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No Leak No MoreA Better Way to Fix a Weeping Timing Chain Cover From the February, 2009 issue of Chevy High Performance By John Nelson Photography by John Nelson
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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? If you're driving a Chevy... 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. 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
 After removing the serpentine...  After removing the serpentine belt, our tech, Mike Vega, dove right in and removed the water pump and smog pump pulleys. As you can see, there's still a little way to go.  When Mike went after the water...  When Mike went after the water pump (after draining the cooling system, of course), he realized he'd need more space. After unbolting the A/C and belt-tensioner brackets, he used a bungee cord to hold the entire assembly out of the way.  With this bracket out of the...  With this bracket out of the way, Mike had access to the water pump hoses and the rest of the bolts holding the unit in place. The water pump then pulled free.  Finally, the timing chain...  Finally, the timing chain cover was in sight. In this shot, the crank pulley has already been removed. Even with the spilled coolant dripping down it, it's obvious that this cover has been leaking for some time.  Mike then used the proper...  Mike then used the proper puller to remove the harmonic balancer.  Taking a brief detour from...  Taking a brief detour from the timing chain cover, check out our harmonic balancer (left). The rubber is shredded, and if it had gone much longer, our balancer would have come to resemble the one on the right. At this point, the balancer can actually wear a hole in the timing chain cover. We took a trip down to the Chevy dealer for a replacement.  Now, the way is clear to remove...  Now, the way is clear to remove the timing chain cover bolts. The next part of the job takes place at the oil pan.  When it comes to the oil pan/timing...  When it comes to the oil pan/timing chain cover junction, you've got two options. One is to loosen the front oil-pan bolts and drop the pan just enough to allow enough clearance to remove the cover and install a new rubber gasket. Since we switched to a one-piece gasket, the entire pan had to be dropped. Here, the oil has been drained, the converter cover removed, the starter loosened and moved, and a small brace set aside.  All that remains is to remove...  All that remains is to remove the pan bolts and pull it free.  In this shot, the groove in...  In this shot, the groove in the timing chain cover is clearly visible. The oil pan fits into this slot, with a rubber gasket sandwiched in between.  With all the pieces out of...  With all the pieces out of the car, and a new four-piece gasket in place, the traditional setup is easily visible.  Here's the gasket we used,...  Here's the gasket we used, right alongside its ancestor. We've outlined the advantages of this design above, but note that this piece is equipped for either left- or righthand dipsticks.  The silicone-rubber Fel-Pro...  The silicone-rubber Fel-Pro Perma-DryPlus oil-pan gasket is much thicker than the old-style cork units...  ...and eliminates the gap...  ...and eliminates the gap you'd usually find at the timing chain and rear motor intersections.  This Edelbrock two-piece stamped-aluminum...  This Edelbrock two-piece stamped-aluminum timing chain cover will allow us to switch cams or change the timing chain without having to mess with the oil-pan gasket.  Here's how it works. The thin...  Here's how it works. The thin stamping in this photo includes the groove for the oil-pan gasket and stays put when the chain cover comes off...  ...The cover and gaskets fit...  ...The cover and gaskets fit together like a sandwich. The cover includes a new oil seal, which will certainly help the cause.  Mike put our timing-chain-cover...  Mike put our timing-chain-cover sandwich together, then bolted it into position using the provided Allen bolts.  Moving back to the underside...  Moving back to the underside of the car, seeing the new gasket in place reinforces the fact that our timing chain-oil pan junction has a better-than-new seal.  Just in case you want to keep...  Just in case you want to keep your one-piece timing chain cover, here's a tip. Snipping off the ends of the seal groove as indicated makes it easier to get the cover off, and without having to drop the front of the oil pan as much.  And finally, if you're going...  And finally, if you're going this far, you'll probably want to replace your timing chain and water pump while everything is apart. Our timing chain and gears were fine, though we went ahead and upgraded to an Edelbrock True-Rolling set; the old Vette's water pump was beginning to leak, so we also swapped in an Edelbrock Victor high-flow unit.
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