REAR MAIN LEAK?

[BIGBLOCKHEAD]

Hey guys, have been lurking here for years and finally completed my 445 stroker recently.  Hooked it up on my buddy's engine run in stand and after about 30 min of run time, started getting a drip in the rear main area.  About a quarter size.  My question is, what is the most common failure, the round journal seal or the the side "slots"?  My machine shop followed the collective technique of this site for rear main seals.  He has a lot of Ford experience and was puzzled we had a leak.  I didn't think to check the oil pan bolts (Canton T pan) until we took it off the stand and heck I snugged them down another 1/4 turn.  Seems like I don't tighten things tight enough sometimes.  Of course without it running it doesn't leak.  Is it pressure pushing the oil out in that area, or just lots of splashing around and oil return from the heads? I don't want to tear down a well sealed up engine if it was just a loose pan.  It has a standard 428 CJ intake and we had the stock pcv system hooked up.  It is also a Scat crank, so don't know if the "knurling" in the rear main area is present.  Jay mentioned that there can be significant crankcase pressure buildup that can sometime contribute to this.  On my old 65 289 project, we ran the stock venting system of breathers for years with no problems, but when I stepped up to a 347 stroker, we were always pushing oil out of the breathers.  I intend to put the engine on a dyno stand soon, and will watch for trouble then.  Whaddayu think?

[GerryP]

A quarter-sized drip is about two or three drops of fluid since oil tends to spread out.  That's not a lot for your detective work to give you an easy result.  The rear main seal is probably not leaking since a rear main seal leak pushes out a lot of oil.  The side seals could be leaking, but so could the valve covers, the intake, the oil gallery plugs, or the oil pan.  Clean it up, put in some tracer dye and check it out after you run it at the dyno.

[blykins]

A quarter-sized drip is about two or three drops of fluid since oil tends to spread out.  That's not a lot for your detective work to give you an easy result.  The rear main seal is probably not leaking since a rear main seal leak pushes out a lot of oil.  The side seals could be leaking, but so could the valve covers, the intake, the oil gallery plugs, or the oil pan.  Clean it up, put in some tracer dye and check it out after you run it at the dyno.

Gerry is usually prudent in his answers and I agree with him.  Generally when a rear main seal lets go, it really lets go and it ends up everywhere, including being slung up on the block by the flywheel. 

[Nightmist66]

I noticed a small line and a very slow drip off the block plate on the 3rd start of my new engine. It was on the test stand luckily. Why it didn't leak the first two times I ran it, I dunno. So, I carefully pop the bell off and removed the flywheel to find a small leak coming from a galley plug. Got lucky! Cleaned, resealed, and had it running a few minutes later. All has been well since.

[GerryP]

...a small leak coming from a galley plug....

I'm not trying to be the grammar police, but I see this being incorrectly used even by automotive journalists.  A galley is ship or the kitchen on a ship.  A gallery is a corridor, channel, or passage way.

I am not at all bothered by the usage as I am too old to care about such things.  Well, okay, people using "prolly" as a word.  That bothers me a bit.

If you want to flip me off, then I'm good with that.   

[fairlaniac]

...a small leak coming from a galley plug....

I'm not trying to be the grammar police, but I see this being incorrectly used even by automotive journalists.  A galley is ship or the kitchen on a ship.  A gallery is a corridor, channel, or passage way.

I am not at all bothered by the usage as I am too old to care about such things.  Well, okay, people using "prolly" as a word.  That bothers me a bit.

If you want to flip me off, then I'm good with that.

I've seen that speech from you in the past. 

Had a guy doing the 'merica thing which bothers me similarly to your "Galley" issue. I responded to the guy who's name was Ted but as he did in America I dropped the first letter and addressed him as Ed. He kept correcting me to the point of being pissed off. I just let it ride, he just wasn't getting it.

[Keith Stevens]

...a small leak coming from a galley plug....

I'm not trying to be the grammar police, but I see this being incorrectly used even by automotive journalists.  A galley is ship or the kitchen on a ship.  A gallery is a corridor, channel, or passage way.

I am not at all bothered by the usage as I am too old to care about such things.  Well, okay, people using "prolly" as a word.  That bothers me a bit.

If you want to flip me off, then I'm good with that.

Table for one?       I have to be careful about that as well. I often see they, their and there being used incorrectly. It drives me nuts sometimes.
Gallery. Also common were cannon were frigates.

[Keith Stevens]

Great advice here!  I thought I had a rear main weep and it turned out to be the corned of the intake running down the back back of the block.

[Lowrider]

I thought I was the only one whose hair would catch on fire when I saw "prolly" used as a word.

[BIGBLOCKHEAD]

Thanks for the responses guys!  I did go around and snug everything down some more, seems like as you heat cycle the engine the first few times, the gaskets compress or something. Does anyone re torque the intake after some run time?  I am going to the dyno and we will keep an eye on it to see if anything changes.  Think I will add some oil dye this go around.  Stew

[Cyclone03]

My last “refresh” broken cam....
I decided to do a few things hoping to have a leak free FE for the first time in about 9 years. I had it decked and squared, something the first builder charged for but did not do. Squared the heads up a verified the chamber  sizes.
One change was at the head gasket to “china rail” junction I put a little dab of sealant under and on top of the head gasket then did the same on the intake gasket and of course the normal bead atop the rails going on 3 years and my garage floor is now clean ,those 4 little spots had me become very good at changing rear main seals on my back,that never worked.

My rear main seal fix was about a foot above the seal.

[wowens]

I thought I was the only one whose hair would catch on fire when I saw "prolly" used as a word.

My 41 year old son still uses "prolly". We have a heated discussion every time he does, pisses me off. Weird thing is he is very smart.

[cammerfe]

Speaking ONLY for myself, my immediate reaction to poor word use is, "Semiliterate". That is different than illiterate in my mind---some people just never learned. I had a Mother who was very careful about such things.

The sort of usage you have listed is different than actual illiteracy because I believe they're misusing words on purpose. That is...
No, I won't say it. Better just to leave things be. 

KS

[turbohunter]

I had no idea it would cause a reaction. I’ve used prolly as a folksy side of probably. Guess I won’t anymore.
Ya know what gets me going is someone asking a legit  question about motors and it devolves into a grammar lesson.

Awe c’mon

[cammerfe]

 

KS