Headgasket causes bent rod ?

blksc

Registered User
Hi, i think i have posted that im changing my head gaskets, and i someone said that if the heads blew with water in the cylinders then its a good chance that something else went wrong on the bottom end.

I have removed the surface rust from the system, and i have oiled the cylinders and rotated the assembly. I dont get any binding and i dont hear any weird noises.

Would i be able to tell the health of the bottom end if i took the oil pan off and rotated the assembly ?
 
Primary danger is the coolant mixing with the oil. Coolant (no effective lubrication) will cause rod and main bearings to fail in a fairly short time. If your oil looked like a chocolate milkshake then I'd be askeered... and do more than just visually check. If the oil looked ok you may be fine but there's no real way to tell unless you disassemble the rotating assembly.

If there was a lot of water/coolant in the combustion chamber you may have hydrolocked it and bent a rod but I'm not sure I ever heard of that happening on a SC.
 
Well, what happens is this...

If you get water into the cylinder, the rod and piston come up to TDC and try to compress the water. Since water cannnot compress, it goes past the rings and usually either bends the rod OR crushes the bearing. If either one happens, the engine will more than likely self-destruct in hours.


In my opinion, your this far along, remove the motor, replace the bearings and ask a machine shop to LOOK at the rods. They could tell you if they are OK.

Then, replace the rings, and just like (Kinda) a new motor.

You'll be a lot safer if you go this route. I know since I threw $500 away when I did what you are doing and the motor blew 1 week later. No water in oil, everything looked fine.

Not trying to scare you, just advising that the best course of action.


Good luck.


Don
 
heads

a shop pressure tested my cooling system, and it forced water into one cylinder. the shop called and said my starter was locked up.. huh? and a blowen headgasket.

i pulled the heads and #4 didn't come up as high as the rest of the pistons when turning the motor over.. something to check

hydo-lock is temporary condition.. i went to pick my car up ther next day and it started and drove home no problem... i was expecting to find a locked up started like the shop said...
 
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Thanks for the replies. There wasnt ALOT of water in the cylinders. If a rod was bent, or the bearings are bad would i noticed it while rotating the assembly ?

Now the guy i talked to said that he was driving the car and then noticed a really loud ticking sound follow by the car stalling.

Crap i guess the best thing to do is just inspect the bottom end. I just need to get the motor runnin well enough to move under its own power on street cleaning days. i am building a High performance motor seperately.

Doesy Hyrolock imply that the assmebly will not rotate ? Because mine rotates without a huge amount of pressure and i dont feel any binding
 
Well, Hydrolock is this...

When a motor hydrolocks, the piston tries to go up in the cylinder. The water does not compress and causes the rod to bend under the extreme stress of trying to compress the water in the cylinder since there is no where for it to go. The starter that was shot is the fact that they tried to start the motor with water in the cylinder and the engine would not turn over. After some time of sitting, the water will get past the rings and the engine will start.


The simple fact that one cylinder does not come all the way up tells it right there......THE ENGINE IS SHOT!!!! .

I would suggest that if you must drive it at all, keep the coolant level very low. The engine is shot no matter what anyone says.

Best of luck to you.


Feel free to call me if you need a better explaination....


(973) 277-4294


Don
 
P.s.

The engine will still run with a bent rod. It will self-destruct though after running for a while.


Don
 
As was posted hydrolock is temporary, it lasts until the water is drained from the combustion chamber. Only takes enough water to fill the combustion chamber and one compression stroke for it to do damage though.

If all you're worried about is getting it to move then go ahead and put new gaskets on it, add some heavy weight oil and cross your fingers it's ok till your other engine is done. If you're looking for a daily driver then take it the rest of the way down and put new bearings in it and have a machine shop look it over. Just my opinion....
 
Im gonna twist fingers and hope things are okay. I dont need it as a daily driver. Do you think i should drain the oil or drop the pan to see if i can visually see anything that sticks out ? i did pull the dipstick and there was no coolant, it was dirty, but no coolant. When i pulled the IC tubing i did find milky substance though.. any thoughts ?

As always your help is so appreciated.
 
Definitely change the oil.... Watch as you open the drain plug, if there's water/coolant in the pan it'll be the first thing out (oil floats on water).
 
Cool. If there is water in the pan, wouldnt it show up on the dipstick ? I am full of questions, but one thing i noticed is that the radiator blew on the car so i dont think water even had a chance to enter the engine in large amounts. I tried to put water in the radiator and it poured right out. Two of my cylinders had water in them (gaskets blew near water jacket) and the rest didnt. the level of water wasnt very much at all.
 
I guess honestly there is no way or person that can promise that the rods are okay. The best way to measure height of the piston, and probably jank th oil pan to see whats lurking inside.
 
Trying to help here....

If there was ANY water in the cylinders and the shop said that the starter didn't work, THIS IS BAD NEWS!!!!


The fact that also the one piston DID NOT come up as high as the others is another indication of a SHOT MOTOR!!!!

Not trying to ruin your day, just trying to help you NOT put money into head gaskets and waste it. You CANNOT tell if a rod is bend by removing the oil pan. The ONLY WAY you can see if a rod is bend or cracked or damaged is by a machine shop. No other method is available. You cannot just remove the pan and see these things. If you are building a HI-PO motor yourself, I severely suggest getting some help in building it if you are having a problem with this engine.

Not being condesending, just the facts that if two cylinders have water in them, rebuild the motor.

I hate seeing someone spending good money on a motor that is no good (TRUST ME, I DID JUST THAT!!!!!).



Good luck,


Don
 
when my HGs blew i fixed it, put it back together, then a day later it bent the rod. so i had to get it rebuilt.
 
Carlos, get yourself a good straight edge to lay on the deck and an accruate way of measuring the piston to deck distance at TDC to compare each. This is a simple way to tell if you have a bent rod without a teardown. If you are not going to drive the car (aside from moving it for parking reasons), dont bother pulling the bottom end apart unless you do find a bent rod.

Paul
 
This rod is from one of the 3.8L's I've disassembled. Apparently the previous owner had driven with a blown headgasket, until one day the engine would not turn over. The owner took the car to a shop, which replaced the headgaskets. Afterward, the engine had a slight knock, but had plenty of power to move the car around.

bent%20rod%20front.jpg


bent%20rod%20side.jpg


It doesn't take much water in a cylinder to cause damage like this.

-Rod
 
Hey BTM thats what i planned to do. Lube70 you did come off a bit rough but its cool. I have built motors before. I wasnt having a problem with this motor. I was asking for everyone's opinion on the possibility of a bent rod.
 
BTM in Cali ?!

I would be most honored to have your help paul. What are you doing this weekend ? As always beverages and food are on me.
 
The weekend looks pretty open at this point, just dont expect me to rise to early :D Give me a call Friday afternoon or evening and we can firm up plans.

Paul
 
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