Salvaging my 318. Advice needed.

[tsteiner61]

If you read my other post, you know that my crate 318 long block tanked on me. Number 6 piston hit valve..broke off...entire contents of cooling system cycles through oiling system...engine shuts down with loud thud...freezes... and won't move.

Now, contrary to what I initially thought, I think the block will be OK. So the question is what can I save, and what is ruined?

Here are my guesses, tell me if I am on the money or not..

1. Oil pump/pickup.........toast!
2. #6 piston...........toast!
3. #6 intake valve.........toast!
4. camshaft........still good
5. pushrods........still good
6. rocker arms and shaft......still good
7. crankshaft............????
once coolant cycles through it, is it ruined (assume the journals are fine)

Thanks for the help.

[9dodge]

I take it, that it has a blown head gasket? How did the coolant get into the motor? I've broke some motors and if a piston lets go it will sometimes take out the cylinder wall.
Also in blown up motors, I've reused alot of stuff, just take a good look at everything and anything that is questionable, toss it.


Michael

[tsteiner61]

Sorry not to explain more, but my other post was very wordy. Basically the #6 intake piston broke in half. Judging by the sound when it happened, I would say it hit the piston. I will know for sure as soon as I get the head off.

Also, I am praying that it got the head and not the block. I'd rather replace the heads because that way the motor can stay in. It was a real bi#ch getting it in there because it's a 4x4 with 35 in. wheels, and the cherry picker I have barely made it over the front crossbar.

Hopefully, I will get the thing off tonight.

I just thought that once coolant got inside the crank oiling passages, it would be toast...I ask, too, because I've only been doing this for about 3 yrs. and I am still developing my eye for inspection of parts. I always tend to pick real losers from the junkyard no matter how carefully I seem to inspect.

Thanks for the help.

[Billydelrio]

I would think that most of the 318 parts will survive the ordeal. The oil pump and pickup should not be hurt by the coolant. They will need to be taken apart and cleaned. Things to look at would be the piston, rod, crank, block, and the head. When a valve breaks and gets between the piston and chamber, the piston and head usually absorb most of the damage. A bent rod is possible. If the rod is not bent, then the crank most likely did not hit a damaging inertia stop.
You just have to take the engine apart and have a look see.
Billy

[PRO]

Well heres my take,your heads will need a thorough exam as its likely you have a guide/valve fit thats too tight(valve stuck open)that head may not survive as this is common when a valve breaks completely off. If you shut it off right after it grenaded its very unlikely any debris made it back to the pump,a quick inspection of the pump rotor and housing for scratches will tell.Coolant wont hurt anything as long as it wasnt run for an extended period.Look carefully at your cylinder wall for imperfections this is probably your biggest concern because youll have to pull the block to rebore.Check the cam it may not be ok depending if any debris got between the cam and lifters.Hopefully you can get another rod/piston and rings and simply reinstall,but dont overlook anything,go slow,check it twice,magnaflux the head for cracks,check for tight guides and hopefully all will survive....PRO....

[tsteiner61]

Well, got the heads off and the damage doesn't look too bad. However, I noticed coolant leaking down from the underside of #6, and I'll have to guess that is bad news. This crate motor came to me bored .040 over and it is a thin wall 4006730 casting so that's the max as far as boring goes according to the Mopar engines book.

What really puzzles me though is how did the coolant get mixed with the oil. The head gasket was in perfect shape (it was new when I installed it). No cracks or wetness on the head.

Is it possible that the coolant was mixing with the oil all along and that caused a sticky valve? Because thinking back, I remember the exhaust was spraying a bit of water, but my friend and I just thought it was junk that had already been in the pipes before I bought it, so we dismissed it. That was probably the coolant mixing with the charge and exhausting out.

Well, all advice is appreciated. I will continue the teardown, and I have some carnage pix, too..Thanks.

[michael_637]

since u have looked in side, u didnot say much bout damage other than piston an valve. I run small blocks also, have had valve smack piston also. I have been lucky though just bent valve. Make sure u magniflux heads an block, The valves guides have a water jacket round them. I have experienced that when a valve hits piston, some times it does break the guide causing anti freeze to leak in to motor. Probably not a lot of help, but maybe some ideas for U. Good luck

[tsteiner61]

This is helpful as I have not checked that yet. Couldn't find any holes anywhere else. Still have yet to turn the crank and inspect the remainder of the cylinder. If cyl. has any damage, though, the block is toast as it is overbored max. allowable.

