A New Oil Leak
 

So after only a week and a half of driving, it appears the rear crank shaft seal is leaking, I was under there finishing up a few things after the rebuild and there's oil all over the exhaust, catalytic converter etc...

The seal did not want to go in well, I had put some silicon on it and it didn't want to press in, it kept oozing back out as if it was "wedged" shaped.
I ended up having totally clean all the sealant off, remove the rear bearing cap, putting it in place and tightening down the cap.

It was quite tight in there, but I think what happened is from heat and oil seepage, it slid out of place again.

When I get in there, I'll hook up the exhaust again, run the engine with out the trans in place so I can clearly see where the oil's coming from.
I wiped everything off and watched for a drip while the engine was running and a drip did develop, so it should be easy to find.
I may even make up a plate out of aluminum and use some machine screws to hold that in place the keep new the seal from moving.

This has been one of the most frustrating engines that I've ever worked on, of all the years that I've been doing rebuilds, this has never happened, not even on a complicated British engine.

I'm not looking forward to dropping the trans, what a PITA !

PCV's blocked off?

I wish it was that simple, the vacuum port on the manifold is blocked off for now and the PCV valve isn't in place, it's just open to the air.
I do this until the engine gets broken in.
There isn't any blow by to speak of anyway.

Just trying to think outside the box, over pressure in crankcase etc, but if it's open, it's not that.

I appreciate your suggestion.
That's the point of a forum like this.

Trans, clutch and flywheel off _ looks like it's the pan gasket _ unbelievable !

When I take it off, I'll find out where it was exactly compromised, but it appears to be leaking right at the bottom of the "round" _ no bolts there so that's probably where it's leaking.

It's a piss poor design.

I'm used to working on engines with cast aluminum pans with machined surfaces, not just some stamped out steel piece of crap with poor fitting gaskets.

EDIT:
Looks like the reason it failed is because I used RTV.

Install Clean and Dry | Technical Bulletins | Fel-Pro Gaskets

Ugh, figures it was something stupid.

Felpro makes two gaskets too, I'm going to call them tomorrow and ask why, is one better then the other, why two ?
One comes with new bolts ???

Should I use RTV or not ?
I've used RTV and it's leaking ! :irked:

Federal-Mogul Motorparts

Federal-Mogul Motorparts

EDIT:
Looks like the reason it failed is because I used RTV.

http://www.felpro.com/technical/tecblogs/clean-dry.html

LMAO - yeah, i'm not sure using RTV with a real gasket is a good idea, apparently not, hopefully you'll get this all done up and oil tight soon.

Here's exactly what Felpro said what would happen, look how the gasket itself is distorted.
Because the RTV is quite thick, it can't squeeze out sufficiently to allow the gasket to make a proper seal, so the job of sealing lands pretty much all on the RTV _ which only lasted a week.

Bugger :)

Oh well, at least the solution is 'simple', good find.

Turns out it wasn't the pan gasket after-all _ kind of wondered too, it was really stuck on there.
Pictures are thousand words....
The one is out of focus on the actual subject, but you can clearly see where it isn't supposed to be.

Never had this happen before, nor have I ever heard of this happening.
Felpro is going to know about it... :irked:

Thinking about it too, for it not to leak oil, then suddenly lots of oil _ didn't act like a pan gasket failure.
Pan gasket failures start of small and take years to produce the amount of oil I was getting.

And really, bad luck, why the hell did that spring come off ?
When it comes to mechanical things I never believed in luck _ good or bad.
When something fails there is always a reason.

So what is that that isn't attached?

It wraps around the inner part of the seal so the business part of it stays in contact with the crank.
With out it, the seal has no tension and the oil just pisses out.
It rests in the groove at the back _ extremely unusual for it to work its way out, or maybe in this case, it popped off.

Can't think of anything to cause the spring to jump its groove.
I take great care to make sure everything goes together correctly and in this case, even more so.
Making a careless mistake here _ well.... you see what can happen.

Upon carful inspection of the seal revealed no real defects that would cause the spring to come out.

The spring was in place, it only started leaking 3 or 4 days after I started driving the truck.
I noticed the smell of cooked oil on the exhaust pipe.

Felpro may argue that the crank is out of round causing the spring to jump its groove, but that's ridiculous, my machine shop would have easily caught that, plus the old seal of the same design worked fine.

And there certainly is/was a problem with the RTV distorting the gasket, but that wasn't the source of the leak as I thought at first.

Weird.
It's a spring seal spring, if you know what i mean, i wonder if it got twisted in fitted, and it walked it's way out during first use?

Very unlikely it was twisted in such a way that it would cause it to come off.
Like I said, I was being extremely carful.
I didn't even have to press the seal in, I removed the bearing cap and carefully placed the seal in place and torqued down the cap _ absolutely no force was required that would have com promised the seal in any way.

This is what's so puzzling why it would fail.

Spoke to Chuck at my machine shop and of course, it's my fault that the spring came off _ installation error.
That doesn't explain why it happened three days after the fact.

Didn't get a response back from Fel-Pro either _ no surprises there...

Just like the oil idler shaft that was sticking up and banging into the crank, I'll never find how that happened either.

All very frustrating.

Wow, alright, i guess the error would be that it won't stay there longer than 3 days? :)

A believable explanation from Fel-Pro and a link on how a PCV valve works.
Looks like the PCV valve needs to be hooked up, simply venting out the crank case gasses into the atmosphere with an engine that was designed for a PCV valve, would cause the crank seal to blow its garter spring.
If the vent holes were bigger in both valve covers, then I may have gotten away with it, but because the vents on both covers are relatively small, it simply couldn't vent fast enough to relieve the crank case pressure.

Rear main seal installation

Positive crankcase ventilation

Whilst i wouldn't have thought it enough to do this, i've always had arguments with people about keeping the PCV system intact on engines designed with them, they seem to think vent to atmosphere is enough.

Like you said, small holes, doesn't quite cut it, besides, i imagine there is quite a bit of blow by on these simple engines.

Obviously, the higher the compression the more blow-by there will be _ so yes, enough to blow the seal at 4000+ RPM in an engine where the rings haven't quite seated yet.

If the vents on both valve covers were big, say a good inch and a half, then that probably would be enough.
But the one on the oil cap side is only as big as a pencil, and the other side is about 3/4's of an inch _ not designed to be run with out the PCV valve.
The way I see it...

Only a competent (thinking) engineer could confirm my theory.

Oh yeah, i forgot about everything being new, not fully seated rings will absolutely increase blow-by, if only temporarily.

This isn't a high comp engine, but it's enough with everything else being equal - i think it's age (design age) and small PCV holes really contribute, most newer stuff has larger holes for it, but honestly, a well functioning PCV system isn't a bad idea anyway.

It's a high compression engine compared to my other vehicles _ don't have to worry about blowing the seals on those engines.

Haha, fair enough, American stuff is so under stressed to me, everything here is "low compression" to me ;)

I thought I raised you better than that. :) Only use RTV when there IS NO gasket. Otherwise, use Permatex gasket adhesive (I guess they still make it).

EDIT: Even though that ultimately wasn't the cause of the leak, best not to use the RTV in that manner.