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340 Blew

HawkRod

Formerly hsorman
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Crap.

My son was driving his 1973 Road Runner (was my first car) on the highway back to college and the engine blew. It's a 340 with a 727. My son said that there was a loud bang, then smoke and that was it.

When we got it home, the engine is completely seized and will not turn at all. In draining the oil, first about a gallon of antifreeze came out, and then clean oil. My suspicion is a rod let loose and gutted an internal water jacket (but there are no external holes in the block).

Now to pull it and see what happened. Any tricks or suggestions for separating the tranny now that I can't get to all the flex plate bolts? Do I just need to pull them as an assembly?

Thanks,

Hawk
 
Pulling the motor and trans together is easiest, separate it when it's out of the car
 
I'd pull it as an assembly then just separate them, torque converter should pull right out with the engine.
 
Pulling the motor and trans together is easiest, separate it when it's out of the car
I'd pull it as an assembly then just separate them, torque converter should pull right out with the engine.

Thanks guys - that's what I figured. I don't think I would have room to pull the torque converter off with the tranny in the car, so I'll do it as an assembly.

Pics of the carnage to come once we dig into it. Not that 1973 Road Runners are worth all that much, but I have had it since 1981 and it is the numbers matching engine. I hope I can save the block.
 
Thanks guys - that's what I figured. I don't think I would have room to pull the torque converter off with the tranny in the car, so I'll do it as an assembly.

Pics of the carnage to come once we dig into it. Not that 1973 Road Runners are worth all that much, but I have had it since 1981 and it is the numbers matching engine. I hope I can save the block.
Definitely post pics once you get into it. Should be able to save it
 
good luck. a '73 340 4 speed road runner was my first Mopar.
PTDC0003.JPG
 
Not that 1973 Road Runners are worth all that much, but I have had it since 1981 and it is the numbers matching engine. I hope I can save the block.
I hope you can save it, yes, not high dollar cars, but they keep climbing in value. I have had my 340 since 83, good luck.
 
Doesn't sound very promising with coolant in the oil:(.
 
Doesn't sound very promising with coolant in the oil:(.

I don't think there is any doubt that it is hurt bad - I just don't know how bad yet. Yes, if you lose a head gasket you can get A/F in the oil, but then it mixes in and you get a foamy froth. With the way it died, and the fact that the oil and A/F are not mixed, AND the fact that the engine won't turn, it almost MUST be a rod that had parked itself somewhere it shouldn't be...:(

I gutted and refinished my hall Bathroom and I am just finishing that up, so my garage is a disaster. Like anything, there is always pre-work before you can settle in on the real task. For now, I am cleaning the garage to get ready for the engine pull!

Thanks all for the replies and good wishes... :thumbsup:
 
I've seen rods break and get into a position where it locks up the crank....and the piston gets shoved into the head and cracking it. Expect the worse and hope for the best.
 
Had a co-worker buy a car with locked engine and when it got separated it ended up as transmission locked up instead. Never know till it's apart, but still expect the worst.
 
Doesn't sound good. My guess is that antifreeze first got into the oil contaminating it, then the motor seized from lack of proper lubrication. Check the filter to see if antifreeze has entered the oiling system.
 
Doesn't sound good. My guess is that antifreeze first got into the oil contaminating it, then the motor seized from lack of proper lubrication. Check the filter to see if antifreeze has entered the oiling system.

The oil was clean, it was not frothy or mixed with antifreeze. Both antifreeze and oil came out of the oil pan, but they were clearly separate. My guess would be with the "bang" that happened, that a rod let loose, damaged internals and after the engine was off the antifreeze found its was into the car. But we will see - you never know!

We spent the day yesterday unhooking and preparing the car for the engine and transmission removal. I have removed the radiator, but the A/C condenser is still in place, as the A/C is charged. I'll have to be careful not to damage the condenser when the engine/trans assembly are removed. Quite frankly, if I didn't need the car to be a roller, I think it would have been easier to drop the K-member instead. Doing this with my 70 Road Runner was awesome and very controlled.

Here is a picture of the car when I had to put it outside for a day to use the garage for other things.

20161229_105148.jpg


Just before starting the tear down...
20161229_104021.jpg
 
The oil was clean, it was not frothy or mixed with antifreeze. Both antifreeze and oil came out of the oil pan, but they were clearly separate. My guess would be with the "bang" that happened, that a rod let loose, damaged internals and after the engine was off the antifreeze found its was into the car. But we will see - you never know!

We spent the day yesterday unhooking and preparing the car for the engine and transmission removal. I have removed the radiator, but the A/C condenser is still in place, as the A/C is charged. I'll have to be careful not to damage the condenser when the engine/trans assembly are removed. Quite frankly, if I didn't need the car to be a roller, I think it would have been easier to drop the K-member instead. Doing this with my 70 Road Runner was awesome and very controlled.

Here is a picture of the car when I had to put it outside for a day to use the garage for other things.

View attachment 428608

Just before starting the tear down...
View attachment 428609
I see what happened.....you stuck her out in the rain and she got pissed at ya!
 
When you remove the trans with the torque convertor on support trans. You need to pull it straight off. You can damage front pump bushing. The guy that owned my car pulled engine with convertor on and screwed it up. Maybe pull the oil pan and see if you can unlock motor before pulling trans?
 
I see what happened.....you stuck her out in the rain and she got pissed at ya!
That was after she broke - that was her punishment!

Daisey's not going to like you breaking her car....
View attachment 428627
Yeah, I can't believe they drove that off of a cliff - for some reason I really liked that car!

When you remove the trans with the torque convertor on support trans. You need to pull it straight off. You can damage front pump bushing. The guy that owned my car pulled engine with convertor on and screwed it up. Maybe pull the oil pan and see if you can unlock motor before pulling trans?
This things kicking my butt. I have an 8 quart oil pan on it (mistake I will now be fixing and putting the stock pan on). I can't move the engine/trans assembly forward and up enough to clear the oil pan before it hits the top of the transmission tunnel. We tried to remove the oil pan but we still can't raise the engine enough to drop the pan all the way out. It's loose but we can't get it. I'm now thinking about trying to separate the engine/trans, but I am worried about damage to the trans like you describe...
 
Just remove the 4 flex plate to T Converter bolts first. Then you can pull the trans back an inch or 2 without damaging anything, and drop it on down. Then you can lift the motor pretty much straight up. It's when you leave the T Converter bolted to the engine flex plate, that's when damage can occur. Because then you have to pull the input shaft straight back out of the T converter, about 3 or 4 inches, without angling the trans downward.
 
IIRC they didn't wreck the '73 road runner, it was a '71 Satellite that dove off the cliff...but still. Never was too crazy about Jeeps after that.
 
Changing the pump bushing isn't hard if you tighten down the front band. If you forget you'll have trans guts on the bench. If you stand trans vertical it's not a problem. Just don't have the trans standing on output shaft. Another member made suggestion about standing trans up, not my idea.
 
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