Leaky front crank seal.

[Billw69]

After replacing the front main seal on my boss, it continues to leak. I’ve changed it twice. I’ve sleeved it with a kit. Still leaks a drop or so after running.
Any secret to installing the damper? I’ve used plenty of lube, SLOWLY seated it on the crank, no other way due to the snug fit. This car sat for many years with minimal usage. The journal on the damper was smooth, with only a polished rub line. On the second seal I attempted to seat the seal in a slightly different depth hoping for a new surface contact point, no joy.

Open to suggestions (aside from pulling the engine!) am I missing something here?

Thanks

 

[Sheriff41]

You want to install the damper by seating it with an installation tool (rent at a parts store). Some will just pull it in with the bolt but that can stress the bolt and the threads in the crank. Whatever you do, don't use a hammer!
Is it leaking at the seal or where it fits in the timing chain cover? Did you apply some sealant around the outer part of the seal when installing it?

 

[mjlan]

Is it possible that you have excessive crankcase pressure?

Maybe the oil slinger got left out when the timing chain set was changed?

Just throwing some ideas out there since you've already covered things that I would think of...

 

[c9zx]

+1 on missing slinger. Chuck

 

[351c1971]

Did you install the damper and seal first before tightening the timing cover bolts? This helps to center the seal on the crank damper and prevent leaks.

 

[Billw69]

Thanks for all tips folks. Here’s a few of my thoughts going forward.
Crankcase pressure has my attention now as a possibility. I put on an older (70) 428 Holley on the car late last year and it didn’t have the hose barbed base plate for the PCV line. So presently the only vent I know of is on the other valve cover to the air cleaner. Maybe that’s not enough vented volume?

I have not used any sealer on the seals metal flange during install to the timing cover.

This weep developed in the last 3-4 months and I have not had the timing cover off for years. Regarding the slinger, since it’s been leak proof for several years, I’m not thinking that’s an issue but, can I visually confirm that it’s installed by looking in the opening after removing the seal?

I did use the crank bolt to seat the damper. It was not excessively tight, in fact used a short handled ratchet for that.

 

[mjlan]

Just confirming so don't get offended- you are pulling a vacuum on the crankcase right?

 

[Cleveland Crush]

Bill,
Consider this sealant for the front seal where it mates on the timing cover:

 

[midlife]

Thanks for all tips folks. Here’s a few of my thoughts going forward.
Crankcase pressure has my attention now as a possibility. I put on an older (70) 428 Holley on the car late last year and it didn’t have the hose barbed base plate for the PCV line. So presently the only vent I know of is on the other valve cover to the air cleaner. Maybe that’s not enough vented volume?

I have not used any sealer on the seals metal flange during install to the timing cover.

This weep developed in the last 3-4 months and I have not had the timing cover off for years. Regarding the slinger, since it’s been leak proof for several years, I’m not thinking that’s an issue but, can I visually confirm that it’s installed by looking in the opening after removing the seal?

I did use the crank bolt to seat the damper. It was not excessively tight, in fact used a short handled ratchet for that.

Yup, you have to attach the PCV line to the carb or intake manifold; otherwise, you're building up pressure in the crankcase.

 

[Billw69]

Thanks guys, I’ll start with the easy ones first…… which is to get a spacer for the carb that will accommodate a vacuum port for the PCV. Currently not pulling off the crankcase, so I’ll fix that. Thanx Matt and Midlife.

Next I’ll look into the presence of an oil slinger. Hopefully I can view that peering into the timing cover with the balancer and current seal removed. Thnx Matt and Chuck.

Thanks Crush for the Permatex tip!

Thanks for the help guys, I’ll report my results after I get some work done on it.

 

[351c1971]

I also agree 100%. As a minimum, you need a road draft tube (older cars) or a PCV valve connected to manifold vacuum.

 

[Billw69]

On it!

 

[rcadd1ct]

Make sure there is a baffle in the valve cover or you might start burning oil via the pcv valve

 

[351c1971]

If you have room under the hood, the stock 1" aluminum pcv/spacer might fit.
It just fits on mine with the Edelbrock 351c performer 2v and NASA hood. You should also get a little additional free torque from the spacer.

 

[Grandmas73]

Not being able to see your situation first hand I thought I had a seal leaking but after some time on a creeper it was a valve cover leak running down the block to the pan lip and creeping around to the front to drip on the floor. I’m sure you’ve already checked that but I just wanted to throw it out there. Good luck

 

[Billw69]

Looks like I found the issue with that pesky leak.

First off, thanks to all who chimed in. That info helped me gain perspective on other issues I hadn’t considered.
The leak was apparently caused by excessive crankcase pressure. Caused by a less than brilliant operator (me) idea. To be clear, a static source, such as the valve cover vent on the 1-4 bank to the air cleaner is NOT enough to unload the positive pressure in crankcase. As I experimented with some different carbs the last one I mounted didn’t have the hose barb typically seen on the aft side of the base, that draws from the PCV. When I decided to eliminate it temporarily to use the new carb I think that turned out to be my big mistake, creating the pressure that forced the oil out.
Interestingly on my last (THIRD) seal replacement, I could see that very little if any oil appeared to come from the seal. Instead the trail pointed to the key way slot on the crank/balancer. On reassembly I used some ultra black in this spot to alleviate that source and that combined with a different carb that has the missing vacuum barb seems to have eliminated the leak!

Thanks again to all that made suggestions, they were all helpful!

Bill

 

[Cleveland Crush]

Good to hear you got it sorted out.

 

[Sheriff41]

Congrats on solving this. The many members on this site are a tremendous resource!

 

[Billw69]

Congrats on solving this. The many members on this site are a tremendous resource!

Thanx….. TOTALLY AGREE!