I hydrolocked my engine a couple of times. What's the chance of a bent con rod?

[rs2k]

While trying to figure out if the engine had a blown head gasket (which it did), a cracked block, or a bad manifold, I hydro locked the engine a couple of times. Each time it happened I pulled the plugs and spun the water out. I didn't try to crank it over when the starter would start to stall.

 

[TilliamWe]

Re: I hydrolocked my engine a couple of times. What's the chance of a bent con rod?

You sure about your exhaust manifolds?

Usually a starter motor will not bend a connecting rod. Of course there is a chance, it's just a smaller chance.

 

[bigred69]

Re: I hydrolocked my engine a couple of times. What's the chance of a bent con rod?

Yes you can bend a rod or break the crank from hydro locking your motor. Depending on how much water is coming into the cylinder and how fast the starter is spinning. IT CAN HAPPEN! I have seen it many times.

 

[wca_tim]

Re: I hydrolocked my engine a couple of times. What's the chance of a bent con rod?

I would reeeaaalllyyy check those manifolds based on what you're posting....

note that water intrusion is an easy way to blow a head gasket, eh?

How old are the manigolds? have you pressure tested them?

 

[rs2k]

Re: I hydrolocked my engine a couple of times. What's the chance of a bent con rod?

Here is what I know:

Engine not on hose:
Engine runs fine.

Engine and both manifolds hooked up to hose:
Engine runs fine until cylinders 2,4,6,8 start to flood.
(When left hooked up to hose like this and engine off the cylinders flood.)

Everything but port manifold hooked up
Engine runs fine.
(When left hooked up to hose like this and engine off the cylinders DO NOT flood)

I pulled the riser off the port manifold and it looks like the gasket might have failed. The gasket is so old it's hard to tell though.

 

[Howard Sterndrive]

Re: I hydrolocked my engine a couple of times. What's the chance of a bent con rod?

What's the chance of a bent con rod?

50/50

do a compression test.

 

[danond]

Re: I hydrolocked my engine a couple of times. What's the chance of a bent con rod?

A cooling system pressure test would be good, too.

 

[Don S]

Re: I hydrolocked my engine a couple of times. What's the chance of a bent con rod?

I pulled the riser off the port manifold and it looks like the gasket might have failed. The gasket is so old it's hard to tell though.

Usually, the gasket doesn't fail, what happens is the gasket surface of the manifold and/or riser corrodes away.

 

[rs2k]

Re: I hydrolocked my engine a couple of times. What's the chance of a bent con rod?

Usually, the gasket doesn't fail, what happens is the gasket surface of the manifold and/or riser corrodes away.

Thanks, that looks like the problem. The surface was corroded. I better replace all 4 manifold gaskets then. I also need new rubber exhaust tubing. Where can I get that tubing and what's the easiest way to install it when the exhaust manifold is not apart?

I have a feeling the previous owner used RV and marine plumbing antifreeze to winterize the motors.

 

[Don S]

Re: I hydrolocked my engine a couple of times. What's the chance of a bent con rod?

If the surfaces of the manifolds and risers are bad, you need new manifolds and risers. Not just gaskets.
The wrong decision can cost you an engine along with the manifolds and risers.

 

[rs2k]

Re: I hydrolocked my engine a couple of times. What's the chance of a bent con rod?

Can they be resurfaced?

 

[Don S]

Re: I hydrolocked my engine a couple of times. What's the chance of a bent con rod?

Clean the gaskets off and post pictures of the gasket surfaces of both the manifold and riser where they go together.
Note: A blurry picture won't help.

 

[rs2k]

Re: I hydrolocked my engine a couple of times. What's the chance of a bent con rod?

The corrosion is not that bad. It is just pitted at the meeting surface. It almost like the gasket was not pressed enough. The part that is still good is still shiny.

 

[rs2k]

Re: I hydrolocked my engine a couple of times. What's the chance of a bent con rod?

Here are some photos. I hope they are not too blurry.

 

[rs2k]

Re: I hydrolocked my engine a couple of times. What's the chance of a bent con rod?

The gasket fell apart upon removal. I did not scrape all the remnants off the engine half of the manifold because I didn't want FOD in the cylinders.

 

[TilliamWe]

Re: I hydrolocked my engine a couple of times. What's the chance of a bent con rod?

Here is what I know:

Engine not on hose:
Engine runs fine.

Engine and both manifolds hooked up to hose:
Engine runs fine until cylinders 2,4,6,8 start to flood.
(When left hooked up to hose like this and engine off the cylinders flood.)

Everything but port manifold hooked up
Engine runs fine.
(When left hooked up to hose like this and engine off the cylinders DO NOT flood)

I pulled the riser off the port manifold and it looks like the gasket might have failed. The gasket is so old it's hard to tell though.

Okay, all your tests and condition of your manifolds point to the manifolds being bad. I can't tell from your photos, cause they are too blurry, but I am guessing that you have junk exhaust manifolds and risers.

 

[rs2k]

Re: I hydrolocked my engine a couple of times. What's the chance of a bent con rod?

Hmm, where's a good place to get 4 OMC exhaust manifolds and risers?

 

[danond]

Re: I hydrolocked my engine a couple of times. What's the chance of a bent con rod?

eBay's always good, but did you mention what kind of engine/drive combo you have?

 

[rs2k]

Re: I hydrolocked my engine a couple of times. What's the chance of a bent con rod?

Twin OMC stringer 800 series with Chevy 350s putting out 260 HP each.

Looks like about $1000 - $1200 to replace all the manifolds.