manifold noise

[DonaldSmith]

Manifold hung from a 2x4, and moved back from the block.  Inspected gasket surfaces.  Leakage pictured, Exhaust 4 and 3, and deterioration at Exhaust 2:   

Gasket on engine block.  (The oily intake is from an attempt to generate smoke.)

Manifold face of gasket.

Engine block face of gasket. 

What to do:

Scrape the surfaces, check surfaces with straight-edge.  Chase all the threads of the studs and nuts.   The long studs backed out; i captured the coolant.  The short studs are still in the block. 

Will thread-lock seal the stud threads in the block? Any dope on gaskets?  

Exhaust pipe flange gasket:  do they make a doughnut shape, instead of flat? 

Any other recommendations? 

 

 

[DonaldSmith]

Manifolds off.  I used all-thread and ratchet straps to raise the manifolds to a 2 x 4 across the fenders, and plumbing strap to secure the manifolds to the 2 x 4.  My son took the heavy end of the 2 x 4, and I took the light end, to remove the manifolds from the engine bay.   The photo shows the manifold faces.  Some soot paths at the two "owl-face" duplex exhaust ports. 

 

I suppose a scraper and straightedge are next. 

 

I'll inspect the joint between the two manifolds.  The end of the heat riser flap seems reasonably tight.  So maybe I don't have to disconnect the two manifolds.  

 

[Sam Buchanan]

I think it would be inadvisable to go to as much trouble as you have and not replace the gasket between the manifolds, it likely has been compromised over time.

[DonaldSmith]

OK, OK, I just ordered the manifold-to-manifold gasket, and also the exhaust flange gasket, from the folks at Andy Bernbaum's.  It'll take maybe a week for the gaskets to arrive.  In the meantime there are other to-do items to do. 

 

I remember the drill.  Assemble the two manifolds loosely, attach the manifolds to the block, and then tighten the bolts connecting the two manifolds together.  That way each manifold will be happily snuggled to the block. 

[DJ194950]

Check mating surfaces with flat edge already done?

 

DJ

[DonaldSmith]

To DJ194950:  Will do.  I'll separate the manifolds and check each for true surfaces;  and also the face of the block.

[DonaldSmith]

Manifolds apart. 

Gap instead of gasket: 

 

Got the 4 bolts out. 

 

 

 

 

[Sam Buchanan]

That is probably where the noise was coming from....was in my case.

 

I didn't want the heat riser flap stuff so installed a block-off plate between the manifolds. I plug-welded a tab onto a bolt to plug the flap shaft holes in the manifold.

 

Edited August 26, 2020 by Sam Buchanan

[Los_Control]

Mopars don't need no stinking gaskets!