Intake manifold leak

[Art Ebeling]

Yesterday was a big day here at Artland. I got the 11 to start and run. However, it runs pretty rough and shorting out the number three and four cylinders does not make much difference. I determined I have an intake manifold leak by spraying brake clean at the rear manifold to block port and slowing or stalling the engine. I have looked thru some old posts that have links to recommended gaskets but the links no longer work. I used the original style gland rings and copper rings and the copper rings appear to be crushed all around and the manifold seated. What gaskets do you recommend? What about the one piece solid copper gland ring and gasket from Snyder's or the three in one style like on a Model A? Thanks, Art

[John Warren]

I like the gland and copper rings the best , It probably needs adjusting or just tightening. Sometimes you can just give them a wrap with a hammer and tighten them a little more to fix this type of problem. Also I use silicone to hold all the pieces in place and to help seal things while assembling. The flat ones work but without the glands there could be an alignment problem. Good luck!

[Russ T Fender]

I ran into an issue like that a few years ago. I had purchased new rings and glands and it turned out that the rings were keeping the manifold from crushing the glands. I don't know if it was because the rings were too wide or that the depressions in the block and/or the manifold that the rings set in were not deep enough but simply grinding down the end edge of the rings solved the problem.

[Adam]

Generally, spraying anything or even just dripping a little gasoline or anything similarly volatile around the rear intake port usually leads to a mis-diagnosis. The vapor tends to get sucked in by the carb and significantly changes the idle speed even if there is no leak at the manifold to block connection. I like to soak the connection with a small amount of mineral spirits. If there is a leak, the raw solvent will get sucked in and you will notice a change at idle but the vapor is not as volatile and won’t cause as much of a change unless you use way too much.

[Mark Gregush]

Tighten them up a bit more, maybe. Did you remember the gasket between the carb and manifold?

[Ruxstel24]

Also make sure it is square to the block. You can kinda see underneath with a mirror...
Warm it up a little and then retighten them.

Propane works as a leak test without getting into the carb as easy.

[Norman Kling]

Several possibilities:
1. The bolt is bottomed out before crushing the gasket. Try removing the bolt and then remove the keeper and thread the bolt back in and measure the distance from the block to the head of the block. Or if you have studs, the nut might bottom out before crushing the gasket. Put the keeper on a flat surface and measure the distance between the flat surface where the keeper pushes on the manifolds and where the head of the bolt might be when in place. That should be greater than the distance between the head of the bolt and the block. If so, grind some off the bolt and the problem should be solved. Note, different style keepers, so you will need to make this measurement yourself.
2. The block has been machined and the distance for the glands to go into the block has decreased. You need to measure both the manifold and the block and possibly grind off a bit from the glands to make them fit.
3. The surface is so eroded that it is impossible to get the rings to seal. You might be able to get the type of flat gaskets to work, especially those which have crush seals around the holes. Last fix would require machining the edge of the block, or maybe even welding onto the block to fill in and then machine. That would take a lot of work and need to pull the engine.
Norm

[Scott_Conger]

#3 above can be augmented by a very slight schmeer of high-temp silicone sealant on the engine side of the copper gasket. I would guess somewhere near 10+% of all old T motors could benefit from this, though probably less than 1% actually get treated with it. Poor running seems to be almost a bragging point for some folks, feeling like they are motoring like "back in the day". Nothing could be further from the truth.

Good luck. You'll whip it.