What to Do While Engine Out of Car - 1970 Cadillac Convertible

[klinebau]

The engine is finally out.  It came out pretty smoothly and it was by no means the hardest job I have had to do on the car.  I still have to get the transmission out, but it doesn't look too hard.  I think removing the coolant lines might be difficult, but I will be careful.

[klinebau]

The transmission is out of the car finally.  It was a little bit difficult to remove the cooler lines without mangling them.  I don't think they are available pre-bent, so I didn't want to mess them up.  A little bit of heat and some penetrant did the trick.  I talked to 5 or 6 different transmission shops and decided that I will have it rebuilt.  That should go into the shop on Friday.



I have been pulling stuff off the motor.  The exhaust manifold came off easily, but they have been off before as there were gaskets.  There was definitely an exhaust leak as one of the gaskets was blown out (see picture).  I have been reading up on what to do about that and I will try to find a place to plane the manifolds flat.  I think I still want to use gaskets, but need to find some multi-layer metal ones as I don't think the fiber/metal ones will hold up (that's what was on there).  I like the idea of separate gaskets for each port versus the one piece.  Someone mentioned copper gaskets in another post, but not sure where to find them.




Before I remove anything sealing the engine, I am going to remove the paint with aircraft stripper and clean up the block as best I can.  Hopefully this way I won't have to worry about compromising the gaskets.  I am going to be painting with Bill Hirsch Cadillac dark blue.  I don't see it available in rattle cans anymore, but I already have a spryer so will just get the quart.  I read that the tins should be primed first but that it isn't necessary on the cast iron. When the tins are off, I will shoot them with some primer.

In the immediate future, I am going to work on assembling the various parts that I need.  I am also going to sandblast the brackets that I have removed and shoot them with some Bill Hirsch paint that I have left over.  The exhaust manifolds will also get sand blasted.

[TJ Hopland]

On the manifolds its not a complex machining process its literally a belt sander so its the kind of thing they can just walk in the back and do vs something more complex that has to be carefully set up in a fancy machine. 

I have had various types of gaskets on these engines (no copper tho) and none of them have ever lasted.  Only thing that has worked was having them surfaced and then no gasket.

[klinebau]

I have had various types of gaskets on these engines (no copper tho) and none of them have ever lasted.  Only thing that has worked was having them surfaced and then no gasket.

It seems like I would have to get other side planed if not using gaskets.  I was hoping to not remove the heads.

[TJ Hopland]

It depends on how long they were leaking or rusting.  The heads are large and solid enough they don't tend to 'warp' but if they did run a lot with a leak the leak can actually erode the metal.

I think one reason gaskets fail in this application is the amount of expansion and movement that goes on with these parts.  A gasket is just one more part in the system with a different expansion rate that at times as things are moving isn't being tightly clamped so can easily be blown out. 

[The Tassie Devil(le)]

You have to remember that these Exhaust Manifolds were designed to slip and slide as they heated up.

If you look at the manifold bolt holes, two will be the correct size, and the rest will be oversize.   This allows for the alignment, and the expansion and contraction.

Installing a gasket between the Manifold and Head to seal up imperfections will try and stop any leakage, PLUS, create a strain on the ability to slip and slide.

The Manifold Bolts have washers that allow the slipping and sliding, if correctly torqued, and over-tightening, or replacing the washers with locking spring washers to stop the movement will lead to trouble.

The Gaskets in the rebuild kits are there to take up uneven surfaces as most rebuilders don't get the Manifolds when they rebuild an engine, and therefore these surfaces get missed when the machining is done.

Many a Manifold has been broken by poor attachment.

Bruce.

[dogbergs]

You have to remember that these Exhaust Manifolds were designed to slip and slide as they heated up.

If you look at the manifold bolt holes, two will be the correct size, and the rest will be oversize.   This allows for the alignment, and the expansion and contraction.

Installing a gasket between the Manifold and Head to seal up imperfections will try and stop any leakage, PLUS, create a strain on the ability to slip and slide.

The Manifold Bolts have washers that allow the slipping and sliding, if correctly torqued, and over-tightening, or replacing the washers with locking spring washers to stop the movement will lead to trouble.

The Gaskets in the rebuild kits are there to take up uneven surfaces as most rebuilders don't get the Manifolds when they rebuild an engine, and therefore these surfaces get missed when the machining is done.

Many a Manifold has been broken by poor attachment.

Bruce.

You're the master in explaining Bruce.
I've always checked/ resurfaced manifolds alignment, but never to leave out the gaskets.

Thank you

[The Tassie Devil(le)]

You're the master in explaining Bruce.
I've always checked/ resurfaced manifolds alignment, but never to leave out the gaskets.
Thank you   

Thank you for that Johan.

But, remember that if the gaskets were meant to be there, the Factory would have put them there.

When using headers, the individual pipes are taking up the movement, therefore there is no need for the slippage.   Plus, the usual 3/8" or less thickness of the flanges of headers allow too much flexibility,  hence the requirement for gaskets.

Bruce.

