Timing cover oil leak

[Kern Dog]

I have dealt with some type of oil leak in my 440/493 since the first build in 2004.
The bottom of the timing cover sits a few thousandths of an inch above the block. I first had a stock steel cover, then a chrome one. Now I have a painted steel one again. Several months back I changed to the gasketless windage tray from Jegs. No leaks on 3 sides but it still weeps a bit at the timing cover area. It was just recently that it occurred to me that despite several attempts to seal this bottom end, each effort resulted in leaks in the same spot.
The timing cover is positioned by the dowel pins. It is held on by the bolts.
I'm wondering if the holes for the dowels can be filed slightly to allow the cover to be positioned slightly lower, effectively being at the same plane as the block. One concern is that the movement from the current position might result in the balancer snout being off center, causing a bigger leak. Maybe the balancer is off center now, huh?
Have you dealt with this before?

[c00nhunterjoe]

In my experience, it is crankcase pressure that causes the leaks. You would be surprised how little it takes.

[Kern Dog]

I'd agree if the crankcase wasn't ventilated. Having a PCV on one side and a breather on the other should be enough on an engine with good ring seal.
Looking at the 440/493, I can clearly see a step where the timing cover meets the oil pan. I just took a look at the 383 and it has the same thing.

[metallicareload99]

Last time I installed the timing cover I put the cover on the damper, and then installed the damper with the timing cover loose.  Then I installed the timing cover, I wanted the cover's position to be determined by the crank, even though the dowel pins probably cancelled out whatever I was trying to do.  That being said, it still leaks, though it seems to be coming from the timing cover gasket itself (I used a really old gasket that was kinda folded over  ).

I know what you mean about the step from the block to the cover.  I thought it was just my cheep timing covers.  This last time I filled the lower parting line of the cover and block with "Right Stuff" and the excess squeezed out was mudded forward to ease the transition of that step.  I still haven't looked to see if that worked out or not, but it couldn't hurt right?  At any rate, the step doesn't seem to be a major issue as the machine shop installed all that dry the last time around and it never leaked    Same block, cover, and using a used windage tray with molded on oil pan gasket combination

[c00nhunterjoe]

If it leaks after multiple covers and seals and a thin bead of rtv, its 99% of the time a crankcase pressure issue. I will dig up photos of my block. It is a ramchargers modified block. They milled a ton off of the oil pan rails to shave weight. I have to use 4  cut stock gaskets to bring the rail "flush" with the timing cover, then use my full oil pan gasket. A thin bead of rtv and no weeps after several years together now.

[66FBCharger]

I have dealt with some type of oil leak in my 440/493 since the first build in 2004.
The bottom of the timing cover sits a few thousandths of an inch above the block. I first had a stock steel cover, then a chrome one. Now I have a painted steel one again. Several months back I changed to the gasketless windage tray from Jegs. No leaks on 3 sides but it still weeps a bit at the timing cover area. It was just recently that it occurred to me that despite several attempts to seal this bottom end, each effort resulted in leaks in the same spot.
The timing cover is positioned by the dowel pins. It is held on by the bolts.
I'm wondering if the holes for the dowels can be filed slightly to allow the cover to be positioned slightly lower, effectively being at the same plane as the block. One concern is that the movement from the current position might result in the balancer snout being off center, causing a bigger leak. Maybe the balancer is off center now, huh?
Have you dealt with this before?

Is there any downside to using the all in one windage tray/ oil pan gasket? I bought one from I think Mancini's and was kind of second guessing my decision to buy it and use it.

[Kern Dog]

If it leaks after multiple covers and seals and a thin bead of rtv, its 99% of the time a crankcase pressure issue. I will dig up photos of my block. It is a ramchargers modified block. They milled a ton off of the oil pan rails to shave weight. I have to use 4  cut stock gaskets to bring the rail "flush" with the timing cover, then use my full oil pan gasket. A thin bead of rtv and no weeps after several years together now.

If it is crankcase pressure, what is the fix?
The plugs don't get gunked up, the AFR readings are good and the engine makes no excessive smoke. Maybe a bad PCV valve?

[Q5XX29]

If it leaks after multiple covers and seals and a thin bead of rtv, its 99% of the time a crankcase pressure issue. I will dig up photos of my block. It is a ramchargers modified block. They milled a ton off of the oil pan rails to shave weight. I have to use 4  cut stock gaskets to bring the rail "flush" with the timing cover, then use my full oil pan gasket. A thin bead of rtv and no weeps after several years together now.

If it is crankcase pressure, what is the fix?
The plugs don't get gunked up, the AFR readings are good and the engine makes no excessive smoke. Maybe a bad PCV valve?

One thing to check (other than the PCV valve, as you mentioned) would be to verify that your breather is in fact, breathing. I've seen some breathers that, once saturated with oil, basically "clog up" and don't ventilate like they should. I've started just removing the filter material from them and running an open breather with a hose, routed down low on the car where any oil can just drip out, taking care to terminate it where any oil that drips won't be in the path of the tires! I also make my own, larger baffles inside the valve covers, with angled edges , on both the PCV location and the breather location, to help minimize the liquid portion of oil from exiting.

[Q5XX29]

And also, I would echo others here that oil leaks occurring where they shouldn't is typically due to excessive crankcase pressure. In addition to the mods I mentioned above (and assuming that your engine internals are in good working order), I also like using the tunable PCV valves from MEWagner on my street cars.  http://mewagner.com
Another route is to run a vacuum pump. They are pretty slick, and I've only run them on my drag engines, but I've been tempted to start using them on my performance street engines.

[Kern Dog]

Thanks.
I recall seeing guys with one way check valves on the header collector plumbed to the valve cover.

[c00nhunterjoe]

Pcv valves are nothing more then a primitive emmisions device. You can test and measure crankcase pressure if you want to get technical. They make the tools to do it. Its not hard. You can try the previius posted options with breather styles or run a vacuum pump.  8" vaccum was worth 25-30 hp vs open breathers on the 572 in the supergas car tested on the dyno