I just put a rebuilt 302 into my old truck, but for some reason it seems to be running rough, like on only 7 cylinders. It has a relatively new carb, new wires, plugs, the whole nine yards. I'm also noticing moisture coming out both exhausts, which could possibly be condensation, but there is quite a bit more than normal condensation in my opinion. Anybody got any ideas?

 

Does the exhaust smell somewhat sweet? If it's running rough, you're seeing extra moisture out the tailpipes, and you're smelling sweet exhaust, sounds like you've probably got a blown head gasket between a water passage and a cylinder. Also check to see if you have:
1) water in the oil (check for milky oil on the dipstick after running)
2) excessive oil in the water (floating in the overflow, or in the radiator)
3) excessive cooling system pressure, like exhaust is being forced into the cooling system

If you're seeing any of this, it's time to pull that top end off.

 

Thanks for the reply. I pulled one of the valve covers earlier, and didn't notice any milkiness in the oil. I'll check into the water/exhaust suggestions tonight when I get home. I had originally thought head gasket, but it's coming out both exhausts, and like I said, it's a recently rebuilt motor, and for both gaskets to be bad seemed a little unusual. I've got a WEIAND 8011 intake manifold on this thing, is it possible for something to be amiss there?

 

First of all ,do a Dry then Wet, compression test and see how that turns out.

Dennis https://www.ford-trucks.com/user_gallery/sizeimage.php?&photoid=1733&.jpg



Please Don't Ask Me Any Tough Questions As:
"I'm Saving My Memory For When I Develop Alzheimer's"


78 F-150 429CJ,Silver
w/Explorer Pkge.
641/2-Mustang 260,Pre-World's Fair Car.
64-Fairlane500 S/C waiting for a 390-4spd.
68-Mustang 289-Sunlit Gold 80,892Mi
78-Buick LeSabre 403 4V
84 Volvo DL Wagon

 

Any chance two spark plug wires are crossed? That would cause the engine to run rough.....but i dont think it would cause lots of condensation

Sparky

 

Or how about a dead plug or wire...just because they are new doesnt always mean they are good

Sparky

 

rough running could be due to a lack of some good hard driving.
cause my truck (1970-250cs,390)if i drive it like a granny
wagon for to long it idles like the timing is way off,it sputters
sounds like its running on less pistons that are firing in the
wrong order. but if i go for a good rip around for a couple hours
it idles normaly. as for steam in exhuast i dunno,cause if everything
is rebuilt it should run normaly.take it for a mad drive and
see if it makes a difference(keep the rpm high)


chevy drivers need a ribbon to take their repair bills home
cause there so damn long!

Fe power

 

I put a new exhaust system on mine about 8 months ago, shortly after I bought it. It had glass packs with dual exhaust out the sides . but the driver's side had rusted through at the glass pack joint and had been patched with a tin can. you could wiggle that whole side with your hand. I never really noticed any moisture coming out. My truck has headers and my engine is also recently rebuilt. After the new exhaust -turbo mufflers with dual pipes straight out , I noticed on start up a good bit of moisture shooting out , then spitting for a few minutes, then vapor , then clear. I think if you got a sound exhaust system full of air(with moisture in it) and you heat it up quickly like those headers do, and when you shut it off in cooler weather, cools quickly -condensates. If that systems solid- water has no where to go until the next time you start it up. what is it, about a cup or so?

 

Thanks again guys...#7 plug wire was bad, it's running like a top now. D'OH! The water problem seems to have cleared up also, apparently it was just condensation.