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Puff puff leaky exhaust manifold.


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I wish every fix was this easy. My car has 6 little copper exhaust manifold gaskets. One was decentered and exhaust gas was shooting out, see the carbon?

 

When I centered it my engine lost the race car sound, but it was worth all 15 minutes to fix it. Now quiet as a mouse.

 

 

Screenshot (134).png

Edited by Morgan Wright (see edit history)
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An intake gasket, an exhaust gasket, and a pilot ring. Was I lucky? My chances are 6 out of 9 its an exhaust ring

 

Exhaust port 1.38 inches, gasket ID 1.42 inches

 

Intake port 1.50 inches, gasket ID 1.54 inches

 

I put the pilot ring in a vice to compress it......it's 1.50 an intake ring

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Posted (edited)
On 7/17/2021 at 1:43 PM, Mark Kikta said:

Just buy a new set of manifold gaskets from Olson’s and you get new ones with it

 

Yeah, to put the ring in the port, I pretty much gotta take the manifolds off. Not something I planned to do in the middle of car show season. I just loosened the nuts, tapped the gasket over with a drift and a tiny hammer, tightened the nuts, and called it fixed. I'll get to it in the fall.

 

I made this video of me driving 4 miles with the puff puff sound and showing the engine running puf puff puff when I got back

 

 

Edited by Morgan Wright
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Caution, running a early six cylinder Buick without pilot sleeves in the exhaust can make you start looking for a manifold made out of unobtainium.  I recently bought a 1915 big six model C-55, it had a exhaust leak and I thought no problem I will change the copper rings.  I soon realized that the manifold had warped toward the front near the radiator, probably heat and the weight of the exhaust pipe hanging down in the front. After some research and talking to some early Ford people who have had this same problem , I feel that the manufacturers did not put these pilots in just to make it easy for you to change the coppers. So I can not put the pilots in now because the front ports no longer line up with each other . I have tried to find a sweet spot but it just leaks somewhere else.  Luckily I have access to the formerly unobtainable manifold and I will be trading it out this week.  I will include a photo of the issue

D1B4F265-38D1-476A-8DB5-78ABD0220E12.jpeg

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I am not familiar with the earlier Buick manifold set up but I do know the 1925 Standard and Master engine as well as the 1937 248 engine. As I stated before the pilot rings only are on the cooler, less susseptable to warp intake manifolds. The exhaust with wide temp variation has none on them.

DSCF6211.JPG.3a85d2098bd32fe9175e14ac8aa723e5.JPG    DSCF6212.JPG.f12726788a2b2f1e2adfc32ed36898e5.JPG

The second set I replaced on my 1937.

Edited by dibarlaw
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The 1915 C-25 uses a common pilot ring (P/N 10E830) for both intake and exhaust manifolds per the factory parts list.  I suspect that the root cause of the exhaust manifold distortion is a metallurgical phenomena called creep.  Creep is caused by mechanical and/or thermally induced stress (load) in the presence of elevated temperature (reduced strength).  The stress could be caused by the difference in thermal expansion of the hot exhaust manifold vs the relatively cooler cylinder heads or exhaust system.  It could also be caused by residual (internal) stresses in the exhaust manifold caused by differential solidification ("freezing") of the liquid iron during the casting process.  It is unlikely the exhaust manifold went through a stress relief heat treat cycle back in the day given the state of metallurgical science at the time (e.g. fatigue cracks/fractures attributed to  "crystallization").  Even today exhaust manifolds produced by some manufacturers have significant distortion issues such that they cannot be re-installed without creating oblong holes for the attachment studs.          

Edited by 21raceabout
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  • 1 month later...
On 7/27/2021 at 9:33 AM, dibarlaw said:

I am not familiar with the earlier Buick manifold set up but I do know the 1925 Standard and Master engine as well as the 1937 248 engine. As I stated before the pilot rings only are on the cooler, less susseptable to warp intake manifolds. The exhaust with wide temp variation has none on them.

DSCF6211.JPG.3a85d2098bd32fe9175e14ac8aa723e5.JPG    DSCF6212.JPG.f12726788a2b2f1e2adfc32ed36898e5.JPG

The second set I replaced on my 1937.

 

Maybe that's because the gasket which covers one intake and 2 exhaust ports also have holes for the studs, which hold the gasket in place. With single hole gaskets like mine, there are no stud holes to line them up. And my parts book shows different gaskets for exhaust and intake, as well as different pilot rings E and I.

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Ok I went through every part I had, and I found one intake port (1.50 inch) gasket and one exhaust port (1.38 inch) gasket. The only pilot ring I had was an intake one which looks like this on the intake gasket.

 

DSCN4147.JPG

 

So I cut a little piece off the pilot ring, and used a vice to shape it smaller (spring steel in those days wasn't like modern manganese spring steel, you can bend it slightly and change the shape), so it fits on the exhaust gasket now.

 

 

DSCN4148.JPG

DSCN4149.JPG

Edited by Morgan Wright (see edit history)
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I made another improvement. I cut another piece off the ring and put a cardboard spacer on it, so it will be easier to line up the port on the block with the port on the manifold. The card stock is .02 inches and the ring is now only 1.34 inches so it will fit easier.

 

Once the engine starts the cardboard will burn off, I might have to re-tighten the nuts a little when it does.

DSCN4150.JPG

DSCN4151.JPG

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It slipped right in, job took under half an hour.

 

The other ports all had pilot rings, I guess the guy who did the job 90 years ago ran out of rings or dropped one on the floor and was too lazy to go after it.

 

Not happy with all these crushed copper gaskets being re-used, they obviously are meant to be used only once, so I'm looking for a new set

DSCN4156.JPG

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13 hours ago, Morgan Wright said:

I ordered a set of 9 new gaskets

 

Aw c'mon -- it's always more exciting when you only have exactly the required number of __________ (fill-in the blank)...  :P

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7 hours ago, EmTee said:

 

Aw c'mon -- it's always more exciting when you only have exactly the required number of __________ (fill-in the blank)...  :P

 

There are 6 exhaust manifold gaskets and 3 intake that's 9.

 

Actually, the exhaust gaskets are fine now, I'm just gonna do the intake because intake vacuum is SUPER important on these marvel mystery carburetors.

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