Hello everyone, about 4 years ago I replaced my 05 Civic's broken plastic intake manifold with a cast aluminium manifold off of a 99 Civic EX VTEC (D16Y8 engine) for performance and durability reasons, a pretty common mod in the Civic community that has successfully been done many times. Everything went well except I had that manifold off several times since then trying to get the gasket to seal properly. I tried stock D17 gaskets as well as a Y8 gasket with no luck, but the stock D17 gasket sealed better than the Y8 gasket. Coating the gasket with RTV silicone and allowing it to cure for 2 days did not work either, it still leaked. I have also had the manifold machined flat by a machine shop in case it was warped, but that did not help either. The most luck I have had was with one of those plastic heat shield gasket, but it only lasted about 2 years before it melted and warped and started leaking again.
At this point I am thinking the problem is that the stock gasket is just a single sheet of thin steel, so it may not have enough give to seal the Y8 manifold since I am only able to use the 5 stock bolt holes since my cylinder head does not have bolt holes in 2 of the locations that the Y8 manifold does, so I am thinking I will need a light coat of some type of sealant on the gasket to get it to seal properly. The problem is I am not sure what sealant would work well in this application. RTV silicone didn't work, perhaps it is not strong enough to hold up to the intake vacuum or maybe the gasoline instantly dissolved it. I am thinking Permatex copper spray may work on the steel gasket, I already have a can of it so trying it wouldn't cost me anything but my time. It does claim to be gasoline resistant. Do you have any other suggestions for a good sealant that would work well in this application?
The other option I have considered but not yet tried is to make my own custom gasket out of a more pliable material such as a silicone sheet or some other type of gasket material. Only problem is most of the sheets of gasket material that I can find do not specifically claim to be gasoline resistant, which may be a problem for an intake manifold gasket.
If you have any suggestions for either a gasket sealant or a gasket material that would work well in this application please let me know, any help would be greatly appreciated. Thank you very much in advance!
At this point I am thinking the problem is that the stock gasket is just a single sheet of thin steel, so it may not have enough give to seal the Y8 manifold since I am only able to use the 5 stock bolt holes since my cylinder head does not have bolt holes in 2 of the locations that the Y8 manifold does, so I am thinking I will need a light coat of some type of sealant on the gasket to get it to seal properly. The problem is I am not sure what sealant would work well in this application. RTV silicone didn't work, perhaps it is not strong enough to hold up to the intake vacuum or maybe the gasoline instantly dissolved it. I am thinking Permatex copper spray may work on the steel gasket, I already have a can of it so trying it wouldn't cost me anything but my time. It does claim to be gasoline resistant. Do you have any other suggestions for a good sealant that would work well in this application?
The other option I have considered but not yet tried is to make my own custom gasket out of a more pliable material such as a silicone sheet or some other type of gasket material. Only problem is most of the sheets of gasket material that I can find do not specifically claim to be gasoline resistant, which may be a problem for an intake manifold gasket.
If you have any suggestions for either a gasket sealant or a gasket material that would work well in this application please let me know, any help would be greatly appreciated. Thank you very much in advance!
