Ramair346

Here's the story.
A few weeks ago we did a cam swap on a C5. Put the original pulley back on because a UD wasn't available and a new bolt. The car has been driven and dynoed (quite high I might add) and it's got a fairly good drip from behind the crank pulley somewhere. I think the pulley might not be on exact because the belt looks like it's starting to slip off.
I guess my question is this, could the pulley not being seated properly cause oil to leak out of that seal? Any help is appreciated.

Tin Indian

You need to look at jmX's install page.

What is happening is the front seal that is pressed into the engines front cover is not aligned properly with the end of the crank pulley snout. This misalignment is causing an oil leak.

The front cover needs to be installed with the mount bolts very loose. Then install the pulley. After the pulley is pulled all the way down, tighten the front cover bolts. This will make the pulley snout ride correctly in the front engine seal that is pressed into the front cover.

GM uses a special alignment tool to properly align the front cover, but, doing it the way that I just discribed works just as well.

Also, since the crank pulley has not been riding in the seal correctly, I would install a new seal in there too. Not much $$ for the seal.

Ron,

Ramair346

Tin Indian,
Thanks! I kinda figured it had to be something along those lines but I just didn't know for sure. We'll take a stab at this and post the outcome.

robertbartsch

agree; the pulley should be installed BEFORE the cover bolts are tightened.,...

At his point it may be worth loosening the bolts, wiggeling the cover and then re-torking...

horist

yup that's what it is... I had the same problem on my car when I did my cam swap... I didn't have the underdrive pulley since it was being machined and In my infinite wisdom decided to eyeball the front cover

Started her up and oil was leaking out the snout... also when I took the cover off again the seal was pretty chewed up

I ended up borrowing the GM Front Cover alignment tool from a friend and it worked like a charm

Cal

iTrader: (1)

Anybody know if this same thing can happen on an LT1? If so that may explain why my old Fbody leaks out the front . . .

-Joseph-

iTrader: (12)

Cal, the LT1 timing cover has dowel pins pressed into the block for alignment so there is no need for an alignment tool. LT1's have many things that can cause oil leaks though...(intake end gasket seals, water pump drive seal, distributor drive seal, and crankshaft hub front seal are a few)

Cal

iTrader: (1)

OK thanks Joseph!

Visceral

iTrader: (1)

My favorite way to solve this problem is just as easy and may work even better...

Each time I take off the front timing cover, I replace the crank pulley seal. The seal has enough "bandwidth" when new that the alignment isnt an issue. But once its been used and abused, you cant really move it on the pulley without it leaking (sometimes alot).

chris

-Joseph-

iTrader: (12)

Here's a small tip for those that don't have the alignment tool. Use one of those fine point black markers and draw a circle around 2 bolts on each side of the timing cover, so when you reinstall the cover and balancer you can see where the timing cover was placed before it was pulled apart, there is quite a bit of movement in the cover and this is an easy way to tell if its centered.

Something I haven't tried yet, but may do some testing on a bad block when I get some time, is to drill (2) 3/16" holes through the cover and into the front of the block just 1/4" deep, then upon reassembly use (2) 3/16" drift punches to realign the cover. Using a bad block to start would help to find a non-critical area to drill, it wouldn't work very well if it went into a cooling passage!

I myself prefer to use the GM alignment tool, but not everyone has access to them.