No Leak No More

A Better Way to Fix a Weeping Timing Chain Cover

John Nelson Nov 24, 2003 0 Comment(s)
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Can we all agree that oil leaks suck? Your engine slowly loses its lifeblood, leading to big problems if you're not paying attention to that dipstick. Not as dangerous, but equally annoying, is how the underside of your pride and joy gets coated in a dirt-attracting oily film and your driveway begins to resemble the hind end of a mangy Dalmatian. If your Chevy is in this sorry state, there's a decent chance that the timing chain cover is the offender, and that's the issue we're going to tackle here.

Now, some of you may protest that this is an amateur-hour subject, too basic for inclusion in CHP. To be honest, that thought crossed our minds, too. But here's the rub: Our small-block-powered subject was leaking from its timing chain cover, right where it meets the oil pan at the front of the engine. As we said, this is pretty common. The lower section of the timing chain cover intersects the oil pan, with a rubber seal sandwiched in between cover and pan. The oil pan rails are sealed with cork gaskets, and a second rubber seal plugs up the rear pan-to-motor intersection. In short, you're got small gaps where the rubber and cork gaskets overlap. It's the traditional way, at least up until 1985 or so, but it's also a weak spot. Several shops we talked to proposed to fix our leak in this manner. But after almost 50 years, there has to be a better way, right?

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If you're driving a Chevy with a serpentine-belt setup, this mess is typical of what you'll have to get through to get at a leaking timing chain cover. Specifics will vary depending your application.

There is. We already intended to use an Edelbrock two-piece timing chain cover, which allows access to the timing chain and cam without disturbing the oil-pan gasket. We then teamed the new cover with a Fel-Pro PermaDryPlus one-piece oil-pan gasket. Fel-Pro calls this gasket "year 2000 technology for a engine designed in 1955." The one-piece design eliminates four possible leak points and makes it easier to install. It's also made from silicone rubber, which is more durable and heat resistant than cork but also compliant, creating a better seal (which is also facilitated by sealing beads). And it comes with stops in the bolt holes, preventing overtightening and gasket crushing. When it comes to the sealing the intersection of timing chain cover and oil pan, as well as the rest of the pan, this is plainly a better way to go.

We were looking for an experienced but forward-thinking wrench-turner to do the deed, mostly so our hands would be free to take photos. We also needed a mechanic who wasn't afraid of our subject vehicle, an '84 Corvette. (It's another small-block beneath the fiberglass, right?) With both factors in mind, we went to J&D Corvette in Bellflower, California. J&D mechanic Mike Vega knows his small-blocks and knows his Vettes, making him the perfect man to show us how the job is done. It took him a day to do the job, and our wallet was considerably lighter afterward; shadetree types may take two days, depending on experience and equipment, but save a bunch of dough. Either way, we think this is a better way to solve a problem, and hopefully you'll only have to solve it once.

Looking for a One-Piece?

If changing from four pieces to one sounds like a good idea to you, here are the Fel-Pro oil pan gasket numbers you'll need to perform the job. A Performance line of gaskets with bigger bolt holes to accommodate aftermarket oil pans is also available. CHP

OS 34509T--Chevrolet small-block V-8 '57-'74
OS 34510T--Chevrolet small-block V-8 '75-'85
OS 30061T--Chevrolet big-block V-8 '65-'90

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