Hydrolock from gas, possible engine damage?
 

I attempted to crank over my engine with my new carb (Quadrajet on crate 350). I guess the float was stuck from shipping so It poured gas everywhere. I didn’t realize that it also flooded the cylinders until I tried to crank it a few days later and it felt like the battery was dead and cranked over maybe two rotations and then froze. I pulled the plugs and gas came out of cylinders 6 and 7. More out of 6 then 7. I spun the engine with the starter with no plugs and cleaned out the engine. Nothing sounded off. I put the plugs back in and it was running rough. Shaking the whole truck. I thought it might be a vacuum leak or bad coil so I changed out the coil and now it only cranks and won’t fire. Is it possible that I bent a rod while trying to turn the engine over when it had gas in a cylinder?
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Re: Hydrolock from gas, possible engine damage?
 

yes, it is possible, but I've never actually seen it. I would run a compression test. If the comp test checks out good, Change the oil and filter before you drive the truck, gas diluted oil can cause severe engine damage.
Hopefully, it just runs bad cuz of the carb.

Re: Hydrolock from gas, possible engine damage?
 

Where is the oil level? Gas in the oil? Will it turn over manually with plugs out?

Re: Hydrolock from gas, possible engine damage?
 

Oil level seemed lightly high. Just a small run over full. I could smell the gas on the dipstick.

Re: Hydrolock from gas, possible engine damage?
 

I've seen it happen. Compression is be slightly low in that cylinder(s)

Re: Hydrolock from gas, possible engine damage?
 

The starter shouldn't have enough force to bend a rod. Washed out rings will make a engine run bad. Change oil, check compression, use oil in any cylinder that might have low compression to see if the compression will come up, if all of the cylinders have good compression rotate plugs and see how well it runs. Are you trying to run it with the same carb that flooded the engine? You might need to try to run it with a donor carb?

Re: Hydrolock from gas, possible engine damage?
 

[QUOTE=BigBird05;8896460]...<snip>...Washed out rings will make a engine run bad. ...<snip>.../QUOTE]

This is exactly what I was thinking. Sounds like the fuel sat in the cylinders for a while too.

Get some oil into those cylinders.

-klb

Re: Hydrolock from gas, possible engine damage?
 

A new set of spark plugs will likely cure the rough running. It is likely the insulators on plugs have been covered in gas and any micro cracks have filled with carbon carried from the cylinder and left by the gas when it burned. This will cause misfires from the shorted electrode.
The starter alone shouldn't be able to cause damage from a hydro-locked cylinder. The literal kicker is if another cylinder fires just prior to the hydro-locking. Then its a whole different situation.
As several members have said a compression check will tell the tale. An oil change is necessary as fuel did go past the rings. It is cheaper to change oil in a SBC than it is to do a fuel dilution test of the oil.

Re: Hydrolock from gas, possible engine damage?
 

Thank you for the advice fellas. I will change the oil tomorrow once I get off work and the plugs. Compression test as well. I’ll update once I get it back together.

Re: Hydrolock from gas, possible engine damage?
 

I think I found the issue lol. Changing the plugs. Haven’t done a compression test yet though.

Re: Hydrolock from gas, possible engine damage?
 

Well, I've never broken a spark plug. :rolleyes: I'm curious- how long have the plugs been in that they have rust on them? Bear in mind that I live in the California desert where rust is a word "furriners" use. :lol:

Re: Hydrolock from gas, possible engine damage?
 

I installed leaky valve covers to keep my plugs from rusting. ;)

Re: Hydrolock from gas, possible engine damage?
 

If I had to guess, I would say these have been on the truck for about a year maybe. I guess a combo of the rain and humidity in Tennessee makes anything that isn’t painted rust up pretty quick.

Re: Hydrolock from gas, possible engine damage?
 

Greasey Harley, Nobody that drives a sbc should ever have rusty spark plugs.

Re: Hydrolock from gas, possible engine damage?
 

I was pulling your leg, bud. ;) I once bought a '72 Le Mans that had spent it's life in Malibu. It was rusted out, bad.

Re: Hydrolock from gas, possible engine damage?
 

Rats got under the hood of my 03 Silverado and dined on a few of the injector wires. I repaired the damage and took it to the car wash to clean up their mess. The truck ran fine but developed a miss fire shortly thereafter. Cracked plug. Apparently cold water on a hot plug is a bad idea!