1931-32 series 60 exhaust manifold valve body, repair or replace

[32buick67]

Help,

Has anyone tried, and succeeded in repairing an exhaust leak from their exhaust manifold valve body?

A repair by the former owner finally failed and now its time to fix or replace this new exhaust leak.

I am ok with welding and re-machining cast iron, but that isn't my first choice.

 

Anyone have thoughts on whether I can pack the small exhaust leak to seal it (JB weld?), or should I weld a permanent repair in the casting?

Or does anyone have an exhaust manifold body?

The manifold is GM# 1248714 from group 3.645, the casting number is 1248702.

This appears to be common only to 1931-32 series 60.

 

Additional specs - the exhaust pipe flange dimensions are 2-5/16" bore ID, 3-13/16" flange bolt hole center to center.

My heat riser function has been plugged by the former owner.  While I would like to make it functional again, that remains as a future project, and for now I am ok with keeping it plugged

Attached pic shows white asbestos tape and a clamp around the failing casting.

 

Thanks all,

Mario

 

[Robert Engle]

attached is a photo of a temporary repair that any good muffler shop can make.

 

I assume that the casting is broken at the hose clamp.  welding is probably the only repair for this part.  On the flapper shaft, you can remove the flapper and shaft, bore the casting for bronze bushings.  I would not try to press bushings into the casting.  I would heat shrink the bushings and then line ream them for the shaft and flapper install.

 

Replacement parts are hard to find.

 

Bob Engle

 

[edinmass]

With today's CNC machines, it would probably be easier to machine new ones over casting. That said, its a complicated part..........and while not a Buick guy.......there are endless people with the same problem over the last 30 years......and it's probable they are different part  for each series...........I'm surprised no one has ever done the project..........you could probably easily make a bypass and remove the entire system....not a perfect solution, but any way you slice it........it's a difficult problem. Not too sure welding on it is a good idea..........most of that stuff tends to disappear when you put het on it........sometime you get lucky, but it's probably very prone to cracking on such a complicated casting. 

[32buick67]

I was also having crazy thoughts of a milled stainless replacement, but I wanted to cool my jets first to see if anything was surprisingly available from a donor scrap pile.

 

I might consider gently hiding a plug deep inside the horizontal cross pipe hole.

I am also concerned about disturbing/losening the exhaust bolts and avoid breaking the ears or other irreplaceable exhaust manifold parts.

 

As a last resort I could go with a modern shunt pipe, but I am not quite there yet.

 

[Str8-8-Dave]

Getting the exhaust diverter valve off the car shouldn't be too risky, it's thru-bolted to manifold and exhaust pipe.  Use good penetrating oil like Aero Kroil to see if they can be wrenched off.  If not that a die grinder could be used to cut nuts or bolt heads off or grind flush with valve casting flanges and tapping bolts out.  JB-weld for this job not a good solution due to heat limitations.  Once off the car it probably could be successfully welded.  

 

Another idea- PM Pete Phillips to see if he has one.   I bought one from him a while ago and it had been repaired by a good welder. 

[edinmass]

Lots of caution with old cast iron is always a good idea. Don’t fault you for finding alternatives. 👍

[tcslr]

Mario,

let me check some products we use at the plant - a very high temp epoxy that is machinable. Tom

[32buick67]

After a small and gentle torque battle, the leaking exhaust manifold valve body is now free.

 

However, its clear that it needs a good solid, and more permanent repair.

 

I am going to try use a high temp epoxy and improve the mechanical structure to try to recover and return to service this rare piece.

I can remove it and replace it with a short modern exhaust spool piece, but what fun would that be?!

 

The assembly is in good shape, except for the Marvel carb heat riser horizontal feed tube OD casting.

 

I will be plugging the heat riser tube using a 1-1/2" plug to ensure no more exhaust gas flows into the carb heat riser.

[EmTee]

Is brazing an option?

[32buick67]

5 hours ago, EmTee said:

Is brazing an option?

Possibly, but the casting is missing a chunk of original iron, so I would need to fab, and I am leary of putting heat on this cast body above what it normally sees when operating.

 

I have successfully welded cast iron in the past, but I have to admit this part has me being extra conservative.

[edinmass]

Gluing it together is a waste of time……….the modern bypass is a fine option till you machine a new one or find a used one. 

[32buick67]

I agree with Ed, not going crazy over this, so I tried Tom's idea of high temp epoxy for the short term driving season, and I installed a freeze plug embedded in the epoxy to provide strength.

After 20min of a little reminiscent play-doh epoxy time, the exhaust valve cleaned up ok for RTS and testing later this week.

 

My grand vision of a well-machined unit can wait until winter if this hardy patch holds for the summer.

 

In addition to plugging the valve assy, I am also going to plug the horizontal riser tube with a 1-1/2" freeze plug to be extra proactive.

I tested the tube and riser pressure/vacuum in-situ to ensure no pinhole leaks, it passed, so now I can be confident that things are likely running ok.  My Marvel carb has been thankfully running awesome.

 

We drove around on Mothers Day for a mileage jaunt, kept the speed around 45mph, and the mpg was around 15, so a nice surprise vs averaging 50mph which gets about 12mpg.

 

If all else fails, I will probably convert to a straight through bypass spool piece as Ed suggests.

Edited May 11, 2022 by 32buick67 (see edit history)

[edinmass]

Having spent almost 50 years of dealing in with old, cracked, and rotted cast iron............even the best guys in the world can only work with it to a minimum extent. Post war stuff takes much better to repairs than the early stuff. Problems like this is what got me into pattern making and casting...........and now 3D printing. Anything short of a brand new part is just a ticking time bomb.......some times you get lucky....most of the time you don't. 

[RUF]

by chance; do you happen to have an "extra" manifold for the model 60 (part# 1239956-1)?  I know someone that has a "spare" valve body.

[32buick67]

46 minutes ago, RUF said:

by chance; do you happen to have an "extra" manifold for the model 60 (part# 1239956-1)?  I know someone that has a "spare" valve body.

Hi,

I am sorry, but I don't know where to find another exhaust manifold 1239956 for the 60 series.

FYI the -1, -2 etc suffix in the part number are likely casting lines and not related to the form/fit/function and are interchangeable.

I don't know why, but the 60 series manifolds seem to be the most difficult to find, so it seems folks tend to repair them.

I would have thought the 80-90 series to be more rare, but parts seem to turn up for these more often (still rare) than the 60 series 272cu engines.

 

If my exhaust manifold failed, I would probably try to repair as a first option, or as a 2nd option replace with a 1933-34-35 manifold and move the exhaust pipe connected to the muffler (these engines used a downspout in the middle of the engine), then as a 3rd option have a race shop weld up a custom manifold.

 

Can you please send me a PM for contact info on the exhaust diverter valve?

 

Thanks,

Mario

 

[smillard]

i have a spare