Hydrolock = bent rod?

[andrew15]

Well, to cap off a pretty terrible week, I went to start the car today and it appears hydrolocked. There was a lot of rain over the last week or maybe a needle valve is stuck open. Either way, I went to start the car today and was met with the engine turning over 1/2 a roation and than stopping.

I'll remove the plugs tomorrow morning to check for fluid, but how can I check for a bent rod? The engine has 2.0 rods, but just a standard starter.

Thanks,
Andrew M

[Raceboy]

If you're unlucky, then yes, it may result in bent rod. But in most cases id doesn't. Usually when one cylinder is has water/fuel in it and others don't and engine tries to start, it means bent rod but if starter motor, then not necessarily.

But I don't have any suggestions how to check for bent rod without taking off the cylinders.

[mb911]

you can also put it in 3 rd gear or so and rock it backward the water will evactuate enough to get it to rotate. I highly doubt a bent rod

[Flat6pac]

Turning the engine 2 revolutions backward will pour all the liquid down the exhaust
Bruce

[rvanderpyl]

It's not likely that a 1/2 revolution with the starter motor will bend a rod, it doesn't have enough torque and you wouldn't have enough RPM's going.

[matt demaria]

A compression check will show a bent rod. A change in .010" deck height will change compression ratio by a quarter of a point.

[E Sully]

Won't turning the engine backwards too much risk valve & piston contact? The chain tensioners only operate properly in one direction.

[Don Settergren]

If you do find water in the cylinders, change the oil ASAP. The magnesium oil pump doesn't like water much. I rebuilt a flood damaged 3.6l and really only had a problem with the oil pump - but of course it is under the last bolts in a total engine tear down.

Does the car show any water lines on the rear wheels\tires (the dirt rises and stays behind at the top of its flood level)? If so, how high did it go? Do you have any moisture any where inside the car?

[304065]

Put the rod on a surface plate so the big end is flush against the plate. Then zero out a dial indicator on a stand on the small end. Flip the rod over, put the indicator point on the small end and note the reading. If the rod is bent this will tell you.

[fastfredracing]

I doubt you bent a rod, I dont think a stock 911 starter has enough oomph to do this. I have seen several 911 motors hydro locked, with same symptoms as yours, and no real damage. Pulled plugs, changed oil, and off to the races, of course , you have to find out where the water/or fuel came from .

[rvanderpyl]

Originally Posted by john_cramer

Put the rod on a surface plate so the big end is flush against the plate. Then zero out a dial indicator on a stand on the small end. Flip the rod over, put the indicator point on the small end and note the reading. If the rod is bent this will tell you.

I don't think he wants to disassemble the motor to check it.

[Bobboloo]

Pull the plugs and the muffler off. Disconnect the ignition and turn the motor over a few turns to pump out the water. Reassemble and start it up.

[andrew15]

Hi Guys, here's the update:

- The engine is twin-plugged, so I removed the lower plugs and water poured out from #4.
- I changed the oil to take care of any water that got into the bottom end via the rings
- Hand cranked it and felt no resistance
- Put in new top and bottom plugs and started it up
- Car seems to be fine with no issues
- I'll perform a compression test and leakdown when I get back from holidays.

The culprit was a missing wingnut on the watershield cover - it left a 1mm gap which was apparently enough to let in copious amounts of water.

Thanks for all the help!