[gthomas]

Soemone more knowledgable than me may have to answer this. I heard that antifreeze reacts with the babbit in bearings and can ruin them. If this is the case, you may have to check the main bearings. Anyone????

[Dr. Righteous]

You would think that water and oil doesn't mix but it is amazing how coolant in the crankcase makes a nice chocolate malt. Coolant in your tranny makes a nice strawberry shake! The water in your coolant will rust and pit your bearing journals. That is the danger. Usually once someone notices they have coolant in their crankcase there is damage already done unless it is found iimediately when it happens. The THIN oil/coolant mixtures doesn't provide a good "hydro wedge" around the bearings journals and they kiss the bearing under load. Bye bye oil pressure, bye bye bottom end.

[tsteiner61]

I would have to guess it was operated the equivalent of 3-5 miles with coolant because the day before it tanked, I was idling it (see above) and I splashed a bunch of mucky black stuff onto my neighbors Honda (hehe), when I revved the engine. At the time, we thought it had accumulated from the previous owner/engine. I think we were wrong.

What I'm still trying to determine is did the coolant/oil mix cause the broken valve (maybe stuck open due to lack of lube) OR did the broken valve (insufficient valve-piston clearance) cause the coolant/oil mix. I can't see any visible runs or cracks in the head, so until I inspect further, I tend to think that maybe it came from the block. I've seen my share of older (this one was cast in 1975) Mopar blocks cracked in the dist. shaft area where the coolant and oil passages run rather close, and the casting is rather thin. But that's not my final answer...

On the piston, it only looks like the valve hit a few times, so I have a hard time believing insuff. valve/piston unless I actually break out the clay. Seems more likely to me that it got stuck open...Then BOOM.

The thing I do know already is that coolant was dripping from the underside of #6 when I pulled the oil pan off. Hopefully tonight I will have a few minutes to inspect the rest of the cylinder and go from there. Maybe some pix, too.

Thanks.

[Billydelrio]

Sounds to me like you might have a pin hole or crack in #6 cylinder. A pin hole is not too common and is a pain to diagnos at times. The only other way for water to get in is from the top (head,gasket, intake). The water could have gotten into the cylinder when you pulled the head off. I don't know the order in which you pulled the engine from together to apart.

good luck
Billy

[tsteiner61]

Well, Billydelrio is right on the money. There is a huge crack in the cylinder running almost top to bottom. At first I thought it might be a scratch from a piece of the broken valve, but it aint no scratch. It's cracked like an old sidewalk would be when a tree grows under it. Raised on one side and lowered on the other. I still think they bored it out too much. Maybe I will have my engine shop sonic test it before I take it back..

I took a bunch of pictures, just because this thing was so huge, but I forgot to bring them with me to work today, so I'll post them soon.

So now the real hassle begins. Trying to get a replacement from the dealership. No receipt, so I'm probably SOL unless I get really creative...

The advice is appreciated.

[9dodge]

I wish you luck, I would just chalk it up as a loss. Go to the junk yard and get a complete motor. 318's are boat anchors around here and the local junk yard throws them away. Not trying to S**t in your cheerios, but another post suggested, put yourself in their shoes.

Good luck

Michael

[5thAve]

Not that it matters now for you now since the engine is toast, but parts could be re-used if anitifreeze mixes with the oil, but bearings would more then likely need replacing and crank should be machined also while it's out.

The valve isn't necesserily fault of the antifreeze. Could also happen as a result of the timing chain skipping/breaking, piston seizing in place, etc... Check the cam before re-using it to make sure no damage occured to that lobe, or others, from kickback.

[Karl43]

If you are going to reuse some of the parts, let me caution you on the pushrods. I overheated a 318 this summer and the even bank head guides swelled and all of the exhaust valves hit the pistons on that side. I even cracket the whole head of #6 exhaust off. Luckily it did not put a hole all the way through the piston.

I took the head back to my head guy with new exhaust valves. He replaced all four of my guides (my valves were stuck in them and they came out with the valves), reground the exhaust seats, and put them all back together.

I had to replace all of the pushrods because they were bent on all of the cylinders that hit the pistons. I also broke one of the #8 lifters that had to be replaced. The cam was fine. The car runs pretty good now.

Good luck finding a 318 block. I hope you can find one of the earlier ones with the good metal.

[tsteiner61]

Well, the whole thing is finally apart, and here's the verdict.

The number 6 cylinder wall has a crack in it the size of Montana. Picture below (if it shows up). When I pulled the #6 piston, surprise, surprise, it the pin was so tight I couldn't even move the rod by hand. I would have to believe this generated the heat which caused the crack and then the broken valve. Just a guess.