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Tech Questions Answered in CC's What's Your Problem?

You Got Questions, We Got Answers

Jeff Smith:
Ever had one of those days when you're moving just a little too quickly? We can't blame Tim for this one-I put the carb back together and later realized I had the main body reversed. Several sharp-eyed readers caught this error and brought it to our attention.

Mystery Oil
Matt O'Brien, Tallahassee, FL: I recently bought a '69 Camaro with a 327 and a Powerglide. I'll admit the car isn't in great shape, but I hope to be able to drop in a Ram Jet 502 and a 4L80E later. For now I want to keep it in at least running condition, and being a college student makes that a little tough money-wise, depending on the work. Recently I have discovered a mysterious oil leak coming from a bundle of wires tucked near the firewall right around the wiper motor. I'm 99 percent sure this car doesn't have an oil cooler. Does this problem sound like something I should junk the motor for? If so, should I save any of the components? It has a Weiand manifold, a Holley 750, and a set of street headers. I had thought about a 383 stroker instead of the big-block and I'm not sure if the manifold, carb, and headers on the 327 would fit a 350 block. If you guys can help out a broke beginner I would really appreciate it.

Terry McGean:
Your oil leak hardly sounds like a reason to junk your engine. It's almost certainly one of two things: Either your oil-pressure sending unit is leaking, either from its housing or from the port in the block, or your intake gasket is leaking at the back of the block. Both are fairly common and both are simple to correct.

If you look at the back of your engine, along the back of the intake manifold to the left (driver side) of the distributor, you should find either a pressure sending unit with a wire connected to it, which would be the stock oil warning-light sensor, or a tube of either transparent white plastic or copper, which would be a feed line for a mechanical oil-pressure gauge. These are common for aftermarket gauges, and in fact, the stock oil-pressure gauge on '69 Camaros, located in the console with four other gauges, used a copper feed tube. Some gauges use an electrical sender as well, though these usually have a larger cylindrical housing than the sender for an idiot light. The plastic feed lines frequently break, either from being tugged or from kinking, and copper lines are also susceptible to damage. Stock senders have crimped-in plastic guts that can also leak or break. If you find you need to replace something that requires installing a new fitting or sender, make sure to use a sealer on the threads-we like Permatex Liquid Thread Sealant with Teflon. Since you're dealing with pipe threads, the fittings won't necessarily seal when tightened and shouldn't be overtightened anyway.

If you find that the leak is at the back of the intake (you did say you had an aftermarket manifold, so someone has been in there at some point), remove the manifold, clean the mating surfaces on the intake, heads, and the ends of the block. Then, after placing your new gaskets on the heads (it's usually best to use a thin film of gasket sealer around the water passages), discard the end seals that come with the gaskets and lay a bead of gasket sealer on the ends of the block instead. The bead should probably be a little more than 11/44 inch high; you may want to set the intake in place with the gaskets and no sealer first to get an idea of how much of a gap there is at the ends-too little and it won't seal, too much and you'll make a mess. Once the manifold is set in place, snug the bolts following the factory-recommended pattern (start with the middle bolts and go around in an expanding circle pattern) and let it sit to cure; we usually give it about 10 minutes when thrashing on the dyno, but an hour would be better. Then come back and tighten the bolts in the pattern to finish it off.

By the way, all of your parts for the 327 should bolt right up to a 350, as they would with most pre-'86 small-blocks.

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