350/300 Steel Intake Manifold - "Cracked"?

[Clark E.]

During the engine rebuild in the mid-90's the shop called and indicated the intake manifold was "cracked" and would have to be replaced. They obtained a numbers correct manifold and gave me back the "cracked" unit that I stashed away. Fast forward 18 years...I just had the manifold visibly checked by a knowledgeable mechanic and neither of us could detect a "crack". Is there a procedure for identifying a "crack" and more importantly, a process for repairing it? Thanks...Clark

[Patrick H.]

Re: 350/300 Steel Intake Manifold - "Cracked"?

Did you check the exhaust crossover under the oil deflection plate? That's where mine cracked. If the plate was reinstalled you might not see the crack.

PS nowadays the ability to repair cast iron is much better than 20 years ago. You can probably have it fixed.

[Terry M.]

Re: 350/300 Steel Intake Manifold - "Cracked"?

During the engine rebuild in the mid-90's the shop called and indicated the intake manifold was "cracked" and would have to be replaced. They obtained a numbers correct manifold and gave me back the "cracked" unit that I stashed away. Fast forward 18 years...I just had the manifold visibly checked by a knowledgeable mechanic and neither of us could detect a "crack". Is there a procedure for identifying a "crack" and more importantly, a process for repairing it? Thanks...Clark

There is a process called Magnaflux (I believe that is a trade name) that can detect cracks that are not visible to the naked eye in ferrous materials. The cast Iron intake of your Corvette is ferrous. Quality engine shops usually have such equipment, and may have the personnel trained to use it. If you live near a large urban area it is likely there are businesses that specialize in non-distructive testing that can also find minute cracks. There are likely nowadays processes that are more sophisticated than Magnaflux that can do the same thing. A few inquiries at engine shops and/or use of an Internet search engine should yield you a location reasonably close to you that can serve your needs - unless you live in the wilderness.

[Clark E.]

Re: 350/300 Steel Intake Manifold - "Cracked"?

Belated thanks Terry...Some would suggest (including the late Willie Don Schaffer) the Eastern Shore of Maryland is "in the wilderness". Will check the Baltimore/DC area for engine shops...Clark