FIRE/SMOKE in Engine Bay

[Dobis]

I bought my '74 Chevy 6 months ago (see Avatar).  I have a driver's license restriction in place so I haven't been able to take it on the streets, but that expires 8/27!

My girlfriend drove it long distances in February and March without any issue.  However, I've done some novice work on it, and now she starts smoking after one minute of running.  SOMETHING even caught on fire (but went out on it's own).

Goal: To not perish as my truck goes up in flames on the freeway.

Work Done:
-New Battery
-Replaced Tie-Rod
-Replaced Spark Plugs
-Removed A/C and Hoses
-Replaced Valve Cover Gaskets
-Degreased and Power Washed Engine
-Oil Change 2 weeks ago

Other things to note:
-I'm a total novice to fixing trucks
-Odometer reads 130xxx miles
-Smoke pours from where exhaust manifold meets tailpipe.  It is clearly loose.  But ran and drove fine months ago.
-The guy I bought this from said it needed new exhaust
-One friend says it needs new exhaust manifold gaskets (see pictures)
-The gas in the truck is about 3 months old

SO, theories on the reason for white smoke billowing from engine?  And how could the fire have started?


Engine Bay.  Smoke begins on exhaust closest to camera vantage point.  Eventually starts smoking on the other exhaust side.



Decent shot of exhaust manifold gasket.  Would this cause smoke/fire?



Bad picture of underneath the truck.  Where exhaust manifold meets tailpipe.  This is clearly where smoke starts to come from, and is loose...

[bake74]

     Pics are not the clearest.  Do you have any oil leaking onto exhaust manifolds when running ?  Could be source of white smoke and fire, but to be safe check all electrical wires, spark plug wires, etc, etc for burn marks or melting and report back.
     Your exhaust manifold "dounuts" need to be checked and most likely replaced if they are loose (they burn up when loose).  Th check take the 3 bolts/nuts that hold the exhaust manifolds to the exhaust pipe off, pull exhaust pipe back and remove round (dounut) gasket and inspect.  If any burn through marks or cracks, replace with new one's, they are cheap.
     The exhaust manifold gaskets (the one's between the manifold and engine block) can be damaged from being loose also.  Check to see it the manifold bolts are loose.  If they are really loose, the gasket could have burned up on the edges.  The only real way to check this is to take off your manifolds and check the gaskets, but if you do that you might as well replace them, you have done all the hard work already.
      Welcome to the wrenching world of having older vehicles. 

[Irish_Alley]

defiantly looks like oil on the manifold. the valve covers are tough to get right without leaking. they make rubber ones with steel reinforcements to prevent them from being crushed. make sure your valve covers arnt bent and get some new cover gaskets if you want the rubber ones. bake covered the exhaust doughnut. if needed when you do the exhaust manifold gasket get the aluminum ones they wont blow out if a bolt gets loose and you can reuse them

[Dobis]

Thanks guys.  Been working on this!  Pictures coming in a bit. 

Manifold gaskets were shot.  About to pick up some aluminum ones now, after thoroughly scraping off the old crusty gasket. 

Quick question - both of the exhaust pipes and donuts are shot so I was planning on removing them.  I know it will be loud!  But can there be any damage done by (temporarily) not having exhaust pipes on when driving?

~Dobis

[bake74]

Thanks guys.  Been working on this!  Pictures coming in a bit. 

Manifold gaskets were shot.  About to pick up some aluminum ones now, after thoroughly scraping off the old crusty gasket. 

Quick question - both of the exhaust pipes and donuts are shot so I was planning on removing them.  I know it will be loud!  But can there be any damage done by (temporarily) not having exhaust pipes on when driving?

~Dobis

      I wouldn't recommend it.  It is a slight chance, probably only if you run it that way in very cold temp's. 
      But after heating up the engine and shutting it off, if cold enough air got in there it could cause damage to the exhaust valves (warping or even cracking), but like I said the chances are slim unless you do it in very cold temp's.
     How long are you planning on driving it this way ?

[Irish_Alley]

http://forum.73-87chevytrucks.com/smforum/index.php?topic=26647.0