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By Fairlane62 - 14 Years Ago
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A portion of the sealing face on the lower intake port broke off at some time in the past. It was apparently still sealing on the remaining thin part but I would like to repair it to minimize the potential for future leaks. Is it possible to repair it with some sort of epoxy or will it require brazing? I would prefer not to braze due to the potential for distortion since this is a good ECZG head otherwise. 
Thanks, James
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By crenwelge - 14 Years Ago
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I would have fears that whatever you would use would come loose and get sucked in the engine. If it was sealing once, it will probably seal again. If it were mine I would put it together and check for a vacuum leak. Vacuum leaks usually don't develop over time. They usually show up right after assembly.
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By 2DRHRDTP57 - 14 Years Ago
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Can you weld, have access to a welder???
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By PF Arcand - 14 Years Ago
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Some ideas; The casting is unlikely to destort. However, unless welded or brazed with the correct material & procedure, there is a risk of cracking. Building it up with Ni rod carefully along with peening should work. Brazing it is also possible. But then it should be cooled slowly & kept from any draft until cooled down. J. B. Weld now makes a product that is more heat resistant than their standard product. However, I can't say it would be necesarily satisfactory for that job.
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By Fairlane62 - 14 Years Ago
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Thanks for the responses. I had the same concern about epoxy coming loose, but I have seen people use it to reshape intake runners in race applications. I have not welded cast iron before. It looks a lot worse in the photo, but the depth of the missing material is only about 1/8" so it probably would not take more than one pass. It may be best to leave it as is. Thanks, James
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By 314 - 14 Years Ago
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j b weld is the way to go.clean it up good first.that stuff will hold anything.i had a 96 crown with the plastic intake .the hole was stripped where the fitting screws in for the heater hose.drove it for 2 years after and that was under pressure all the time.
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By NoShortcuts - 14 Years Ago
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I've heard good things about J-B Weld, too. I've used Devcon products extensively before with no-fail results. Devcon offers a number of different epoxies for different applications. Consider using the one described below. Google 'Devcon epoxy compounds' for others. Clean the metal surface to be bonded to with lacquer thinner, acetone, or denatured alcohol (depends on base material) to insure good adhesion. -Make sure that the surface is totally dry before product application. On smooth surfaces, I always abrade the surface first by blasting with aluminum oxide or using a 24 or 36 grit disc.
Plastic Steel® Putty (A)
Plastic Steel® is the original metal-filled epoxy putty used for hundreds of routine maintenance, production, and tooling applications. Patch and repair areas where welding or brazing would be undesirable or impossible.
KEY FEATURES
* Bonds to most metals, concrete and some plastics
* Cures at room temperature and forms a tough durable metallic mass that can be drilled, tapped, machined or painted
* Excellent resistance to oil, gasoline, water and many chemicals
Regards,
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By 46yblock - 14 Years Ago
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NoShortcuts (3/6/2011)
I've heard good things about J-B Weld, too. I've used Devcon products extensively before with no-fail results. Devcon offers a number of different epoxies for different applications. Consider using the one described below. Google 'Devcon epoxy compounds' for others. Clean the metal surface to be bonded to with lacquer thinner, acetone, or denatured alcohol (depends on base material) to insure good adhesion. -Make sure that the surface is totally dry before product application. On smooth surfaces, I always abrade the surface first by blasting with aluminum oxide or using a 24 or 36 grit disc.
Plastic Steel® Putty (A)
Plastic Steel® is the original metal-filled epoxy putty used for hundreds of routine maintenance, production, and tooling applications. Patch and repair areas where welding or brazing would be undesirable or impossible.
KEY FEATURES
* Bonds to most metals, concrete and some plastics
* Cures at room temperature and forms a tough durable metallic mass that can be drilled, tapped, machined or painted
* Excellent resistance to oil, gasoline, water and many chemicals
Regards,This sounds like a different brand of the same product I have used a couple times. The brand used was Thermo-Steel. I used it to repair some exhaust manifold cracks on a RamsHorn, and the manifold is still in use now, 3 years later. Also used it to repair an intake manifold that had very heavy pitting at the exhaust crossovers. It is rated to take 2000 degrees. The key to success is an extremely clean surface, preferrably which has been bead blasted, and lots of setup time before forming and finishing.
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By Speedbump - 14 Years Ago
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JB will work great in that app. Make sure you use the old style 24 hour stuff and not the newer quick setting stuff. Since the port is the bottom one, you could drill from the bottom and thread in a couple of small pins to hold and support the JB. You could make them a little long and countour them at the same time you countour the JB weld. I've even used small pins in brazing applications to locate and support the part during the operation. Works well.
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By NoShortcuts - 14 Years Ago
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The product Mike describes has a higher temperature tolerance than the Devcon product I suggested. Devcon has been used in the tool and die industry for quite a while because of its ability to be suitable for machining to include drilling and tapping.
I haven't reviewed the Devcon product web site, but I don't think that any of their product applications are rated to withstand temperatures in the range of exhaust headers.
Thanks for the input, Mike.
Regards,
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By Fairlane62 - 14 Years Ago
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Thanks for all of the replys. That gives me several options to consider. James
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By Ron - 14 Years Ago
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In the engine masters challenge, they use epoxy to reshape the runnners and ports on their intakes and heads. The only thing is I don't know what kind they used, but have seen it done. They got quite a bit of dough to lose if that stuff came loose, so I think if it was a big risk, they wouldn't use it. The main point would probably be to clean the part(s) so there is not a trace of oil, dirt, grease, etc.. on the part you want to put it on, so the stuff don't come loose.
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By Ted - 14 Years Ago
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As good as some of the modern expoxies are, I would consider most of them not being a permanent repair. I’ve found that using epoxy resins in intakes for contour and smoothing purposes is only good for about six years or so under continuous use. After that, the fuel eventually makes its way under the hardened filler and loosens the bonded material from the metal it’s attached to. Welding the head in that area would be the long term solution to fixing that particular problem. A good welding shop can fix that without much trouble and at minimal expense.
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