5.7 Oil Leak at the Timing Cover

[LiquidC]

I'm assembling a new 5.7 crate motor, and I was testing a new electric fuel pump when I noticed that oil started to leak from behind the balancer. I took a closer look, and noticed it leaking from the base of the timing cover. See the pic, the oil is coming out of the hole that is circled.



Is this a leak in the oil pan gasket, or timing cover gasket, or maybe worse??

 

[Don S]

Re: 5.7 Oil Leak at the Timing Cover

Hard to say why. Could be a cracked cover, oil could be dripping down from the shaft seal.

 

[LiquidC]

Re: 5.7 Oil Leak at the Timing Cover

Anything but a shaft seal would be fine with me. The motor is still under warranty until I put it in the boat & run water through it. The block is a "Hencho en Mexico" block, and I've read other posts saying that the quality of the assembly is poor.

I'll have to put it back on the engine stand for a better look. I'll see what I can find without pulling the balancer off, at first. The timing cover is plastic, and the hole at the bottom is for a crank position sensor (I think). It's a Vortec motor, so is there any issue in replacing the timing cover with a standard (non-vortec) cover?

 

[Idlespeedonly]

Re: 5.7 Oil Leak at the Timing Cover

That hole is used for the crank sensor. Look in there and see if it is plugged off or if you can see the stator wheel.

 

[LiquidC]

Re: 5.7 Oil Leak at the Timing Cover

I'll take a look when I get home.

Do you mean that there's supposed to be a plug in there???? That would a simple solution, I like those. I thought it was for a magnetic type of sensor, and a small screw goes into the brass threaded screw hole to hold it in place. I didn't think the hole was open to the timing chain & sprocket, I'm curious to find out now ...

 

[Idlespeedonly]

Re: 5.7 Oil Leak at the Timing Cover

Since you said it has a warranty till you run water through it, im guessing this may not be a marine spec replacement. The hall effect crank position sensor would go in there. Hopefully there will be a plastic bottom in there. If not you will either plug it off or get a sensor to put in it.

 

[achris]

Re: 5.7 Oil Leak at the Timing Cover

That looks like a standard cover (I have LOTS of experience with them :facepalm, and that hole is indeed for the crank position sensor, and it is open. There should be a plug for it. If it's a crate motor they are expecting you to use the old sensor, or plug, from the previous engine. No, you can't replace it with a non-vortec cover (different drill pattern)... and if you pull one off, toss it in the trash, they are a 'one-time' part. And don't buy the new one from Merc, they want $220 of it. Get it from a GM dealer for $39.... and, DON'T use the Chinese ones!

Chris......

 

[LiquidC]

Re: 5.7 Oil Leak at the Timing Cover

Thanks guys. Turns out that there is a strip of plastic at the top of the hole, which led me to believe that the hole was solid at first. On a second look, there are two "crescent moon" shaped holes at both sides of the top of the hole. The center strip of plastic must be to shield the crank sensor from oil thrown from the timing chain. I don't have a sensor or a plug, so I'll take a trip to the scrap yard tomorrow.

Idle - Its an L31 vortec crate motor, the one I picked up was made to marine specs, everything except the warranty!!

 

[Don S]

Re: 5.7 Oil Leak at the Timing Cover

Don't go to a junk yard, buy a new one. The seals are all one time use and made into the cover. Get a new cover and do the job right the first time so you don't have to do it the second time.

 

[achris]

Re: 5.7 Oil Leak at the Timing Cover

Don't go to a junk yard, buy a new one. The seals are all one time use and made into the cover. Get a new cover and do the job right the first time so you don't have to do it the second time.

I think (hope) he's talking about getting a plug or old sensor from the junk yard, not a cover....

 

[LiquidC]

Re: 5.7 Oil Leak at the Timing Cover

I never took the cover off, the original cover has large text on it that it is not replaceable. I just need a plug or a sensor, and should be good to go

 

[Silly Seville]

Re: 5.7 Oil Leak at the Timing Cover

No, you can't replace it with a non-vortec cover (different drill pattern)

Not entirely true...if you are not using a fuel injected setup, you can put a standard SBC metal timing cover (with the timing tab) on a Vortec block. The bolt hole pattern IS the same, but one must install metal dowel pins or studs into the block in specific hole locations to facilitate the timing cover having correct mating surface support in that area. I've done it, and it works fine.

Another reason for doing this...it allows you to run a double roller chain if you want, which is impossible with the plastic Vortec cover.

 

[achris]

Re: 5.7 Oil Leak at the Timing Cover

Not entirely true...if you are not using a fuel injected setup, you can put a standard SBC metal timing cover (with the timing tab) on a Vortec block. The bolt hole pattern IS the same, but one must install metal dowel pins or studs into the block in specific hole locations to facilitate the timing cover having correct mating surface support in that area. I've done it, and it works fine.

Another reason for doing this...it allows you to run a double roller chain if you want, which is impossible with the plastic Vortec cover.

Thanks... but don't the metal covers have 10 bolts and the plastic only 6? (or is that just for the V6?)