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Discussion Starter #1
in trying to get my car to run today, i pulled the plugs. the top of the piston on #4 was coverd in gass. would this:
#1 cause the motor to hydrolock
#2 cause the motor to not turn over
#3 distroyed the motor


could i have maybe edged past a blown motor since it never ran..it was just cranked over with the starter?
 

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Pull the fuel pump fuse and all the spark plugs. Now crank the motor over and let all the gas come out of the spark plug holes. You might want to change your oil, since the gas will get past the rings and contaminate the oil.
 

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I guess the definition would be something like "Petrolock" then Storm ;-)

Fact of the matter is that hydrolocking an engine involves the fact that liquids can not be compressed, so you could hydrolock an engine with Apple Juice if you let a 2 year old next to the car for too long...

Tom
 

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but even then it would be the water in the applejuice that would actually cause teh damage. Since gas doesnt have water in it, then no, you cant "petrolock" the motor. I would say the worst that can happen is detonation. Which is still pretty bad...
 

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Discussion Starter #6
well, im not talking a little bit of fuel..im talking about seeing gas on top fo the piston with a flashlight..like enough to look like a puddle. i repalced 3 of the 4 o rings but i still have 2 that leak with a slow drip. im hoping that with my one new remaining o-ring and one old one that i have, i can get the car running long enough to take it to a shop and just buy new injectors. i aparenly cant get these things in without messing them up. i figure i will buy the injectors so i dont have to pay the shop markeup and then let them put them in..that way if they mess up o-rings its there fault :)
 

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The gas would need to fill the chamber a great deal to actually "lock" the motor. Any fluid can do that. Seems unlikely that a leaky inj would provide enough fuel in a short enough amount of time to cause that damage. Anything is possible but not likely.
 

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Discussion Starter #8
good point, but that one injector was just spraying gas..i mean, it was awful. it was like a couple squirt guns...and that was just when the lines pressurized!! i didnt know what it was at first..so i kept trying to start the car. since the motor wasn't running..and it was just the starter motor trying to start the motor, it might have been all right. i know the motor would crank and then just stop..and then i would wait a bit and it would stop. seemed to stop pretty violently. i dont know..i guess i will find out soon enough. i put my old O2 back in, so i dont ruin the new one until i got this problem solved
 

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So has anyone hydrolocked their engine? And what are the symptoms and/or long term effects of this ? TIA
 

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Yes, I have done exactly what you described. When I tried to crank it (I didn't know it was um, beyond just flooded) the car just made a loud clunk and wouldn't do anything. Pulled the plugs and one cylinder was like looking down a well. There was no permanent damage. Do the procedure Eric listed in the first reply. And uh, don't light up when you do this.

The cause of the problem in my case btw was o-rings. We were testing a set of 370s and a new JWT ecu, and didn't use new o-rings. Live and learn. Put a lil' coat of grease on _new_ ones when you put 'em in, works great.
 

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combustion needs oxygen, so if too much gasoline got in the cylinder and not enough oxygen, then yes, it would have the same effect as a hydrolock. It's like when a room is leaking gas and near the upper flammable limit, you flood it with gas to get it above the flammable limit so it can't ignite. I think it is a similar scenario when you flood a lawnmower engine. Granted, it would have to be a nasty leak. Bad gas could provide enough water with the leaky injector.
 

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Discussion Starter #12
thanks Calum - thats ome of the best news i have heard all day :)
 

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Too much gas would definately not cause detonation. Too little gas will (running too lean).

If *ANY* liquid, in enough quantity gets into the cylinder and the piston comes to the top of the chamber, it will probably cause damage (bend a valve, in really bad cases a rod, crack a piston, ruin the head gasket, etc).

Gasses compress (I'm talking Oxygen, Hydrogen, etc - not gasoline), liquids don't - they can't. When the engine goes into the compression cycle and there's liquid there, something's got to give, and it's the engine that does. Yup - water, unburned gasoline, oil, and even apple juice can bend a valve or a rod.

Tom
 

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Yea, but the saving grace I think in this case is that the engine wasn't actually running when it was locked. So the the lock isn't stopping the force of a running engine, its just stopping the starter. That still can't be good, but at least in my case the starter wasn't strong enough to bend a valve. Funnily enough not too awful long after this occured I got starter squeel.
 

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Calum said:
Yea, but the saving grace I think in this case is that the engine wasn't actually running when it was locked. So the the lock isn't stopping the force of a running engine, its just stopping the starter. That still can't be good, but at least in my case the starter wasn't strong enough to bend a valve. Funnily enough not too awful long after this occured I got starter squeel.
Right, because the crank and other rotating parts weren't running at 5000 rpm, they didn't have a lot of energy to really bend or break items in the cylinder.
 

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Discussion Starter #16
we have a heart beat!!!

i FINALLY got the car to turn over. all the injecters where not leaking when i put them back in for the final time, but it still took a lot to get the car to finally turn over. its been running for about 20-30 min now, and im going to let it stay like that until i leave to go to work. thanks for your help everyone!
 

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Great news man! I hope it all clears up for you now.

Brent
 

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yeah you can hydro lock a motor with oil too if oil leaks from your valve cover you take the spark plug outand trun the motor over to launch the oil out i had to do this. it takes alot to hydro lock a motor any way and plus you wouldn't have to do this for the gas you could just take the plug out and it would just evaporate sence it has such a low boiling point but sence you got it to work it kinda sounded like the injectors were priming but the plugs never got a spark and you just flooded your motor. well congrats on geting it running later
 

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If a little gas gets in the cylinder and the piston moved up and compresses it enough the gas will ignite. Thats how a diesel engine works. The pressure has to be pretty high though and there does have to be oxygen. The question is, at that kind of pressure whether the fuel would ignite before and engine components were damaged.
 

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I was replacing the fuel injectors in my 91 highport and hydrolocked the #3 piston. it can be done and it sucks cause your going to be replacing parts that shouldn't break. the highport is especially suseptable to hydrolock if you remove the injectors. The fuel rail is above the intake valves. Because of this the fuel will dump down into the open vavles on on to the piston. with the lowport, the intake design wont allow that to happen. . I've done it once and wont do it again. like was said. if you see a puddle, remove the plugs, the fuel pump fuse AND the fuse for the ignition coil. Sure would suck to have the fuel spray out of the engine and have a spark throw from a wire.
 
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