74 vette EXPLOSION! (help)
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1st Gear
Joined: Mar 2013
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74 vette EXPLOSION! (help)
hey guys, an interesting thing happened today. Me and my brother have been working on a 74 corvette with a 350 in it not sure of the model. We were trying to get it to start and stay running, after we installed the exhaust and bled the brakes, and while spraying the carb with starting fluid to try to get it to stay running long enough to see if we could see why it wouldnt stay running all of a sudden the passenger side muffler exploded open. Then, after taking both mufflers off we started it a couple more times to find out that the pass side of the motor isnt firing, only the driver side exhaust pipe gets anything, pass side gets nothing, pass side exhaust manifold isnt even close to warm let alone hot. And the firing order is correct. We are kinda stumped, initially (before the explosion) we thought maybe it needed a new carb. But now we think maybe the rocker arms arent adjusted correctly? Dont know need help anybody?
Safety Car
Joined: Dec 2012
Posts: 3,797
Likes: 1,707
From: Summerville SC
Blueyes, you really REALLY need to be carful of the starting fluid. This time was just the muffler, but imagine if your combustion chambers are full of that, it ignites, and not all your valve are open. As for not starting, maybe the firing order is correct, but your timing is off. Double check your TDC and make sure.
Drifting
Joined: Dec 2004
Posts: 1,714
Likes: 42
From: Austin Texas
It doesnt take much cranking to prime the fuel pump and push gas to the carb.
Do you get an accelerator pump shot? Work the throttle manually with the car off and see if fuel squirts down the throat of the primaries. If yes, the carb is getting fuel past the filter.
It is probably time to do a tune up on the ignition system and replace plugs, wires, cap rotor and maybe points and condensor if its not HEI.
If you have never seen the motor run, then treating it like a new start up and finding tdc and setting the timing is wise as well.
Do you get an accelerator pump shot? Work the throttle manually with the car off and see if fuel squirts down the throat of the primaries. If yes, the carb is getting fuel past the filter.
It is probably time to do a tune up on the ignition system and replace plugs, wires, cap rotor and maybe points and condensor if its not HEI.
If you have never seen the motor run, then treating it like a new start up and finding tdc and setting the timing is wise as well.
Safety Car
Joined: Aug 2001
Posts: 4,883
Likes: 11
From: North Easton Mass
If you have one side of the engine not firing that seems like a good assumption that there is something wrong in the cylinder head. Pull both valve covers and compare the valve movements while cranking the engine. Sounds like you muffler explosion may have been caused by raw gas running into the muffler and a random spark igniting the fumes in the pipe.
My father used to blow mufflers off his Model T deliberately back in the 30's by coasting down a hill with the ignition off so gas would flow into the muffler. At the bottom of the hill he'd turn the ignition back on and boom! went the muffler.
Rick B.
My father used to blow mufflers off his Model T deliberately back in the 30's by coasting down a hill with the ignition off so gas would flow into the muffler. At the bottom of the hill he'd turn the ignition back on and boom! went the muffler.
Rick B.
Melting Slicks
Joined: May 2002
Posts: 2,716
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From: Sulphur LA
St. Jude Donor '05-'06,'11,'13-'14,'16,'18,'19,'24, '25
before you take things apart take a spare sparkplug install one of the plug wires on it and ground it to the engine while turning the engine over to see if it fires. Do each plug wire to see if they are firing, if they are not firing than look at the ignition, if they are firing than start trouble shooting at the carb (flooding) and valve adjustment.
My guess is the plugs are fouled on that side of the engine due to excess fuel and that caused the muffler to light off. I don't think the starting fluid caused this to happen.
You probably have a carb issue so you may start there.
Neal
My guess is the plugs are fouled on that side of the engine due to excess fuel and that caused the muffler to light off. I don't think the starting fluid caused this to happen.
You probably have a carb issue so you may start there.
Neal
Last edited by chevymans 77; Mar 8, 2013 at 10:58 AM.
