bar you can find and hand crank at the damper pulley bolt. If you can hand crank it 360° you are good to go.
 
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Old 11-14-2012, 02:06 PM
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Originally Posted by PaysonPSD
If you are still worried about hydrolocking get a 24MM socket and the longest breaker bar you can find and hand crank at the damper pulley bolt. If you can hand crank it 360° you are good to go.
Thanks! That seems to be the definitive test per you, Shake-N-Bake, SSJ, Tugly, etc.:

If one can crank the damper pulley bolt 720° with wrench by hand, then the engine is simply not hydrolocked.*


 

Last edited by Tim Hodgson; 11-14-2012 at 07:13 PM. Reason: *revised per Cleatus12r
  #12  
Old 11-14-2012, 02:22 PM
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What if the engine hydrolocks, how do you fix that problem? Do you pull the injectors out again and repeat the steps in the instructions to evacuate the oil and try it again?
 
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Old 11-14-2012, 02:23 PM
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Originally Posted by robbragiel
What if the engine hydrolocks, how do you fix that problem? Do you pull the injectors out again and repeat the steps in the instructions to evacuate the oil and try it again?
Just remove the glow plugs.
 
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Old 11-14-2012, 02:32 PM
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Got it, Thanks Robin
 
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Old 11-14-2012, 06:56 PM
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Originally Posted by Tim Hodgson
Thanks! That seems to be the definitive test per you, Shake-N-Bake, SSJ, Tugly, etc.:

If one can crank the damper pulley bolt 360° with wrench by hand, then the engine is simply not hydrolocked.

720 degrees. 360 will only ensure 4 cylinders have gone through a compression stroke with no issues.
 


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