Exhaust: Intake Manifold-Exhaust Manifold—oh my..!

[Josephine]

Hello folks...

After rebuilding just about every system in Josephine (a 1941 M5) I finally installed a spanking new Flowmaster muffler and 2" piping.

The GOOD news—the rig sounds great. The bad news (there always seems to be a tad of this) is that the exhaust manifold revealed its true nature—LEAKY..!

Soooo...

I have questions, besides whyJosephine would do this to me:

(1) who sells a modern comparable replacement? (2) can my old manifold be reconditioned? If yes—can you steer me to the right folks, that can transform it back into driving shape?

In the meantime—I'll be jumping on rebuilding the carburetor, as it's about 84 years PAST due of some TLC and full of gook and mickey-mousing hacks..!!

Grazie mille... and Best Always..!

[PackardV8]

Many/most intake/exhaust manifolds which have been heated near-red-hot and cooled for thousands of cycles over eighty years will develop leaks. The good news is if you can find an old-school automotive shop which has a stone surfacer, grinding it flat again is a fifteen minute operation and should cost less than $50. This is the type we use.



jack vines

[Josephine]

Thanks so much Jack..? I'm in the LA area, so there should be an 'old school automotive' shop with a stone grinder. Will update once I've done research...

[StudeRich]

I think you will have better luck looking for "Automotive Machine Shops", Not Auto Repair Shops.
And they do not need to be "Old School", modern is OK, just Good matters !

I hope this helps.

[PackardV8]

I think you will have better luck looking for "Automotive Machine Shops", Not Auto Repair Shops.
And they do not need to be "Old School", modern is OK, just Good matters !

I hope this helps.

Yes, no, maybe, Rich. Agree, he's looking for a machine shop. But as to those, most of the automotive machine shops in Spokane closed years ago and when aluminum heads became common, those few which remain got rid of the stone table surfacer and went to an overhead CBN machine. Because it's a time-consuming process to jig up an exhaust manifold on the modern surfacer, most machine shops today won't touch them.

jack vines

[Josephine]

Thank you both, Jack and Rich... on the prowl. So far—NO LUCK... but LA is a big place and I'm an unflappable optimist.! The heat riser is a hot mess—should I just remove it and close it up with a flange cover?

[altair]

I was lucky, my manifolds were both uneven, with a straight edge you could see copious amounts of daylight, I had them ground with an overhead type grinder. When I say I was lucky the shop closed right after I had them ground. I had three sets and they were all open. As far as the heat riser issue, try to restore it. The heat riser is an important component as it heats the fuel gases when the engine is cold and it directs the heat supply for the for the choke furnace to operate the automatic choke. Yes, a hand operated choke can be installed but is is a bit awkward to operate.

[PackardV8]

Our guy is in El Lay; they don't know from cold and/or humidity. A choke and heat riser is only for real world operation.

jack vines

[StudeRich]

It's ANDREA !

[Josephine]

Too funny...!

[Josephine]

In El Lay, cold's a scary myth,Humidity? They plead the Fifth. Rain’s a rumor, coats are flair—They freak if there’s a chill in air. Seasons? Nah. Just sun on loop. It’s weather-lite for the glammy troop.

[DEEPNHOCK]

Down on the farm..... They used to lay a straight edge on the assembled manifold flanges. You'd immediately see the high and low.
Then, if a machine was not available, some gentle work on the high ones with a decent belt sander would get them close enough so the intake/exhaust gasket would work.
Them farmers kept their stuff running.

[StudeRich]

Yee, ha ! .....

[Josephine]

Jeff—I must be a farmer... great results, with a metal square, hand files and 45 minutes of patience..! See attached picture, about 20 minutes in..

[StudeRich]

If a straight edge says it's level, it's good to GO !

[altair]

I had a cast aluminum oil pan on a Ford that had an 8-10 thou dip in it, there was no evidence of an impact and it leaked profusely. I filed it flat with bastard file, it took 60 strokes to make it flat. Cast iron takes a little longer. I would do exactly what you are dong.