PS.   I have found that the worst offenders in the manifold cracking department are the Ford FE engines.   Really thin castings, plus too much spacing on the attaching bolts, with overtightening resulting in broken lugs.

[klinebau]

The Manifold Bolts have washers that allow the slipping and sliding, if correctly torqued, and over-tightening, or replacing the washers with locking spring washers to stop the movement will lead to trouble.

There were no washers on the bolts.  Am I missing these or were they added after 1970?

[Cadman-iac]

There were no washers on the bolts.  Am I missing these or were they added after 1970?

 On the 472/500 motors at least, the bolts have the washer built into the head, or what I call washer-headed bolts.

 Rick

[klinebau]

On the 472/500 motors at least, the bolts have the washer built into the head, or what I call washer-headed bolts.

 Rick

Are talking about bolts with captured washers?  The bolts I took out were flanged except for the two where the heat stove attaches.

[Cadman-iac]

Are talking about bolts with captured washers?  The bolts I took out were flanged except for the two where the heat stove attaches.

I'm referring to the bolts that retain the manifold to the head, which is what Bruce was referring to I believe.
 The pipe-to-manifold bolts are studs in most cases, they screw into the bottom of the manifold and seat against it, then a nut holds the pipe to the manifold via the flange.
  Your bolts should look like this:


 This particular bolt isn't from a 472, but it's almost identical. I don't have a 472 bolt handy at the moment.

 Rick

[The Tassie Devil(le)]

These are the bolts on a 1969 Cadillac Manifold.   The loose bolts have missing washers and were being replaced.

Bruce.

[klinebau]

Mine look like this.  As you can see the bolts are flanged (except for the two odd ones) with no separate washers.  There are 14 bolts like the one on the left and 2 like the one the right.  The two odd bolts are for attaching the heat stove for the thermostatically controlled air cleaner.

[Cadman-iac]

These are the bolts on a 1969 Cadillac Manifold.   The loose bolts have missing washers and were being replaced.

Bruce.

 Bruce,
 Did yours have loose, or separate washers on the manifold bolts? Mine were/are all one piece.

 Rick

[Lexi]

Mine look like that in Rick's post #31, (with the built in flange). As I recall most were the same length, except there was one short one. Clay/Lexi

[The Tassie Devil(le)]

Bruce,    Did yours have loose, or separate washers on the manifold bolts? Mine were/are all one piece.
 Rick   

G'day Rick,

I haven't seen the car since I completed the rebuild back in 2008, but I am pretty sure that there were no separate washers, but looking at the pictures, I believe that they have the washers built into the head stamping.

Bruce.  

[Dr. John T. Welch]

The best approach to leaking exhaust manifold problems like ones mentioned in this thread is:

1.) be sure the manifold is not severely warped, cracked or  deeply pitted on mating surfaces. A machinist's straight edge is applied and feeler gauges passed between it and the mounting flanges to measure any distortion. A high quality Nicholson file  can serve this purpose well and can be used to manually correct any deficiencies. Usually they are small and the file will correct them. Dress the cylinder head ports in a similar fashion.

2.) Do not use any gaskets between the manifold and the cylinder head ports. Chase the bolt threads in the cylinder head with a high quality tap and use new bolts and flat washers of the specified design to secure the manifolds. Dress the washers with the file to be absolutely sure they are flat. Dry the manifold and cylinder head mating surfaces with acetone or Brake Kleen and apply a very thin film of FelPro Hi Temp RTV sealer (orange in color) to the manifold and cylinder head ports.  This thin film is only to compensate for any small surface irregularities.  Torque the bolts to the specified value and let the assembly cure for at least 24 hours before applying any engine heat.

I have used this approach for over 30 years on Cadillacs with never an exhaust leak.

Reference was made to Ford FE exhaust manifolds. They are much thinner than Cadillac manifolds. To compensate for thermal expansion/contraction, a one piece.005" steel shim was applied between the head and the manfold. Star locks were applied to the bolt heads after they were torqued to just 25 ft. lbs. to secure their position.  This approach when all parts involved were new allowed for thermal expansion and contraction without leaks for the life of the engine. I worked in the Dearborn Engine Plant for two summers in the 60s where FEs were assembled, and among other tasks I installed thousands of FE exhaust manifolds.  I have also rebuilt many FEs since and can say almost without exception that every one that had exhaust manifold gaskets installed at some time during life had broken bolt ears and/or cracks in the main manifold body.

             

[klinebau]

I got the transmission back from the shop after the rebuild.  They said it had a couple of burnt clutches and hardened seals.  Now that is a lot cleaner, it looks like only the bell housing had been painted by the factory although much of the paint is worn off.  I suppose it could have been painted later, but the color looks factory correct.  I didn't think that these were painted at all from the factory.  In any case, I think I am going to clean it up some more and paint it whatever color looks most like clean unpainted aluminum.

[The Tassie Devil(le)]

One has to remember that the Factory never liked to waste paint.   What was on the bellhousing was mostly overspray from painting the engine.

Bruce.