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68RIVGS

Exhaust Manifold R and R.

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Posted (edited)

Finally getting ready to change the cracked passenger exhaust manifold on my '68 Riviera 430.

It's only been that way for a few years now, and I figure I've procrastinated long enough.

Got a good used replacement manifold, Remflex gasket set, and new, shiny  SST manifold bolts.

Got a good mechanic with torches, and the use of a bud's warm, spacious heated garage.

Say a few prayers for me and my car !

Fingers crossed.

. . . will keep y'all posted

Manifold 1.jpg

Manifold 2.jpg

Manifold 3.jpg

Edited by 68RIVGS
. . . to add photos (see edit history)
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DON'T use stainless bolts for ANYTHING on the exhaust!!!!

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. . . any particular reason(s) why not SST bolts Tom ?

Please share with the group !

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Posted (edited)

. . . update:

Got the old crusty, crscked passenger side exhaust manifold off !

Did it the easy way -  simply torched the heads off the bolts, since the manifold was no good anyway.

Now each one of the exhaust bolt studs will need to be removed from the head.

A slow and time consuming process, don't want to break any !

Run a tap through each location, and the replacement manifold is good to go.

Edited by 68RIVGS (see edit history)
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Randy,

  Do you have 4 note horns on your `68? If so, can you snap and post a pic while you`re under the hood?

Tom Mooney

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I do, and I will Tom, probably tomorrow or next day !

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Don't install the new manifold until you put a straight edge across the runners and check for warpage. If it is warped, a machine shop can true it up.

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Randy,

 

   I replied to your PM which you can share with the group. DON'T use gaskets on the exhaust as Buick originally designed them for metal-metal contact.  The manifold probably cracked because of an exhaust leak causing the manifold to become overheated even though you may not have heard any loud exhaust noise.        For the BEST results have the manifold "Refaced" at a machine shop for the best no leak results.

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Thanks Winston and Tom - your advice is most appreciated !

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Without gaskets, the manifolds also act as a heat sink and pull heat from the head. 

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Posted (edited)

Well the entire exercise has turned into a project, as the stubborn manifold bolts would not budge -

I managed to get 1 out of 6 out of the head - not bad for a beginner eh ?

Even after careful heating with an oxy/acetylene torch the bolts simply would not turn.

Heck, they have only been in there since 1967.

After breaking two of the through bolts, with no choice, we decided to remove the head on the right side of the engine to drill out the remaining bolts.

As expected, this has turned into a major job, but it's much too late to turn back now ! 

Onward and upward is the only way to go !

Man over machine, sez I !

Also on the + side, a good time to detail that intake manifold.

Edited by 68RIVGS (see edit history)
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Always look for the silver lining.  Lots of times, it's the only thing that gets you through.

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Thanks Ed ! :)

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Thank goodness for Heli-coils, or Perma-Threads !!

 Had to use a few for some of the stubborn 3/8" manifold bolts  that were welded to the head.

All set to go now with some new manifold gaskets, a new head gasket, and new intake gasket and seals.

At least the job went reasonably well, with good help from a fellow car bud and his machinist  friend !

I knew pretty well before we started it was not going to be an easy job,

and I will feel much better after it's all put together and running again !

Didn't forget your 4-note horn pics Tom, just no time to do them.

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AGAIN, NO GASKETS on the manifold. It was designed from Buick that way.  Don't forget to use silicone around the water ports, but NOT on the intake ports.  And also in the corners where the head & block meat up on the four corners.  Did you replace the head gasket with another shim steel Gasket???  IF you used a composite gasket on only one side the actual compression ratio will be about  .6-1 less compression on the one side.

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Thanks Tom - 

NO  exhaust gaskets,  I know that's the way it was built + a  shim steel head gasket, no composit gasket.

Silicone around the water ports, and the 4 corners of the intake manifold  and block seals

I was quite surprised how clean the head and valves looked with about 60-75 K miles on the 430.

The cylinder walls were in good shape visually too, with no ridges at the top of the cylinders.

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After saying all that it appears it was WELL taken care of.  Hopefully the previous owner has done the proper service so you don't need to do any major servicing in the future.

GOOD LUCK!!!

 

Tom T.

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Posted (edited)

Well we finished everything up today !

Great fun, and a real challenge - I could never have done the job on my own, and fortunately had the expertise of some fellow car buds !

One with tools, torches, and knowledge, the other with a well lit, heated garage, and well stocked fridge.

Anyways -  the car fired right up, without any annoying exhaust noise, and no coolant leaks!

Here's your 4 note horn pics Tom M.,  along with my freshly painted up 430  engine.

. . . my thanks to all for sharing their expertise !

 

4 note horns A.jpg

4 note hpns B.jpg

430 RH Exhaust.jpg

59039539_2275125535864452_7891272901909807104_n.jpg

Edited by 68RIVGS (see edit history)
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Hi Randy,

  Thanks for posting this pic. Apparently, the illustration in the `68 shop manual of the 4 note horn installation is incorrect and must be a carry over from `67. In the `68 shop manual illustration, the horn mounting points are reinforced by a flat steel "clip" which was added during the `66 model year. But I recently acquired a 4 note horn option from a `68 and the flat metal plate on your car was the reinforcement. The `69 shop manual shows the flat steel plate.

  Thanks again,

Tom

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On ‎4‎/‎30‎/‎2019 at 1:50 PM, 1965rivgs said:

Hi Randy,

  Thanks for posting this pic. Apparently, the illustration in the `68 shop manual of the 4 note horn installation is incorrect and must be a carry over from `67. In the `68 shop manual illustration, the horn mounting points are reinforced by a flat steel "clip" which was added during the `66 model year. But I recently acquired a 4 note horn option from a `68 and the flat metal plate on your car was the reinforcement. The `69 shop manual shows the flat steel plate.

  Thanks again,

Tom

 

. . . your welcome Tom !

Must have changed sometime during the '68 production run. One of my parts cars with the 4 note option had the reinforcing clips per the illustration,

and my resto car had the flat, ribbed reinforcing plate you see in the photo. Much stronger than the original '66, ''67 and partial '68 design.  (...imho)

That long trumpet horn  has a tendency to flex much more than the smaller horn !

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On ‎4‎/‎28‎/‎2019 at 9:10 PM, 68RIVGS said:

430 RH Exhaust.jpg

Randy, what did you use to coat your exhaust manifolds? It would be interesting to see them again after they have really "cooked" the coating.

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Hi Mike -

It was just a VHT rattle can, very high heat, flameproof header paint - silica ceramic coating in a Cast Iron finish #CSP998.

Supposed to be good for1300  - 2000 degrees F, or 704-1092 degrees C.

It simply looked much better than the replacement rusty finish manifold - how long it lasts remains to be seen?

Certainly a definite improvement over the old "cracked" manifold it replaced !

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Posted (edited)

Mike,

 

Check out Calyx (CAL - ix) manifold dressing.  Easy to "patch" if necessary, no need to R&R or mask to apply.  Use a small foam brush or but some on with your finger ONLY IF YOU'RE WEARING A RUBBER GLOVE.  It's not a paint, it's a coating. Won't burn off.  Check YouTube for videos.  

 

 

Edited by RivNut (see edit history)
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